High pre - transplant TREC levels indicate good prognosis after hematopoietic stem cell transplantation

Background Thymus-dependent T-cell reconstitution plays a role in immune recovery after stem cell transplantation (HSCT). High pre-HCST thymic function has been associated with higher survival, lower incidence of acute and chronic graft versus host disease (GVHD) and lower incidence of infections. The aim of this study was to analyze the relationship between pre-HSCT peripheral blood levels of T-cell receptor excision circles (TREC) and post-HSCT clinical events in recipients of HLA-identical hematopoietic stem cell transplants. Method Delta deletion signal joint TRECs (sjTRECs) formed by the dREC-yJa rearrangement were quantified by real time PCR in peripheral blood lymphocytes of 62 HSCT recipients. Results Univariate analysis revealed an association between low TREC levels and a higher incidence of grade II-IV acute GVHD (p=0.026), bacterial infection (p=0.005) and cytomegalovirus infection (p=0.033), whereas high TREC levels were associated with higher overall survival (p=0.028). In the multivariate analysis, low pre-HSCT TREC levels remained independently associated with lower survival (p=0.032; RR 2.6), occurrence of grade II-IV acute GVHD (p=0.031; RR: 2.5), bacterial infection (p=0.006, RR: 6.6) and cytomegalovirus infection (p=0.039; RR:2.8). Conclusion Our results corroborate the concept that pre-HSCT recipient ́s thymic function is an important predictor of risk for acute grade II-IV GVHD and infection. 1,2 1 3