Combined immunodeficiency disease associated with adenosine deaminase deficiency. Report on a workshop held in Albany, New York, October 1, 1973.

Fifty-five children with CID and known ADA status were studies at a workshop held in Albany, New York. Erythrocyte ADA determinations were performed in 22 of the 55 patients, 13 of whom were ADA negative. The ADA defect appears to be transmitted as an autosomal recessive trait. Some patients with CID and ADA deficiency have characteristic radiologic abnormalities of the skeleton, which are not found in other illnesses. The thymus glands of all patients with CID and ADA deficiency who could be examined have evidence of thymic involution manifested by presence of Hassall's corpuscles and differentiated germinal epithelium; this is in contrast to "classic" thymus findings in CID with normal ADA. Adenosine deaminase probably plays an important, although as yet undefined, role in lymphocyte development and/or function. The deficiency of ADA in CID is the first enzyme defect observed in a deficiency disease of specific immunity.