Decreased monocyte surface expression of HLA-DQ is associated with prolonged duration of septic shock

There is increasing evidence for a protective role of Human-Leukocyte-Antigen (HLA)-DQ in response to infection. This study was performed: (1) to investigate the kinetics of monomorphic (m)HLA-II (HLA-DR,-DP,-DQ) and HLA-DQ expression on monocytes during septic shock; (2) to clarify whether maintaining mHLA-II and HLA-DQ expression within normal range (NR) could predict improved recovery and survival. In total, 16 patients (11 males, 5 females) in septic shock have been investigated. mHLA-II and HLA-DQ median fluorescence intensity (MFI) on monocytes have been monitored daily using flow cytometry. Normal range was determined in 19 healthy volunteers. MFI of mHLA-II and HLA-DQ expression throughout septic shock was significantly reduced when compared to control (P < 0.05). All patients showed median mHLA-II expression below normal range regardless of duration of septic shock and survival. In contrast, median HLA-DQ expression demonstrated negative correlation with the duration of septic shock (Phi-square = 0.73). Patients with HLA-DQ below normal range showed almost a three-fold prolonged term of septic shock as compared to patients with HLA-DQ expression within normal range (15.2 ± 6.3 days versus 5.5 ± 1.7 days; P < 0.015). Although, there was no correlation between median HLA-DQ and survival, all non-survivors showed HLA-DQ expression below normal range. In conclusion, HLA-DQ expression below normal range may predict prolonged duration of septic shock and increased mortality and could be an indicative marker of immune surveillance in critically ill patients.