Immune complex-mediated inhibition of lymphocyte Fc-gamma receptors in the plasma of patients with type 1 (insulin-dependent) diabetes mellitus: association with anti-ssDNA antibodies.
Sera of 43 patients with type 1 (insulin-dependent) diabetes and from 42 normal subjects were examined for the presence of Fc-gamma receptor-blocking IgG immune complexes, detected by EA rosette inhibition, and for the presence of anti-ssDNA antibodies by ELISA. Forty-four percent of diabetic patients had levels of inhibition above the upper limit of normality in comparison to 7% of normal controls. Anti-ssDNA antibodies were found in the sera of 14 out of 43 diabetic patients. Ten out of 14 anti-ssDNA positive patients (71.5%) had inhibition levels above the upper limit of normality in comparison to 9 out of 29 (31%) of the anti-ssDNA negative population. The difference was statistically significant (P less than 0.005). Levels of EA rosette inhibition were found to be high in patients with duration of diabetes of less than 2 years and correlated with high prevalence of anti-ssDNA antibodies. The percentage of EA rosette inhibition was found not to correlate with the levels of C1q-binding immune complexes, suggesting that immune complexes detected by EA rosette inhibition may belong to a pool of noncomplement-fixing immune complexes. The possible role of immune complexes with autoantibodies anti-ssDNA in the mechanism triggering and perpetuating autoimmune phenomena in diabetes is discussed.
Guarnotta
G
G
Istituto di Clinica Medica I, University of Palermo, Italy.
Triolo
G
G
D000367:Age Factors; D000974:Antibodies, Antinuclear / Q000276:immunology*; D000936:Antigen-Antibody Complex / Q000276:immunology*; D000943:Antigens, Differentiation / Q000276:immunology*; D004277:DNA, Single-Stranded / Q000276:immunology*; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D011961:Receptors, Fc / Q000276:immunology*; D017452:Receptors, IgG; D012397:Rosette Formation
D000974:Antibodies, Antinuclear; D000936:Antigen-Antibody Complex; D000943:Antigens, Differentiation; D004277:DNA, Single-Stranded; D007074:Immunoglobulin G; D011961:Receptors, Fc; D017452:Receptors, IgG