B lymphocytes in primary and secondary deficiencies of humoral immunity.

The quantitative studies of B lymphocytes in peripheral blood have been performed in various forms of primary and secondary immunodeficiency disease in man. X-linked agammaglobulinemia was found to comprise two sub-types, one lacking B-cell population, the other showing low numbers of B lymphocytes. The absence of B cells in severe combined immunodeficiency was corrected by marrow transplants in 3 children. Cases of DiGeorge syndrome and lepromatous leprosy showed an absolute increase in numbers of B lymphocytes in peripheral blood, probably a compensatory mechanism in the market deficit of T-cell population and function. The reconstitution of DiGeorge syndrome by fetal thymus transplant reversed the abnormally high percentage of B lymphocytes.