Lymphocyte membrane alpha-1-acid glycoprotein: a cellular synthesis during lymphocyte activation

Soluble alpha 1 acid-glycoprotein is considered an "acute phase protein" with an inhibitory effect on lymphocyte activity; it has recently been shown that a lymphocyte modulatory variant of alpha 1 acid-glycoprotein has a positive role on T cell activation. It is not clear whether the presence of this glycoprotein on lymphocyte membranes is due to an endogenous production or to a passive uptake of soluble alpha 1 acid-glycoprotein by its carbohydrate moiety. Our data show an increase of membrane alpha 1 acid-glycoprotein both in peripheral blood lymphocyte and T-enriched lymphocytes after phytohemagglutinin stimulation. Peripheral blood lymphocyte enzymatic treatment by neuraminidase does not affect alpha 1 acid-glycoprotein expression while pronase digestion induces a strong decrease of alpha 1 acid-glycoprotein positive lymphocytes and a resynthesis after phytohemagglutinin stimulation. Furthermore, the presence of alpha 1 acid-glycoprotein was prevalently, found on helper/inducer lymphocytes. These data support the hypothesis of a synthesis of alpha 1 acid-glycoprotein by T lymphocytes during their activation process.     

Cellular immunosuppression in children with acute lymphoblastic leukemia: Effect of consolidation chemotherapy

Summary The present study was designed to evaluate the chemotherapy-induced cellular immunosuppression in 20 children with acute lymphoblastic leukemia (ALL) in remission and receiving maintenance chemotherapy. Peripheral blood was serially obtained from leukemic children during vincristine/cyclophosphamide/6-mercaptopurine/prednisone combined consolidation chemotherapy. The mean absolute number of peripheral blood lymphocytes as well as the mean absolute numbers of lymphocyte subsets (T cells, T cell subsets, B cells, and natural killer cells) from leukemic children before consolidation chemotherapy were all significantly lower than in control subjects; however, the percentages of lymphocyte subsets were similar in both groups. After consolidation chemotherapy, the percentages of CD4⁺ T lymphocytes and natural killer (NK) cells were significantly decreased and the percentages of monocytes and CD8⁺ T lymphocytes were significantly increased. Phytohemagglutinin- and 12-O-tetradecanoylphorbol-13-acetate-induced production of interleukin-2 (IL-2) and NK-cell-mediated cytotoxic activity by peripheral blood mononuclear cells (PBMC) were also substantially decreased in the post-therapy groups. NK activity correlated with the percentage of NK cells in PBMC. In contrast, OK432-induced production of tumor necrosis factor (TNF) and killer activity against NK-resistant target cells were significantly increased after therapy as compared with the pre-therapy and control groups. TNF production correlated with the percentage of monocytes in PBMC. These results demonstrate that substantial quantitative and qualitative chemotherapy-induced abnormalities of the cellular immune system are present in the majority of patients treated with ALL. It is also suggested that the increased TNF production by monocytes and the appearance of potent killing activity against NK-resistant targets might compensate for the defects of IL-2 production and NK activity during intensive consolidation chemotherapy.This work was supported by a grant-in-aid for cancer research from the Ministry of Health and Welfare, Japan, and a grant-in-aid from the Association for the Support of Children with Cancer     

Changes in blood leucocyte populations induced by acute maximal and chronic submaximal exercise

Absolute (x 10(3).mm-3) or relative (%) numbers of blood leucocyte types (monocytes, lymphocytes, neutrophils) and lymphocyte subsets (T11+, T4+, T8+, B1+, and NKH1+) reacting with specific monoclonal antibodies were determined at rest, immediately after maximal exercise on a treadmill, in six controls (C), and in six young cyclists before training (BT) and after 5 months of training (AT). Maximal exercise significantly increased the absolute number (mobilization) of virtually all the types of leucocytes and subsets of lymphocytes in C, BT and AT subjects. In these subjects mobilization of natural killer cells (NKH1+) and cytotoxic/suppressor T lymphocytes (T8+) was greater than mobilization of the other leucocyte types and lymphocyte subsets; however, maximal exercise induced no significant changes in the relative numbers of any leucocyte types and lymphocyte subsets, except in the case of T4+ lymphocytes in At cyclists. Chronic submaximal exercise induced increased mobilization of neutrophils and decreased mobilization of lymphocytes during maximal exercise, except in the case of B lymphocytes (B1+) and NKH1+ cells, and decreases in the absolute and relative number of neutrophils at rest. It remains to be seen how these results can explain the modifications of leucocyte activities noted in vitro after isolated or chronic exercise.     

Effects of human soluble BAFF synthesized in Escherichia coli on CD4+ and CD8+ T lymphocytes as well as NK cells in mice

B cell-activating factor belonging to the TNF family (BAFF, also called BLyS, TALL-1, zTNF-4, or THANK) is an important survival factor for B lymphocytes. In this study, we injected mouse abdominal cavity with human soluble BAFF (hsBAFF, 0.01, 0.1, 0.5, 2 mg/kg body mass) synthesized in Escherichia coli. On the 8th day after injection, we investigated the effects of hsBAFF on immune functional activities of splenic B lymphocytes, CD4(+) and CD8(+) T lymphocytes and natural killer (NK) cells in mice. The results showed that B lymphocyte proliferation significantly increased in hsBAFF-treated groups with dosages of 0.1 mg/kg (p<0.05), 0.5 and 2 mg/kg (p<0.01). We observed a dose-dependent increase of CD4(+) T lymphocyte percentage and significantly higher values in 0.5 and 2 mg/kg hsBAFF-treated groups (p<0.05 and p<0.001, respectively) compared to control group, but CD8(+) T lymphocyte percentage remained unchanged. The ratio of CD4(+) to CD8(+) T lymphocytes rose with increasing hsBAFF dosage (p<0.05 for 2 mg/kg hsBAFF vs. control). Significantly stronger NK cell activities were found in 0.5 and 2 mg/kg hsBAFF-treated groups (p<0.05). The main finding of this study is that the hsBAFF can enhance immune responses in the body by increasing B lymphocyte and CD4(+) T lymphocyte function as well as elevating NK cell activity.     

儿童传染性单核细胞增多症淋巴细胞亚群的变化及意义

目的 通过对儿童传染性单核细胞增多症(infectious mononucleosis,IM)外周血淋巴细胞亚群的检测,探讨其细胞免疫功能变化与疾病的关系.方法 采用流式细胞仪对35例IM患儿外周血T、B和NK淋巴细胞亚群进行检测,30例健康儿童作为对照组;对患儿中的7例进行治疗2周后细胞亚群的测定以观察动态变化;对患儿进行外周血异型淋巴细胞计数.结果 IM患儿CD3、CD8 T淋巴细胞水平明显升高,CD19、NK、CD4和CD4/CD8值水平明显降低,分别与正常对照组比较差异均有统计学意义.7例IM患儿治疗2周后T细胞亚群的测定值与入院时比较差异有统计学意义,治疗前CD4、CD4/CD8值低于治疗后,治疗前CD8高于治疗后.IM患儿急性期CD8、CD4/CD8水平与患儿外周血异型淋巴细胞百分率(≤10％和＞10％)的差异有统计学意义.结论 检测淋巴细胞亚群对评估IM患儿的细胞免疫状况,辅助诊断和指导治疗具有重要的临床价值.     

Immunologic studies with LFA-1- and Mo1-deficient lymphocytes from a patient with recurrent bacterial infections

A patient and his parents, deficient for lymphocyte function associated antigen-1 (LFA-1) and Mo1 (OKM1), were studied with respect to leukocyte surface marker expression and functional properties. The patient had a history of severe recurrent bacterial infections. Two siblings had already died of bacterial infections. The patient's granulocytes, monocytes, and lymphocytes expressed low but detectable amounts (less than or equal to 10%) of LFA-1 and Mo1. Intracellularly, LFA-1 and Mo1 (OKM1) were detectable and LFA-1 expression was enhanced on patient T cells stimulated with phytohemagglutinin. Granulocytes and monocytes of both the patient's parents expressed markedly decreased amounts of LFA-1 and Mo1. Lymphocytes of the mother expressed 40 to 60% of the amount of LFA-1 expressed on control lymphocytes, but his father's lymphocytes showed a normal LFA-1 expression. Granulocytes of the patient and of his deceased sister showed normal phagocytosis, but they had a dysfunction in the activation of the oxidative metabolism. Functional activities mediated by patient T cells were all normal. Moreover, all lymphocyte functions, including killer (K), natural killer (NK), cytotoxic T cell activity, helper activity for in vitro immunoglobulin (Ig) production by normal B cells, and PHA-induced proliferation were inhibitable by anti-LFA-1 monoclonal antibodies. K and NK activity mediated by patient leukocytes was 100-fold more sensitive to the inhibiting effect of anti-LFA-1 antibody than K and NK activity of normal donor leukocytes. Thus, although the amount of LFA-1 expressed was strongly reduced, it was still sufficient and required for the functional activity exhibited by patient T cells. The major functional defect observed with leukocytes of the patient and his father was an apparent B cell defect. B cells of the father and of the patient failed to produce Ig in the pokeweed mitogen (PWM)-driven system. The B cells of patient and of his father only produced Ig when cultured with T cells of the father, and not with normal donor T cells or T cells of the mother, in the presence of exogenous interleukin 2 (IL 2). In addition, the father's B cells produced Ig when cocultivated with patient T cells in the IL 2-driven system. This restriction of helper T cell activity is noteworthy because PWM- and IL 2-driven Ig synthesis by normal lymphocytes show no histocompatibility requirements between cooperating T and non-T cell populations.(ABSTRACT TRUNCATED AT 400 WORDS)     

Various parameters of humoral and cellular immunity in children with iron deficiency

Serum IgA, IgM and IgG as well as percentage of lymphocytes T and B in peripheral blood were determined in 50 children aged between 6 months and 3 years with iron deficiency anaemia. A significant decrease in lymphocyte T number in these children was found in comparison with control group of healthy children. Lymphocyte T count positively correlated with serum iron concentration. Moreover, a decrease in serum IgA and IgG was found in children with iron deficit.     

Interrelation between the activity of hepatitis, liver fibrosis and immune status in children with chronic hepatitis B and C

The lesion of the liver in viral hepatitis was found to depend on the state of the immune system. Relationship between the content of lymphocyte subpopulations (CD3+, CD4+, CD8+, CD20+) in the blood and immunoglobulins (IgG, IgM, IgA) with parameters of semi-quantitative evaluation of the activity of hepatitis and the stage of liver fibrosis in children with chronic virus hepatitis B, C, B + C was studied. The characteristic feature of all hepatitis was a decrease in the number of T lymphocytes CD4+ below the normal level and an increase in the content of B lymphocytes. The correlation between the morphological activity of hepatitis and the amount of T lymphocytes CD8+ was established only in chronic hepatitis B. In chronic hepatitis B and B + C the absolute amount of blood lymphocytes decreased with the increase of the age of the patients, but in chronic hepatitis B this was accompanied by the decrease of the morphological activity of hepatitis and in hepatitis B + C by its increase. The amount of lymphocytes CD4+ rose with the increase of liver fibrosis in chronic hepatitis B. In children with chronic hepatitis C and B + C the amount of blood lymphocytes was found to be unrelated to the morphological activity of hepatitis.     

Expression of cell surface markers on T and B lymphocytes after long-term chemotherapy of acute leukemia

The aim of this study was to determine the distribution of peripheral blood T and B lymphocytes in children with ALL in remission, before and after cessation of 3 yr of immunosuppressive therapy. Immunofluorescence of viable cells and rosette formation were the two methods used to identify B and T cells, respectively. Though combination chemotherapy depresses the total lymphocyte population, B lymphocytes were more depressed than T lymphocytes. On the last day of therapy, the population of lymphocytes bearing IgG-M (B cells) was markedly reduced, but the percentage of RFL (T cells) was within normal values. After chemotherapy was stopped, and in the absence of extrinsic antigenic stimulation, there was an immunological rebound in the B cell compartment. During the first 3 months off therapy, there was an increase in intensity of fluorescence and in the proportion of IgG-M-bearing lymphocytes above the levels of normal controls. Assays of lymphocytes bearing IgG, IgM and IgA indicate that there was a rebound of IgG and IgM but not IgA lymphocytes. Changes in the proportion of RFL as a function of time off therapy were inversely proportional to those observed for IgG-M-bearing lymphocytes, that is, the percentage of RFL decreased during the first 3 months off therapy. When the absolute numbers of B and T cells were compared, it was found that B lymphocytes reached a plateau phase after 2–3 months off therapy, but T lymphocytes continued to rise beyond this period, reaching normal levels at 12+ months off therapy.These results provide evidence, at the single cell level, of the immunological rebound that occurs after cessation of therapy and suggest that the kinetics of recovery are different for T and B lymphocytes.     

Lineage-specific telomere shortening and unaltered capacity for telomerase expression in human T and B lymphocytes with age

Age effects on telomere length and telomerase expression in peripheral blood lymphocytes were analyzed from 121 normal individuals age newborn to 94 years and revealed several new findings. 1) Telomere shortening was observed in CD4+ and CD8+ T and B cells with age. However, the rate of telomere loss was significantly different in these populations, 35 +/- 8, 26 +/- 7, and 19 +/- 7 bp/year for CD4+ and CD8+ T and B cells, respectively. In addition, CD4+ T cells had the longest average telomeres at all ages, followed by B cells, with CD8+ T cell telomeres the shortest, suggesting that these lymphocyte populations may have different replicative histories in vivo. 2) Telomerase activity in freshly isolated T and B cells was indistinguishably low to undetectable at all ages but was markedly increased after Ag and costimulatory receptors mediated stimulation in vitro. Furthermore, age did not alter the magnitude of telomerase activity induced after stimulation of T or B lymphocytes through Ag and costimulatory receptors or in response to PMA plus ionomycin treatment. 3) The levels of telomerase activity induced by in vitro stimulation varied among individual donors but were highly correlated with the outcome of telomere length change in CD4+ T cells after Ag receptor-mediated activation. Together, these results indicate that rates of age-associated loss of telomere length in vivo in peripheral blood lymphocytes is specific to T and B cell subsets and that age does not significantly alter the capacity for telomerase induction in lymphocytes.     

The decline in murine splenic PHA and LPS responsiveness with age is primarily due to an intrinsic mechanism

Changes in splenic B and T lymphocyte number and mitogenic activity with age were quantitated in (A X C57BL/6)F1 (AB6F1) hybrid mice. Although both the B and T lymphocyte proliferative reactivity to their respective mitogens, lipopolysaccharide (LPS) and phytohemagglutinin (PHA), declined significantly with age, an earlier and more marked reduction was recorded for the T cell response. The decline in B and T lymphocyte mitogenic activity with age could not be correlated with a corresponding reduction in the percentage of splenic B or T lymphocytes. The main focus of this study was to determine if the reduction in T and B lymphocyte mitogenic activity with age results primarily from a mechanism intrinsic to the lymphoid lineage itself or from adverse extracellular factors that increase with age. Bone marrow cells (BMC) derived from individual young and old donor AB6F1 mice were transplanted into the neutral environment of young, lethally irradiated syngeneic recipients. Number and mitogenic activity of splenic T and B lymphocytes were recorded for the original BMC donors as well as for the recipients of the young and old BMC lines 9 mo after the BMC transplants. A predominance of the donor (male) rather than recipient (female) karyotype within the mitogen-responding populations of recipient mice confirmed a donor BMC take. The PHA and LPS response levels exhibited by the old donors were 30% and 70% of those of the young donors, respectively. These differences in PHA and LPS reactivity recorded between young and old donors were maintained between recipients of young and old donor BMC lines. Thus, even under the influence of a young recipient environment, old BMC were incapable of giving rise to mitogen responding cells with a functional competence equivalent to that of their younger counterparts. This finding would lend further support to the theory that an intrinsic mechanism is responsible for the decline in murine mitogenic activity with age.     

Changes of the blood lymphocyte subpopulations and their functions following 131I treatment for nodular goitre and 32P treatment for polycythemia vera

The blood lymphocyte population was examined in 34 patients who were treated with 131I for toxic or atoxic nodular goitre. One to three doses of 300-550 MBq of 131I were administered at 1-week intervals. Lymphocyte counts were found to be significantly reduced at both 1 and 6 weeks after treatment. This decrease was accompanied by a changed composition of the lymphocyte subpopulations. The frequency of lymphocytes expressing membrane receptors for C'3 (EAC-rosette forming cells) was significantly reduced at 1 and 6 weeks following 131I administration. At 6 weeks there was a small but statistically significant increase of the frequency of T cells as identified by Leu 1 monoclonal antibodies. This was essentially due to an increased proportion of helper/inducer T cells as identified by Leu 3 monoclonals. 131I treatment also decreased the capacity of lymphocytes to secrete immunoglobulins (Ig) when stimulated with pokeweed mitogen (PWM). The greatest effect was observed for IgM. Secretion of IgG and IgA were less reduced. Mitogenic stimulations of lymphocytes with phytohemagglutinin (PHA) and concanavalin A were not significantly changed. It is concluded that these findings, with the exception of mitogen reactivity, are largely similar to those occurring following external radiation therapy for cancer. It is suggested that blood lymphocytes passing through the continuously irradiated gland are damaged mainly by beta-rays. The effect of 32P treatment on the blood lymphocyte population was examined in 16 patients with polycythemia vera. Before treatment the lymphocyte counts were within the normal range but the expression of certain membrane structures, as identified by monoclonal antibodies against total T cells (Leu 1 and 4), helper/inducer (Leu 3) and suppressor/cytotoxic T cells (Leu 2), were slightly decreased. Moreover, mitogenic responses of the lymphocytes to PHA and PWM-induced Ig secretion were impaired. Following a single oral dose of 32P (150-305 MBq), which normalized the production of erythrocytes and/or platelets, the blood lymphocyte counts were reduced by approximately 40 per cent 12 weeks after treatment. Examination of subsets demonstrated that the proportion of B-cells, as identified by B1 monoclonal antibodies, was decreased by the highest relative extent. On the other hand, lymphocytes expressing the above-mentioned T cell markers were somewhat increased. 32P treatment markedly increased PHA reactivity but it further reduced PWM-induced Ig secretion. The latter observation was in agreement with the finding that serum concentrations of Ig were reduced after treatment.     

Peripheral blood lymphocyte subpopulations in sarcoidosis.

We have determined the numbers of thymus-derived (T) and bone marrow-derived (B) lymphocytes in the peripheral blood of 20 patients with sarcoidosis and 15 healthy controls. T cells were estimated from the number of lymphocytes forming rosettes in vitro with unsensitized sheep red blood cells, and B cells were enumerated by immunofluorescent assesssment of membrane-bound immunoglobulins. The total lymphocyte count was lower in patients with sarcoidosis owing to a depletion of T lymphocytes from the blood. Nonetheless, the relative and absolute numbers of B lymphocytes were significantly increased. These alterations in lymphocyte subpopulations did not show any consistent correlation with the duration of the disease, clinical stage, activity, or treatment. Changes in the subpopulations may be related to both decreased cellular immunity and increased reactivity of the antibody-forming system as commonly seen in sarcoidosis.     

Biologic and molecular characterization of the IgG serum blocking factor (SBF-IgG) isolated from sera of patients with EBV-induced infectious mononucleosis

Our laboratory has previously reported the isolation of a serum blocking factor (SBF) from infectious mononucleosis (IM) patients. The SBF has been purified by a combination of Sephadex QAE-50 ion exchange and Sephadex G-200 molecular sieve chromatography. This material was found to be devoid of soluble immune complexes, and immunochemically and biochemically was characterized as IgG and, hence, termed SBF-IgG. The SBF-IgG was shown to significantly (alpha = 0.05) suppress antigen specific (Influenza A-1[H1N1]) in vitro lymphocyte stimulation (LS) as well as leukocyte migration-inhibition (LMI) reactivity. Also, the SBF-IgG significantly suppressed the in vitro.LS response to phytohemagglutinin. In addition, the SBF-IgG when bound to normal donor lymphocytes significantly reduced the high affinity E-rosette (HAR) reactivity at 29 degrees C. A purified T lymphocyte subpopulation of normal donor lymphocytes specifically bound SBF-IgG, and the latter could be r covered using glycine-HCI. It appears that SBF-IgG is a nonspecific antibody; it binds neither lymphokines nor specific antigen, but apparently elicits its in vitro vitro cell-mediated suppressive effect at the level of the T lymphocytes.     

Induction and disappearance of DNA single-strand breaks in human B and T lymphocytes after exposure to ethylnitrosourea

Using the alkaline filter elution technique we monitored the induction and disappearance of DNA single-strand breaks (SSB) in 3 different human lymphocyte populations: (1) freshly isolated peripheral blood lymphocytes (PBL); (2) B and T cell-enriched lymphocyte fractions; and (3) actively proliferating T cells, after exposure to ethylnitrosourea (ENU). Between these different lymphocyte populations no significant differences were observed in the number of SSB induced by a 20-min treatment with 0.5 mM ENU. SSB disappearance was observed in PBL of some but not all individuals, confirming our earlier results (Boerrigter et al., 1990a). Determinations on B and T cell-enriched lymphocyte populations indicated that ENU-induced SSB were removed only in T lymphocytes; no significant amount of SSB disappearance was observed in B lymphocytes. In contrast, no differences in SSB repair between B and T lymphocytes were found after gamma-irradiation. Induction and disappearance of ENU-induced SSB were found not to be dependent on the proliferative status of T lymphocytes; no differences were observed between quiescent PBL or T lymphocytes and actively proliferating T cells from the same donor, with respect to either the rate or the total amount of ENU-induced SSB disappearance.     

Autologous mixes lymphocyte reaction in human cord blood lymphocytes: decreased generation of helper and cytotoxic T-cell functions and increased proliferative response and induction of suppressor T cells

T lymphocytes from neonates proliferated significantly more than peripheral blood T lymphocytes from adults in autologous mixed lymphocyte reactions (AMLR). AMLR-activated cord, as compared to adult T lymphocytes, exerted significantly less nonspecific cytotoxic activity on PHA-stimulated adult mononuclear cells and Epstein-Barr virus-transformed target cells. The impaired generation of cytotoxicity of cord T cells was not corrected by Interleukin-2. Blood T lymphocytes from adults activated in AMLR synthesized a helper factor that supported PWM-induced proliferation and immunoglobulin production in both adult and cord B lymphocytes. In contrast, cord blood T lymphocytes failed to produce the helper factor for B lymphocytes. T cells from AMLR cultures established with neonatal lymphocytes showed suppressor activity, as assessed in PWM-stimulated immunoglobulin synthesis of adult peripheral-blood mononuclear cells, significantly higher than that exhibited by T cells from AMLR cultures performed with lymphocytes from adults. Finally, neonatal B lymphocytes could be activated to the production of IgM but not IgG by either adult AMLR-derived helper factor plus PWM or by Epstein-Barr virus, whereas adult B cells secreted both IgM and IgG under the same type of stimulation.     

Differential regulation of fibronectin receptor subunit gene and cell surface expression in human peripheral blood T lymphocytes.

Members of the beta 1 subfamily of heterodimeric integrins, such as the fibronectin receptors alpha 5 beta 1 and alpha 4 beta 1, are expressed on human T lymphocytes. The presence of these two adhesion receptors on T lymphocytes suggests an involvement in cell-cell and cell-extracellular matrix interactions that may be important for the development of immune and inflammatory reactions. We have examined the cell surface expression of alpha 5, alpha 4, and beta 1 subunits on purified peripheral blood T lymphocytes before and after activation with Con A and PMA. Freshly isolated T lymphocytes contained distinct fractions expressing high or low levels of alpha 5 and beta 1. Only a high expressing T lymphocyte population was present after 72-h culture with Con A and PMA. Time course analysis indicated that the shift in alpha 5 and beta 1 expression occurred during the first 24 h after addition of activating agents and occurred in the absence of proliferation. In contrast to alpha 5 and beta 1, essentially all freshly isolated T lymphocytes expressed high levels of alpha 4. After 72-h culture with Con A and PMA, a wide distribution of alpha 4 expression was observed. Further experiments showed that after activation, a proportion of CD4-positive cells decreased their surface expression of alpha 4, but increased their surface expression of alpha 5 and beta 1. In contrast, most CD8-positive cells increased their surface expression of alpha 5, beta 1, and alpha 4 upon activation. An examination of mRNA levels in pan-T lymphocyte cultures after activation indicated that alpha 5 and alpha 4 mRNA expression decreased, whereas beta 1 mRNA expression was unchanged, in Con A/PMA-activated cells as compared to those cultured in medium alone. Our results indicate that T lymphocyte activating agents may differentially affect the expression of alpha 5 beta 1 and alpha 4 beta 1, thus providing a mechanism for the selective regulation of binding interactions that occur at sites of immune reactions.     

Alpha-fetoprotein and human lymphocyte subpopulations.

Peripheral blood lymphocytes were incubated with varying concentrations of alpha-fetoprotein and enumerated for total and "active' T lymphocytes, B lymphocytes, and their proliferative responses to phytohemagglutinin. No significant effect was observed on total T or B lymphocyte proportions. However, there was a dose-related increase in proportions of the so called "active" T lymphocytes. The response of human lymphocytes to phytohemagglutinin was markedly depressed. The alteration in the proportion of active T cells and the inhibition of T lymphocyte response to phyto hemagglutinin by alpha-fetoprotein occurred at higher concentrations than are present in amniotic fluid, serum of pregnant women, or serum of adults, but well within the range reached in fetal serum. The immunoregulatory role of alpha-fetoprotein is discussed.     

Selected immunologic parameters and infections in children in over 1 year after completion of the treatment of acute lymphoblastic leukemia

An analysis of infection incidence within one year after completion of the treatment for the acute lymphoblastic leukemia was performed in the group of 24 children. Infections incidence was related to the selected immunological parameters, mainly T4 and T8 lymphocyte subpopulations assayed with monoclonal antibodies. T4/T8 cells ratio (Ix) was determined. It was found that moderate decrease in the total lymphocyte count and Ix exist in children one year after completion of the treatment. This index is more significantly lower in children with more frequent infections while the absolute numbers of T4 and T8 lymphocytes are relatively increased. The obtained results suggest that no significant immunosuppression is observed in children affecting the number and the course of infections.