Investigation of the role of interleukin 27 in the immune regulation of Treg and Th17 cells in neurosyphilis patients.

Abstract

Neurosyphilis (NS) is known as a sexually transmitted disease that is very difficult to diagnose and its diagnosis is delayed. Some studies have suggested that the level of interleukin (IL)-27 decreases in syphilis patients and the level of IL-17 increases in these patients, and these immunological changes can be a therapeutic target for these patients. The present study aims to evaluate IL-27's role in the immune regulation of Treg and Th17 cells in NS patients. 400 documented diagnosed syphilis patients were enrolled to the study and divided into two groups of neurosyphilis (NS) and non-neurosyphilis (S). Also 40 healthy volunteers were enrolled as a healthy control group (C). Peripheral blood mononuclear cells (PBMCs) from peripheral blood and cerebrospinal fluid (CSF) by lumbar puncture were collected as samples. mRNA expression and level of IL-27, IL-17, Th17, IL-17-producing CD4 + T cells and also protein concentration and VDRL of CSF were investigated. To obtain proposed results, flow cytometry, RT-PCR and ELISA were used. The mRNA expression of IL-27 in PBMCs declined significantly in NS patients compared to healthy controls ( p = 0.002) and S patients ( p = 0.005) and decreased significantly in CSF of NS patients in comparison to healthy controls ( p = 0.002) and S patients ( p = 0.003). The frequency of IL-17-producing CD4 + T cells increased significantly in PBMCs of NS patients in comparison to healthy controls ( p = 0.004) and S patients ( p = 0.004). This frequency also increased significantly in CSF of NS patients compared to C ( p = 0.007) and S patients ( p = 0.003). Adding rIL-27 significantly prevented the frequency of IL-17-producing CD4 + T cells from naïve CD4 + T cells under Th17 polarizing conditions from NS patients ( p = 0.043), C ( p = 0.043), and S patients ( p = 0.002) in PBMCs, and also 0.03, 0.02 and 0.03 respectively for NS, S and C of CSF. The results revealed a significant negative relationship between CSF protein and VDRL concentrations and CSF IL-27 levels. This study confirms previous efforts on the critical role of IL-17 in NS. Also, it supports other results on the inhibitory effects of IL-27 on the therapeutic potential of IL-27 in NS and the inflammation process.