Now these glycosylated IgA1 antibodies are identified by the body and degraded IgA when too much of it accumulates.

这些糖基化的IgA1被机体识别，在其数量过多时被降解。

In IgA nephropathy, though, there is abnormal glycosylation of these serine and threonine residues, causing them to be galactose-deficient.

而在IgA肾病中，有一系列丝氨酸、苏氨酸残基异常糖基化，导致它们无法连接半乳糖。

Soon, IgA levels start rising again, and the danger passes.

不久，该蛋白水平开始增加，危险也随之过去。

IgA is the main antibody found in breast milk, tears, saliva, and the mucosal secretions of respiratory tract, gastrointestinal tract, and the genitourinary tract.

IgA是乳汁、泪液、唾液中最多的抗体，也是呼吸道黏膜、胃肠粘膜、泌尿生殖道粘膜最常见的抗体。

IgA nephropathy, sometimes known as Berger disease, is the most common form of nephropathy worldwide, and it happens when an abnormal IgA forms and deposits in the kidneys, causing kidney damage.

IgA肾病，有时也叫Berger病，是全球最常见的肾病；该病有异常IgA形成，沉积于肾，造成肾损伤。

These centroblasts have a rearrangement of their immunoglobulin genes, and some of them undergo a class switch where they change from producing IgM antibodies to producing IgG or IgA antibodies.

这部分中心母细胞的免疫球蛋白基因发生了重排，其中的一些会经历Ig类别转换，从产生IgM变成产生IgG或IgA。

Now, IgA comes in subclasses—IgA1 and IgA2, IgA1 is found mainly in the serum while IgA2 is more often found in the mucus secretions, typically in its dimeric form.

IgA分两个亚型：IgA1和IgA2；IgA1主要存在于血清中，IgA2主要以二聚体形式存在于粘膜分泌液中。

Unlike other antibodies, IgA can be secreted out in pairs, or a dimeric form called secretory IgA, which is literally two IgA antibodies attached together.

与其他抗体不同，IgA可以以成对或二聚体形式分泌，也就是两个IgA连接在一起。

IgA nephropathy is therefore a type III hypersensitivity disorder, meaning that pathology and inflammation will happen at the site the immune complexes deposit, not where they are formed.

因此IgA肾病是一种III型超敏反应，意味着病理和炎症反应会发生在免疫复合物沉积的地方，而不是发生在免疫复合物形成的地方。

Those immune complexes can also be visualized on immunofluorescence, although one important finding that can help differentiate from other immune-complex mediated nephropathies is that these complexes involve IgA.

用免疫荧光电镜也可以看到这些免疫复合物，但有一点需要注意，有助于和其他免疫复合物介导的肾病区分，就是这些免疫复合物包含IgA。