GM ALLOTYPES AS INDICATORS OF NONATOPIC AND ATOPIC BRONCHIAL-ASTHMA

69 Caucasian children, 34 with non-atopic and 35 with atopic bronchial asthma, demonstrated different, Gm-associated IgG antibody responsive ness. The non-atopic bronchial asthma group showed a preponderance of the Gm(a,'',g) haplotype, while the atopic study group showed a prepon derance of the haplotype with the alternative allotypes on all IgG sub class loci, namely Gm(f,n,b). Patients with non-atopic bronchial asthm a showed a significantly increased frequency of the phenotypes contain ing the Gm(a,'',,g) haplotype, namely the Gm(a, g/a,'',g) and Gm(a,'', g/f,'',b), and an increased number of individuals were homozygous G2m( '','') on the IgG2 locus. The 2 asthma groups showed different charact eristic IgG subclass patterns, the non-atopic group with significantly decreased IgG2 and IgG3, especially those of the Gm(a,'',g/a,'',g) ph enotype, and the atopic group with significantly increased IgG1 and Ig G4, especially those of the Gm(f,n,b/f,n,b) phenotype. The characteris tic IgG subclass patterns originate from the different Gm phenotypes f ound in the 2 groups. The results emphasize the presence of qualitativ ely and quantitatively different IgG molecules in non-atopic and atopi c bronchial asthma patients and show the interest in studying IgG gene s and IgG molecules as markers of pathogenesis. G2m('','') homozygosit y is a new important marker of non-atopic bronchial asthma.