Increases in soluble CD8 antigen in plasma, and CD8+ and CD8+CD38+ cells in human immunodeficiency virus type-1 infection

Markers of immune activation: novel biomarkers to predict the early-warning indicator of patients with papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) is an indolent tumor that is exploding with increasing thyroid nodules (TN). Environmental carcinogens, lifestyle changes increased the incidence of thyroid carcinoma. With the development of B-ultrasound imaging, more and more thyroid cancer has been found. There has been a debate about whether thyroid cancer is overtreated.

Methods

The expression of T cell subsets and plasma cytokines in 191 patients, including 79 patients with PTC (PTC group), 58 patients with thyroid nodules (TN group) and 54 healthy individuals (HP group) were analyzed by flow cytometry.

Results

High levels of natural killer cells (NK) were detected in PTC and TN groups than in HP group. High activities of CD8⁺HLA-DR⁺ and CD8⁺CD38⁺ showed a gradual upward trend from HP group to PTC group. The rise in the levels of TNF-α in PTC patients’ was evident when compared with HP group. CD8⁺CD38⁺ showed a significant correlation with lymph node metastasis. CD8⁺CD38⁺ co-expression was higher in Nx stage than N₀ stage, while the proportion of IL-10 was dramatically decreased in the Nx stage.

Conclusions

These results indicated that CD8⁺CD38⁺ might act as a biomarker of PTC lymph node metastasis. The combination of CD8⁺HLA-DR⁺, CD8⁺CD38⁺ and TNF-α can be used as useful biomarkers for the early-warning indicator of PTC.

Roles of CD38 in the Immune Response to Infection

CD38 is a multifunctional protein widely expressed in cells from the immune system and as a soluble form in biological fluids. CD38 expression is up-regulated by an array of inflammatory mediators, and it is frequently used as a cell activation marker. Studies in animal models indicate that CD38 functional expression confers protection against infection by several bacterial and parasitic pathogens. In addition, infectious complications are associated with anti-CD38 immunotherapy. Although CD38 displays receptor and enzymatic activities that contribute to the establishment of an effective immune response, recent work raises the possibility that CD38 might also enhance the immunosuppressive potential of regulatory leukocytes. This review integrates the current knowledge on the diversity of functions mediated by CD38 in the host defense to infection.

Biomarkers predicting progression of human immunodeficiency virus-related disease

Biomarkers in predicting the progression of HIV infected individuals to a state of HIV disease (AIDS) are studied over more than a decade. Use of surrogate markers in the past for tracking clinical progression of the disease was limited, as little knowledge existed about the disease. The aim of this review was to address various changes in biomarker related studies taking place over the last five years, especially the trend towards use of newer biomarkers and experimentation with novel molecules in a quest for halting HIV disease progression. An open search of PUBMED database was made with search 'key words' such as 'Biomarkers' and 'AIDS (Acquired Immunodeficiency Syndrome)'.The following were the inclusion criteria for articles: a) all articles published in English language, b) years of publication between 2002-2008 and c) articles limited to adult population. This yielded a total of 417 articles. The criteria used for further judging these studies considered a) type of research design, b) number of biomarkers studied, c) validity of the biomarkers, d) techniques to assess the biomarkers and the impact of the studies in furthering biomarker research, e) sample size for the studies and f) article title or abstracts having the following key words 'biomarker' or 'biomarkers' and 'predict progression to AIDS'. A total of 27 abstracts were reviewed and 12 studies met the above criteria. These 12 different studies consisted of three reviews, four cohort designs, three cross-sectional designs, one each of an observational, and an in-vitro design. The various biomarkers emerging as a results were primarily a mix of viral, neural, immunological, HLA (human leukocyte antigen) markers along with lymphocyte counts. Although there have been quite a few advancements in biomarker-related studies, majority of the novel biomarkers discovered need to be further evaluated and replicated in bigger, long-term efficacy trials. Efforts should also be made to discover newer genetic markers of disease progression. Biomarker feedback, a new concept, can be utilized in future studies addressing prevention of HIV infection or halting disease progression.

Evolution and function of the ADP ribosyl cyclase/CD38 gene family in physiology and pathology

The membrane proteins CD38 and CD157 belong to an evolutionarily conserved family of enzymes that play crucial roles in human physiology. Expressed in distinct patterns in most tissues, CD38 (and CD157) cleaves NAD(+) and NADP(+), generating cyclic ADP ribose (cADPR), NAADP, and ADPR. These reaction products are essential for the regulation of intracellular Ca(2+), the most ancient and universal cell signaling system. The entire family of enzymes controls complex processes, including egg fertilization, cell activation and proliferation, muscle contraction, hormone secretion, and immune responses. Over the course of evolution, the molecules have developed the ability to interact laterally and frontally with other surface proteins and have acquired receptor-like features. As detailed in this review, the loss of CD38 function is associated with impaired immune responses, metabolic disturbances, and behavioral modifications in mice. CD38 is a powerful disease marker for human leukemias and myelomas, is directly involved in the pathogenesis and outcome of human immunodeficiency virus infection and chronic lymphocytic leukemia, and controls insulin release and the development of diabetes. Here, the data concerning diseases are examined in view of potential clinical applications in diagnosis, prognosis, and therapy. The concluding remarks try to frame all of the currently available information within a unified working model that takes into account both the enzymatic and receptorial functions of the molecules.

Parallel decline of CD8+/CD38++ T cells and viraemia in response to quadruple highly active antiretroviral therapy in primary HIV infection

OBJECTIVES

To monitor changes in the numbers of CD8 lymphocytes expressing the activated CD38++ phenotype in peripheral blood samples from patients with primary HIV infection (PHI) treated with highly active antiretroviral therapy (HAART).

METHODS

Zidovudine, lamivudine, abacavir and amprenavir were initiated during PHI as part of the Quest study. Absolute numbers of CD8+/CD38++ T cells were determined using three-colour flow cytometry, and plasma viral load (VL) was measured using the Roche Amplicor method.

RESULTS

The median, pre-therapy CD8+/CD38++ T cell count was 461/mm(3)(interquartile range 216, 974) in 131 patients compared with normal control values of less than 20 cells/mm(3). Levels fell markedly in parallel with VL within the first 2 weeks of HAART initiation, to a median of 47 cells/mm(3) at 28 weeks (median 436 cell decline; P < 0.001). At that time, 80% of patients had a VL less than 50 copies/ml, and 16.3% of all patients had less than 20 CD8+/CD38++ T cells/mm(3). A continued decrease in CD8+/CD38++ T cell count occurred in 67.2% of patients whose VL was maintained below 50 copies/ml (median change from first to last value -18 cells/mm(3); P < 0.001).

CONCLUSION

After the initiation of HAART in PHI, CD8+/CD38++ lymphocytes declined rapidly in parallel with VL, and allowed for a normalization of CD8+/CD38++ T cell numbers in a subset of patients at week 28. Cell numbers continued to decline in patients who maintained VL below 50 copies/ml, indicating that the CD8+/CD38++ T cell count may represent a marker of residual viral replication when VL falls below detectable levels after HAART intervention.

Resting CD4(+) T cells with CD38(+)CD62L(+) produce interleukin-4 which contributes to enhanced replication of T-tropic human immunodeficiency virus type 1

A significant increase in the CD38(+) population among T lymphocytes has been observed in human immunodeficiency virus type 1 (HIV-1)-infected carriers. We previously reported a higher replication rate of T-tropic HIV-1 in the CD4(+)CD38(+)CD62L(+) than CD38(-) subset under conditions of mitogen stimulation after infection. Here, we revealed a similarly high susceptibility in the CD38(+) subset on culture with conditioned medium containing Th2 cytokine, interleukin (IL)-4 that was produced endogenously from this subset on stimulation with mitogen or anti-CD3 antibody for 3 days. The contribution of IL-4 to the upregulated production of virus in the CD38(+) subset was confirmed by culture of this subset with recombinant human IL-4. In contrast, the rate of replication in the CD38(-) subset was not augmented in the conditioned medium from either subset or with IL-4. However, there were no differences in the surface expression of IL-4 receptor or HIV-1 receptors CD4 and CXCR4 between the two subsets. Thus, the CD4(+)CD38(+)CD62L(+) subset comprises a specific cell population secreting endogenous Th2 cytokine that contributes to the efficient production of T-tropic HIV-1 through upregulation at a certain stage of the viral life cycle, probably after the adsorption step.

Positive and negative aspects of the human immunodeficiency virus protease: development of inhibitors versus its role in AIDS pathogenesis

In this review we summarize multiple aspects of the human immunodeficiency virus (HIV) protease from both structural and functional viewpoints. After an introductory overview, we provide an up-to-date status report on protease inhibitors (PI). This proceeds from a discussion of PI structural design, to how PI are optimally utilized in highly active antiretroviral triple therapy (one PI along with two reverse transcriptase inhibitors), the emergence of PI resistance, and the natural role of secretory leukocyte PI. Then we switch to another focus: the interaction of HIV protease with other genes in acute and persistent infection, which in turn may have an effect on AIDS pathogenesis. We conclude with a discussion on future directions in HIV treatment, involving multiple-target anti-HIV therapy, vaccine development, and novel reactivation-inhibitory reagents.

Pregnancy, HLA allogeneic challenge, and implications for AIDS etiology

Because of the large HLA genetic polymorphism, a human fetus usually has several paternal HLA antigens allogeneic to its mother. The maternal gamma-immunoglobulin (IgG) antibody response to fetal HLA alloantigens is noncytotoxic and associated with local suppression of maternal cell-mediated immunity (CMI) at the maternal-fetal interface. When mother and fetus are syngeneic for most HLA antigens, an increased risk exists for a maternal anti-placental cytotoxic CMI responses, compromising fetal survival. Local suppression of maternal CMI by an anti-HLA IgG response may have evolved to protect the fetoplacental unit from a maternal CMI cytotoxic reaction against expressed developmental neoantigens. A negative aspect of this adaptive response is that infectious organisms bearing HLA-homologous alloantigens (e.g. human immunodeficiency virus type 1, HIV-1) may generate a systemic IgG response suppressing CMI. Findings are reviewed suggesting this is an etiologic factor in the acquired immune deficiency syndrome (AIDS).

Changes in immune activation markers during pregnancy and postpartum

Changes in CD4 + cell levels and other immune parameters have been reported to occur during pregnancy but the timing of these alterations and their relationship to changes in immune function have not been well characterized. In addition, the influence of sociodemographic, obstetric, and other covariates on these relationships is largely unknown. We measured three immune activation markers, soluble interleukin-2 receptor (sIL-2Ralpha), soluble CD8 antigen (sCD8), and neopterin during pregnancy and postpartum in 170 HIV-1-seronegative women enrolled in the Mothers and Infants Cohort Study. Ante-partum and postpartum changes in these markers were examined using multivariable longitudinal random effects models. Neopterin levels began to rise well before delivery and were in decline by 2 months postpartum. sIL-2Ralpha and sCD8 levels increased at or near delivery and peaked by 2 months postpartum. After adjustment for other variables, the peak in sIL-2Ralpha was greater among women with pre-term than full-term deliveries (P = 0.05). All three markers were higher in whites than non-whites and in 'hard' drug users than non-users (P < or = 0.001 for each). After adjustment for these and other variables, hepatitis C virus (HCV) seropositivity was associated with higher levels of sCD8 and neopterin (P < or = 0.001 for each) but not sIL-2Ralpha (P = 0.27). These longitudinal data indicate that a state of broad immune activation develops at or near delivery. A number of maternal variables appear to influence the magnitude of these changes.

The prognostic significance in HIV infection of immune activation represented by cell surface antigen and plasma activation marker changes

One hundred and eighteen HIV-infected homosexual men without AIDS and 40 control seronegative homosexual men were assessed for 23 parameters reflecting immune activation to determine prognostic significance for occurrence of AIDS. Samples cryopreserved in 1987-1989 were analyzed, with AIDS occurrence determined by mid-1992. Cell surface antigens assessed on the major lymphocyte subsets were HLA-DR, CD38, CD71, and CD25. Soluble serum molecules assessed were tumor necrosis factor alpha, soluble TNFalpha receptor II, soluble IL-2 receptor alpha, neopterin, and beta2-microglobulin. Using a proportional hazards model, prognostic markers included decreased CD4 number and percentage; increased sIL-2R, neopterin, and beta2M; increased percentage HLA-DR+ total lymphocytes and CD4+ cells; increased CD38+ total lymphocytes and CD8+ cells; increased CD71+ total lymphocytes and CD4+ cells; and decreased CD25+ total lymphocytes and CD19+ cells. After adjustment for CD4 cell levels, sIL-2R, neopterin, beta2M, and CD25+ CD19 cells remained significant, indicating that additional information about AIDS risk was provided by these markers.

Highly active antiretroviral therapy results in a decrease in CD8+ T cell activation and preferential reconstitution of the peripheral CD4+ T cell population with memory rather than naive cells

OBJECTIVE

Highly active antiretroviral therapy (HAART) can produce marked increases in peripheral blood CD4+ T cells and decreases in HIV plasma RNA copy numbers. However, it is not clear whether these absolute changes will be accompanied by a recovery in the known naive CD4+ T cell depletion or a decrease in the marked CD8+ T cell activation.

DESIGN

Twenty-nine patients were enrolled in studies of either nucleoside therapy alone or nucleoside therapy combined with a protease inhibitor (zidovudine + lamivudine + indinavir). One hundred and ninety-one examinations were carried out at three baseline time points and during 40 weeks of follow-up to evaluate the effect of HAART on CD4+ memory/naive phenotype and CD8+ T cell activation.

METHODS

CD4+ and CD8+ T cell number, CD62L/CD45RA expression on CD4+ T cells and CD38 expression on CD8+ T cells were measured by three-color flow cytometry.

RESULTS

Most protease inhibitor treated patients had a significant rise in CD4+ numbers. The marked rise in the CD4+ T cells seen in individuals in this study was not accompanied over a 40-week period by a change in the abnormally low CD4+ naive compartment, and thus was almost completely of memory phenotype. The CD38 expression on CD8+ cells fell during treatment, and decreased to a greater degree than the comparable rise in CD4+ T cell counts. This decrease continued in many patients after the CD4+ T cell rise or viral load decline had plateaued.

CONCLUSION

HAART results in changes in activation to a greater extent than absolute changes in CD4+ T cell numbers, but is not accompanied by an increase in naive CD4+ T cells. Measurements of CD4+ T cell numbers alone may not allow appropriate interpretation of immune activation or immune competence in patients receiving those drugs.

Azacytidine plus verapamil induces the differentiation of a newly characterized biphenotypic human myeloid-B lymphoid leukemic cell line BW-90

The biphenotypic cell line BW-90 was established from the peripheral blood of a a patient with a refractory acute myelomonocytic leukemia. All cells were HLADr+, CD34-. Dual color flow cytometry showed simultaneous expression of myeloid (CD33) and B-lymphoid surface markers (CD19) on 60% of cells, CD54 on 91% of cells. Lymphoid lineage markers included CD20/CD22 coexpressed on 89% of cells, CD71 (70%), CD11a (48%), CD18 (54%), and surface lambda light chain (33%). Exposure to various cytokines individually and in combination for up to 14 days had no effect on cell proliferation or differentiation. Only long-term (10-14 days) exposure to 5637 cell-conditioned medium (CCM) induced growth inhibition and differentiation along the monocytic pathway. Differentiation-inducing agents retinoic acid (RA), dimethyl sulfoxide (DMSO) and phorbol 12-myristate 13-acetate (PMA) did not induce differentiation. Differentiation into the monocytic pathway was induced by 5-azacytidine (5AzaC) alone or in combination with verapamil (VP). The BW-90 cell line may serve as a model to study early steps of leukemogenesis and early hematopoiesis. It may provide insight leading to development of an effective therapy for treatment-resistant biphenotypic leukemias.

HIV infection and aging: mechanisms to explain the accelerated rate of progression in the older patient

Age is an important predictor of progression in HIV infections. Not only do older individuals' develop AIDS more rapidly than younger persons, they die more quickly after developing an AIDS-defining illness. While the elderly have higher morbidity and mortality rates from viral and bacterial infections, the mechanism(s) responsible for the more rapid progression of HIV infection in older individuals has not been described. Our results demonstrate that the destruction of T cells in both young and old HIV infected patients progresses at the same rate. HIV 1-infected cells from older individuals do not appear more susceptible to immune mediated destruction. The more rapid progression appears due to an inability of older persons to replace functional T cells that are being destroyed. These findings suggest that improved survival in older HIV infected individuals will require more aggressive antiretroviral therapies as well as continued research to identify and preserve immune system elements that control the virus.

Concentrations of soluble CD95 and CD8 antigens in the plasma and levels of CD8+CD95+, CD8+CD38+, and CD4+CD95+ T cells are markers for HIV-1 infection and clinical status

Apoptosis mediated via the CD95 (FAS/APO-1) receptor is thought to play a role in the depletion of CD4+ T cells in HIV infection. In the present study expression of the CD95 antigen on lymphocyte subsets and the plasma level of soluble CD95 (sCD95) were determined in HIV-1-infected adults. The expression of CD95 was increased on CD8 cells in all groups of HIV+ individuals, while increased expression of CD95+ cells on CD4 cells was limited to individuals with CD4 counts of < 200 mm3. The proportion of CD4+ that expressed CD95 was inversely correlated with the percentage of CD4+ PBL. The concentration of sCD95 was significantly higher in the plasma of HIV-infected individuals than in normal controls. The level of sCD95 in HIV-infected subjects showed no correlation with the percentage of PBL expressing CD95, indicating that the increased level of sCD95 did not reflect release from CD95+ PBL. The plasma sCD95 concentration was significantly correlated with the percentage of CD8+ cells and, particularly, with CD8+ CD38- cells. A striking inverse correlation was found between the sCD95 plasma concentration and the proportion of CD4+ CD95+ cells out of the total CD4+ population. There was no correlation between the serum level of sCD95 and that of soluble CD8 (sCD8), both of which were increased in the plasma of HIV+ individuals. Unlike the level of sCD95, the level of sCD8 in the plasma of HIV+ individuals. Unlike the level of sCD95, the level of sCD8 in the plasma of HIV+ individuals was correlated with the percentage of CD95+ and CD8+ CD38+ cells. The present study indicates that plasma sCD95 may be one of the factors that regulate apoptotic death of lymphocytes in HIV infection.

The expression of CD8 on B lymphocytes in HIV-infected individuals

In HIV-1 infected individuals the CD8 + T lymphocyte population is markedly activated as reflected by increased expression of the CD38 and CD45RO activation markers and elevated serum levels of soluble CD8 antigen. We have previously shown that in vitro activation of peripheral blood lymphocytes results in the appearance of T cell markers on B cells. In the present study B lymphocytes from HIV-1-infected individuals were tested for the expression of the CD8 T cell antigen, using F(ab')2 fragments of antibodies against the CD8 and CD19 antigens. The proportion of CD19 + B cells which co-expressed CD8 was significantly elevated among 55 HIV-infected individuals (7.20 +/- 1.24%, mean +/- S.E.) as compared with among 22 normal controls (3.32 +/- 0.70%). The proportion of CD4 + cells decreased significantly in HIV-infected individuals in accordance with the progression of the infection, but no significant change in the level of CD8 + CD19 + B cells was seen in different stages of the disease. In contrast, the proportion of CD8 + B cells showed a significant correlation with the proportion of CD8 + cells.

Activation of tumor necrosis factor--alpha system in HIV-1 infection: association with markers of immune activation

The relationships between serum levels of soluble tumor necrosis factor receptors (sTNFRs) and other prognostic and immunological parameters in different immunological subgroups of 64 HIV-1 infected patients were studied. In the patient group as a whole, the raised serum levels of sTNFRs were significantly inversely correlated to the numbers of CD4+ and CD8+ lymphocytes and significantly positively correlated with serum levels of neopterin, HIV-1 p24 antigen and the soluble CD8/CD8+ lymphocyte ratio. However, when the patients were classified into three separate immunological subgroups according to the numbers of CD4+ lymphocytes, only serum levels of neopterin were significantly correlated to levels of sTNFRs in all the defined immunological subgroups. These results indicate that HIV-1 infection is associated with a persistent and chronic immune activation in the TNF system manifested by raised serum levels of sTNFRs, which may reflect sustained activation of the immune system particularly in monocytes/macrophages. Further, these results confirm that, when comparing immunological and virological parameters in HIV-1 infection, different results may be obtained in different immunological subgroups of patients.

Markers predicting progression of human immunodeficiency virus-related disease

Human immunodeficiency virus (HIV) interacts with the immune system throughout the course of infection. For most of the disease process, HIV activates the immune system, and the degree of activation can be assessed by measuring serum levels of molecules such as beta 2-microglobulin and neopterin, as well as other serum and cell surface phenotype markers. The levels of some of these markers correlate with clinical progression of HIV disease, and these markers may be useful as surrogate markers for development of clinical AIDS. Because the likelihood and timing of development of clinical AIDS following seroconversion, for any particular individual, are not readily predictable, the use of nonclinical disease markers has become critically important to patient management. Surrogate markers of HIV infection are, by definition, measurable traits that correlate with disease progression. An ideal marker should identify patients at highest risk of disease progression, provide information on how long an individual has been infected, help in staging HIV disease, predict development of opportunistic infections associated with AIDS, monitor the therapeutic efficacy of immunomodulating or antiviral treatments, and the easily quantifiable, reliable, clinically available, and affordable. This review examines the current state of knowledge and the role of surrogate markers in the natural history and treatment of HIV infection. The clinical usefulness of each marker is assessed with respect to the criteria outlined for the ideal surrogate marker for HIV disease progression.

Serum soluble CD8 concentration is an indicator of disease activity in patients with Graves' disease

Cell-mediated immunity is important in the pathogenesis of Graves' disease. Activation of T cells is apparently associated with the release of soluble CD8 (sCD8) and CD4 (sCD4) molecules from the corresponding T cell subset. To test the possibility that the concentrations of these molecules may be related to Graves' disease activity, we measured serum sCD8 and sCD4 concentration in 58 Graves' patients using ELISA technique before and after treatment with methimazole as well as in 10 patients with toxic nodular goiter. sCD8 was significantly elevated in thyrotoxic patients [609.9 +/- 118 (SD) U/ml] compared to controls (264.1 +/- 98.8, p < 0.001) and normalized when patients became euthyroid as a result of methimazole treatment (278.7 +/- 89.1). The mean sCD8 concentration in the patients with toxic nodular goiter was 302 +/- 28 U/ml, no different from control. The sCD4 level in the Graves' disease group was not different from control values and did not change significantly with treatment. Correlations were found between the levels of serum thyroid hormone(s) and sCD8 concentration but not with anti-TSH receptor antibodies in the 50 patients with Graves' disease. In addition, serum sCD8 studied prospectively in eight patients after discontinuation of methimazole, increased before the rise in serum T4, and well before the clinical relapse of thyrotoxicosis. It is concluded that sCD8 is a useful marker for the activation of CD8+ cells in Graves' disease.

Soluble tumour necrosis factor receptors (sTNF-R) and HIV infection: correlation to CD8+ lymphocytes

The objective of this study was to determine sTNF-R, type I (p55) and type II (p75) in sera of HIV-infected male homosexuals and correlate them to T lymphocyte subpopulations and course of HIV infection. Serum samples were obtained from 39 HIV-1+ asymptomatic male homosexuals, 10 symptomatic (ARC and AIDS) male homosexuals and 44 HIV- non-homosexual healthy controls. sTNF-R levels were determined by ELISA with specific MoAbs and polyclonal antibodies to the sTNF-R proteins. sTNF-RI and II levels were significantly elevated in 72% and 74% respectively of HIV+ asymptomatic male homosexuals and in all of the symptomatic male homosexuals. In sequential studies a highly significant positive correlation was found between sTNF-RI and sTNF-RII (r = 0.8, P < 0.001) and between both sTNF-R and CD8+ lymphocyte counts (r = 0.6 and 0.92, respectively, P < 0.01-0.001) during the asymptomatic stage of the infection. All these correlations were lost, however, during the symptomatic phase of the disease. These results suggest that: (i) HIV infection is associated with elevation of sTNF-R serum levels; (ii) sTNF-R levels are strongly correlated to CD8+ lymphocytes during the asymptomatic stage of HIV infection.

Immunobiological aspects of HIV treatment

Recent information on the efficacy of anti-retroviral therapy and vaccination strategies has been disappointing as well as confusing. The recently announced Concorde study suggested that there is no advantage to early treatment of asymptomatic HIV infection with azidothymidine alone, even though the levels of CD4+ cells in the treated group were consistently higher than in the untreated group. This will lead to increasing attention being paid to the mechanisms whereby HIV causes AIDS, which have sadly been sidelined in the rush to produce classically based therapies and vaccines. Over the last year many different theories on how HIV kills CD4+ cells and leads to AIDS have been discussed and tentatively explored.

Prognostic significance of cytotoxic T cells in individuals infected with human immunodeficiency virus

Nine dual-fluorescence combinations were used to enumerate T-cell subsets in 112 human immunodeficiency virus type 1-infected patients. Two blood samples were analyzed, with a 6-month interval between the tests, in 53 of these 112 patients. The alteration in CD4 over this period of time correlated with the change in CD8 and CD8S6F1 (P < 0.02 and P < 0.01), irrespective of the disease stage. Two groups of patients were defined by the CD8S6F1 subset at the first normal levels. Changes in numbers of CD4, CD4CD45RA, and CD4CD29 were significantly higher in group B than in group A patients. The absolute count of CD8S6F1 could thus serve as an indicator of the ensuing depletion of the CD4 population, as well as the CD4 subsets.

Elevated levels of soluble CD54 (ICAM-1) in human immunodeficiency virus infection

Soluble CD54 levels in sera were quantitated in asymptomatic intravenous drug users, homosexuals, and patients with lymphadenopathy, AIDS-related complex, or acquired immunodeficiency syndrome. Soluble CD54 levels were elevated in human immunodeficiency virus (HIV)-seronegative asymptomatic intravenous drug users, reflecting infections like cytomegalovirus, Epstein-Barr virus, and hepatitis B virus. The sera of human immunodeficiency virus-seropositive groups of patients also had elevated levels of soluble CD54, reflecting infections like cytomegalovirus and human immunodeficiency virus infection.