Evaluating the Clinical Course and Prognostic Factors of Posttransplantation Immunoglobulin A Nephropathy

IntroductionPrevious reports have suggested that posttransplantation immunoglobulin (Ig) A nephropathy displays a relatively benign course, hardly ever affecting graft function. However, more recent studies with longer follow-up have shown that posttransplantation IgA nephropathy may be a significant contributor to graft loss. Additionally, there may be other clinical or pathological factors that affect long-term graft outcome. We retrospectively analyzed 30 kidney transplant recipients with biopsy-proven IgA nephropathy in their allografts to determine the clinical course and prognostic factors in posttransplantation IgA nephropathy. The median duration of follow-up was 36 months (range, 1 month–17 years). The median onset of IgA nephropathy was 33.6 months posttransplantation (range, 5 days–103 months). The most common presentation was an abnormal urine examination (96.6%). Fifteen (50%) displayed microscopic hematuria with proteinuria more than 1 g/d. Fifteen patients (50%) lost their grafts at a median time of 24 months after the onset of disease (range, 1–93 months). Allograft loss was associated with a high serum creatinine level at the time of diagnosis (3.68 ± 2.23 vs 1.79 ± 0.34 mg/dL; P = .006), a greater level of proteinuria at the time of diagnosis (2.43 ± 0.76 vs 1.29 ± 1.07 g/d; P = .003), and more than 50% extracapillary proliferation (P = .05). Fibrinoid necrosis on allograft pathology impacted 1-year allograft survival (P = .025).ConclusionPosttransplantation IgA nephropathy worsens allograft outcomes among patients with increased serum creatinine level or significant proteinuria at presentation or significant glomerular inflammation and/or tubulointerstitial damage.