MAIT Cell Proliferation Is a Potential Early Diagnosis Marker for Blood Stream Infection in AML Patients

Objectives To explore the role and dynamics of MAIT (Mucosal-associated invariant T) cells in blood stream infection of AML (Acute myeloid leukemia) patients. Methods Healthy adults and hospitalized adult AML patients that with blood stream infection, non-infection, or in completely remission (CR) were prospectively enrolled. Characteristics of MAIT cells in peripheral blood of enrolled subjects were analyzed by flow cytometry. Results Both gram negative and gram positive bacteria could induce sepsis in AML patients. MAIT cells significantly increased in AML patients with blood stream infection comparing with non-infected AML patients, healthy subjects and AML patients in completely remission. Increased MAIT cells were mainly consists of CD8+ T cells and were activated. There is no significant difference in the recruitment and death of MAIT cells, while their proliferation is significantly increased. The proliferation of MAIT cells occurs before traditional infection indicators such as CRP, PCT, endotoxin in plasma and fever. MAIT cells in neutropenic blood stream infected mice were increased as we observed in AML patients. Conclusions MAIT cells increased without bacterial specificity, and were activated and proliferated in AML patients with blood stream infection that caused by various bacteria. They may enhance host defense and play a vital role in fighting against pathogenic microbial infections. Proliferation of MAIT cells can be applied as a monitoring indicator for blood stream infection in AML patients, which helps to reduce the mortality rate of them. No relevant conflicts of interest to declare.