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

Abstract

IntroductionReduced 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.However, traditional monitoring of mHLA-DR by flow cytometry has disadvantages due to specific laboratory requirements. An mRNA-based HLA-DR monitoring by polymerase chain reaction (PCR) would improve the clinical usage and facilitate conduction of large multicenter studies. In this study, we evaluated an mRNA-based HLA-DR monitoring by quantitative real-time PCR (qRT-PCR) as an alternative method to traditional flow cytometry.MethodsFifty-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).ResultsA 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.ConclusionsPatients 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.

Immune Cell Phenotype and Function in Sepsis

“…Microarray analysis of genes involved in inflammation revealed the modulation of genes further confirmed by quantitative RT-PCR (85). RT-PCR has also been used to study the decrease of HLA-DR expression in monocytes at gene level with promising results (86). Genotyping of HLA-DRB1 identified 4 alleles associated with a lower need of renal replacement therapies in patients with sepsis-associated AKI (87).…”

Release of Danger-Associated Molecular Patterns following Chemotherapy Does Not Induce Immunoparalysis in Leukemia Patients

“…These DAMPs elicit an immune response in a similar manner to the pathogen-associated molecular patterns (PAMPs) derived from invading pathogens in infectious diseases such as sepsis [7,8], but they may subsequently also result in the deactivation of the immune system, a phenomenon known as immunoparalysis in the sepsis field [9,10]. Two major hallmarks of immunoparalysis that are related to immune cell dysfunction are (1) the attenuated production of cytokines by leukocytes ex vivo stimulated with PAMPs like lipopolysaccharide (LPS), and (2) decreased leukocyte HLA-DR expression [9,11]. As such, DAMP-induced leukocyte immune dysfunction could contribute to the decreased function of the remaining immune cells in leukemia patients treated with chemotherapy.…”

Non-neoplastic portal vein thrombosis in HCV cirrhosis: the weight of inflammation on a fragile hemostatic balance

“…Along with hemostatic parameters they found a reduction in HLA-DR expression in PVT-groups and increased levels of monocyte co-stimulatory molecule CD46 independently by the presence of cirrhosis. These indexes of profound immunological disturbance (15,16) are coherent, although not specific, with the link between immune-system and hemostasis and warrant further investigations. The absence of differences between cirrhotic and non-cirrhotic PVT suggests the determinant role of immune system in the susceptibility to PVT whatever the degree of liver damage.…”