The role of sIgA as a noninflammatory antibody is highlighted in sIgA‐deficient patients in whom an increased risk of autoimmunity and allergy is observed.23 Extensive research of mucosal secretions supports the role of sIgA in passive and potentially active immune protection of newborns within colostrum and breast milk IgA.24 Furthermore, adult sIgA maintains homeostasis of microbiota diversity and growth and contributes to passive immunity from invading pathogens.11 In comparison, the role of serum IgA (mIgA, dIgA or pIgA) is relatively understudied. Here, CD79A is linked to Autoimmunity.