Blanco Quirós A, Blanco C, Alvarez J, Solis P, Conde F, Gomez S
Facultad de Medicina, Pediatría, Vallodolid, Spain.
Eur J Pediatr. 1994 Feb;153(2):103-6. doi: 10.1007/BF01959218.
Circulating immune complexes (CIC) that simultaneously contain IgG and IgA are frequently found in IgA nephropathy (IgA-N) and the Schönlein-Henoch syndrome (SHS). The presence of anti-immunoglobulin antibodies (IgA anti-IgG and IgG anti-IgA) was studied by ELISA in the serum of 39 children with SHS and compared to 30 normal children. The mean level of IgG anti-IgA antibodies (240 +/- 104 u/ml) in SHS patients was similar to control values (251 +/- 85 u/ml); the IgA anti-IgG antibodies were increased, although only the antibodies against Fc fraction of IgG were elevated (185 +/- 71 u/ml in patients vs 127 +/- 24 mu/ml in controls, P < 0.0001) without a significant increase of IgA anti-IgGFab antibodies (141 +/- 54 mu/ml vs. 137 +/- 25 u/ml); 16/39 (41%) of the patients had increased levels of IgA anti-IgGFc and 6 of these had also high IgA anti-IgGFab. None of these patients had high IgA anti-IgGFab antibodies without simultaneous augmentation of IgA anti-IgGFc. Only 3/39 (7.7%) of SHS patients showed high levels of IgG anti-IgA antibodies. The correlation of IgA anti-IgGFc antibodies with IgA anti-IgGFab was very strong (P < 0.0001) but lower with IgG anti-IgA antibodies (P < 0.002). In addition, 8/39 children had renal involvement, nevertheless in these patients the findings were quite similar, with a non-significant elevation of IgA anti-IgGF ab antibodies. These results show that the IgA anti-IgG antibodies are more frequently increased than IgG anti-IgA antibodies in the SHS; moreover they are mainly directed against Fc fraction and are IgA-FR isotype. Our findings suggest that the CIC in SHS are likely formed by the reaction of IgA anti-bodies against IgG and not vice versa.
同时含有IgG和IgA的循环免疫复合物（CIC）常见于IgA肾病（IgA-N）和过敏性紫癜（SHS）。通过酶联免疫吸附测定法（ELISA）研究了39例SHS患儿血清中的抗免疫球蛋白抗体（IgA抗IgG和IgG抗IgA），并与30例正常儿童进行比较。SHS患者中IgG抗IgA抗体的平均水平（240±104 u/ml）与对照值（251±85 u/ml）相似；IgA抗IgG抗体升高，不过只有针对IgG Fc片段的抗体升高（患者为185±71 u/ml，对照为127±24 u/ml，P<0.0001），而IgA抗IgGFab抗体无显著升高（141±54 u/ml对137±25 u/ml）；39例患者中有16例（41%）的IgA抗IgGFc水平升高，其中6例的IgA抗IgGFab也升高。这些患者中没有一例IgA抗IgGFab抗体升高而IgA抗IgGFc不同时升高。SHS患者中只有3/39（7.7%）的IgG抗IgA抗体水平升高。IgA抗IgGFc抗体与IgA抗IgGFab的相关性非常强（P<0.0001），但与IgG抗IgA抗体的相关性较低（P<0.002）。此外，39例儿童中有8例有肾脏受累，不过在这些患者中结果非常相似，IgA抗IgGFab抗体无显著升高。这些结果表明，SHS中IgA抗IgG抗体比IgG抗IgA抗体更常升高；此外，它们主要针对Fc片段，且为IgA-FR同种型。我们的研究结果表明，SHS中的CIC可能是由IgA抗体与IgG反应形成的，而非相反。
