Alternate-Day Versus Consecutive-Day Anti-T Lymphocyte Globulin Induction in First Living-Donor Kidney Transplant Recipients at Low Immunological Risk: A Retrospective Cohort Study

Background/Objectives: Anti-T lymphocyte globulin (ATLG) is widely used as induction therapy in kidney transplantation; however, the clinical impact of the interval between individual ATLG doses remains poorly defined. We compared alternate-day and consecutive-day ATLG administration in first living-donor kidney transplant recipients at low immunological risk. Methods: This retrospective single-center cohort study included 195 first living-donor kidney transplant recipients who received ATLG induction therapy (alternate-day, n = 97; consecutive-day, n = 98). All recipients underwent their first kidney transplantation, received grafts from related living donors, were negative for donor-specific antibodies before transplantation, and received standardized maintenance immunosuppression. ATLG was initiated at approximately 2.0–2.5 mg/kg per administration, with subsequent doses individualized according to peripheral CD3+ T-cell and lymphocyte counts. The primary outcome was the occurrence of at least one bacterial infection during the first post-transplant year. Secondary outcomes included biopsy-proven acute rejection, BK virus and cytomegalovirus (CMV) positivity, graft function, graft loss, and patient survival; rejection, graft loss, and mortality were recorded throughout the available follow-up. Multivariable logistic regression analysis was performed to identify independent predictors of bacterial infection. Results: Baseline recipient and donor characteristics were generally comparable between groups, although recipients receiving consecutive-day ATLG had higher rates of PRA class I and II positivity. Cumulative weight-adjusted ATLG exposure was comparable between the alternate-day and consecutive-day groups (7.4 [7.1–7.8] vs. 7.2 [5.4–10.2] mg/kg, p = 0.207). The incidence of bacterial infection during the first post-transplant year was virtually identical in the alternate-day and consecutive-day groups (50.5% vs. 50.0%, p = 1.000). Likewise, no significant between-group differences were observed in biopsy-proven acute rejection (2.1% vs. 8.2%, p = 0.100), BK virus positivity (18.6% vs. 14.3%, p = 0.446), CMV positivity (17.5% vs. 12.2%, p = 0.321), graft loss (4.1% vs. 4.1%, p = 1.000), or all-cause mortality (7.2% vs. 4.1%, p = 0.372). In multivariable analysis, the ATLG administration schedule was not independently associated with bacterial infection (adjusted OR 1.21, 95% CI 0.64–2.30, p = 0.560). Recipient body mass index was the only independent predictor of bacterial infection (adjusted OR 1.08 per kg/m2, 95% CI 1.00–1.15, p = 0.041). Conclusions: Among first living-donor kidney transplant recipients at low immunological risk, alternate-day ATLG administration was associated with a similar incidence of bacterial infection during the first post-transplant year. When cumulative weight-adjusted ATLG exposure was accounted for, the interval between individual doses was not independently associated with bacterial infection. Crude secondary-outcome comparisons should be interpreted cautiously because overall follow-up differed between groups. These findings support further prospective evaluation of flexible ATLG administration schedules in carefully selected kidney transplant recipients.