Fine T-Cell Subsets in Alcoholics as Determined by the Expression of l-Selectin, Leukocyte Common Antigen, and β-Integrin

Alcoholics admitted to the hospital solely for detoxication have been studied by flow cytometry to evaluate changes in the surface markers of peripheral blood leukocytes. As we have shown previously, such patients have an elevated percentage of CD8^hl lymphocytes that are HLA DR⁺; we now demonstrate that they also have striking alterations in the quantitative relationships of the fine T-cell subsets. Both CD4⁺ and CD8^hl lymphocytes have a sharply reduced percentage of the l -selectin⁺ CD45RA⁺ subset, increased percentages of the CD45RA-subsets, and several other fine subset alterations. The fine subset profile suggests, according to current correlations of phenotype and function, that both CD4⁺ suppressor inducer and CD4-dependent CD8⁺ suppressor effector cells are reduced, whereas other subsets, including CD8⁺ CTL or their precursors, are increased in relative percentages. Some of the phenotypic changes are reversible over the several days following withdrawal. In other results, the percentage of CD8^hl lymphocytes expressing CD11b (β-integrin) is shown to be reciprocal with the percentage expressing l -selectin both in normals and alcoholics. However, the regression function of CD11b vs. l -selectin on CD8^hl cells is different for the alcoholics than for the normals, indicating an abnormality in the regulation of the expression of these two adhesion markers. Taken together, this abnormality of adhesion molecules and the fine subset alterations previously described indicate widespread changes in the peripheral lymphocytes of currently drinking alcoholics. These changes suggest functional deficiencies that may include alterations of lymphocyte traffic and other adhesion-dependent functions, and a shift in the balance of regulatory interactions.     

T-cell activation and subset patterns are altered in B-CLL and correlate with the stage of the disease

Two-color FACS analysis was used to study activated and "functional" T and natural killer (NK) cell subsets of circulating lymphocytes in 23 patients with B-type chronic lymphocytic leukemia (B-CLL) and in 30 healthy subjects. As compared with controls, B-CLL patients had increased absolute numbers of phenotypically activated, HLA-DR+ CD4+ and CD8+ cells and T suppressor/effector (CD11b+CD8+) cells. When patients in Rai stages II through IV (n = 11) were compared with cases in Rai stages O through I (n = 12), the former group of patients had higher numbers of activated CD4+ and CD8+ T cells and decreased levels of suppressor/effector T cells. The absolute numbers of T suppressor/inducer (CD45R+CD4+) cells were elevated in patients with stage O through I disease but within normal range in stage II through IV leukemia. We further showed that the absolute numbers of NK-like (CD16+) cells and their activated counterparts (DR+CD16+) are elevated in B-CLL patients as compared with healthy subjects. The comparison of relative T and NK subsets in the blood of patients and controls showed that the proportions of CD4+, CD8+, and CD16+ cells expressing the activation marker HLA-DR were increased in B-CLL. Furthermore, the percentage of T-suppressor/inducer (CD45R+) cells within the CD4+ population was decreased in the patients. The proportion of T- suppressor/effector (CD11b+) cells within the CD8+ subset was reduced in subjects with stage II-IV disease only. When stimulated in vitro with the T-cell-dependent inducer TPA, B-CLL cells from patients in Rai stages II through IV secreted larger amounts of IgM as compared with cells from stage O through I patients. A positive correlation was observed between the degree of phenotypic activation of CD4+ T-helper cells and their functional capacity to augment IgM secretion by autologous B-CLL cells. Our findings indicate a tumor cell-directed regulatory role of T cells (and possibly NK cells as well) in B-CLL. Furthermore, monitoring of phenotypically activated and functional T- cell subsets may be helpful in the prediction of disease progression and timing of therapy in B-CLL.     

Blood B,T, CD4+ and CD8+ lymphocytes in female Wistar rats

Summary We have established reference values of peripheral blood lymphocyte subsets in healthy female Wistar rats under highly standardized conditions. Using monoclonal antibodies and flow cytometry, T lymphocytes (OX19⁺), B lymphocytes (OX6⁺ and antiIg⁺), T-helper/inducer (W3/25⁺), and T-suppressor/cytotoxic subsets (OX8⁺) were determined, from week 11 to week 21 after birth. The mean percentages of T and B lymphocytes with respect to total lymphocytes were 78.5% and 18%, respectively; the mean percentages of T-helper/inducer and T-suppressor/cytotoxic cells in relation to T lymphocytes were 59% and 25%, respectively (n=48). No difference in total leukocyte count, differential leukocyte analysis, or lymphocyte subsets was observed during the 10 weeks the rats were studied under standard housing conditions. Therefore, the period considered seems the most appropriate in which to carry out experiments that could involve lymphocyte subset disturbances.     

Lymphocyte Subsets in Peripheral Blood and Smoking Habits

The investigation of peripheral blood lymphocyte (PBL) subpopulations is of interest in a wide variety of inflammatory diseases. Since the number of circulating lymphocytes has been shown to be affected by smoking habits, it seems useful to know how PBL subpopulations are influenced. We therefore determined percentages and absolute numbers of a wide range of PBL subpopulations in smokers (n= 14) and nonsmokers (n= 14). PBLs were obtained from healthy volunteers and analyzed by flow cytometry using antibodies for the detection of CD3, CD4, CD8, CD19, CD56, CD57, CD45RO, CD45RA, α/β and γ/δ T cell receptor epitopes. With the exception of CD3⁺ cells, no differences between smokers and nonsmokers were found regarding percentages of PBL subpopulations. Smokers were found to have higher absolute numbers of PBLs in the following subpopulations compared with nonsmokers: CD3⁺, CD4⁺, CD3⁺α/β⁺, CD45RO⁺/CD4⁺, and CD45RA⁺/CD4⁺. Cytotoxic lymphocytes, natural killer cells, and B cells did not differ in number between smokers and nonsmokers. There was likewise no difference in the number of the CD8⁺α/β⁺ and all cells bearing the γ/δ T cell receptor. Smoking increased the number of T cells and mainly CD4⁺ PBLs. The smoking habits of healthy control groups should therefore be taken into account when comparing lymphocyte subpopulations in different diseases. Accepted for publication: 13 February 1997     

Phenotypic characterization of isolated intraepithelial lymphocytes in patients with ulcerative colitis and normal controls

A method was developed to isolate colonic intraepithelial lymphocytes in patients with ulcerative colitis (N=8) and normal controls (N=13) in order to characterize their phenotype using a panel of monoclonal antibodies and flow cytometry. In both groups, the majority of the cells are of the CD3⁺CD8⁺ phenotype associated with cytotoxic/suppressor function. The CD4/CD8 ratios were similar. Virtually no B cells or macrophages were found. An increase in cells coexpressing the CD3 and HLA-DR molecules and a decrease in natural killer cells (CD3, CD16⁺CD56⁺) were found in ulcerative colitis, but this was not significant. There were no differences in the proportions of CD8⁺ and CD4⁺ cells expressing the Leu8 antigen between ulcerative colitis and controls. Thus a population of colonic intraepithelial lymphocytes has been isolated and, although they may be functionally different in ulcerative colitis compared with controls, this cannot be explained in terms of phenotypic characteristics.     

Interleukin 4 responses in acute leukaemia patients with severe chemotherapy-induced leucopenia

Abstract: T lymphocyte functions in acute leukaemia patients with severe chemotherapy-induced leucopenia were investigated using 3 different approaches: (i) analysis of serum concentrations of the T cell cytokine interleukin 4 (IL4) demonstrated that serum IL4 levels increased during complicating bacterial infections. However, this response was modulated by a concomitant increase in serum levels of the potential IL4 antagonist soluble IL4 receptor α chain (sIL4Rα). (ii) Even during leucopenia a subset of T lymphocytes derived from leucopenic patients expressed the activation markers CD25 (IL2 receptor), CD71 (transferrin receptor) and HLA-DR. (iii) Subsets of circulating CD4⁺ and CD8⁺ T lymphocytes could undergo clonogenic proliferation in vitro, and a majority of these clones secreted IL4. CD4⁺ clones showed higher IL4 levels than CD8⁺ clones. Our results indicate that T lymphocytes can be activated and contribute to cytokine responses in acute leukaemia patients with severe chemotherapy-induced cytopenia.     

Activated CD4+ and CD8+ T-cell subsets in Wegener's granulomatosis

Several lines of evidence argue in favour of an involvement of T cells in the pathogenesis of Wegener's granulomatosis (WG). These include the presence of highly specific IgG autoantibodies to proteinase 3, perivascular T-cell infiltrates and elevated amounts of soluble interleukin-2 (IL-2) receptors in patient's serum. In order to further address this question we evaluated by double immunoflourescence and flow cytometry the expression of several cell surface molecules associated with T-cell activation. As compared to healthy controls (n=15), the CD4⁺ subset was significantly diminished, while the percentage of CD8⁺ T cells was elevated in WG patients (n=24). Within the CD4⁺ T-cell subset we found a highly significant increase in activation/memory markers (CD25, CD29, HLA-DR). Within the CD8⁺ T-cell subset the expression of CD11b, CD29 and CD57 was significantly elevated, while the expression of VD28 was reduced. The use of 10 V-, 1 V-and 1 V-specific monoclonal reagents failed to reveal any significant bias in the peripheral T-cell receptor V-gene repertoire of WG patients. There was also no correlation between T-cell activation markers and laboratory parameters [C-reactive protein (CRP), ESR], disease duration or therapy. A significant correlation was found only for the degree of organ involvement and the increase in CD4⁺ T cells coexpressing HLA-DR, as well as the increase in CD57 expression on CD8⁺ T cells. In conclusion, both CD4⁺ and CD8⁺ T-cell subsets were activated in WG. Cytotoxic CD8⁺ CD57⁺ CD11b⁺ CD28^– T cells may directly contribute to damage of vascular endothelium.     

The effects of extracorporeal photochemotherapy on T cell activation and regulatory mechanisms in patients with systemic sclerosis

In the study, we investigated the influence of extracorporeal photochemotherapy (ECP) on lymphocyte activation and cell death by determining CD95, Annexin V, CD69 and human leukocyte antigen (HLA)-DR expression on circulating T and B cells in systemic sclerosis (SSc) patients and assessed their changes after ECP therapies. Moreover, we evaluated the relationship between lymphocyte activation and the observed changes in immunoregulatory functions following ECP treatments. We enrolled 19 SSc patients, who received 12 ECP treatments in total. Blood samples were taken prior to the first therapy and 6?weeks after each cycle. Samples were also obtained from 16 healthy controls. Lymphocyte subgroups were quantified by flow cytometry. Initially, patients had higher numbers and percentages of peripheral CD95⁺ T cells, but not CD95⁺ B cells, compared to control values. After ECP treatments, values of CD95⁺ T cells decreased and became similar to controls. Annexin V expression on T and B cells did not change during the therapy. We observed a significant negative correlation between the changes in percentages of peripheral CD95⁺ T cells and CD4⁺CD25⁺ Treg cells. Although neither early-activated (CD69⁺) nor late-activated (HLA-DR+) T lymphocytes showed significant changes after ECP, clear negative correlations developed between them and the functional ability of CD4⁺CD25⁺ Treg cells after the last treatment. Our results indicate that the initial increase of CD95⁺ expression in SSc presumably reflects a physiological response to the pronounced autoimmune processes, which can be effectively attenuated by the restoration of regulative T cell numbers and functions as the result of ECP therapy.     

Increase in activated T cells and reduction in suppressor inducer T cells in systemic sclerosis.

Blood lymphocytes from 37 patients with systemic sclerosis were characterised using monoclonal antibodies in a two colour flow cytometric (fluorescence activated cell sorter (FACS)) analysis. The ratio of helper CD4+ to suppressor/cytotoxic CD8+ T cells was raised in patients compared with that in 30 healthy controls owing to decreased CD8+ cells. In the patients CD4+ and CD8+ cells displayed an increased expression of the activation marker HLA-DR. The relative number of CD11b+ CD8+ lymphocytes (suppressor T cells) was normal, but the calculated absolute counts of this cell type were slightly reduced. The proportions and absolute numbers of suppressor inducer T cells, defined as CD45R+ CD4+ cells, were on average only half the levels observed in controls. These findings were not related to the inflammatory activity as measured by acute phase plasma proteins or serum immunoglobulins. Activated T cells were seen at all stages of the sclerotic process and especially during the early stages of the disease and in patients who had suffered occupational exposure to silica dust. A high proportion of activated T cells was also linked with impaired small intestine function but not with the degree of skin or lung involvement. A loss of suppressor inducer T cells was more pronounced later in the disease and in patients with the CREST (calcinosis, Raynaud's phenomenon, oesophageal dysmotility, sclerodactyly, telangiectasia) syndrome. These data provide further evidence for an involvement of T cell mediated immunity in the perpetuation of systemic sclerosis.     

Immune reconstitution and cytomegalovirus infection after allogeneic stem cell transplantation: the important impact of in vivo T cell depletion

We analyzed cytomegalovirus (CMV) infection risk factors and immune reconstitution kinetics in 89 patients after allogeneic stem cell transplantation (allo-SCT). The use of alemtuzumab for in vivo T cell depletion (TCD) had, besides the donor/recipient CMV serostatus, the strongest influence on the CMV infection risk in univariate and multivariate analyses. In comparison to without use of in vivo TCD, the CMV infection risk [hazard ratio (HR)] was 4.82-fold after TCD with alemtuzumab, but only 1.40-fold after TCD with antithymocyte globulin (ATG). Alemtuzumab strongly depressed CD4⁺ and CD8⁺ T cell reconstitution, whereas ATG only delayed CD4⁺ T cell reconstitution. Considering the reconstitution kinetics of CD4⁺ and CD8⁺ T cells, CMV-specific CD8⁺ T cells, NK cells and the IgG concentration, only a low day +60 NK cell count (≤161 versus >161/μl) was significantly associated with CMV infection development (HR 2.92, p = 0.034). CMV-specific CD8⁺ T cells were detected in 57% of patients with a CMV-seropositive donor, but in none of the patients with a CMV-seronegative donor on day +30 (p = 0.01). Our data indicate that the type of in vivo TCD (alemtuzumab or ATG) differentially influences both the CMV infection risk and CD4⁺/CD8⁺ T cell reconstitution kinetics in patients after allo-SCT.     

Expansion of CD8+CD57+ T cells after allogeneic BMT is related with a low incidence of relapse and with cytomegalovirus infection

Summary. Peripheral blood lymphocytes of 46 recipients of lymphocyte-depleted bone marrow allografts were pheno-typically analysed over a period of 1 year. We investigated the repopulation of lymphocyte subpopulations and their relation with clinical parameters such as graft-versus-host disease (GVHD), graft-versus-leukaemia and cytomegalovirus (CMV) infection. The number of repopulated T cells varied strongly between the blood samples of the recipients. In 45% of the recipients the number of T cells recovered to or above normal levels within 3 months after bone marrow transplantation (BMT), whereas the other recipients remained below normal up to 1 year after BMT. In recipients with a high repopulation, the CD8⁺ T-cell subset contributed more to this high repopulation than the CD4⁺ T-cell subset. We showed that the majority of T cells of these recipients expressed the a/3 T-cell receptor, CD8, CD57 and CDllb. HLA-DR was also highly expressed reflecting the activation stage of T cells in these recipients. BMT recipients with a high repopulation of CD8⁺ T cells showed a lower incidence of leukaemic relapse than recipients with a low repopulation. The 3-year probability of relapse was 19% versus 64% (P=O03), respectively. The relative high number of CD8⁺ T cells at 3 months after BMT was not associated with the incidence of GVHD. In contrast, occurrence of CMV infection after BMT was significantly higher in these recipients. Our results indicate that CD8⁺ T cells, predominantly CD57⁺, of BMT recipients with an expansion of these cells represent an in vivo activated cell population. This CD8⁺ T-cell population may consist partially of cytotoxic cells with anti-leukaemic activity as suggested by a low relapse rate. The signal for the strong expansion of these CD8+CD57+ T cells after BMT is still unclear, but association with CMV infection suggests that viral antigens are involved.     

Transfusions enriched for W3/25+ helper/inducer T lymphocytes prevent spontaneous diabetes in the BB/W rat

Summary Transfusions of spleen cells are known to prevent spontaneous autoimmune diabetes in susceptible BB/W rats, while T cell-depleted transfusions are ineffective. To characterize further the protective cell(s), we transfused young diabetes prone rats with splenocytes from diabetes resistant BB/W rats that were treated in vitro to enrich them in either OX8⁺ (suppressor/cytotoxic) T cells or W3/25⁺ (helper/inducer) T cells. Diabetes subsequently occurred in 19 of 29 (66%) recipients of OX8-enriched, W3/25-depleted cells and 20 of 37 (54%) controls, but in only 7 of 30 (23%) recipients of W3/25-enriched, OX8-depleted cells (p<0.005). Transfusion of spleen cells from diabetes resistant donor rats pretreated in vivo to deplete OX8⁺ cells also prevented diabetes in susceptible BB/W recipients. We conclude that transfusions of W3/25⁺ helper/inducer splenic T lymphocytes obtained from diabetes resistant animals prevent spontaneous diabetes in the BB/W rat.     

Idiotype-specific T lymphocytes in monoclonal gammopathies: evidence for the presence of CD4+ and CD8+ subsets

Tumour-specific CD4⁺ T helper (Th) and CD8⁺ T cytotoxic (Tc) cells may participate in the control and eradication of tumour cells. In the present study, idiotype-specific stimulation of CD4⁺ and CD8⁺ blood T cells from patients with monoclonal gammopathy of undetermined significance and patients with untreated multiple myeloma stage I was examined. Activation was measured in the CD4⁺ and CD8⁺ subsets enriched by magnetic microbeads as the incorporation of ³H-thymidine and the secretion of interferon (IFN)-γ, interleukin (IL)-2 and IL-4 by single cells using the enzyme-linked immunospot assay. Idiotype-specific T cells were found in four of seven patients. Stimulation was mainly confined to the CD4⁺ subset in three of the four responding patients. This type of response was major histocompatibility complex (MHC) class II restricted as it could be inhibited by monoclonal antibodies against MHC class II (HLA-DR), but not against class I (HLA-ABC) molecules. Idiotype-specific CD8⁺ T cells were also demonstrated in these patients although at a lower frequency. One patient showed a strong and dominating activation of CD8⁺ T cells which could be blocked by antibodies against HLA-ABC but not against HLA-DR. Idiotype-specific CD4⁺ or CD8⁺ T cells were mainly of the type-1 subsets as judged by their secretion of IFN-γ and IL-2. Thus, this study provides evidence for the presence of idiotype-specific and MHC-restricted CD4⁺ and CD8⁺ T cells of the type-1 subsets in patients with monoclonal gammopathies. Such T cells with the potential to control the growth of tumour B cells may be a suitable target for immunotherapeutic interventions in patients.     

Lymphocyte phenotype and lymphokines following anti-thymocyte globulin therapy in patients with aplastic anaemia

Twenty-two patients with adult onset aplastic anaemia were analysed before and after therapy with anti-thymocyte globulin (ATG). Lymphocyte phenotype, lymphokine levels or production, and haematopoietic progenitor cell number were measured 3 months after therapy; clinical response was determined 1 year post-therapy. By flow cytometry there was a significant reduction in both the proportion and absolute number of peripheral blood lymphocytes expressing activation antigen Tac (IL-2 receptor) and in the proportion of HLA-DR+ lymphocytes. For T cells bearing HLA-DR, there were proportional decreases in both activated helper and suppressor cells. There was no statistically significant difference pre-ATG to post-ATG in the absolute numbers of total, helper and suppressor lymphocytes. In all 10 haematologic responders the number of Tac bearing lymphocytes after ATG therapy was in the normal range, but half of 12 non-responding patients continued to have abnormally elevated numbers of Tac+ T cells. The proportion of Tac+ cells were not related to transfusion history. Gamma-interferon levels in serum by radioimmunoassay were elevated in almost half the aplastic patients; post-ATG, gamma-interferon was detectable in only three patients. Haematologic response to ATG therapy was associated with increased numbers of haematopoietic progenitors post-treatment, but pre-treatment values were not predictive of a response. These results are consistent with a pathogenic role for activated T-cells and their lymphokine products and suggest that the target of ATG therapy may be a Tac+ lymphocyte.     

The relationship between absolute counts of lymphocyte subsets and clinical features in patients with pulmonary tuberculosis

BackgroundThe aim of the present study is to investigate the clinical value and characteristics of peripheral blood lymphocyte subsets in patients with pulmonary tuberculosis (PTB) using flow cytometry.MethodsThe absolute counts of T, CD4⁺T, CD8⁺T, natural killer (NK), NKT and B lymphocytes in 217 cases of PTB were detected, and the variations in lymphocyte subset counts between different ages and genders and between aetiological detection results and chest radiography results were analysed.ResultsIn 75.3% of the patients with PTB, six subset counts were lower than the normal reference range, and 44% showed lower‐than‐normal CD4⁺T lymphocyte levels. The counts of T, CD4⁺T, CD8⁺T and B lymphocytes were significantly lower in patients aged >60 years, and the NKT cell counts were significantly lower in female patients than in male patients. Among the patients with positive aetiological results, 40.8% had reduced CD8⁺T counts; these were significantly lower than those in patients with negative aetiological results (P = 0.0295). The cell counts of T, CD4⁺T, CD8⁺T and B lymphocytes reduced as lesion lobe numbers increased. The counts of T, CD4⁺T and CD8⁺T lymphocytes were significantly higher in the group with lesions affecting one lobe than in the groups with two to three lobes or four to five lobes, and the counts of B lymphocytes were significantly higher in the group with one lobe and the group with two to three lobes than in the group with four to five lobes. The counts of CD4⁺T and CD8⁺T lymphocytes were highest in the no cavity group and showed a downward trend with the increase in cavities; the T lymphocyte count was significantly higher in the no cavity group than in the group with five or more cavities (P = 0.014), and the CD8⁺T lymphocyte count was significantly higher in the no cavity group than in the group with one to two cavities and the group with five or more cavities (P = 0.001 and 0.01, respectively).ConclusionsIn most patients with tuberculosis, immune function is impaired. The absolute counts of peripheral blood lymphocyte subsets are closely related to the aetiological results and lesion severity in patients with PTB; this could be used as evidence for immune intervention and monitoring curative effects.     

Analysis of T-lymphocyte subpopulations in inflammatory bowel diseases by three-color flow cytometry

In order to better define changes in the relative proportion of peripheral blood T-lymphocyte subpopulations in patients with inflammatory diseases of the bowel, we performed simultaneous three-color fluorescence-activated cytometric (FACS) analysis using fluorophore-conjugated monoclonal antibodies with specificity for CD4, CD8, Leu 8, and CD45RA on 22 normal control subjects, 28 patients with Crohn's disease (CD), 15 patients with ulcerative colitis (UC), and 11 patients with intestinal inflammation secondary to etiologies other than inflammatory bowel disease (NIBD). This staining combination allowed enumeration of distinct T-cell subpopulations as follows: virgin CD4⁺, recall antigen helper T cells, nonspecific B-cell helper T cell, virgin CD8⁺, cytotoxic effector and suppressor effector and recall antigen cytotoxic T cells based on a synthesis of published functional analyses. No differences in the proportion of CD4⁺ or CD8⁺ cells or in the CD4⁺/CD8⁺ ratios were evident when UC and NIBD patients were compared to normal subjects. A significant reduction in the proportion of CD4⁺ cells and an increase in CD8⁺ cells was observed, however, in the CD group. When two-color analysis was performed, several significant differences in the proportions of circulating lymphocytes were seen. Specifically, these included significant increases in the number of CD4⁺, Leu 8^– (P<0.01) cells in all disease groups and an increase in CD4⁺, CD45RA⁺ cells in the NIBD group. Conversely, significant decreases in the proportions of CD8⁺, Leu 8⁺ (P<0.01) cells were evident in the Crohn's disease group. Three-color FACS analysis revealed significant differences in the relative proportions of the defined T-cell subpopulations enumerated in the various groups as compared with the normal controls. These included a decrease in the proportions of Leu 8⁺, CD45RA⁺, (virgin) CD8⁺ T cells (P<0.05) and Leu 8^–, CD45RA⁺, (putative recall antigen helper) CD4⁺ T cells (P<0.01) in all patient groups as compared with normal controls. Conversely, an increase in the proportions of Leu 8^–, CD45RA⁺, (putative suppressor effector) CD8⁺ T cells (P<0.01), and Leu 8^–, CD45RA⁺, (function unknown) CD4⁺ T cells (P<0.05) was seen in all patient groups as compared with normal controls. CD patients but not UC or NIBD patients demonstrated a significant increase in the proportion of Leu 8^–, CD45RA⁺, (putative cytotoxic effector) CD8⁺ T cells (P<0.01). An increase in the ratio of Leu 8^–, CD45RA⁺, CD8⁺ (suppressor effector)/Leu 8⁺, CD45RA^–, CD8⁺ (putative cytotoxic effector) T cells was observed in all of the patient groups, but was most accentuated in those with Crohn's disease. Significant decreases in the ratios of Leu 8^–, CD45RA^–, CD4⁺ (putative nonspecific B cell helper)/Leu 8⁺, CD45RA^–, CD4⁺ (recall antigen helper) T cells and Leu 8⁺, CD45RA^–, CD4⁺ (recall antigen helper)/Leu 8^–, CD45RA⁺, CD4⁺ (function unknown) T cells were observed in all of the disease groups studied as compared with normal controls. These results suggest that the proportions of certain peripheral blood T-cell subpopulations are significantly altered in gastrointestinal inflammatory states. Further analysis of these T-lymphocyte subpopulations in the blood and tissues might provide valuable insights into immunological aberrations in inflammatory bowel diseases and might be of value in distinguishing among inflammatory diseases of the intestine.     

Defective proliferation and regulatory function of CD4+ T cells bearing Leu-8 homing receptor in primary biliary cirrhosis

The majority of circulating CD4⁺ T cells express the Leu-8 peripheral lymph node homing receptor, and these cells have previously been shown to have suppressor-inducer and suppressor function. In the present study, it was found that CD4⁺, Leu-8⁺ T cells from patients with primary biliary cirrhosis (PBC) have a significantly (P<0.01) lower proliferative response when stimulated with phytohemagglutinin (PHA), concanavalin A (Con A), or pokeweed mitogen (PWM) compared to normal controls. The proliferative response of CD4⁺, Leu-8^– T cells was similar in patients and controls. However, the proliferative responses of CD4⁺, Leu-8⁺ from patients with PBC was normal when cells were stimulated with PHA, Con A, anti-CD3 monoclonal antibody, or ionomycin in combination with phorbol myristate acetate (PMA). CD4⁺ T cells from patients with PBC mediated normal helper function for PWM-stimulated immunoglobulin synthesis at high T/B ratios and their regulatory function was similar to that of normal CD4⁺ T cells that had been irradiated to inactivate their suppressor activity. When CD4⁺ T cells from patients with PBC were precultured with the combination of Con A and PMA, they mediated potent inhibitory activity similar to that of normal CD4⁺ T cells. Thus, CD4⁺, Leu-8⁺ T cells from patients with PBC have a defect of proliferation and suppressor function that is reversed by coculture with PMA. This finding suggests that impairment of a PMA-inducible lymphocyte activation pathway contributes to abnormal lymphocyte function in PBC.     

Analysis of lymphocyte subsets in patients with aplastic anaemia

Lymphocyte subsets have been measured in the blood of 28 patients with aplastic anaemia. The mean helper/inducer:suppressor/cytotoxic T lymphocyte ratio (1.24 +/- 0.74) was significantly decreased in the total population in comparison to mean ratios in a normal population (1.78 +/- 0.57) and in patients with other haematological diseases (1.82 +/- 0.92). A reversed ratio (less than or equal to 1) was present in a large proportion (53%) of aplastic patients, due both to an absolute deficiency of helper/inducer lymphocytes and an increase in suppressor/cytotoxic lymphocytes. Increased HLA-DR expression, evidence of lymphocyte activation, was present in seven of 12 patients evaluated and was confined to the suppressor/cytotoxic lymphocyte population. In the bone marrow, the percentage of lymphocytes was increased two-fold compared to normal bone marrow but the ratio of T cell subsets was not abnormal. Two of four patients evaluated after haematopoietic recovery following ATG treatment showed a return to normal of the T4/T8 ratio; in two others a low T4/T8 ratio persisted despite recovery. These results indicate that lymphocyte subset imbalance and lymphocyte activation are present in many patients with aplastic anaemia, either as a contributing factor or as a result of bone marrow failure.     

Changes in peripheral blood mononuclear cell subpopulations during antithymocyte globulin therapy for severe aplastic anemia

The short-term effect of a domestically produced equine antithymocyte globulin (ATG) was analyzed in 6 patients with acquired severe aplastic anemia (AA). All patients received 5 doses of ATG every other day in a 60-min intravenous infusion. Five peripheral blood immunoregulatory mononuclear cell (MNC) subsets, defined by monoclonal antibodies, were enumerated before and 24 h after each application of ATG. Following the first dose of ATG there was a significant and transient reduction in the absolute number of helper T lymphocytes. There was no statistically significant difference pre-ATG to post-ATG in the absolute number of MNC expressing activation antigen Tac (interleukin-2 receptor). However, Tac+ cells, which were significantly increased before ATG therapy, decreased to nearly normal levels after the fourth dose of ATG. A significant and sustained increment in the absolute number of monocytes (CD14+ cells) occurred following the third dose of ATG. The absolute numbers of MNC, suppressor T lymphocytes and cells bearing HLA-DR antigen remain without significant change along ATG treatment. These results suggest that: (a) Tac+ cells are probably involved in the pathogenesis of AA; (b) the target of ATG may be a Tac+ cell, and (c) ATG may stimulate monopoiesis.