T-cell abnormalities may include CD4+ lymphopenia, diminished lymphoproliferative responses to antigens and mitogens and impaired cytokine production.1, 2, 3, 4, 5, 6, 32, 36 Our patient also displayed low CD3+ T cells and markedly impaired response T-cell responses to recall antigens, suggesting a combined T- and B-cell defects. The gene discussed is CD4; the disease is lymphopenia.