Comparative analysis of T and B-cell subpopulations in normal thymus and thymus of myasthenia gravis

Abstract

A clinico-pathological investigation was performed, examining T and B-cell subpopulations of normal and myasthenia thymus. The proportion of T-cells in healthy human thymus was found to be high (96-99%), as detected by the cytotoxicity method using the antithymocyte serum plus complement (T-ATS). A second test, likewise, confirmed this with similar results, using the E-rosette method with SRBC (T-E). B-cells in healthy thymus were low (0-3%), when measured by the EAC-rosette method employing SRBC and anti-SRBC antibody with mouse complement. However, in tests on myasthenic thymus cells the proportion of T-cells was low (43-88%). On the other hand, B-cells were found to be significantly higher (10-35%) than for healthy thymus cells. Furthermore, the use of these two testing methods, i.e. T-E and T-ATS, provided a noticeable difference between their results in the total T-cell counts for each group. A further item of interest was detected by the dissociation between the proportion of T-ATS and T-E for myasthenic cells. In most cases, healthy thymus cells were sensitive to even the lowest concentrations of ATS (1 : 2, 408). On the other hand, some myasthenic thymus cells seem to have a low amount of thymic antigen, even at high concentrations, since they were not killed by higher dilutions of ATS. This tendency was similar for both cell samples collected from thymomatous and non-thymomatous areas of myasthenic patients.