Risk factors for impaired CD4(+) T-cell reconstitution following rabbit antithymocyte globulin treatment in kidney transplantation

To describe long-term CD4(+) T-cell reconstitution after rabbit antithymocyte globulin (rATG) treatment and identify predictive factors following kidney transplantation. A single-center retrospective study analyzed lymphocyte subsets in rATG-treated kidney transplant recipients (1986–2009). 589 patients were analyzed (maximum follow-up 21 years). A comparator group (n = 298) received an anti-IL-2 receptor monoclonal antibody. CD4(+) T-cell lymphopenia (<200/mm(3)) was present in 48.5%, 9.2%, 6.7%,2.0%, and 0% of patients at one, three, five, 10, and 20 years post-transplant, respectively. CD4(+) T-cell count increased during the first 10 years but remained below the pretransplant count even after 20 years. At 1, 3, and 6 months post-transplant, mean CD4(+) T-cell count was significantly lower in patients with CD4(+) T-cell lymphopenia at 12 months versus patients without lymphopenia. On multivariate analyses, significant independent predictors for long-term impaired CD4 T-cell reconstitution were recipient age, pretransplant CD4(+) T-cell count, 12-month CD4(+) T-cell count, and tacrolimus or MMF therapy. Recipient age >40 years was identified as a cutoff point. CD4(+) T-cell reconstitution following rATG treatment remains impaired even after 21 years. Most risk factors for long-term impaired CD4(+) T-cell reconstitution may be evaluated pretransplant or are modifiable post-transplant.