IgG SUBCLASSES IN CHILDREN WITH IgA DEFICIENCY

Abstract

Children having normal serum levels of IgG and IgM but IgA below 5mg/dl were considered as having “selective IgA deficiency”. Those with-2 SD from the normal mean for the age were defined as “partial selective IgA deficients”. Deficiency of IgG subclasses was considered in those patients whose values were below the 5th percentile data from the literature. Igs were determinated by radial immunodifusion and IgG subclasses by ELISA. Preliminary data from 27 children is presented: 22 with classic selective deficiency and 5 with partial deficiency. The former group consisted of 11 males and 11 females between 1 and 14 years of age (x=6.8) while the latter were 4 males and 1 female between 3 and 12 years (x=6.6). All had recurrent infections of the upper respiratory tract. Besides, 8 had asthma, 2 pneumonias and 7 other pathologies such as chronic diarrhea, urinary tract infections, recurrent meningitis, celiac disease and rheumatoid arthritis. Deficiency of one or more IgG subclasses were present in 77.8% of the 27 children. Classic and partial IgA deficiencies had the same frequency as IgG subclas ses deficiency. There was no correlation between clinical features and isotype deficiency, except in asthmatic patients in whom IgG 4 subclasses deficiency was predominant. Patients with other associated pathologies had predominantly normal levels of the IgG subclasses. There was no IgG 1 subclass deficiency, probably because of the criteria applied for selection of patients. The frequent association between deficiencies of IgG subclasses and of IgA will probably require a new definition of this latter.