Elevation of CD5⁺ B lymphocytes in schizophrenia

Background: A variety of immunologic alterations have been observed in patients with schizophrenia. These findings have lent support to theories that autoimmune mechanisms may be important in some patients with the illness. The CD5⁺ B lymphocyte, a B-cell subset associated with autoimmune disease, has been the subject of two previously published studies yielding disparate results. Methods: In this study, we used immunofluorescent flow cytometry to measure CD5⁺ B cells, total B and T cells, and CD4 and CD8 subsets in patients with schizophrenia and in normal control subjects. Results: A significantly higher percentage of patients with schizophrenia, relative to normal control subjects, exhibited an elevated level of CD5⁺ B cells (27.6% vs 6.7%). Antipsychotic withdrawal had no effect on CD5⁺ B-cell levels, suggesting that medication effects were not the cause of this difference. No other studied lymphocyte subsets differed between the two groups. Conclusions: A subset of patients with schizophrenia have elevated levels of CD5⁺ B cells. This finding replicates an earlier study by another group and provides further evidence suggestive of autoimmune manifestations in schizophrenia. Copyright (C) 1999 Society of Biological Psychiatry.