Kappa-chain deficiency.

A decreased concentration of immunogesting that the synthesis of molecules globulin molecules of one light chain bearing K-chains was decreased. The type (K) was found in a young girl with patient improved considerably with the recurrent respiratory infections and regular administration of 7-globulin. It diarrhea. She had, in addition, deis possible that biological as well as creased yA and yE globulin, partial chemical differences exist between imalbinism, and intestinal lactase demunoglobulins of the two light-chain ficiency. No eosinophils were detected types and that an optimal immune In blood, bone marrow, or nasal response is dependent on a normal smears. Radiolabeled Kand Atype complement of Kand A-chains. molecules survived equally well, sugI NCREASED SUSCEPTIBILITY to pyogenic infections, has been a common manifestation of immunoglobulin deficiency. In patients with frequent infections, the degree of immunoglobulin deficiency has been variable in that some patients exhibit extreme depression of all immunoglobulin classes and others are deficient in only a single class.’3 In some patients with recurrent infections, decreased concentration of even one or two subclasses of 1G globulin has been implicated.4 Class and subclass distinctions of immunoglobulins are based on differences in heavy chains, and immune disorders attendant on deficiencies of a class or subclass have been taken as presumptive evidence for the biological importance of the deficient class or subclass. Immunoglobulins also differ by virtue of their light chains (K and A), and selective deficiency of one or the other light chain might be expected to result in compromised humoral immunity. However, to date, deficiency of immunoglobulins of a single light-chain type has not been described. This report concerns a young girl with repeated respiratory infections and diarrhea whose serum and secretory immunoglobulins were found to have a selective deficiency of K-type molecules. The survival of administered 7-globulin was normal with respect to both light-chain types, suggesting that K-chain synthesis was selectively suppressed.