DNA TYPING OF DQ AND DR ALLELES IN IGA-DEFICIENT SUBJECTS

IgA deficiency (IgA-D) represents the most common immunodeficiency syn drome of infancy. In most cases IgA-D represents an isolated immunolog ical disorder, while sometimes it is associated with IgG subclass defi ciency or with the presence of autoantibodies. We investigated the pat tern of association of IgA-D with DRB1 and DQB1 loci of the HLA region by DNA molecular typing, which allows the identification of previousl y serologically undefined specificities. We also compared the gene fre quency of DRB1 and DQB1 allelic variants between IgA-D subjects with o r without serum autoantibodies. Our results indicate that the gene fre quency of the DRB1()0102 subtype and of the DRB1(*)0102, DQB1(*)0501 haplotype is significantly higher in IgA-D than in the general populat ion. Furthermore, the IgA-D subjects with autoantibodies showed a posi tive association with DR4 and DR13 subtypes, thus supporting the hypot hesis that genetic factors are also involved in the association betwee n IgA-D and autoantibodies.