Rabbit Antithymocyte Globulin for Treatment of Corticosteroid Refractory Acute Cellular Rejection After Lung Transplantation.

Background: Chronic lung allograft dysfunction (CLAD) remains a major cause of death after the first year posttransplant, with acute cellular rejection (ACR) being a major risk factor for CLAD. We evaluated the use of rabbit antithymocyte globulin (rATG) for corticosteroid refractory ACR in lung transplant recipients.

Methods: We retrospectively identified 112 adult lung transplant recipients who received rATG for refractory ACR after lung transplantation. The primary endpoint was the incidence of ACR on follow-up transbronchial biopsy. Secondary endpoints included freedom from ACR within 1 y post-rATG, CLAD progression at 1 y post-rATG, and all-cause mortality at 1 y post-rATG.

Results: A complete resolution of ACR was observed in 60.2% of patients, an improvement but not complete resolution in 22.1%, and no response on follow-up biopsy in 17.8%. Mean A grade 1 y post-rATG was 0.51 in complete responders, 1.01 in partial responders, and 2.19 in nonresponders ( P  < 0.001). Complete responders had significantly less new or worsening CLAD at 1 y than partial responders (17% versus 40%; P  = 0.02). All-cause mortality rate was 14.9% in complete responders, 40% in partial responders, and 30% in nonresponders ( P  < 0.01).

Conclusions: rATG appears to be an effective treatment of refractory ACR in lung transplant recipients. Failure to respond to rATG carries an increased risk of early CLAD and death.