REGIONAL DEFICIENCY OF SECRETORY IgA IN A PATIENT WITH COMBINED IMMUNODEFICIENCY OF THE ADA DEFICIENT TYPE

Abstract
The Ig[immunoglobulin]A system in a patient with SCID [severe combined immunodeficiency disease] and ADA [adenosine deaminase] deficiency showed heterogeneity. Serum IgA and stool secretory IgA (SIgA) levels were normal, but with altered .kappa./.lambda. and A1/A2 subclass ratios. IgA in saliva and urine was deficient. Amounts of secretory component were normal. Jejunal and rectal biopsies showed prominent lymphonodular hyperplasia, but no cells containing IgA. A normal serum IgA level does not always predict an intact secretory IgA system.