Evaluation of systemic and secretory IgA concentrations and immunohistochemical stains for IgA-containing B cells in mucosal tissues of an Irish setter with selective IgA deficiency.

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Immunoglobulin A is the predominant secretory antibody at mucosal surfaces . In the dog , immunoglobulin A deficiency (IgAD ) is characterized by low to absent serum IgA and normal to elevated serum immunoglobulin G (IgG ) and immunoglobulin M (IgM ) concentrations . However , studies comparing serum and secretory IgA in dogs have often documented a poor correlation , suggesting that serum concentrations should not be used to estimate mucosal secretion of this antibody . This report demonstrates the concurrent use of serum IgA , IgG , and IgM ; secretory IgA (from bronchoalveolar lavage fluid ); and immunohistochemical stains on bronchial and duodenal mucosa for IgA-containing B cells in a young Irish setter with recurrent respiratory and gastrointestinal signs .