[IgG subclasses and autoantibodies in adult patients with selective IgA deficiency].

Selective IgA deficiency is the most common primary immunodeficiency disease, but the etiopathogenesis is unknown. In a portion of patients disturbed IgA production is accompanied by various immunological abnormalities. Serological laboratory results of 30 female and 22 male adult patients with selective IgA deficiency were compared with sex- and age-matched healthy controls. Hypergammaglobulinemia IgG was observed in 31 patients and only in 2 control persons. Serum IgG1 was increased in 12 and/or IgG3 in 18 patients, the increase in IgG2 was less common (6 persons). The number of persons with increased IgE did not differ from the control group. The occurrence of autoantibodies (antinuclear antibodies, rheumatoid factor, antithyroglobulin and anti-thyroid microsomal antibodies, anti-gastric parietal cells, reticulin, smooth muscle, anticardiolipin, and anti-gliadin antibodies) did not differ significantly from the control group. IgG hypergammaglobulinemia, which, according to our results, is the most frequent accompanying serological abnormality in IgA deficiency, may be caused by compensatory increased production, but may also reflect more profound immunological dysregulation in the disease.