Hiki Yoshiyuki, Horie Akeyo, Yasuda Yoshinari, Iwase Hitoo, Sugiyama Satoshi
Department of Internal Medicine, Fujita Health University School of Medicine, Kutsukake-cho, Toyoake, Aichi, Japan.
Acta Otolaryngol Suppl. 2004 Dec(555):28-31. doi: 10.1080/03655230410003314.
Human immunoglobulin A1 (IgA1), which is the predominant subtype to be deposited in glomeruli in IgA nephropathy (IgAN), has a unique mucine-like structure in its hinge region. Namely, it contains O-glycans and proline-rich peptides We previously observed underglycosylation of the hinge region in serum and deposited IgA1 in IgAN. On the other hand, clinical development and exacerbation of IgAN are frequently preceded by episodes of upper respiratory tract infection, and palatine tonsils represent the predominant immunocompetent tissue of the upper respiratory tract. Therefore, we hypothesized that tonsils were one of the origins of glomerular IgA1 in IgAN, and investigated the O-glycan structure of IgA1 produced by tonsillar lymphocytes (tonsillar IgA1). A significant increase in asialo-agalacto type O-glycans was found in the tonsillar IgA1 hinge in IgAN. These results suggest that the tonsils produce underglycosylated IgA1 molecules, which enter the bloodstream and are then deposited in the glomeruli.
人免疫球蛋白A1（IgA1）是IgA肾病（IgAN）中沉积于肾小球的主要亚型，其铰链区具有独特的黏蛋白样结构。也就是说，它含有O-聚糖和富含脯氨酸的肽段。我们之前观察到IgAN患者血清中铰链区糖基化不足，且IgA1沉积于肾小球。另一方面，IgAN的临床进展和病情加重常先于上呼吸道感染发作，而腭扁桃体是上呼吸道主要的免疫活性组织。因此，我们推测扁桃体是IgAN中肾小球IgA1的来源之一，并研究了扁桃体淋巴细胞产生的IgA1（扁桃体IgA1）的O-聚糖结构。在IgAN患者的扁桃体IgA1铰链区发现无唾液酸-无半乳糖型O-聚糖显著增加。这些结果表明，扁桃体产生糖基化不足的IgA1分子，这些分子进入血液循环，然后沉积于肾小球。
