Polyclonal anti T-lymphocyte antibody therapy monitoring in kidney transplant recipients: comparison of CD3+ T cell and total lymphocyte counts.

OBJECTIVE: To investigate the correlation between total lymphocyte and CD3+ T cell counts in peripheral blood in renal transplant patients treated with anti-thymocyte globulin, and discuss related outcomes.

METHODS: A single-center, retrospective study involving 226 patients submitted to kidney transplant between 2008 and 2013, and treated with anti-thymocyte globulin for induction or treatment of cellular rejection. Doses were adjusted according to CD3+ T cell or total lymphocyte counts in peripheral blood.

RESULTS: A total of 664 paired samples were analyzed. The Spearman's correlation coefficient was 0.416 (p<0.001) for all samples combined; the overall Kappa coefficient was 0.267 (p<0.001). Diagnostic parameters estimated based on total lymphocyte counts were also calculated using the number of CD3+ T cells (gold standard), with a cut off of >20 cells/mm3.

CONCLUSION: Total lymphocyte and CD3+ T cell counts in peripheral blood are not equivalent monitoring strategies in anti-thymocyte globulin therapy.