Gluten-induced experimental IgA glomerulopathy.

The effect of alimentary gluten and of its lectin-like fraction gliadin in inducing IgA mesangial deposits in BALB/c mice was investigated. In the pilot study G1 (4 mice), G2 (4 mice) and G3 (6 mice) received ovalbumin, human gamma-globulins, and crude gluten, respectively. The antigens, 1 mg/ml, were given in drinking water for 14 weeks. G4 (20 mice) were fed with standard mouse fodder. Gluten, as well as other alimentary antigens, induced IgA mesangial deposits with intense IgA staining in each animal, however a positive IgA staining was also observed in 10 of 20 adult controls. Antigliadin IgA antibodies were detected in renal tissue eluates from gluten-immunized mice but were found in eluates from control animals too. IgA deposits and antigliadin IgA in renal tissue were also observed in 3 of 7 adult mice (G7) fed for 30 weeks with standard fodder, then for 1 month with a protein-free diet supplemented with 20% amino acids. Conversely, there were no IgA mesangial deposits or IgA anti-gliadin antibodies in renal eluates of 1- or 2-week-old mice (G5 and G6). For the definitive protocol, 4-week-old BALB/c mice were selected and fed with basal glutenfree diet. G8 (14 mice) did not receive any alimentary immunogen in the drinking water, whereas G9 (15 mice) and G10 (15 mice) received ovalbumin and gliadin, respectively. G11 (15 mice) had standard gluten-containing diet. IgA deposits semiquantified by immunofluorescence scores were found to be significantly greater in G9 and G10 than in G8 (Student' t-test p1 less than 0.003, Mann-Whitney test p2 less than 0.001 and p1 less than 0.01, p2 less than 0.007, respectively), and in G11 than in G8 (p1 and p2 less than 0.05). The presence of positive IgA staining (greater than or equal to 2/6 scores) was significantly less frequent in G8 in comparison to G9 (chi-square test p3 less than 0.002), G10 (p3 less than 0.02) and G11 (p3 less than 0.04). Total serum IgA were significantly higher in orally immunized G9 and G10 than in G8 control mice (p1 less than 0.005, p2 less than 0.002). Anti-gliadin IgA in circulation as well as in renal deposit eluates were significantly increased in gluten-eating mice (G10 and G11) as compared with the gluten-free control group G8. These observations indicate that gliadin does induce IgA immune deposits in BALB/c mice.(ABSTRACT TRUNCATED AT 250 WORDS)