Saulsbury F T
Department of Pediatrics, University of Virginia Medical Center, Charlottesville 22908.
J Clin Lab Immunol. 1987 Jul;23(3):123-7.
The present study was performed to investigate the role of IgA rheumatoid factor (RF) in the formation of IgA-containing immune complexes and to determine the IgA subclass composition of IgA RF in patients with Henoch-Schönlein purpura (HSP). Immune complexes were isolated from the sera of 22 children with HSP and 13 controls by means of polyethylene glycol (PEG) precipitation. The percentage of IgG, IgA, and IgM precipitated by PEG was significantly greater in HSP patients than controls (p less than 0.01). There was a strong correlation (r = 0.723, p less than 0.001) between the amount of IgG and IgA in the PEG precipitates from HSP patients, but not controls. HSP patients had significantly higher levels of IgA RF in their serum (p less than 0.05) and in their PEG precipitates (p less than 0.05) compared to controls. There was a strong correlation between IgA RF concentrations in the serum and PEG precipitates in HSP patients (r = 0.910, p less than 0.001). PEG precipitation eliminated IgA RF activity from the serum of 7 of 8 HSP patients tested, and substantially reduced the titer in the remaining patient. IgA RF was recovered in the PEG precipitates from all patients. Testing of HSP patients showed that IgA1 was the predominant IgA subclass of the serum IgA RF (p less than 0.02) and PEG precipitate IgA RF (p less than 0.01). These results indicate that IgA RF is a constituent of IgA-containing immune complexes in HSP, and that IgA RF is composed primarily of IgA1.
本研究旨在探讨IgA类风湿因子（RF）在含IgA免疫复合物形成中的作用，并确定过敏性紫癜（HSP）患者中IgA RF的IgA亚类组成。通过聚乙二醇（PEG）沉淀法从22例HSP患儿和13例对照者的血清中分离免疫复合物。HSP患者中PEG沉淀的IgG、IgA和IgM百分比显著高于对照组（p<0.01）。HSP患者PEG沉淀物中IgG和IgA的量之间存在强相关性（r = 0.723，p<0.001），而对照组不存在。与对照组相比，HSP患者血清（p<0.05）和PEG沉淀物（p<0.05）中的IgA RF水平显著更高。HSP患者血清中IgA RF浓度与PEG沉淀物之间存在强相关性（r = 0.910，p<0.001）。PEG沉淀消除了8例受试HSP患者中7例血清中的IgA RF活性，并大幅降低了其余患者的滴度。所有患者的PEG沉淀物中均回收了IgA RF。对HSP患者的检测表明，IgA1是血清IgA RF（p<0.02）和PEG沉淀IgA RF（p<0.01）的主要IgA亚类。这些结果表明，IgA RF是HSP中含IgA免疫复合物的一个组成部分，且IgA RF主要由IgA1组成。
