Role of severity and inflammation on the decrease of monocyte HLA-DR (MHLA-DR) in critically ill patients

Background: The critically ill patient has unique characteristics that make him part of a very delimited group of patients. One example is the transient immunosuppression that appears during their stay at ICU. One of the parameters in which this alteration is observed is the membrane expression of HLA-DR on monocytes ( _MHLA-DR). The aim of this study was to establish the factors associated with the low expression of _MHLA-DR, as measured by the percentage of monocytes expressing HLA-DR (% HLA-DR) and the quantification of HLA-DR molecules per monocyte (MFI HLA-DR). Methods: The study included 84 critically ill patients without infection at admission and without previous pathology conditioning immunosuppression. To assess severity and inflammation, we used the APACHE II and CRP variables, respectively, quantified at the time of admission. Results: We found that the higher the APACHE II and CRP values, the lower the % HLA-DR and MFI HLA-DR values. In the analysis of the robust linear regression between APACHE II and % HLA-DR, a coefficient of −0.588 was obtained, with an R ² of 0.0965 and p < 0.05. The robust linear regression between APACHE II and MFI HLA-DR obtained a coefficient of −40.5, with an R ² of 0.0679 and p < 0.05. In the analysis of the CRP value and % HLA-DR, a coefficient of −0.06092 was obtained, with an R ²: 0.285 and p < 0.05. Conclusion: The degree of immunosuppression is related to systemic inflammation and the severity of the patient.