Sarcoid lymphocytes: B- and T-cell quantitation.

Bone-marrow-derived B lymphocytes and thymus-dependent T lymphocytes were quantitated in a group of 38 patients with histologically confirmed sarcoidosis. B lymphocytes were identified by detecting surface immunoglobulins (Ig, IgG, IgM, and IgA) and complement receptors. T lymphocytes were identified by E-rosette assay. The untreated patients with both limited and disseminated disease had lymphopenia, reduced T-cell number, and low E/Ig cell ratios. Absolute numbers of circulating E-rosette lymphocytes did not show any correlation with cutaneous anergy. The numbers of Ig-bearing lymphocytes or the sum of the numbers of IgG, IgM, and IgA(GMA)-bearing lymphocytes were elevated in patients with disseminated disease, whereas the numbers of complement receptor lymphocytes were normal in all groups. It is proposed that this discrepancy of results on B-lymphocyte subpopulations might be explained by the presence of antibody or extrinsic antigen-antibody complexes bound to lymphocytes, as supported by elevated GMA/Ig ratios. The numbers of circulating B lymphocytes, as detected by any of three markers employed in this study, showed no correlation with the levels of serum immunoglobulins. The mechanisms of T-cell depletion and increase of immunoglobulin-bearing cells remain to be determined.