Czerkinsky C, Koopman W J, Jackson S, Collins J E, Crago S S, Schrohenloher R E, Julian B A, Galla J H, Mestecky J
J Clin Invest. 1986 Jun;77(6):1931-8. doi: 10.1172/JCI112522.
Circulating immune complexes (CIC) containing IgA and C3 were elevated in 48% of IgA nephropathy patients; IgA1 was the predominant subclass. IgA1-IgG CIC were detected in 44%, IgA2-IgG CIC in 7%, and IgM-IgA1 CIC in 16% of the patients. No IgM-IgA2 CIC were detectable. Sucrose gradient ultracentrifugation indicated that IgG-IgA1 CIC were predominantly of intermediate (13-19S) size whereas IgA1-C3 CIC sedimented from 11S to 19S. At acid pH, isolated CIC revealed the presence of substantial amounts of 7S IgA. One third of the patients had elevated serum IgA rheumatoid factor (RF) of both polymeric and monomeric forms despite normal levels of IgM-RF; 87% of patients with elevated IgA-RF had IgA1-IgG CIC. These results indicate that the IgA1 component of CIC in patients with IgA nephropathy is not necessarily of mucosal origin and suggest that a portion of these CIC consists of IgA RF immunologically complexed with autologous IgG.
48%的IgA肾病患者循环免疫复合物（CIC）中含有IgA和C3升高；IgA1是主要亚类。44%的患者检测到IgA1-IgG CIC，7%检测到IgA2-IgG CIC，16%检测到IgM-IgA1 CIC。未检测到IgM-IgA2 CIC。蔗糖梯度超速离心表明，IgG-IgA1 CIC主要为中等大小（13-19S），而IgA1-C3 CIC沉降范围为11S至19S。在酸性pH值下，分离出的CIC显示存在大量7S IgA。三分之一的患者尽管IgM-RF水平正常，但聚合和单体形式的血清IgA类风湿因子（RF）均升高；87% IgA-RF升高的患者有IgA1-IgG CIC。这些结果表明，IgA肾病患者CIC中的IgA1成分不一定来自黏膜，并提示这些CIC的一部分由与自身IgG免疫复合的IgA RF组成。
