Long-term immunological reconstitution by peripheral blood leucocytes in severe combined immune deficiency disease: implications for the role of mature lymphocytes in histocompatible bone marrow transplantation.

A 7 month old girl with severe combined immunodeficiency disease (SCID) received a single transfusion of peripheral blood leucocytes from her histocompatible grandfather in an attempt to achieve immunological reconstitution. There was rapid restoration of humoral and cellular immunity which has persisted undiminished over a 54 month follow-up period and the patient has remained free of any significant infections. Lymphocytes of donor karyotype were repeatedly demonstrated in the patient's peripheral blood. In contrast, no evidence of donor cell engraftment in her bone marrow could be obtained by karyotypic, antigenic or enzyme phenotypic analyses. These observations suggest that long term immunological reconstitution may be achieved solely by peripheral engraftment of mature lymphocytes. A review of the literature reveals that this mechanism of immunological reconstitution may not be uncommon following histocompatible bone marrow transplantation for treatment of SCID.