Immunological abnormalities in dyskeratosis congenita.

The recently described classical case of dyskeratosis congenita (DC)(1) lacked information as to whether the patient had features of immunodeficiency. The immune abnormalities described in X-linked DC include hypogammaglobulinemia (low IgM levels), severe B cell lymphopenia, low numbers of T cells, increased rate of apoptosis and marked reduction in cellular proliferation in short-term cultures(2,3). DC can occasionally present as T+B-NKsevere combined immunodeficiency (complete absence of B and NK or natural killer cells) in the most severe form, referred to as Hoyeraal-Hreidarsson syndrome(4). Recurrent infections and deaths secondary to Pnemocystis pneumonia and cytomegalovirus infections have been reported. Osteoporosis, liver and lung fibrosis are also seen and hence use of busulfan or excessive radiation are considered to be relative contraindications.