The recurrence of IgA nephropathy (IgAN) after kidney transplantation is frequent and can cause graft losses. The prediction of the recurrence cannot be performed from the only clinical parameters, but could rely on biomarkers. The aim of our study was to assess the ability of the quantitative measurement of (i) the galactose deficient IgA1 (Gd-IgA1),the auto-antigen of the disease, and (ii) the Gd- IgA1-specific IgG and IgA (autoantibodies) to predict the recurrence of IgAN after renal transplantation.

We selected 96 consecutive first-renal-transplant recipients with IgAN as native disease (70 men; 92 deceased donors; mean age=48.1 yr) under calcineurin inhibitors and followed them over 10 yr for long-term outcomes: death, allograft failure, and clinico-pathological recurrence (CPR, clinically evident and all biopsy-proven). We used sera obtained at time of transplantation (for all recipients) and at time of diagnosis of native-kidney IgAN (30 patients only) to measure levels of Gd-IgA1 and levels of Gd- IgA1-specific IgG and IgA autoantibodies. Control sera were from 30 healthy individuals. The predictive value of these markers for CPR was assessed by time dependent Cox regression analysis and receiver operating characteristic (ROC) curves.

Overall, 13 patients died, 34 kidneys failed (17 due to CPR), and 34 recipients developed CPR after a mean interval of 5.85 yr. Serum Gd-IgA1 level was significantly elevated at time of transplantation and at diagnosis, but did not predict CPR. Normalized serum IgG autoantibody was significantly elevated at time of transplantation, had been even higher at diagnosis, and predicted CPR: hazard ratio 2.68 (confidence interval: 1.26-5.71), p=0.01 and by ROC curve: area under the curve 0.622 [0.505-0.739], p=0.05; it kept its prediction value when tested with significant clinical covariates. The IgA autoantibody level did not change between diagnosis and transplantation and was not predictive of outcome, except for a significant association with allograft loss due to CPR.

This study emphasizes the prediction value of normalized IgG anti-glycan autoantibody.

CITATION INFORMATION: Maillard N, Suzuki H, Mohey H, Mariat C, Novak J, Julian B, Berthoux F. Predictive Value of Serum Biomarkers of Autoimmunity for Recurrence of IgA Nephropathy After Kidney Transplantation. Am J Transplant. 2017;17 (suppl 3).

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