Chronological Change of the Serum IgA/C3 Ratio Indicates the Efficacy ofTonsillectomy for IgA Nephropathy

Background/aims: Although the serum IgA/C3 ratio is a good biomarker to predict the diagnosis, histological findings, and prognosis of IgA nephropathy (IgAN), the chronological change of the IgA/C3 ratio has not been discussed. The present study evaluates the chronological change of the IgA/C3 ratio. Methods: The serum IgA/C3 ratio of 43 IgAN patients was measured at the time of biopsy and on the nearest consultation day in an outpatient clinic since April 30th, 2014. The change rate of the serum IgA/C3 ratio (�IgA/C3/ year) was calculated. The correlation between �IgA/C3/year and other parameters, including the change rate of serum creatinine (�Cr/year), clinical and histological grades, and the risk stratification for end-stage kidney disease (ESKD) in IgAN patients determined by Japanese Society of Nephrology (JSN). Results: The patients with tonsillectomy had a smaller �IgA/C3/year than those without tonsillectomy. �IgA/C3/ year was positively correlated with �Cr/year. �IgA/C3/year decreased along with the severity of histological grade, clinical grade, and ESKD risk. The patients with a combination of tonsillectomy and steroid pulse therapy show a strong down-regulation of �IgA/C3/year and conserved their renal function. A multiple regression analysis revealed that significant enhancers for �IgA/C3/year are tonsillectomy and ESKD risk grade 3, and that those for �Cr/year are tonsillectomy, steroid therapy, and the clinical grade. Conclusion: The serum IgA/C3 ratio does not only show the activity of IgAN, but also the chronological change of the IgA/C3 ratio indicates the efficacy of tonsillectomy for IgAN patients.