HLA-D compatibility between parent and child: increased occurrence in severe combined immunodeficiency and other hematopoietic diseases.

Weak or weak intermediate reactions in one-way mixed lymphocyte culture (MLC) were seen between a patient and at least one parent in the families of 6 of 15 patients with severe combined immunodeficiency disease, 3 of 4 patients with Fanconi's anemia, and 3 of 7 patients with congenital neutropenia (CN). In control family material, weak MLC reactions were seen in 1.4 per cent (4 of 285) of individual parent-child and child-parent combinations or in 2.1 per cent (3 of 143) of the total number of parent-child pairs. The increase in frequency of weak MLC reactions seen in the familes of patients with severe combined immunodeficiency disease and Fanconi's anemia occurred most frequently between mother and patient. This finding could be relevant to the pathogenesis of these diseases. In children with CN, the disease seems to be associated with the HLA antigen B12; in addition, two of the patients with CN appear to be homozygous for HLA-D. Because of the relatively frequent compatibility seen in MLC reactions between parents and children with severe combined immunodeficiency disease, Fanconi's anemia, and CN, it is suggested that those parents could be potential donors for bone marrow transplantation.