Itoh Akihiko, Iwase Hitoo, Takatani Toru, Nakamura Ikuko, Hayashi Miyuki, Oba Kazuhito, Hiki Yoshiyuki, Kobayashi Yutaka, Okamoto Makito
Department of Otolaryngology, Kitasato University, Sagamihara, Kanagawa, Japan.
Nephrol Dial Transplant. 2003 Jun;18(6):1108-14. doi: 10.1093/ndt/gfg108.
There are many reports of incompletely glycosylated O-linked oligosaccharides on the IgA1 hinge region in certain IgA nephropathy patients. In addition, other reports have noted a relationship between tonsillectomy and IgA nephropathy.
Immunoglobulins from extracts of tonsillectomized tissue and other sources were analysed by isoelectric focusing (IEF) and by enzyme-linked immunosorbent assay (ELISA).
The IEF profile of tonsillar IgA differed from that of serum IgA and it was enriched in cationic IgA. However, extracts from tonsillitis controls and IgA nephropathy patients exhibited profiles that were very similar. Enzymatic removal of sialic acid induced a shift of the peaks to the cathode side. The profiles of IgA from treated tonsillar extract and treated serum were closely overlapped. In addition, asialo Galbeta1,3GalNAc was clearly present in cationic IgA from tonsillar extract and in aberrant IgA1 from serum following enzymatic transfer of sialic acid to IgA1. Serum IgA also contained partly sialylated IgA1. Quantitative analysis of IgA and IgG in the extracts indicated that IgA was significantly higher, whereas IgG was significantly lower in IgA nephropathy patients.
We found that the IgA1 produced in tonsillar tissue differed from serum IgA1. Furthermore, an overproduction of asialo IgA1 resulted from the disordered balance between IgA- and IgG-producing cells in the tonsils from the IgA nephropathy patient. Although it is unclear how such asialo IgA1 molecules are transferred from tonsil tissue to serum, a tonsillar source may produce a few micrograms of aberrant IgA1 that then appears in serum.
有许多报道称，某些IgA肾病患者的IgA1铰链区存在不完全糖基化的O-连接寡糖。此外，其他报道指出扁桃体切除术与IgA肾病之间存在关联。
通过等电聚焦（IEF）和酶联免疫吸附测定（ELISA）分析扁桃体切除组织及其他来源提取物中的免疫球蛋白。
扁桃体IgA的IEF图谱与血清IgA不同，且富含阳离子IgA。然而，扁桃体炎对照组和IgA肾病患者的提取物表现出非常相似的图谱。酶法去除唾液酸导致峰向阴极侧移动。处理后的扁桃体提取物和处理后的血清中IgA的图谱紧密重叠。此外，在将唾液酸酶促转移至IgA1后，扁桃体提取物中的阳离子IgA和血清中的异常IgA1中均明显存在去唾液酸Galβ1,3GalNAc。血清IgA中也含有部分唾液酸化的IgA1。提取物中IgA和IgG的定量分析表明，IgA肾病患者中IgA显著升高，而IgG显著降低。
我们发现扁桃体组织中产生的IgA1与血清IgA1不同。此外，IgA肾病患者扁桃体中产生IgA和IgG的细胞之间平衡失调导致去唾液酸IgA1产生过多。尽管尚不清楚这种去唾液酸IgA1分子如何从扁桃体组织转移至血清，但扁桃体来源可能产生几微克异常IgA1，然后出现在血清中。
