Maternal T-cell engraftment associated with severe hemophagocytosis of the bone marrow in untreated X-linked severe combined immunodeficiency

Maternal engraftment of T cells in severe combined immunodeficiency can lead to graft-versus-host disease of the skin and liver. We report the case of an infant with X-linked severe combined immunodeficiency, confirmed by DNA sequencing of the common gamma chain gene locus, in which this disorder's characteristic peripheral lymphocyte phenotype [T(-)B(+)NK(-)] was obscured by the postnatal onset of hemophagocytic syndrome that included severe B-cell lymphopenia, neutropenia, and anemia. Hemophagocytosis was most likely owing to maternal graft-versus-host disease, as perforin-expressing CD8 T cells, presumably of maternal origin, were prominent in the bone marrow and there was no concurrent severe infection.