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The expression of the CD11b antigen and the presence of the S-100 (and, specifically, its β subunit) protein within the T4- subpopulation of normal human peripheral blood lymphocytes were investigated by panning techniques, itnmunofluorescence analysis and immunoelectronmicroscopy. Both antigens are known to be absent in the T4+ lymphocytes. However, CD11b+ T lymphocytes represented about 30% of the T4- population; a part of them (over 1/3) belonged to and completely filled up the T4- T8- subpopulation, whereas the remaining part (almost 2/3) shared the T8 positivity. Interestingly, S-100+ T lymphocytes, which always were CD11b+ too, represented about one half of the CD11b+ T cells, but were excluded from the T4- T8- CD11b+ subpopulation, whereas they represented up to 80% of theT4- T8- CD11 b+ subset. Such findings demonstrate that the S-100+ T lymphocytes are exclusively restricted to a discrete T cell compartment which shows the T8+ CD11b+ immunophenotype. Since such T8+ CD11b+ cells had been shown to possess suppressive capabilities, we herein propose that S-100+ lymphocytes might to some extent modulate the immune responses. However, the exact functional significance of the S-100 protein stilt remains unknown. [ABSTRACT FROM AUTHOR]

The effect of iron (Fe3+) and normal human liver ferritin on the proliferative response of normal human lymphocytes to tetanus toxoid was examined. This proliferative response involved memory T4+ lymphocytes as shown by a selective depletion study. Limit dilution analysis revealed that iron, present as ferric citrate, affected the initiation of clone development, and that concentrations of ferric citrate from 30 μM to 1 mM were able to reduce significantly the cloning efficiency of precursor T cells (up to 90% reduction). The reduced cloning frequency was not due to immunological suppression. Clone size was also reduced when iron was present during culture. In contrast, the presence of normal human liver ferritin during culture (concentration range: 300μg/l-10,000 /μg/1) had no effect on lymphocyte proliferation. The data indicate that low molecular weight iron (as ferric citrate) in concentrations similar to those which have been reported in the serum of patients with iron overload diseases, can interfere with antigen-specific lymphocyte responses and this may have implications for the development of infections and neoplasia in diseases of iron-overload. [ABSTRACT FROM AUTHOR]

We studied the possible in vivo influence of cimetidine on peripheral blood lymphocyte (PBL) subpopulations defined with monoclonal antibodies (MoAb) in eight haematologically normal patients with uncomplicated duedenal ulcers before cimetidine treatment, 1 week after the start, and finally 1 week following cessation of therapy. Alter cimetidine had been given for 3-5 weeks there was a significant decrease, compared with pretreatment numbers, in the proportion of T3+ cells (64.6±8.1 (mean ± s.d.) v 51.0 ± 7.8%) and in T4+ cells (47. 3 ± 4 .3 v 30. 8 ± 4.7%). The number of T8+ cells was not affected (20. 3 ± 4 .3 v 20.1 ±6.7%). These changes resulted in a significant reduction in the T4/T8 ratio (2.46 ± 0.8 v 1.67 ± 0.6). The total numbers of lymphocytes and monocytes as well as the percentage of B1+ lymphocytes did not change significantly. The observed decrease in T4/T8 ratio after cimetidine treatment is explained by a reduction in the number of T4+ cells and the appearance of a new subpopulation of T3-, T4-, T8-, B1- lymphocytes. The underlying mechanism, however, is not clear. Cimetidine does not seem to have a direct receptor-modulating effect, since in vitro exposure of normal lymphocytes to the drug did not change the proportions of the T cell subsets. [ABSTRACT FROM AUTHOR]

Twenty-two patients with active pulmonary sarcoidosis had the subpopulations of the lymphocytes in the bronchoalveolar lavage (BAL) fluid measured. All 12 with hypergammaglobulinaemia had a ratio less than 2.0 (χ²=5.18, P<0.025). When an increased number of T4 lymphocytes was present in the BAL fluid, there was a significant decrease in the absolute number of T4 lymphocytes in the peripheral blood (χ²=6.84, P<0.01). The number of T4 lymphocytes in the BAL fluid correlated with the subsequent response to daily steroid therapy for 2 months, as assessed by improvement in vital capacity (r=0.89, P<0.01). [ABSTRACT FROM AUTHOR]