Association of neutrophil and complement defects in two twins with Shwachman syndrome.

Immunological functions were studied in two 22-month-old dizygotic twins with the characteristic features of Shwachman syndrome. A severe defect of neutrophil motility was found in both children, but not in their parents. An impairment of the activity of the alternative pathway of complement was present in the sera of both patients. This defect, in association with the neutropenia and the chemotactic defect, might be related to the recurrent infections displayed by the twins.