Lymphocyte subpopulations in ataxia-telangiectasia.

Peripheral blood lymphocyte subsets were analyzed in nine patients with ataxia-telangiectasia (AT) and their immediate family members. Absolute lymphocyte numbers were slightly low. T-helper/inducer cell, as well as B-cell, percentages were comparable to normal in patients with AT. The percentage of T-suppressor/cytotoxic cells was decreased in five of nine patients. The percentage of large granular lymphocytes was elevated in three patients. No generalities consistent with a disease hypothesis could be made on the basis of lymphocyte subpopulation data.