The Vancouver Lymphadenopathy-AIDS Study: 4. Effects of exposure factors,cofactors and HTLV-III seropositivity on number of helper T cells.

Results of testing for antibody to human T-lymphotropic virus (HTLV-III) and absolute numbers of helper T cells in 219 participants in the Vancouver Lymphadenopathy-AIDS (acquired immune deficiency syndrome) Study were analysed. The mean absolute helper T-cell counts in the 141 HTLV-III seronegative and the 78 seropositive men were 897/mL and 659/mL respectively (p less than 0.001). Established AIDS risk factors such as elevated lifetime number of male sexual partners and frequent receptive anal intercourse did not appear to have any significant effect on number of helper T cells that was independent of HTLV-III antibody status. Seropositive men with less than 100, 100 to 500 or more than 500 male sexual partners in their lifetime had mean absolute helper T-cell counts of 667/mL, 651/mL and 662/mL respectively. Most other risk factors, as well, did not appear to exert any effect on absolute number of helper T cells that was independent of the effect of HTLV-III antibody status. However, independent effects of a history of mononucleosis or hepatitis and of cigarette smoking were noted. The data support the hypothesis that no immune dysfunction beyond that due to the initial infection alone arises from repeated exposure to HTLV-III. Most risk factors appear to act as exposure factors, exerting their effect on the immune system merely by increasing the probability of contact with the agent. The independent effects of a history of mononucleosis or hepatitis suggest that viral agents may be cofactors in the production of immune dysfunction.     

Risk factors for infection with human immmunodeficiency virus among European expatriates in Africa.

The pattern of cases of AIDS in Belgium suggests that Europeans infected with human immunodeficiency virus (HIV) acquired the infection in Africa. The prevalence of infection was assessed in Belgian advisers and European expatriates and risk factors for infection defined in a case-control study of expatriate men. Fifteen (1.1%) of 1401 Belgian advisers working in Africa and 41 (0.9%) of 4564 European expatriates living in Africa, were positive for antibody to HIV in a voluntary screening programme in Belgium. Among subjects with antibody to HIV the ratio of men to women was 3:1. These subjects did not have a history of intravenous drug abuse or blood transfusion and only one was homosexual. In a case-control study of 33 expatriate men who had antibody to HIV and 119 controls the men with antibody reported significantly more female sexual partners, who were more commonly local; and significantly more sexual contact with prostitutes in Africa. They had a significantly higher prevalence of history of sexually transmitted disease and had received significantly more injections by unqualified staff in Africa during the previous five years. No specific sexual practices were associated with having antibody to HIV. After multivariate analysis sexual contact with local women (adjusted odds ratio 14.7; 95% confidence interval 2.81 to 76.9), sexual contact with prostitutes (adjusted odds ratio 10.8 (1.6 to 71.9), and injections by unqualified staff (adjusted odds ratio 13.5 (3.7 to 49.8) remained independent risk factors for infection. European expatriates in Africa were at increased risk from infection with HIV and were a means of introducing HIV into the heterosexual population in Europe. Transmission from women to men by vaginal intercourse seemed to be the most probable route of infection.     

Changes in sexual behaviour and the fall in incidence of HIV infection among homosexual men.

To investigate the epidemiology and normal course of infection with HIV the prevalence and incidence of the infection were studied among two cohorts of homosexual men in Amsterdam in 1980-7. The cumulative incidence of infection increased from a weighted 2.2% in 1980 to 39.0% in 1987. The estimated yearly incidence of HIV was 3.0% in 1981, rose to 8.8% in 1984, and fell gradually to 0% in 1987. During the study the sexual behaviour of the cohorts was examined. The number of men with whom anopenetrative intercourse was practised fell from a mean of 10.6 to 1.4 for those positive for HIV antibody, whereas the number with whom anoreceptive intercourse was practised fell from a mean of 3.7 to 0.5 for those negative for the antibody. In addition, there was a reduction in the number of cases of hepatitis B and syphilis among men in general. The decline in infection with HIV was assumed to be linked to changes in sexual behaviour. Such changes practised early in the course of the epidemic probably had a strong effect on the number of cases of AIDS among homosexual men in Amsterdam.     

HIV infection in patients attending clinics for sexually transmitted diseases in England and Wales. Collaborative Study by Consultants in Genitourinary Medicine and the Public Health Laboratory Service.

A national study of the prevalence of HIV antibody designed to monitor sexual spread of HIV infection in England and Wales was made of homosexual and heterosexual patients attending sexually transmitted disease clinics in four districts in 1985, seven in 1986, and 14 in 1987. Patients were invited to participate and were counselled. Among homosexual men in two clinics in south east England, HIV antibody was found in 92 (12.9%) of 711 in 1985, 65 (15.2%) of 428 in 1986, and 81 (14.6%) of 556 in 1987: corresponding findings in the other regions were 16 (5.0%) of 321, 41 (6.3%) of 654, and 21 (3.1%) of 678. The prevalence of HIV antibody was higher in homosexual than bisexual men, in patients aged 25 years or more, or with one or more specified minor complaints. Among heterosexual patients in the south east in 1986, HIV antibody was found in seven (3.0%) of 230 men and three (1.3%) of 233 women and in 1987 in 10 (1.0%) of 962 men and seven (0.7%) of 949 women. In other areas corresponding findings in 1986 were two (0.2%) of 950 men and three (0.4%) of 752 women and in 1987 were three (0.06%) of 5312 men and one (0.02%) of 4778 women. All but one of the heterosexual patients with the antibody were intravenous drug abusers or had had sexual contacts in or were from an area abroad with a high prevalence of AIDS. Failure to identify a heterosexual patient with HIV antibody not in a risk group (other than that of being an attender at the clinic) or who did not have a sexual partner in a risk group suggests that their prevalence in the patient population of the clinics in the south east is less than one in 700 and in the other regions less than one in 3000. Refusals to participate increased during the study but comparisons of patients who agreed and refused in terms of age, the presence of symptoms suggesting AIDS, travel abroad, and number of sexual partners a month showed little evidence of selective bias.     

Sexually transmitted diseases and HIV-1 infection among homosexual men in England and Wales.

OBJECTIVE--To examine surveillance data for evidence of changing sexual behaviour and continuing transmission of HIV-1 among men who have sex with men. DESIGN--Analytic study of surveillance data on sexually transmitted diseases. SETTING--England and Wales. MAIN OUTCOME MEASURES--Number of cases of rectal gonorrhoea and newly diagnosed HIV infection in homosexual men. RESULTS--New cases of gonorrhoea among men attending genitourinary medicine clinics increased by 7.7% in 1989 and by 4.2% in 1990. Reports of rectal isolates of Neisseria gonorrhoeae also rose and the male to female ratio for patients with rectal gonorrhoea changed from 0.3:1 during 1988-9 to 2.6:1 in 1990-1. Although the overall number of cases of acute hepatitis B fell during 1988-91, 81 and 82 homosexual men were infected in 1990 and 1991 respectively compared with 50 and 42 in 1988 and 1989. 1526 men had HIV-1 infection diagnosed in 1991, the largest number since 1987. Twenty eight of the 97 (29%) men who seroconverted between January 1989 and December 1991 were aged less than 25. The proportion of men aged 15-19 who were found to be infected with HIV-1 at their first test increased from an average of 2.4% up to 1990 to 4.7% in the first nine months of 1991. The prevalence of HIV infection in men under 25 attending genitourinary medicine clinics in London was 17% compared with 7.8% outside London. CONCLUSION--Unsafe sexual behaviour and HIV transmissions have increased among homosexual men after a period of decline. Recent HIV transmissions may disproportionately affect younger men.     

AIDS: a syndrome of immune dysregulation, dysfunction, and deficiency

Acquired immune deficiency syndrome (AIDS) is a disease caused by the human immunodeficiency virus (HIV) in which cellular immune functions are severely impaired. Acute infection and subsequent destruction of helper T cells, although occurring readily in cell cultures, do not appear to be the only mechanisms mediating helper T cell loss. Other mechanisms that may account for the loss of helper T cells include: T cell syncytia formation, decreased T cell production, and autoimmune-related destruction of helper T cells. Immune abnormalities seen early in the course of HIV infection include immune hyperactivation and autoimmune phenomena suggestive of immune dysregulation rather than immune deficiency. Many changes in immune function are, in fact, seen in HIV-seropositive patients who possess a normal number of helper T cells. Mechanisms (other than the loss of helper T cells) that may contribute to the immune abnormalities seen in these patients include noninfectious effects of HIV and HIV proteins, effects of HIV on non-T cells, autoimmune-related manifestations of HIV infection, and HIV-induced activation of normal immunosuppressive circuits.     

Trends in mortality statistics in England and Wales with particular reference to AIDS from 1984 to April 1987

Death certification should be able to provide accurate data on the number of deaths due to AIDS as a basis for predicting future deaths from the syndrome. Trends in deaths from other causes may identify conditions that have not been recognised to be associated with HIV infection. Mortality statistics with reference to AIDS in England and Wales were completed from death certificates. Increases in deaths from selected causes likely to be associated with AIDS or HIV infection suggested that in some patients with HIV infection, AIDS was not stated on the death certificate or subsequently notified by the doctor who signed the certificate. From calculations of excess deaths between the beginning of 1985 and the end of April 1987, compared with 1984 at least 495 deaths possibly associated with HIV infection were estimated to have occurred among men aged 15-54 during that period. In 261 AIDS or HIV infection was stated on the original or amended death entry as the cause of death, and of these 198 were included in the estimated number of excess deaths.Accurate notification of the underlying cause of death and associated diseases is required for the precise monitoring of trends in mortality from AIDS and possible identification of unrecognised conditions associated with HIV infection.     

The Vancouver Lymphadenopathy-AIDS Study: 1. Persistent generalized lymphadenopathy

The Vancouver Lymphadenopathy-AIDS (acquired immune deficiency syndrome) Study is an ongoing prospective study of over 700 homosexual men attending six primary care practices in central Vancouver. A case-control study of risk factors for persistent generalized lymphadenopathy in homosexual men was conducted in five of the practices. The participants completed a questionnaire and underwent a complete physical examination at the time of enrolment and at a subsequent visit not less than 3 months later, and laboratory tests were performed after both visits. Persistent generalized lymphadenopathy was defined as the presence of lymph nodes greater than 1 cm in diameter at two or more extrainguinal sites for more than 3 months. Of the 519 patients who had completed both visits by February 1984, 126 (24%) were found to have the disease, and two controls without lymphadenopathy were frequencymatched on the basis of age and practice to each subject. More than 100 male sexual partners during one''s lifetime, frequent receptive anal intercourse, a history of gonorrhea, use of illicit drugs and sexual contact in Los Angeles were identified as independent risk factors for persistent generalized lymphadenopathy. The similarity of these risk factors to those established for AIDS supports the hypothesis of a common etiology for the two diseases, and the high prevalence rate of persistent generalized lymphadenopathy further supports the hypothesis that AIDS is an uncommon response to a relatively common agent.     

Determinants of human immunodeficiency virus (HIV) prevalence in homosexual and bisexual men screened for admission to a cohort study of HIV negatives in Belo Horizonte,Brazil: Project Horizonte

Project Horizonte, an open cohort of homosexual and bisexual human immunodeficiency virus (HIV-1) negative men, is a component of the AIDS Vaccine Program, in Belo Horizonte, Minas Gerais, Brazil. The objective of this study was to compare volunteers testing HIV positive at cohort entry with a sample of those who tested HIV negative in order to identify risk factors for prevalent HIV infection, in a population being screened for enrollment at Project Horizonte. A nested case-control study was conducted. HIV positive volunteers at entry (cases) were matched by age and admission date to three HIV negative controls each. Selected variables used for the current analysis included demographic factors, sexual behavior and other risk factors for HIV infection. During the study period (1994-2001), among the 621 volunteers screened, 61 tested positive for HIV. Cases were matched to 183 HIV negative control subjects. After adjustments, the main risk factors associated with HIV infection were unprotected sex with an occasional partners, OR = 3.7 (CI 95% 1.3-10.6), receptive anal intercourse with an occasional partner, OR = 2.8 (95% CI 0.9-8.9) and belonging to the negro racial group, OR = 3.4 (CI 95% 1.1-11.9). These variables were associated with an increase in the risk of HIV infection among men who have sex with men at the screening for admission to an open HIV negative cohort.     

Is risk of Kaposi's sarcoma in AIDS patients in Britain increased if sexual partners came from United States or Africa?

OBJECTIVE--To determine whether the risk of Kaposi''s sarcoma in patients with AIDS is increased by sexual contact with groups from abroad with a high incidence of Kaposi''s sarcoma. DESIGN--Analysis of risk of Kaposi''s sarcoma in patients with AIDS, according to country of origin of their sexual partners. SETTING--United Kingdom. PATIENTS--2830 patients with AIDS reported to the Communicable Disease Surveillance Centre and the Communicable Disease (Scotland) Unit up to March 1990, of whom 566 had Kaposi''s sarcoma. MAIN OUTCOME MEASURES--Percentage of patients with AIDS who had Kaposi''s sarcoma. RESULTS--537 of 2291 homosexual or bisexual men (23%) with AIDS had Kaposi''s sarcoma; 10% (14/135) of the men and women who acquired HIV by heterosexual contact had Kaposi''s sarcoma. None of the 316 subjects who acquired HIV through non-sexual routes had Kaposi''s sarcoma. Kaposi''s sarcoma was more common among homosexual men whose likely source of infection included the United States (171/551, 31%) or Africa (9/34, 26%) than among those infected in the United Kingdom (119/625, 19%) (p less than 0.05). CONCLUSION--The data suggest that Kaposi''s sarcoma is caused by a sexually transmissible agent which was introduced into the British homosexual population mainly from the United States [corrected].     

Incidence of AIDS and excess of mortality associated with HIV in haemophiliacs in the United Kingdom: report on behalf of the directors of haemophilia centres in the United Kingdom.

OBJECTIVE--To estimate the cumulative incidence of AIDS by time since seroconversion in haemophiliacs positive for HIV and to examine the evidence for excess mortality associated with HIV in those who had not yet been diagnosed as having AIDS. DESIGN--Analysis of data from ongoing national surveys. SETTING--Haemophilia centres in the United Kingdom. PATIENTS--A total of 1201 men with haemophilia who had lived in the United Kingdom during 1980-7 and were positive for HIV. INTERVENTION--None. END POINTS--Diagnosis of AIDS; death in those not diagnosed as having AIDS. MEASUREMENTS AND MAIN RESULTS--Estimation of cumulative incidence of AIDS and number of excess deaths in seropositive patients not diagnosed with AIDS. Median follow up after seroconversion was 5 years 2 months. Eight five patients developed AIDS. Cumulative incidence of AIDS five years after seroconversion was 4% among patients aged less than 25 at first test positive for HIV, 6% among those aged 25-44, and 19% among those aged greater than or equal to 45. There was little evidence that type or severity of haemophilia or type of factor VIII or IX that had caused HIV infection affected the rate of progression to AIDS. Mortality was increased among those who had not been diagnosed as having AIDS, especially among those with "AIDS related complex." Thirteen deaths were observed among 36 patients diagnosed as having AIDS related complex against 0.65 expected, and 34 deaths in 1080 other patients against 22.77 expected; both calculations were based on mortality rates observed in haemophiliacs in the United Kingdom in the late 1970s. CONCLUSIONS--Rate of progression to AIDS depended strongly on age. There is a substantial burden of fatal disease among patients positive for HIV who have not been formally diagnosed as having AIDS.     

The forms and analysis of the results of work in preventing HIV infection among youth

Specialists of the AIDS Centre distributed questionnaires, specially developed by them, among a group of students of the Pedagogical University. The questionnaire contained 35 questions; of these, 21 questions were intended to find out what information on HIV infection and AIDS the students had and 14 questions dealt with their sexual history and their attitude to the problem. The answers to the questionnaires distributed among 100 students (68% were females and 32% were males) showed that 58% of the respondents had previous sexual experience. 68.5% of the respondents had sexual intercourse after taking alcohol, 7.4% always used condoms, 38.8% seldom and 53.7% never used condoms. The behavior of 68.8% of the respondents was not influenced by information on HIV infection they received, 16% reduced the number of casual sexual partners, 8.6% started using condoms, 6.5% reduced the number of sexual partners.     

Comparison of immunodeficiency and AIDS defining conditions in HIV negative and HIV positive men with haemophilia A.

OBJECTIVE--To investigate the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia. DESIGN--A comparison of AIDS defining conditions and CD4 counts in HIV positive and HIV negative patients with haemophilia matched for usage of clotting factor concentrate. SETTING--A comprehensive care haemophilia centre. SUBJECTS--17 HIV positive and 17 HIV negative male patients with haemophilia A (age range 12-60 at beginning of study period) who had received similar amounts of clotting factor concentrate yearly over the years 1980-90. MAIN OUTCOME MEASURES--Clinical events listed as AIDS defining in the Centers for Disease Control AIDS definition; CD4 lymphocyte counts; death. RESULTS--Of 108 HIV positive male patients with haemophilia A, only 17 could be matched to an HIV negative patient. This was due to the much higher average usage of factor VIII in the HIV positive group. Between 1980 and 1990, 16 clinical events occurred in nine of the 17 HIV positive patients. No event occurred in the 17 HIV negative patients. In each pair the mean CD4 count during follow up was, on average, 0.5 x 10(9)/l lower in the HIV positive patient. CONCLUSION--These data reject the hypothesis that high usage of clotting factor concentrate, rather than HIV infection, is the cause of immunodeficiency and AIDS in men with haemophilia.     

Diagnostic utility of lymphocyte subset analysis in AIDS case finding.

Abnormalities of lymphocyte subsets, especially low absolute number of helper T cells, are characteristically present in acquired immune deficiency syndrome (AIDS). Similar abnormalities can be found in patients with persistent generalized lymphadenopathy (PGL) or AIDS-related complex (ARC) and, to a lesser degree, in asymptomatic people who have been exposed to human T-lymphotropic virus type III (HTLV-III). Nevertheless, there appears to be a widespread perception that lymphocyte subset analysis may be useful in AIDS case finding within high-risk groups. We evaluated the diagnostic utility of absolute number of helper T cells and ratio of helper to suppressor T cells in 33 patients with AIDS, 43 patients with PGL who had been referred for lymph node biopsy, 90 patients with PGL and 195 male homosexual controls. At conventional cutoff levels the tests did not appear to revise the probability of AIDS upward to any clinically significant degree when the pretest probability of AIDS was low. Lymphocyte subset analysis does not appear to be a cost-effective method of AIDS case finding in identified groups at risk in which the prevalence of AIDS is low.     

National cross sectional study of views on sexual violence and risk of HIV infection and AIDS among South African school pupils

Objective To investigate the views of school pupils on sexual violence and on the risk of HIV infection and AIDS and their experiences of sexual violence.Design National cross sectional study.Setting 5162 classes in 1418 South African schools.Participants 269 705 school pupils aged 10-19 years in grades 6-11.Main outcome measure Answers to questions about sexual violence and about the risk of HIV infection and AIDS.Results Misconceptions about sexual violence were common among both sexes, but more females held views that would put them at high risk of HIV infection. One third of the respondents thought they might be HIV positive. This was associated with misconceptions about sexual violence and about the risk of HIV infection and AIDS. Around 11% of males and 4% of females claimed to have forced someone else to have sex; 66% of these males and 71% of these females had themselves been forced to have sex. A history of forced sex was a powerful determinant of views on sexual violence and risk of HIV infection.Conclusions The views of South African youth on sexual violence and on the risk of HIV infection and AIDS were compatible with acceptance of sexual coercion and “adaptive” attitudes to survival in a violent society. Views differed little between the sexes.     

Incidence of tuberculosis among reported AIDS cases in Quebec from 1979 to 1996

BACKGROUND: The impact of HIV infection on tuberculosis (TB) rates in Quebec has not been fully established. Because concurrent HIV infection is the single most important factor in TB reactivation, the authors used Quebec AIDS surveillance data to quantify the extent of TB among reported AIDS cases and to identify the characteristics of AIDS patients with TB. METHODS: The study population comprised people aged 15 years and over with AIDS diagnosed between Jan. 1, 1979, and Dec. 31, 1996, and reported by Mar. 13, 1997. Patients with TB (all forms) and those without TB were compared. Multivariate logistic regression analysis was used to examine the independent effect of each variable on the AIDS-TB cases. The authors also compared the number of AIDS-TB cases with the number of TB cases to estimate the effect of HIV infection on TB incidence. RESULTS: Of the 4684 people with AIDS reported in Quebec, 242 (5.2%) had active TB at some point during the course of their illness. During 1992-1995, 9.6% of the people with TB in Montreal, and 5.8% in the province of Quebec, also had HIV infection. Those with AIDS and TB were predominantly male (75.2%), manual workers (40.1%) and residents of Montreal (86.4%) and were born in an HIV-endemic country (63.8%). The multivariate analysis indicated that AIDS patients who were born in HIV-endemic countries in the Caribbean, sub-Saharan Africa or other developing regions were 21.8 times (95% confidence interval [CI] 19.5-28.5), 17.9 times (95% CI 12.7-27.1) and 4.9 times (95% CI 3.5-7.0) more likely to have TB than those born in Canada; manual workers and unemployed people with AIDS were 1.6 times (95% CI 1.3-2.0) and 2.0 times (95% CI 1.5-2.6) more likely to have TB than professional workers; and people who acquired HIV infection through heterosexual contact were 2.1 times (95% CI 1.6-3.1) more likely to have TB than men who acquired it through sexual contact with other men. INTERPRETATION: AIDS seems to contribute significantly to the number of TB cases. The results of this study reinforce the importance of offering HIV testing to people in high-risk groups, such as those born in a country where HIV and TB is endemic.     

Perception of risk of HIV/AIDS and sexual behaviour in Kenya

The association between perception of risk of HIV infection and sexual behaviour remains poorly understood, although perception of risk is considered to be the first stage towards behavioural change from risk-taking to safer behaviour. Using data from the 1998 Kenya Demographic and Health Survey, logistic regression models were fitted to examine the direction and the strength of the association between perceived risk of HIV/AIDS and risky sexual behaviour in the last 12 months before the survey. The findings indicate a strong positive association between perceived risk of HIV/AIDS and risky sexual behaviour for both women and men. Controlling for sociodemographic, sexual exposure and knowledge factors such as age, marital status, education, work status, residence, ethnicity, source of AIDS information, specific knowledge of AIDS, and condom use to avoid AIDS did not change the direction of the association, but altered its strength slightly. Young and unmarried women and men were more likely than older and married ones to report risky sexual behaviour. Ethnicity was significantly associated with risky sexual behaviour, suggesting a need to identify the contextual and social factors that influence behaviour among Kenyan people.     

Prostitution and risk of HIV: male partners of female prostitutes.

OBJECTIVE--To describe risk behaviours for infection with HIV in male sexual partners of female prostitutes. DESIGN--A cross sectional study. SETTING--Genitourinary medicine clinic, St Mary''s Hospital, London. SUBJECTS--112 self identified male sexual partners of female prostitutes: 101 who reported commercial sexual relationships only, five who reported non-commercial relationships only, and six who reported both commercial and non-commercial relationships. MAIN OUTCOME MEASURES--Reported risk behaviours for infection with HIV. RESULTS--Of the 40 men who had had previous HIV tests or were tested during the study, two (5%) were infected with HIV. Of the men who would answer the questions, 34/94 reported having sex with other men, 2/105 reported using injected drugs, 8/105 had a history of blood transfusion, 14/108 reported a past history of gonorrhoea, 44/102 reported paying for sex abroad, and 8/92 said that they had also been paid for sex. Of the 55 men who reported paying for vaginal intercourse in the past year, 45 (82%) said that they had always used a condom. In contrast, of the 11 non-paying partners of prostitutes, only two (18%) reported ever using a condom with their partners. CONCLUSIONS--Men who have sex with female prostitutes cannot be assumed to be at risk of infection with HIV only by this route: homosexual contact may place them at greater risk. Despite the heterogeneity among male sexual partners of prostitutes, patterns of use of condoms were uniform when they were considered as a reflection of the type of relationship a man had with a female prostitute rather than a consequence of an individual''s level of risk.     

The relationship of abnormalities of cellular immunity to antibodies to HTLV-III in homosexual men

A comprehensive evaluation of the cellular immune system (total T-cell, helper cell, suppressor cell, and natural killer cell numbers; in vitro interleukin-2 production, T-cell responses to mitogens and antigens, serum beta 2 microglobulin levels, and delayed hypersensitivity skin tests) was performed on 36 HTLV-III seronegative and 16 HTLV-III seropositive healthy homosexual men, 48 asymptomatic homosexual men with the chronic lymphadenopathy syndrome, 41 patients with AIDS, and 29 heterosexual controls without any known risk factors for AIDS. Our studies demonstrate that HTLV-III seronegative homosexual men have normal cellular immunity and are comparable to heterosexual controls. The abnormalities of lymphocyte subsets observed in HTLV-III seropositive healthy homosexual men are comparable to subjects with chronic lymphadenopathy. Assays of lymphocyte function, with the exception of delayed type hypersensitivity (DTH) skin tests, are similar in each group except patients with AIDS. Subjects with chronic lymphadenopathy were less responsive to DTH skin tests and HTLV-III seropositive healthy homosexuals were comparable to chronic lymphadenopathy subjects. We conclude that immunologic abnormalities in homosexual men are attributable to infection with HTLV-III.     

HIV-induced immunodeficiency. Relatively preserved phytohemagglutinin as opposed to decreased pokeweed mitogen responses may be due to possibly preserved responses via CD2/phytohemagglutinin pathway

We studied the proliferative response of PBL to the mitogens PHA and PWM and Candida albicans Ag in 301 HIV seropositive homosexual men, of whom 55 had AIDS. The responses to PHA were reduced only in the clinically ill HIV seropositive subjects. In contrast, the responses to PWM were profoundly reduced in most HIV seropositive subjects including the asymptomatic group. Further analysis of 16 HIV seropositive subjects showed that the proliferative responses were reduced in both CD4 and CD8 T cell subsets. A total of 15 HIV seropositive individuals with low responses to PWM, of whom seven had AIDS and eight controls were chosen for the following studies. Expression of T3, Ti, delta receptors, and CD2 was investigated and showed an increased percentage of CD2 receptors positive cells in HIV seropositive subjects without AIDS. The proliferative responses of PBL to stimulation with PHA, PWM, antibodies to CD3, or antibodies to CD2 were investigated and showed significant correlation in controls, whereas in contrast, only the responses to PHA and CD2ab correlated in patients with AIDS. The proliferative responses to CD2ab and CD3ab in controls were larger than the responses to both PHA and PWM. In patients, these responses were less suppressed than the responses to PWM indicating that stimulation with mitogens is more complex than a simple stimulation of Ti/T3 and CD2 receptors. Further investigations were done on resting T cells, i.e., lymphocytes depleted of macrophages and pre-activated cells. Addition of PHA to these cells resulted in preactivation with expression of IL-2R (CD25) but not in proliferation. In contrast, addition of PHA plus SRBC, which bind to the CD2 receptors caused IL-2R expression, IL-2 production, and proliferation. Addition of PWM + SRBC did not result in proliferation. A comparison of the responses to PHA + SRBC of resting T cells from 26 HIV seropositive individuals, of whom seven had AIDS and 12 seronegative controls, showed that these responses were normal or only slightly decreased in the 19 seropositive men without AIDS whereas it was decreased in AIDS patients. Nevertheless, all AIDS patients showed clear-cut responses in this assay. Thus, the discrepancy between responses to PHA and PWM may be explained by an at least partially preserved function of the PHA/CD2-dependent pathway. We suggest that the defect induced by the HIV infection primarily concerns T3/Ti-induced responses.