Chu et al. (1984) studied a 10-year-old Lebanese male with a history of recurrent pneumonia and otitis media beginning at age 2 months. At age 3 years, he had an episode of severe herpes zoster. He had failed ... Chu et al. (1984) studied a 10-year-old Lebanese male with a history of recurrent pneumonia and otitis media beginning at age 2 months. At age 3 years, he had an episode of severe herpes zoster. He had failed to grow in height or weight for several years. Family history showed that 3 brothers died in infancy of recurrent infections, and 5 other sibs were healthy. The levels of immunoglobulins and the distribution of circulating T-cell subsets were normal. The in vitro proliferative response of his peripheral blood mononuclear cells to phytohemagglutinin was depressed (40% of normal), however, and the response of these cells to antigen was lacking. Furthermore, delayed hypersensitivity skin tests and in vitro response to tetanus toxoid remained absent despite repeated immunizations. Monocyte function was judged normal by several criteria. The defect seemed to lie in the response of T cells to interleukin-1 (IL1; see 147760). The defect might, of course, be an X-linked recessive rather than an autosomal recessive.