SIGNIFICANCE OF HIGH-LEVELS OF SERUM IGA AND IGA-CLASS CIRCULATING IMMUNE-COMPLEXES (IGA-CIC) IN PATIENTS WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS

Significance of serum IgA and IgA-class circulating immune complexes ( IgA-CIC) elevation in patients with non-insulin-dependent diabetes mel litus (NIDDM) was described. Seventeen patients with NIDDM and 17 pati ents with diffuse mesangial proliferative glomerulonephritis without d eposition of IgA (DPGN) as controls were examined. The levels of serum IgA in patients with NIDDM were significantly higher than those in pa tients with DPGN (p less than or equal to 0.01). The levels of IgA-CIC in patients with NIDDM were also significantly higher than those in p atients with DPGN (p less than or equal to 0.01). Production of IgA de rived from B cells and the proportion of IgA bearing B cells in patien ts with NIDDM were not significantly higher than those in patients wit h DPGN. Furthermore, the levels of IgA in pharyngeal washings from dia betic patients were not significantly higher than those for DPGN patie nts. Duration of diabetes, the level of HbA(1c), and the presence of h ypertension, microalbuminuria, or retinopathy showed no significant co rrelations with the levels of serum IgA or IgA-CIC in patients with NI DDM. It was postulated that the elevations of serum IgA and IgA-CIC we re based on subclinical infection of the mucosa and/or deterioration o f IgA clearance in patients with NIDDM.