Evaluation of Toll-like,chemokine, and integrin receptors on monocytes and neutrophils from peripheral blood of septic patients and their correlation with clinical outcomes

Recognition of pathogens is performed by specific receptors in cells of the innateimmune system, which may undergo modulation during the continuum of clinicalmanifestations of sepsis. Monocytes and neutrophils play a key role in host defenseby sensing and destroying microorganisms. This study aimed to evaluate the expressionof CD14 receptors on monocytes; CD66b and CXCR2 receptors on neutrophils; and TLR2,TLR4, TLR5, TLR9, and CD11b receptors on both cell types of septic patients.Seventy-seven septic patients (SP) and 40 healthy volunteers (HV) were included inthe study, and blood samples were collected on day zero (D0) and after 7 days oftherapy (D7). Evaluation of the cellular receptors was carried out by flow cytometry.Expression of CD14 on monocytes and of CD11b and CXCR2 on neutrophils from SP waslower than that from HV. Conversely, expression of TLR5 on monocytes and neutrophilswas higher in SP compared with HV. Expression of TLR2 on the surface of neutrophilsand that of TLR5 on monocytes and neutrophils of SP was lower at D7 than at D0. Inaddition, SP who survived showed reduced expression of TLR2 and TLR4 on the surfaceof neutrophils at D7 compared to D0. Expression of CXCR2 for surviving patients washigher at follow-up compared to baseline. We conclude that expression of recognitionand cell signaling receptors is differentially regulated between SP and HV dependingon the receptor being evaluated.