Monitoring t cell kinetics at early recovery period of lung transplantation cases by TCR excision circle (TREC) levels

T Cell Receptor Excision Circle is the circular DNA, produced during T cell receptor gene rearrangement in the thymus and indicates naive T cell migration from thymus, which is called thymic output. Even though thymus involutes and becomes adipose tissue after puberty (thymic involution), it continues to support peripheral T cell pool. 33 samples obtained from 11 patients were included. In this study, we aimed to reveal thymic output's short term effects on post-transplantation progress. TREC copy numbers were analysed with RT-PCR (Real Time Polymerase Chain Reaction). For the second stage of the study, pro-inflammatory cytokine levels were measured with bead based array on flow cytometry. According to results; compared to post operational values, elevations of neutrophil percentages on 24 hours and 7 days were found statistically significant (p:0.003; p<0.05). Average MPO and sICAM-1 values of patient group were found significantly higher than control group (p:0.003; p<0.05). Post-operational sTNF-R (p:0.008; p<0.05) and MCP-1 (p:0.038; p<0.05) values on 24 hours; and IL-6 (p:0.011; p<0.05) value on day 7, compared to 24 hours were found significantly different. Decrease of lymphocyte percentages after transplantation compared to pre-operation are statistically significant (p:0.003; p<0.05). Post operational 1x106 TREC numbers and TREC/ml values were found higher compared to pre- operational values, but differences are not statistically significant. All these results together suggest that naive T cell migration from thymus increases as a result of peripheral lymphocyte loss.