MicroRNA -21 expression as an auxiliary diagnostic biomarker of acute brucellosis.

BACKGROUND: This study aimed to measure the expression levels of peripheral blood miRNAs in brucellosis and their involvement in the different phases of the brucellosis. METHODS: The expression levels of miRNAs including miR-210, miR-155, miR-150, miR-146a, miR-139-3p, miR-125a-5p, miR-29 and miR-21 were quantified in 57 brucellosis patients subgrouped into acute, under treatment & relapse phase and 30 healthy controls (HCs) using real-time polymerase chain reaction (RT-PCR). The receiver operating characteristic (ROC) analysis curve analysis was performed to find a biomarker for discrimination of different phases of brucellosis. RESULTS: The expression of miR-155, miR-146a, miR-125a-5p, miR-29, and miR-21 was found to be elevated in the acute brucellosis patients compared to HCs. miR-29 changed in under-treatment patients, while miR-139-3p and miR-125a-5p showed alterations in relapse cases. The ROC curve analysis depicted the potential involvement of miR-21 in the pathogenesis of acute brucellosis. CONCLUSION: The expression level of miR-21 is significantly augmented in acute brucellosis and has the potential to be a contributing diagnostic factor for acute infection.

Direct correlation between Th1 and Th17 responses in immunity to Brucella infection.

Th1 cells play a central role in immunity to brucellosis, while the exact role of Th17 cells has remained unknown. This study aimed to evaluate the peripheral distributions of Th1 and Th17 cells and serum levels of IFN-γ, IL-17A and IL-22 cytokines in brucellosis patients. One hundred patients (36 acute, 41 under-treatment and 23 relapsed) and 30 age- and sex-matched healthy controls were included. The frequencies of Th1 and Th17 cells were determined by flow cytometric analysis. Serum levels of IFN-γ, IL-17A and IL-22 were measured by multi-analyte flow assay. Increased frequencies of Th1 and Th17 cells were observed in acute and relapsed brucellosis versus under-treatment patients and healthy controls (P < 0.05). The mean serum levels of IFN-γ were significantly elevated in acute and relapsed groups compared to under-treatment patients (P = 0.002 and P = 0.01 respectively). Acute patients showed higher levels of IL-22 than under-treatment (P = 0.008). Direct correlations were found between increased frequencies of Th1 and Th17 cells in acute and relapsed patients (P = 0.007 and P = 0.001 respectively) and between IL-17A and IL-22 in both groups of patients. Our findings indicate a cooperative role for Th1 and Th17 cells in immunity to brucellosis which is more evident during acute and relapse phases of brucellosis.