Pediatric Nephrology
March 2015, Volume 30, Issue 3, pp 451-457
Effect of plasma exchange and immunosuppressive medications on antibody titers and outcome in anti-complement factor H antibody-associated hemolytic uremic syndrome
Priyanka Khandelwal, Aarti Gupta, Aditi Sinha, Savita Saini, Pankaj Hari, Marie-Agnes Dragon Durey, Arvind Bagga

Abstract
Background
Anti-complement factor H (anti-CFH) antibody-associated hemolytic uremic syndrome (HUS) is an important cause of acute kidney injury in Indian children. While management comprises plasma exchange and immunosuppression, information on the impact on serial antibody titers and outcomes is limited.
Methods
This retrospective study included 45 patients with anti-CFH-associated HUS who were followed for ≥12 months. Following the initial plasma exchange sessions, patients received prednisolone and either intravenous (IV) cyclophosphamide (n = 31) or IV rituximab (n = 14), followed by maintenance immunosuppression.
Results
The median anti-CFH antibody titers fell from 3,215.5 [interquartile range (IQR) 1,977.9–8,453.9 to 414.6 (IQR 251.6–1,368.2) AU/ml with plasma exchange therapy (P < 0.0001), and the decline was similar with three, five, or seven plasma exchange sessions (P = 0.08). Serial anti-CFH titers were similar in patients receiving IV cyclophosphamide- and rituximab-based regimens during the 12-month follow-up (P = 0.63). Renal outcomes and relapse frequencies at the 15.4-month follow-up were comparable. Seven patients relapsed 6.5 (IQR 2.2–12.3) months from treatment onset. Patients with relapse had higher antibody titers during remission (P = 0.017). Titers of ≥1,300 AU/ml at 6 months predicted subsequent relapses.
Conclusions
Our patients with anti-CFH antibody-associated HUS showed a significant fall in antibody titers following daily plasma exchange sessions. Therapy with cyclophosphamide- or rituximab-based regimens was associated with similar outcomes and a comparable decline in antibody titers.
Keywords
Plasma exchange Rituximab Thrombotic microangiopathy Cyclophosphamide Complement factor H