Reconstitution of defective cellular immunity with foetal thymus and dialysable transfer factor. Long-term studies in a patient with chronic mucocutaneous candidiasis.

Extensive studies of a 9-year-old boy with recurrent pulmonary infections and chronic mucocutaneous candidiasis disclosed a severe defect in cell-mediated immunity but normal humoral immune responses. These immunological defects were not improved by initial treatment with transfer factor. After receiving a foetal thymus transplant the patient developed positive delayed-type skin tests, could be sensitized with chlorodinitrobenzene, and showed progressive improvement of in vitro lymphocyte functions including spontaneous formation of rosettes with sheep erythrocytes and positive responses to phytohaemagglutinin, concanavalin A and allogeneic leucocytes. Moreover, lymph node cellularity increased, especially in the thymus-dependent zones. Though the in vitro responses persisted for over 1 year, skin tests became unreactive at 38 weeks. However, in contrast to the pre-transplant experience transfer factor was now effective in inducing positive skin tests. These studies provide a chronological account of the effect of the thymus on expression of lymphocyte-mediated immune responses in man and suggest that thymus-derived cells are required for acquisition of transfer factor-induced cellular immunity.