Serum CXCL8 Concentration Can Be Used as a Noninvasive Marker of Subclinical Rejection After Pediatric Liver Transplantation

Background. This study aimed to explore whether serum CXCL8 concentration can be used as a noninvasive marker of subclinical rejection (SCR) after pediatric liver transplantation (pLT). Methods. Firstly, RNA sequencing (RNA-seq) was performed on 22 protocol liver biopsy samples. Secondly, several experimental methods were used to verify the RNA-seq results. Finally, the clinical data and serum samples of 520 LT patients in the Department of Pediatric Transplantation of Tianjin First Central Hospital from January 2018 to December 2019 were collected. Results. RNA-seq results indicated that CXCL8 was significantly increased in the SCR group. The results of the 3 experimental methods were consistent with RNA-seq results. According to the 1:2 propensity score matching, 138 patients were divided into the SCR (n = 46) and non-SCR (n = 92) groups. Serological test results indicated that there was no difference in preoperative CXCL8 concentration between the SCR and non-SCR groups ( P > 0.05). However, during protocol biopsy, CXCL8 in the SCR group was significantly higher than in the non-SCR group ( P < 0.001). In diagnosing SCR, receiver operating characteristic curve analysis showed that the area under the curve of CXCL8 was 0.966 (95% confidence interval, 0.938-0.995), sensitivity was 95%, and specificity was 94.6%. In differentiating nonborderline from borderline rejection, the area under the curve of CXCL8 was 0.853 (95% confidence interval, 0.718-0.988), sensitivity was 86.7%, and specificity was 94.6%. Conclusions. This study demonstrates that serum CXCL8 concentration has high accuracy for the diagnosis and disease stratification of SCR after pLT.