AIDS: acquired immunodeficiency syndrome.

Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi''s sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of utmost importance.     

Some Opportunistic Parasitic Infections in AIDS: Candidiasis, Pneumocystosis, Cryptosporidiosis, Toxoplasmosis

Almost 80% of patients with AIDS die from infections other than human immunodeficiency virus (HIV). These infections usually occur late in the course of disease when CD4(+) T-cell count has fallen below 200 permm(3) cells per milliliter. Most of these infections are caused by organisms that do not normally afflict healthy individuals and are thus considered to be opportunistic. In this article, Lloyd Kasper and Dominique Buzoni-Gatel review the host-parasite interaction for four important pathogens: Candida albicans and Pneumocystis carinii (usually non-invasive pathogens), Cryptosporidium parvum (invades the cells but remains localized in the gut) and Toxoplasma gondii (penetrates through the gut to cause systemic infection). These organisms, which generally cause limited or even insignificant clinical evidence of infection in the normal host, were chosen because of their high prevalence in AIDS patients and because they exhibit different invasive abilities. The reason why individuals with AIDS are susceptible to this particular group of pathogens is uncertain.     

Opportunistic infections and acquired cellular immune deficiency among Haitian immigrants in Montreal.

Eight Haitian immigrants (five with acquired immune deficiency syndrome [AIDS] and three with the signs and symptoms of AIDS but without opportunistic infections or malignant diseases) are described. All had malaise, weight loss, fever and generalized lymphadenopathy. All five of those with opportunistic infections died from the infections, which were multiple in four cases. Septic shock due to Escherichia coli or Klebsiella pneumoniae developed in two patients. Evidence of immune deficiency in the AIDS patients included anergy, lymphocytopenia (in all but two), polyclonal hypergamma-globulinemia and abnormal sizes of the subsets of circulating T lymphocytes. Autopsies revealed no recognizable causes for immune deficiency; the lymph nodes showed follicular hyperplasia in four cases and lymphocyte depletion in one case. Except for the absence of opportunistic infections, the illness in the three patients not classed as having AIDS was indistinguishable from that in the other five, which suggests that this syndrome is AIDS-related, like the persistent generalized lymphadenopathy that occurs in homosexual men and patients with hemophilia.     

Intestinal Parasitosis in Relation to Anti-Retroviral Therapy,CD4+ T-cell Count and Diarrhea in HIV Patients

Intestinal parasitic infections are one of the major causes of diarrhea in human immunodeficiency virus (HIV) seropositive individuals. Antiretroviral therapy has markedly reduced the incidence of many opportunistic infections, but parasite-related diarrhea still remains frequent and often underestimated especially in developing countries. The present hospital-based study was conducted to determine the spectrum of intestinal parasitosis in adult HIV/AIDS (acquired immunodeficiency syndrome) patients with or without diarrhea with the levels of CD4⁺ T-cell counts. A total of 400 individuals were enrolled and were screened for intestinal parasitosis. Of these study population, 200 were HIV seropositives, and the remaining 200 were HIV uninfected individuals with or without diarrhea. Intestinal parasites were identified by using microscopy as well as PCR assay. A total of 130 (32.5%) out of 400 patients were positive for any kinds of intestinal parasites. The cumulative number of parasite positive patients was 152 due to multiple infections. A significant association of Cryptosporidium (P<0.001) was detected among individuals with CD4⁺ T-cell counts less than 200 cells/μl.     

Epidemiology of Invasive Fungal Infections in Patients with Acquired Immunodeficiency Syndrome at a Reference Hospital for Infectious Diseases in Brazil

Invasive fungal infections (IFIs) represent one of the main causes of morbimortality in immunocompromised patients. Pneumocystosis, cryptococcosis and histoplasmosis are the most frequently occurring IFIs in patients with acquired immunodeficiency syndrome (AIDS). Fungi, such as Candida spp. and Aspergillus spp., may cause severe diseases during the course of an HIV infection. Following the introduction of highly active anti-retroviral therapy, there has been a marked reduction of opportunistic fungal infections, which today is 20–25 % of the number of infections observed in the mid-1990s. This study is an observational and retrospective study aimed at the characterising IFI incidence and describing the epidemiology, clinical diagnostic and therapeutic features and denouement in HIV/AIDS patients. In HIV/AIDS patients, the IFI incidence is 54.3/1,000 hospitalisation/year, with a lethality of 37.7 %. Cryptococcosis represents the main opportunistic IFI in the population, followed by histoplasmosis. Nosocomial pathogenic yeast infections are caused principally by Candida spp., with a higher candidemia incidence at our institution compared to other Brazilian centres.     

HIV and HTLV-I antibody studies: pregnant women in the 1960s, patients with AIDS, homosexuals, and individuals with tropical spastic paraparesis

To investigate the possible occurrence of human immunodeficiency virus (HIV) or human T-cell lymphotropic virus, type I (HTLV-I) infections in the United States prior to 1979-1981, when acquired immune deficiency syndrome (AIDS) was first recognized, we tested sera from 310 pregnant women who participated in the Collaborative Perinatal Project during the period 1959-1964 for HIV and HTLV-I antibody. These samples included sera from 53 pregnant women who were intravenous drug users. The remainder were from women who had cervical epithelial abnormalities, who developed cervical carcinomas, who had had children with erythroblastosis fetalis, who had had children that developed malignant neoplasms early in life, or normal pregnant women. None of the 310 women had confirmed HIV or HTLV-I antibody. The rate of false-positive reactions with the HIV enzyme-linked immunosorbent assay (ELISA) antibody test in these long-frozen samples was similar to that observed in fresh sera. HIV antibody was detected in homosexual patients with AIDS; HTLV-I antibody was not detected in any of these sera. HTLV-I antibody was detected in 17 of 20 patients with tropical spastic paraparesis (TSP) and in two of seven patients with other neurological diseases diagnosed as transverse myelopathy and multiple sclerosis, and in none of nine normal controls; HIV antibody was not detected in any of these sera patients. Thus, we conclude that there was no serological evidence of infection with HIV or HTLV-I in the pregnant women studied; however, HIV antibody was present in all AIDS patients tested, and HTLV-I antibody was found in the majority of patients with TSP.     

AIDS in Haitian immigrants and in a Caucasian woman closely associated with Haitians.

In Montreal the acquired immune deficiency syndrome (AIDS) was seen in eight Haitian immigrants and one Caucasian woman who had lived with Haitian immigrants for 3 years before the onset of her illness. AIDS was characterized by opportunistic infections alone in seven patients, by opportunistic infection and Kaposi''s sarcoma in one patient and by chronic generalized lymphadenopathy in one patient. Five of the patients had presented with Mycobacterium tuberculosis infections 1 to 12 months before the onset of opportunistic infections. All nine patients were found to have recall anergy by skin testing for delayed hypersensitivity. Enumeration of the lymphocyte subpopulations in three patients showed a marked inversion of the ratio of helper to suppressor T lymphocytes. Six of the patients died as a result of the opportunistic infections; autopsies showed no recognizable causes of immunodeficiency. Thus, there is in Montreal a third clustering of AIDS cases in North America related to Haitian immigrants.     

Parasite infections in AIDS

'Illnesses no one's got' was the epidemiological clue that led to the identification of AIDS as a new disease in 1981 when a rare infectious organism Pneumocystis carinii was seen in previously healthy homosexuals. Since then a wide range of parasite infections has been recognized in AIDS patients. However, these patients are not susceptible to just any passing parasite. The human immunodeficiency virus (HIV) produces a specific immune defect and only parasites that can exploit that defect will be able to flourish. In this review Diana Lockwood and Jonathan Weber explore the spectrum of parasite diseases recognized in AIDS and also consider those parasites that occur infrequently in AIDS. Analysis of parasitic infections that AIDS patients do not suffer from will yield valuable information about immune recognition and handling of these parasites.     

Idiopathic CD4 lymphocytopenia: a case of missing, wandering or ineffective T cells

Idiopathic CD4 lymphocytopenia (ICL) is a presumed heterogenous syndrome with key element low CD4 T-cell counts (below 300/mm³) without evidence of HIV infection or other known immunodeficiency. The etiology, pathogenesis, and management of ICL remain poorly understood and inadequately defined. The clinical presentation can range from serious opportunistic infections to incidentally diagnosed asymptomatic individuals. Cryptococcal and non-tuberculous mycobacterial infections and progressive multifocal leukoencephalopathy are the most significant presenting infections, although the spectrum of opportunistic diseases can be similar to that in patients with lymphopenia and HIV infection. Malignancy is common and related to opportunistic pathogens with an oncogenic potential. Autoimmune diseases are also seen in ICL with an increased incidence. The etiology of ICL is unknown. Mechanisms implicated in CD4 reduction may include decreased production, increased destruction, and tissue sequestration. New distinct genetic defects have been identified in certain patients with ICL, supporting the hypothesis of the lack of a common etiology in this syndrome. The management of ICL is focused on the treatment of opportunistic infections, appropriate prophylactic antibiotics, and close monitoring. In selected patients with life-threatening infections or profound immunodeficiency, strategies to increase T-cell counts or enhance immune function could be considered and have included interleukin-2, interferon-gamma, interleukin-7, and hematopoietic stem cell transplantation. The prognosis is influenced by the accompanying opportunistic infections and may be affected by publication bias of severe cases with unfavorable outcomes. As newer laboratory investigation techniques are being developed and targeted experimental treatments become available, our comprehension and prognosis of this rare syndrome could be significantly improved.Idiopathic CD4 lymphocytopenia (ICL) was described in 1992 as an immunodeficiency syndrome characterized by opportunistic infections and low CD4 T-cell counts in the absence of HIV infection. Despite the 20 years that have elapsed, the clinical spectrum, pathogenesis, and possible treatment for ICL remain obscure. Here, we attempt to summarize the salient features of this condition on the basis of the available literature to date.     

An overview of antifungal peptides derived from insect

Fungi are not classified as plants or animals. They resemble plants in many ways but do not produce chlorophyll or make their own food photosynthetically like plants. Fungi are useful for the production of beer, bread, medicine, etc. More complex than viruses or bacteria; fungi can be destructive human pathogens responsible for various diseases in humans. Most people have a strong natural immunity against fungal infection. However, fungi can cause diseases when this immunity breaks down. In the last few years, fungal infection has increased strikingly and has been accompanied by a rise in the number of deaths of cancer patients, transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients owing to fungal infections. The growth rate of fungi is very slow and quite difficult to identify. A series of molecules with antifungal activity against different strains of fungi have been found in insects, which can be of great importance to tackle human diseases. Insects secrete such compounds, which can be peptides, as a part of their immune defense reactions. Active antifungal peptides developed by insects to rapidly eliminate infectious pathogens are considered a component of the defense munitions. This review focuses on naturally occurring antifungal peptides from insects and their challenges to be used as armaments against human diseases.     

AIDS awareness among rural Utah physicians.

Studies of physicians'' attitudes and knowledge of the acquired immunodeficiency syndrome (AIDS) and the clinical precautions they take against exposure to the human immunodeficiency virus (HIV) have focused on urban physicians. To determine rural physicians'' knowledge and attitudes about AIDS, a questionnaire was mailed to 321 physicians practicing in rural Utah. Of the 169 physicians who completed questionnaires, 96% thought that their community or area of service had only a minor or no problem with AIDS; 89%, however, thought that their chance of seeing a patient who was HIV-positive was fair to moderate. Of the 169 respondents, 3% were not sure whether they would even treat a patient who had AIDS, 67% said they would, and 30% said they would not. Although all physicians are at risk of seeing a patient who has had exposure to HIV and other blood-borne diseases such as hepatitis B, only 55% of the respondents felt a need to take clinical precautions to prevent their exposure to the virus. Our study shows the need for all rural Utah physicians to reevaluate their risk of exposure to HIV, to increase precautionary measures for their own protection, to consider the ethical responsibility of treating AIDS patients, and to take a more active role in teaching their patients how to protect themselves from exposure to the virus.     

Changing disease patterns in patients with AIDS in a referral centre in the United Kingdom: the changing face of AIDS.

OBJECTIVE--To study the changes in morbidity, mortality, and survival patterns in a population of patients with AIDS in the United Kingdom from 1982 to 1989. DESIGN--A retrospective analysis of inpatient and outpatient records of patients with AIDS. SUBJECTS--347 Patients with AIDS, predominantly homosexual or bisexual men. SETTING--Departments of immunology and genitourinary medicine, St Mary''s Hospital, London. MAIN OUTCOME MEASURES--Presenting diagnosis of AIDS, occurrence of other opportunist diseases, cause of death, and survival since AIDS was diagnosed, in particular for those patients with Pneumocystis carinii pneumonia or Kaposi''s sarcoma. RESULTS--The overall proportion of patients who developed P carinii pneumonia dropped from 56% (20/36) in 1984 to 24% (46/194) in 1989, although it has remained the index diagnosis in about half of new patients. Kaposi''s sarcoma has decreased as index diagnosis from 30% (20/67) to 20% (15/74) over the same period, though the prevalence has remained constant at around 35%. P carinii pneumonia accounted for 46% (16/35) of known causes of death in 1986 but only 3% (1/31) in 1989. Conversely, deaths due to Kaposi''s sarcoma rose from 14% (1/7) to 32% (10/31) between 1984 and 1989. Lymphoma accounted for an increased proportion of deaths among these patients with 16% (5/31) of deaths in 1989. Their median survival increased from 10 months in 1984-6 to 20 months in 1987. CONCLUSIONS--The changing patterns of disease in patients with AIDS have important implications both for health care provision and future medical research. Medical and nursing provision must be made for the increased morbidity of these diseases and the increased survival of these patients. Research should now be directed towards developing effective treatments for the opportunist infections which are currently more difficult to treat, the secondary malignancies of AIDS, as well as more effective immunorestorative treatments. Future changes in disease patterns must be recognised at an early stage so that resources can be adequately planned and allocated.     

General practitioners and management of infection with HIV

General practitioners will have an increasingly important role in the management of patients with the acquired immune deficiency syndrome (AIDS) and infections with human immunodeficiency virus (HIV) as the numbers of cases increase. Altogether 280 general practitioners working in Oxfordshire were sent a postal questionnaire inquiring about their education, knowledge, current practice, and attitudes in relation to managing infections with HIV. Of the 235 (84%) general practitioners who replied, nine out of 10 were giving advice about infection with HIV to their patients. One in two were testing patients for such infection, and one in four were caring for infected patients. Nevertheless, uncertainty remained about the risks of transmission of infection with HIV and general practitioners'' knowledge of educational activities for their patients could be improved.The introduction of a facilitator to work with general practitioners in managing patients with AIDS or infection with HIV is planned, especially to help general practitioners develop the skills needed for prevention.     

The value of primate models for studying human immunodeficiency virus pathogenesis

Abstract: Research on human immunodeficiency virus (HIV) infection is compromised by the obvious limitation in having for study only virus-infected individuals or those exposed to the virus. Steps involved in transmission or pathogenesis require planned experimentation. The identification of animal models of acquired immunodeficiency syndrome (AIDS) has therefore been helpful for evaluating phases of HIV pathogenesis. Of the seven subgenera of lentiviruses now recognized, two share the characteristics with HIV of a T cell tropism and the associated loss of CD4+ cells in the host associated with disease: the feline immunodeficiency virus (FIV) and the simian immunodeficiency virus (SIV) (Table 1). The other animal lentiviruses grow best in macrophages and their infection generally reflects clinical sequellae of infection of this cell type. This review addresses those features of SIV, HIV, and SHIV infections of non-human primates that illustrate the importance of the animal models of AIDS.     

Inflammatory joint disease and human immunodeficiency virus infection

Nine men positive for antibody to human immunodeficiency virus (HIV) who developed peripheral, non-erosive arthritis were followed up. The clinical features were compatible with reactive arthritis but were atypical in several respects: the joint symptoms were generally severe, persistent, and unresponsive to non-steroidal anti-inflammatory drugs. The onset of arthritis was associated with various infections, none of which are known to be associated with the development of reactive arthritis. HLA typing was performed for three patients, all of whom were positive for HLA-B27. HIV was isolated from the synovial fluid of one patient. No patient had AIDS before developing arthritis, but four progressed to having AIDS after a mean of 7·5 months, and two died. Arthritis resolved in only one patient.The possibility of HIV infection should be considered in all patients with conditions suggesting reactive arthritis. Synovitis in patients with severe immunodeficiency has important pathogenetic implications.     

Derivation and characterization of a highly pathogenic isolate of human immunodeficiency virus type 2 that causes rapid CD4+ cell depletion in Macaca nemestrina

With few exceptions, humans are the only species known to develop acquired immunodeficiency syndrome (AIDS) after human immunodeficiency virus (HIV) infection. We report here that an isolate of HIV type 2, EHO, readily established persistent infection in 100% of Macaca nemestrina in three consecutive transmission studies. Of the eight infected animals, five showed persistently high virus load and six developed AIDS-like diseases or CD4+ cell depletion within 4 years of infection. The pathology and clinical signs closely parallel those of HIV-1 infection of humans, including lymphadenopathy, anemia, CD4+ cell depletion, and opportunistic infections. A cell-free virus stock was established from the lymph nodes of an animal that developed AIDS-like diseases. This virus, HIV-2/287, was highly pathogenic in M. nemestrina, causing CD4+ cell depletion within 2-8 weeks postinfection. While both HIV-2 EHO and HIV-2/287 use predominantly CXCR4, the latter shows greatly enhanced replicative capacity in macaque peripheral blood mononuclear cells (PBMCs). The establishment of a human immunodeficiency virus that causes rapid and reproducible CD4 cell depletion in macaques could facilitate the study of HIV pathogenesis and the development of effective vaccines and therapy against AIDS.     

艾滋病合并侵袭性肺真菌病的诊治

近年来,侵袭性真菌感染的发病率不断增加,其中肺真菌感染居首位,己成为免疫功能下降或缺陷宿主常见的死亡原因。艾滋病是经典免疫功能缺陷性疾病,合并真菌感染时需及时识别、治疗,以降低其病死率。国内、外各种有关侵袭性真菌感染诊治指南的不断问世,极大地提高了临床医生对侵袭性真菌病的认识和诊治水平。该文就艾滋病常见侵袭性肺真菌病:肺念珠菌病、肺孢子菌肺炎、肺马内菲青霉病、肺隐球菌病、肺曲霉病的诊断及治疗进展进行综述。     

Characterization of the acquired immune deficiency syndrome at the cellular and molecular level

Summary The acquired immunodeficiency syndrome (AIDS) is a new disease characterized by severe dysfunction of both the T cell and B cell systems, occurring in previously healthy individuals. Affected individuals may have recurrent and chronic opportunistic infections and/ or Kaposi's sarcoma or other malignancy. Analysis of the cellular and subcellular components of immunity demonstrates a profound depression in the number and function of helper/ inducer T cells bearing the OKT4 (Leu 3) differentiation antigen and a concomitant defect in the synthesis of the immuno-enhancing soluble growth factor, interleukin 2 (IL-2). Hypotheses to explain the etiology of the immunological dysfunction and implications for future therapy of AIDS are discussed.     

Immunology of fungal infections: lessons learned from animal models

The continuing AIDS epidemic coupled with increased usage of immunosuppressive drugs to prevent organ rejection or treat autoimmune diseases has resulted in an increase in individuals at risk for acquiring fungal diseases. These concerns highlight the need to elucidate mechanisms of inducing protective immune responses against fungal pathogens. Consequently, several experimental models of human mycoses have been developed to study these diseases. The availability of transgenic animal models allows for in-depth analysis of specific components, receptors, and signaling pathways that elicit protection against fungal diseases. This review focuses on recent advances in our understanding of immune responses to fungal infections gained using animal models.