Altered expression of CXCR3 and CCR6 and their ligands in HTLV‐1 carriers and HAM/TSP patients

Recruitment of leukocytes by chemokines and chemokine receptors to CNS plays a crucial role in the induction of inflammatory response in HTLV‐1‐associated myelopathy/tropical spastic paraparesis (HAM/TSP). In the present study, chemokine and chemokine receptors involved in trafficking of lymphocytes to the CNS were measured in HAM/TSP patients, HTLV‐1 asymptomatic carriers (ACs), and healthy controls. The PVL, CCR6, and CXCR3 mRNA expression, and CXCL9 and CXCL10 protein levels were measured in all subjects. The PVL of HAM/TSP patients was higher than that of ACs (P = 0.02). CCR6 expression was higher in HAM/TSP patients and in ACs compared to the healthy controls (P = 0.005 and P = 0.04, respectively). A significant difference was observed in CCR6 expression when a combination of HAM/TSP patients and ACs were compared to the healthy individuals (P = 0.005). Furthermore, there was a significantly lower CXCR3 expression between HAM/TSP and control groups (P = 0.001), and between the ACs and healthy controls (P = 0.001). However, the increased CXCR3 expression in ACs compared to HAM/TSP patients was not significant. Furthermore, the CXCL10 protein levels in HAM/TSP patients was higher than in controls (P = 0.012), and CXCL9 protein levels was also higher in the HAM/TSP and ACs groups than in the controls (P = 0.001 and P = 0.004, respectively). In conclusion, it seems that decreased expression of CXCR3 and higher expression of CCR6 were associated with HTLV‐1 infection, what indicate that these alterations may favor virus dissemination but not disease manifestation.