title: Reduced serum level of transforming growth factor-beta in patients with IgA deficiency.
abstract: Seventeen patients with IgA deficiency, 13 subjects with selective IgA deficiency and 4 with a combined IgA and IgG2 deficiency, were assessed for serum levels of cytokines relevant for B cell differentiation. Transforming growth factor (TGF)-beta was quantified by bioassay and interleukin (IL)-4, IL-6, and IL-7 by immunoassay. The serum levels of TGF-beta were significantly lower in patients with IgA deficiency than in healthy blood donors. Of the patients with IgA deficiency, 4 had detectable IL-4 levels while 4 of the others had detectable IL-6 levels in serum. IL-4 and IL-6 were not detected in the controls. Serum IL-7 levels were similar in patients and controls. A significant, negative correlation was found between serum TGF-beta and the number of circulating B lymphocytes in the patients with IgA deficiency. No association was found between serum cytokine levels and the occurrence of infections at the time of study. Since TGF-beta has been implicated in IgA isotype switching in man, and our study demonstrates an association between low serum TGF-beta levels and IgA deficiency, dysregulation of TGF-beta might be a contributing factor in the pathogenesis of IgA deficiency.
authors.affiliation: Kaptein W. Wilhelmsen og frues Institute of Bacteriology, Oslo, Norway.
authors.forename: F
authors.initials: F
authors.lastname: Müller
authors.forename: P
authors.initials: P
authors.lastname: Aukrust
authors.forename: D E
authors.initials: DE
authors.lastname: Nilssen
authors.forename: S S
authors.initials: SS
authors.lastname: Frøland
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D017098:IgA Deficiency / Q000276:immunology*; D017099:IgG Deficiency / Q000276:immunology; D007075:Immunoglobulin M / Q000097:blood; D015847:Interleukin-4 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D015851:Interleukin-7 / Q000097:blood; D007378:Interleukins / Q000097:blood*; D007753:Laboratories / Q000592:standards; D016131:Lymphocyte Subsets / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D016212:Transforming Growth Factor beta / Q000097:blood*
chemical_list: D007075:Immunoglobulin M; D015850:Interleukin-6; D015851:Interleukin-7; D007378:Interleukins; D016212:Transforming Growth Factor beta; D015847:Interleukin-4