Pretransplant CD28 Biomarker (Levels of Expression and Quantification of Molecules per Cell) in Peripheral CD4+ T Cells Predicts Acute Rejection Episodes in Liver and Kidney Recipients

Background. Acute rejection (AR) remains a significant cause of graft loss. Better approaches to predict AR are being investigated. Surface CD28 protein is essential for T-cell proliferation and survival as well as cytokine production. Patients and Methods. Pretransplant CD4(+)CD28(+) peripheral T cells were examined in 30 liver recipients (LRs) and 31 kidney recipients (KRs) by flow cytometry. Results. Pretransplant CD4(+)CD28(+) T cells in LRs were significantly lower in rejectors than nonrejectors (P = .002). Furthermore, the total number of CD28 molecules per cell in LRs (P = .02) as well as KRs (P = .047) was significantly lower in rejectors than non rejectors. The healthy group did not display differences when compared with patients with end-stage liver disease or renal failure; however, stratification analysis displayed higher levels of CD4(+)CD28(+) when compared with rejected LRs (P = .04) but not KRs. CD28 levels <41.94% were able to discriminate LRs at high risk of AR (P = .003). Similarly, a total number of CD28 molecules <= 8359 (P = .031) in LRs and <= 7669 (P = .046) in KRs correlated with high risk of AR. Conclusion. The preliminary results presented herein exhibit a fast and noninvasive method that assists clinicians to prevent AR by monitoring CD4(+)CD28(+) peripheral T cells.