Early on, minutes after the exposure to the allergen, smooth muscle around the bronchioles start to spasms and there is increased mucus secretion.

早期，在接触过敏原的几分钟后，细支气管周围的平滑肌开始痉挛，粘液分泌增多。

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。