IL-6 induces CD45 expression on myeloid cells

Objectives: Activation of IL-6 facilitates CD45 expression in myeloma cells, but little has been reported for myeloid malignancies. This study aimed to investigate whether IL-6 enhances CD45 expression on myeloid malignancies and whether myeloid cells are dependent on IL-6 activation to express CD45 on their cell membrane. Methods: This study was conducted from January to March 2022 at the Queen’s University Belfast, UK. Myeloid cell lines such as HEL and OCI-AML3 which expressed higher levels of CD45, and UT-7 and the pro-B NALM-6 cell lines that had lower CD45 levels as well as primary cells were used. The correlation between CD45 expression and IL-6 activation in myeloid cells was studied in terms of survival and response to chemotherapy such as cytarabine. Results: It was found that IL-6 enhances cellular survival in myeloid leukaemia cells. Expression of CD45 could be correlated with IL-6 activation in myeloid leukaemia cells. Quantification of IL-6 confirms the significant effect on cellular proliferation. More importantly, IL-6 significantly alters CD45 expressed myeloid leukaemia cellular response to chemotherapy such as cytarabine. Conclusion: IL-6 significantly induced alteration to cytarabine cellular response in those cells of higher CD45 expression, while its effect on cells of lower CD45 expression was minimal. This suggests the importance of CD45 in the activation of IL-6 pathway and initiation of cellular proliferation events with its consequences of cytarabine chemo resistance and enhancement of leukaemia cells survival and proliferation by inhibiting the apoptotic activities of cytarabine.