a novel xlinked combined immunodeficiency disease a novel xlinked combined immunodeficiency disease was found in five living males in an extended family in the united states the age of the affected males ranged from 25 to 34 yr the most prominent clinical abnormalities were a paucity of lymphoid tissue recurrent sinusitis otitis media bronchitis and pneumonia severe varicella and chronic papillomavirus infections the principal immunologic features of the disorder were normal concentrations of serum immunoglobulins but restricted formation of igg antibodies to immunogens normal numbers of b cells and nk cells but decreased numbers of cd4 and cd8 t lymphocytes particularly the cd45ra subpopulations diminished proliferative responses of blood t cells to allogeneic cells mitogens and antigens and decreased production of il2 by mitogen stimulated blood lymphocytes thus affected males in this family carry an abnormal gene on their x chromosome that results in a combined immunodeficiency that is distinct from previously reported disorders