MO236: Serological Markers of Celiac Disease in Patients With IGA-Nephropathy: Prevalence and Diagnostic Significance

BACKGROUND AND AIMS It is known that IgA-nephropathy (IgAN) can be secondary to liver disease, skin disease, lung disease, etc. There is also evidence of an association between IgAN and celiac disease. In the Russian population, there are no studies aimed at identifying the prevalence of IgAN and celiac disease in adult. The aim of this study was to determine the incidence of celiac antibody (СА) in patients with IgAN and to compare the clinical and laboratory features within groups. METHOD fifty patients with IgAN were included in the study. Of these, 46 (92%) were male and 4 (8%) were female, ranging in age from 18 to 63 years. The mean age was 35.9 ± 9.8 years. All patients underwent general clinical blood and urinalysis, daily urinary protein excretion. Serum concentrations of IgA, total protein, albumin, creatinine, urea, uric acid, IgA antibodies to tissue transglutaminase (tTG), to deamidated gliadin peptide (DGP), to endomysium (EMA) and IgA and IgG antibodies to reticulin (ARA) were assessed, GFR was calculated using the CKD-EPI formula, the ‘office’ blood pressure was measured. Patients with positive CA underwent fibrogastroduodenoscopy (FGDS) with biopsy of the retro-bulbar of the duodenum. The results of the celiac marker study were compared in two groups of patients with IgAN. Group I (n = 10) were patients with IgAN and positive CA; Group II (n = 40) were patients with IgAN and negative CA. Statistical analysis of the data was performed using the SPSS 26.0. The null statistical hypothesis of no difference and no relationship was refuted at P < .05. RESULTS Positive serological markers were found in 20% of the total group of patients with IgAN. IgA antibodies to DGP were positive in 100% of cases; one patient had a one-step increase in IgA antibodies to DGP and IgA antibodies to tTG. No increase of antibodies to ARA and EMA was observed in any case. All Group I patients underwent FGDS; changes in the architectonics of the duodenum were not found. Four patients underwent biopsy of the retro-bulbar of the duodenum according to the Marsh histological classification; all biopsies were classified as Marsh 0–1. The mean concentration of protein in the urine of group I patients was 1.36 (0.76–1.58) g/L and statistically significantly higher than in group II patients 0.6 (0.4–0.93) g/L. (Р = .033). The mean daily proteinuria in celiac antibody-positive patients was 2.38 (0.78–2.8) g/day and was statistically significantly higher than in group II patients at 0.7 (0.6–1.36) g/day (Р = 0.049). We compared the incidence of arterial hypertension (AH) depending on the presence of CA in patients with IgAN. Consistent with the findings, the incidence of AH was statistically significantly higher in group I compared to group II (P = .031). The odds of AH in patients with CA were 9 times higher than in patients with negative CA [95% confidence interval (CI) 1.041–77.803]. The mean diastolic blood pressure was statistically significantly higher in group I—105.1 (96–115) mm Hg. compared to group II—92 (86–98) mm Hg (P = .032). We compared the incidence of chronic tonsillitis (CT) according to the presence of CA in patients with IgAN. According to the data, the incidence of CT was statistically significantly higher in group I compared to group II (Р = .023). The likelihood of having CT was 8.2 times higher in patients with positive antibodies than in those with negative CA (95% CI 1.461–46.272). CONCLUSION Although the patients with IgAN and positive CA did not have gastrointestinal symptoms, and FGDS with a biopsy of the retro-bulbar of the duodenum did not provide convincing evidence for a violation of the intestinal architectonics, we found statistically significant deviations in clinical and laboratory in this group of patients. Our preliminary findings suggest that an isolated increase in CA to exacerbate the course of IgAN. Whether the screening detection of CA, without disrupting intestinal architectonics, can be an additional diagnostic and prognostic marker for patients with IgAN remains a matter of debate to date. In the meantime, further research on this issue is needed, both at clinical and experimental level.