Natural killer activity in two cases of ataxia telangiectasia

We report two cases of ataxia telangiectasia in which a small number of T cells and a slightly diminished response to phytohaemagglutinin or concanavalin A were observed. In one case, serum IgA was undetectable. In spite of T and/or B cell involvement, natural killer activity and the percentage of natural killer cells determined by monoclonal antibodies Leu 7 were normal in both cases.