Combined immunodeficiency associated with xeroderma pigmentosum.

We report a 15-month-old boy with xeroderma pigmentosum, a history of repeated infections, and immune deficiency who developed a fatal pneumonia with parainfluenza type 1. Immunologic evaluation revealed a severe combined immunodeficiency with hypoglobulinemia, C3 deficiency, anergic response to skin testing, and an abnormal lymphocytic response to mitogens. We suggest that patients with xeroderma pigmentosum be evaluated carefully for immune deficiencies, should repeated infections occur.