Salah H Elsafi, Mohamed M Abu Hassan, Alexander Woodman, Suliman Y Al Omar, Lamjed Mansour, Hafez Halawaani, Huda A Ahmed
Although MAIT cells regulate the pathogenesis of various inflammatory diseases, their roles in the development of colorectal cancer are still unclear. The objective of this study is to investigate the level of circulating MAIT cells and the level of expression of the membranous KIRs receptors among CRC patients and control subjects. A total number of 89 subjects were recruited, 46 of them represented the patients who were diagnosed with colorectal cancer during the study. The remaining 43 subjects represented normal healthy control. The cases in this group were blood bank donors who visited the same medical center and did not have a known personal or family history of cancer. Peripheral blood mononuclear cells (PBMCs) were isolate and of MAIT cells were phenotypically identified by flow cytometry using various monoclonal antibodies. The presence of HLA-C1 and HLA-C2 groups were typed by PCR.
High frequency of HLA-C2 among patients with CRC (87%) compared with control subjects (74.4%). The frequency of HLA-C1 was higher in control subjects (72.1%) compared with CRC patients (65.2%). In addition, genotype distribution showed that the frequencies of HLA-C1C2 washigher in CRC patients (52.2%) compared with control subjects (48.8%). Although statistically insignificant, the percentage of MAIT cells were higher in CRC patients compared to control subjects. The percentage of MAIT cells was higher in patients with CRC in stage III and IV, but lower in stage II compared with control subjects. The protein expression of MAIT cells associated phenotyping antigens and some KIR receptors such as CD45RA, CD45RO, CD62L, CD11a, CD158a, CD158b, CD158e and CD158f were reported. A relatively lower percentage of CD45RA expression was seen in CRC patients compared with control subjects. There was a significant reduction in CD45RO, CD62L, CD158a, CD158e and CD158f expression in CRC patients. Stratification analysis of 46 CRC patients indicated that the percentages of circulating MAIT cells were lower in stage II and higher in stages III, and IV. The frequencies of circulating MAIT cells had not been reduced in patients with colorectal cancer.