Evaluation of Interleukin-32 and cyclooxygenase-2 expression in HAM/TSP patients and HTLV-1 asymptomatic carriers

Hatatian, N., Boostani, R., Mohammadi, A., Mehraban, S., Mahdifar, M., Zemorshidi, F., Mozhgani, S., Haji Ghadimi, A., Foroughipour, M., RafatPanah, H

Iranian Journal of Basic Medical Sciences, 2021;24(7):992-996. doi: 10.22038/ijbms.2021.50821.11569

OBJECTIVE(s): HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neuroinflammatory disorder associated with HTLV-1. Cytokines and inflammatory mediators have a major role in forming inflammation in HAM/TSP patients. This study aimed to measure the levels of IL-32, a proinflammatory cytokine associated with autoinflammatory disorders, and also cyclooxygenase -2 (COX-2) as a key mediator of inflammatory pathways in HAM/TSP patients and HTLV-1 asymptomatic carriers (ACs).

Materials and Methods: Peripheral blood monocyte cells (PBMCs) were isolated from HAM/TSP patients, ACs, and healthy controls (HCs), and DNA and RNA were extracted to evaluate HTLV-1 proviral load (PVL) and expression of IL-32 and COX-2, using real-time PCR. Serum levels of IL-32 were determined by using an ELISA assay.

Results: The expression level of IL-32 was significantly higher in ACs compared with HAM/TSP patients and HCs (P<0.0001 and P>0.05, respectively). There were no statistically significant differences in the expression levels of Cox-2 and protein levels of IL-32 between the study groups.  HTLV-1 PVL was higher in HAM/TSP patients compared with ACs.

Conclusion: Results showed increased mRNA levels of IL-32 in ACs. Since HTLV-1 PVL in ACs is lower than in HAM/TSP patients, it could be concluded that IL-32 might be an HTLV-1 inhibitor that seems to control virus replication. Despite the difference in IL-32 mRNA levels between study groups, no statistically significant differences were observed in IL-32 serum levels. Also, there were no significant differences in COX-2 expression.

Keywords: Cyclooxygenase-2 , HAM/TSP, HTLV-1, Interleukin-32, Inflammation