[Relationship between intestinal permeability and antibodies against food antigens in IgA nephropathy]

Elevated antibody titers to food antigens and increased intestinal permeability in IgA nephropathy (IgA NP) suggest that these factors may be interdependent and play a role in the pathogenesis of the disease. In 1989 IgA and IgG antibodies against eight common food antigens were examined in the sera of 35 IgA NP patients and 12 controls using the ELISA method. Intestinal permeability was determined in 29 IgA NP patients and 20 controls using the 51Cr-EDTA test. Both examinations were carried out in 17 patients. Twenty-one patients allowed the intestinal permeability examinations to be repeated five years later. Compared with controls, significantly elevated IgA antibody titers against gliadin, soy, HAV (salt extracted antigens of oat flour) and ovalbumin were found. Intestinal permeability was significantly higher in IgA NP patients both in 1989 (3.86% +/- 0.29 vs. control, 2.72% +/- 0.23; p < 0.005) and in 1994 (4.57% +/- 0.63; p < 0.02) than in controls. A strong correlation was observed between the intestinal permeability and the IgA type of antibody titers against soy (p < 0.01; r = 0.72) and HAV (p < 0.02; r = 0.57). In patients without azotemia (serum creatinine > 150 mumol/l; n = 22) the decrease in creatinine clearance was significant only in the cases of increased intestinal permeability. On the basis of these data we assume that there is a connection between intestinal permeability and the production of IgA type antibody against food antigens in least a proportion of patients with IgA NP, and as a results of the lasting increase in intestinal permeability the production and the mesangial deposition of IgA immunocomplexes also increase.