Identification And Evaluation Of Proteins Related To Renal Acute Allograft Rejection

Aims To identify proteins in the sera from the patients of renal acute allograft rejection by combined application of Tricine-SDS-PAGE electrophoresis, SELDI-TOF-MS and western-blot. To provide some dependable and sensitive markers for early diagnosis and treatment.Methods The alteration of proteome from sera between acute allograft rejection group, stable transplant group and disease comparison group was investigated by SELDI-TOF-MS. We found some proteins related to renal acute allograft rejection. There were two high content proteins with M/Z of 11731 and 9285, respectively. We studied and identified the protein with M/Z of 11731 firstly. The protein was separated by Tricine-SDS-PAGE electrophoresis and cut after staining of coomassie brilliant blue. Then we used trypsin to digest the gel. The differentially expressed peptides were analyzed by PMF based on SELDI-TOF-MS and searched in the Profound protein database. Finally we checked the protein by western-blot. We also detected its expression between acute allograft rejection group and stable transplant group to observe if the protein had a distinguished variability between them. Then we estimated the diacritic value of the protein by ROC curve plotting.Results The PMF contained the peptides had M/Z of: 1043.93, 1068.52, 1079.05, 1095.20, 1157.53, 1293.60, 1538.60, 1717.94, 1843.18, 2614.44, 2893.64, 3004.98, 3021.00, 3149.33, 3371.73, 3395.91, 3838.97, 4539.083. Searching in the Profound protein database, we found the protein was a member of the immunoglobulin superfamily. Through western-blot, we identified it asβ2-MG. The content ofβ2-MG in the acute allograft rejection group was noticeably higher than the stable transplant group(P<0.01). For aβ2-MG cut off level of 3.545 mg/L, the sensibility was 90% and the specificity was 90.5%. The increase ofβ2-MG in the sera of the acute allograft rejection group was significantly earlier than the creatinine and clinical symptom.Conclusions We used SELDI-TOF-MS and western-blot to identifyβ2-MG as a protein related to renal acute allograft rejection. Our study proved combined use of that SELDI-TOF-MS and western-blot could identify unknown proteins. Compared to creatinine, clinical symptom and histopathological examination, the value ofβ2-MG is higher. These results could provide a reference to the study of the occurrence and progression of acute allograft rejection.