Preliminary results in quantitation of HLA-DRA by real-time PCR: a promising approach to identify immunosuppression in sepsis

Abstract

Introduction: Reduced monocyte human leukocyte antigen (mHLA)-DR surface expression in the late phase of sepsis is postulated as a general biomarker of sepsis-induced immunosuppression and an independent predictor of nosocomial infections.

Methods: Fifty-nine patients with sepsis and blood culture growing pathogenic bacteria were studied. Blood samples were collected at day 1 or 2 after admission, for measurement of mHLA-DR by flow cytometry and mRNA expression of HLA-DRA and class II transactivator (CIITA) by qRT-PCR. Blood samples from blood donors were used as controls (n = 30).

Results: A significant reduced expression of mHLA-DR, HLA-DRA, and CIITA was seen in septic patients compared with controls. HLA-DRA mRNA level in whole blood was highly correlated with surface expression of mHLA-DR.

Conclusions: Patients with sepsis display a diminished expression of HLA-DR at the monocyte surface as well as in the gene expression at the mRNA level. The mRNA expression level of HLA-DRA monitored by qRT-PCR correlates highly with surface expression of HLA-DR and appears to be a possible future biomarker for evaluation of immunosuppression in sepsis.

Figure 1

HLA-DR expression in septic patients with different sepsis severity. mRNA expression levels (A) and monocyte surface expression (B) of human leukocyte antigen (HLA)-DR at day 1 or 2 after admission. Statistical differences between septic patients and controls were demonstrated in both HLA-DRA (A) (P = 0.036) and mHLA-DR (B) (P <0.0001) expression. Significant differences were demonstrated in HLA-DRA (A) (P = 0.009) and mHLA-DR (B) (P = 0.029) expression when the severity groups of non-severe (n = 48) and severe sepsis/septic shock (n = 11) were compared.

Figure 2

HLA-DRA in relation to mHLA-DR. mRNA expression levels of HLA-DRA in whole blood and monocyte surface expression of HLA-DR in 59 patients with sepsis at day 1 or 2 after admission.

Figure 3

HLA-DR expressions in Gram-positive and Gram-negative non-severe sepsis. mRNA expression levels (A) and monocyte surface expression (B) of human leukocyte antigen (HLA)-DR at day 1 or 2 after admission. Significant differences were demonstrated in both mRNA expression levels of HLA-DRA (A) (P = 0.022) and monocyte surface expression of HLA-DR (B) (P = 0.003) when the groups of Gram-positive and etiology were compared.