Multireactive pattern of serum autoantibodies in asymptomatic individuals with immunoglobulin A deficiency.

Selective immunoglobulin A (IgA) deficiency (sIgAD) is associated with certain autoimmune states. Increased production of autoantibodies and eventual development of overt autoimmune disease are related in part to genetic and environmental factors as well as to the immune deficiency. We surveyed serum specimens from 60 healthy subjects with sIgAD for the presence of 21 different autoantibodies by enzyme-linked immunosorbent assays. The frequencies of 16 autoantibodies were higher in sIgAD patients than in normal healthy controls. Autoantibodies to Jo-1 (28%), cardiolipin (21%), phosphatidylserine (20%), Sm (15%), asialo-GM1 (21%), sulfatide (32%), sulfoglucuronyl paragloboside (11%), and collagen type I (10%) were detected at high frequencies in comparison to those of normal healthy controls. Many of the serum samples were multireactive (i.e., exhibited binding to more than two autoantigens). Forty percent (24 of 60) of sIgAD serum samples reacted against six or more autoantigens; 10% (6 of 60) of sIgAD serum samples were not reactive with any of the 21 autoantigens. Three percent (7 of 209) of consecutive serum samples submitted for autoimmune antibody analysis that were positive for autoantibodies were from patients with IgA deficiency. Our finding of an increased frequency of autoantibodies in sIgAD patients supports the notion of polyclonal stimulation by repeated environmental stimuli as an etiologic mechanism. Alternatively, the increased frequency may be caused by a dysregulation of the immune response in such individuals. The mere detection of autoantibodies cannot predict whether a subject with sIgAD will develop an autoimmune disease or determine which specific disease will emerge.

Autoimmune aspects of primary pulmonary hypertension.

Although primary pulmonary hypertension (PPH) is considered to be an idiopathic condition, it has been postulated that autoimmunity may play a role in the pathogenesis of the disease. This argument has been based on frequent coexisting clinical and serological rheumatic findings. Moreover, approximately in a third of the patients with PPH, and antinuclear factor can be detected. Pulmonary hypertension may appear as a secondary complication to various autoimmune conditions. In light of these findings we examined sera derived from 40 patients diagnosed as having PPH for the presence of 18 different autoantibodies by the ELISA and immunofluorescent techniques. Of the 40 patients, 62.4% had circulating autoantibodies and 47.5% presented with multiantibody responses. Autoantibodies most commonly observed were antinuclear (42.5%), anti-ssDNA (25%) and antithyroglobulin (30%) antibodies. These results may imply that in a subgroup of patients with PPH the disease may be ascribed to an immune dysregulation or alternatively that autoantibodies accompany the disease progression as an epiphenomenon.