Leu-2a Cells Research Articles

Dual labelling of circulating CD8 cells in patients with multiple sclerosis.

Peripheral blood T cell phenotypes have been analysed in serial samples from patients with multiple sclerosis, their unaffected relatives and controls using a panel of antibodies chosen to distinguish T suppressor and activated suppressor cells from other CD8 lymphocytes. Overall, the percentage of Leu 2a cells correlated with alterations in the Leu 2a/15 suppressor sub-population (r = 0.79, p less than 0.001). Fewer circulating Leu 2a and Leu 2a/15 positive cells were identified in multiple sclerosis patients than unaffected individuals but there was no alteration in percentage of activated (Leu 2a/DR) CD8 cells. These findings suggest that the fluctuations in CD8 cells, characteristic of patients with multiple sclerosis, are due to alterations in T suppressor phenotype; this may then lower the threshold for activation of other T cell subpopulations.

Antigen responsiveness during tuberculosis: regulatory interactions of T cell subpopulations and adherent cells.

Previous studies from this laboratory demonstrated that adherent mononuclear cells selectively decreased in vitro tuberculin responses in some anergic patients with tuberculosis; subsequently this adherent suppressor cell was characterized as a monocyte. The current study of 41 patients with active pulmonary tuberculosis examined whether T cell subpopulations also acquired antigen-specific suppressor function during Mycobacterium tuberculosis infection, contributed to monocyte-mediated suppression of tuberculin responses, or both. Alteration in the numbers of circulating T-helper (Leu 3a) and T-suppressor (Leu 2a) cells was not observed in patients with tuberculosis, nor did Leu 2a cells selectively modulate in vitro tuberculin responses. The numbers of circulating T gamma cells, a subset of T cells identified by surface receptors for the Fc portion of IgG (Fc gamma R), was increased twofold in patients with active pulmonary tuberculosis. Depletion of T gamma cells from in vitro cell culture consistently and selectively increased tuberculin responsiveness of T cells from patients with tuberculosis. In addition, in the absence of T gamma cells, monocyte-mediated suppression of tuberculin responses was demonstrated in each patient observed. These studies demonstrate that during M. tuberculosis infection T gamma cells acquire antigen-specific suppressor cell activity and suggest that T gamma cells also contribution to immunoregulation modulating the expression of tuberculin-specific suppression by monocytes.

Lymphocyte subsets in primary sclerosing cholangitis.

As an initial step in testing the hypothesis that immunoregulatory abnormalities are important in the pathogenesis of primary sclerosing cholangitis, we determined the number and percentage of lymphocyte subsets in the peripheral blood of 33 patients with primary sclerosing cholangitis. In these patients, when compared with normal and diseased controls, there was a significant reduction in the total number of circulating T cells because of a disproportionate decrease in Leu-2a (suppressor/cytotoxic) cells. This decrease resulted in a significantly increased ratio of Leu-3a to Leu-2a cells. Patients with cirrhosis had significantly higher Leu-3a/Leu-2a (helper/suppressor) ratios than did noncirrhotic patients; both disease groups, however, had ratios that were significantly higher than controls. The number and percentage of B cells were significantly increased. Alterations in the percentage of B cells correlated significantly with histologic stage and concentrations of gamma globulin, serum IgG, and bilirubin. We conclude that these abnormalities are suggestive of a defect in immunoregulation in primary sclerosing cholangitis, which is not secondary to advanced liver disease alone and appears to be independent of chronic ulcerative colitis or obstructive jaundice.

Lymphocyte subpopulations in Spanish parenteral drug addicts.

Lymphocyte subpopulations were studied in 29 symptom-free Spanish prisoners who were active parenteral drug abusers. In 16/29 drug addicts (55%) the helper-inducer/suppressor-cytotoxic ratio (Leu 3a/Leu 2a) was less than 1. None of these 16 patients had lymphopenia and only 2 had a reduction in the number of Leu 3a cells. In drug addicts the number of lymphocytes (p less than 0.01) and the number and percentage of Leu 2a cells (p less than 0.001) were significantly raised. The addicts also had a higher absolute number of T cells when measured by their ability to react with the Leu 4 antibody (p less than 0.01). However, the E-rosette forming cells were significantly reduced. Thus the E-rosette test may lead to an overestimation of "null" cells. Furthermore drug addicts had a higher percentage (p less than 0.001) of Leu 7 positive cells (NK and K cells), but a normal percentage of B and phagocytic cells. Five drug addicts had generalized persistent lymphadenopathies, and 2 had skin anergy. We believe that most of the immunologic abnormalities seen in these apparently healthy drug abusers can be explained by an antigenic overload.

T lymphocyte subsets in homosexual men from Copenhagen.

Screening of sixty-six asymptomatic homosexual men from Copenhagen revealed significantly lower Leu-3a/Leu-2a ratios as compared to controls. Ten (15%) of the homosexuals had a ratio less than or equal to 1.0. The low Leu-3a/Leu-2a ratios were the result of an increase in the absolute number of Leu-2a cells. Homosexuals with many partners and those who had been sexual partners of patients with the acquired immuno-deficiency syndrome (AIDS) had significantly lower ratios than those without these features. Cytomegalovirus was isolated from urine and/or sputum of 15% and this was associated with a Leu-3a/Leu-2a ratio less than or equal to 1.0. The observed immunological abnormalities could either represent latent infection with the putative AIDS agent or alternatively be caused by repeated infections and/or exposure to allogenic spermatocytes or lymphocytes.

T lymphocyte subsets in autoimmune thyroid diseases and subacute thyroiditis detected with monoclonal antibodies.

Peripheral T lymphocyte subsets were analysed with monoclonal antibodies, by highly standardized fluorescence-activated cell sorter analysis instead of manual counting by the indirect immunofluorescence method, in autoimmune thyroid diseases and subacute thyroiditis. Total lymphocyte counts were increased in patients with thyrotoxic Graves' disease and subacute thyroiditis. The percentage of total T (Leu 1) cells was significantly lower in patients with thyrotoxic Graves' disease and Hashimoto's disease with destructive thyrotoxicosis than in normal subjects. No significant changes were observed in the percentages of suppressor-cytotoxic T (Leu 2a) cells or helper-inducer T (Leu 3a) cells or in the Leu 3a-Leu 2a ratio in different groups of patients. There were no correlations between the percentages of E rosette-forming cells and Leu 1 cells and between the percentages of T gamma cells and Leu 2a cells in normal subjects and patients. The peak position of fluorescence intensity of Leu 2a cells showed a significant sex difference even in normal controls. The most important finding was a significant decrease in the peak position of Leu 2a cells in patients with thyrotoxic Graves' disease and with hypothyroid or thyrotoxic Hashimoto's disease. These findings indicate the significant association of qualitative, but not quantitative, abnormality of suppressor-cytotoxic T (Leu 2a) cells with thyroid dysfunction in autoimmune thyroid diseases.