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Background: In anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, antigen specificity varies between myeloperoxidase (MPO) and proteinase 3 (PR3). This has been reported to vary in relation to age, gender, geography and extrarenal manifestations. However, studies are difficult to compare as criteria for inclusion vary. The aim of this study was to investigate the relationship between ANCA serotype, latitude, ultraviolet (UV) radiation levels, age, gender and renal function at diagnosis in a large study with uniform inclusion criteria., Methods: Patients with biopsy-proven ANCA-associated glomerulonephritis were identified from regional or nationwide registries in 14 centres in Norway, Sweden, the UK, the Czech Republic, Croatia, Italy and the USA during the period 2000-13. UV radiation levels for 2000-13 in Europe were obtained from the Swedish Meteorological and Hydrological Institute., Results: A total of 1408 patients (45.2% PR3-ANCA) were included in the study. In univariable analysis, PR3-ANCA was significantly associated with male gender {odds ratio [OR] 2.12 [95% confidence interval (CI) 1.71-2.62]}, younger age [OR per year 0.97 (95% CI 0.96-0.98)] and higher glomerular filtration rate [OR per mL/min 1.01 (95% CI 1.01-1.02); P < 0.001] at diagnosis but not with latitude or UV radiation. In multivariable logistic regression analysis, latitude and UV radiation also became significant, with higher odds for PR3-ANCA positivity at northern latitudes/lower UV radiation levels. However, the latitudinal difference in MPO:PR3 ratio is smaller than differences previously reported concerning microscopic polyangiitis and granulomatosis with polyangiitis., Conclusions: The ratio between PR3-ANCA and MPO-ANCA varies in glomerulonephritis with respect to age, gender, renal function and geographic latitude/UV radiation levels.

Background: Helminth infections were reported to slightly modulate the host immune system response and decrease the risk of an autoimmune disorder, but on the other hand any infection may activate the immune system and trigger autoimmune reaction. In this study, we aimed to measure eosinophil levels and antibodies against Toxocara spp. in patients with clinically isolated syndrome (CIS) and multiple sclerosis (MS)., Methods: In total, 220 CIS patients and 62 MS patients were examined. Antibodies against Toxocara secretory/excretory antigens (TES) were measured with an ELISA method., Results: A total of 1,983 measurements of eosinophil levels were performed in CIS patients, out of which 95 results in 21 different patients were above the upper normal limit of the laboratory, but it was mostly only a relative increase. Two patients showed eosinophil levels above 20 % but both of them suffered from severe allergy. None of the CIS patients had any clinical signs of parasitic infections and the serological tests for antibodies against Toxocara were all negative. In all MS patients, eosinophil levels were in normal range. Antibodies against TES were detected in only 1 out of 62 (1.6%) MS patients., Conclusions: Based on our results it does not seem that Toxocara infection represents a potential trigger of MS. Nevertheless, our study indirectly confirms the hypothesis that parasitic infection may protect from autoimmunity.