Evaluating the value of soluble form of toll-like receptors 2 and 4 as a potential biomarker in multiple sclerosis

Available studies have suggested significance of soluble toll like receptor 2 and 4 (sTLR2, and 4) as endogenous first-line blockers of TLR signalling pathway. We hypothesized that sTLR2 and 4 may have the potential to be used as biomarkers in multiple sclerosis (MS) patients during relapses. To address this issue, serum and urine samples from MS patients during relapse and remission and from healthy individuals (H.C) were analysed with ELISA to determine the level of sTLR2 and 4. In serum samples, the concentration of sTLR2 was significantly higher in relapse patients compared with H.C (p value=0.025). However, no significant differences were observed in serum sTLR2 levels between relapse and remission states, or between remission and H.C. Urine sTLR2 levels in MS patients showed no significant differences between relapse, remission and H.C groups. Additionally, there were no significant differences in the levels of sTLR4 between relapse, remission and H.C groups both in serum and urine samples. The higher levels of sTLR2 may reflect an active state of the immune system during MS relapse. A patient with high sTLR2 value in urine was positive in the dipstick test, indicating a possible correlation between sTLR2 levels and sign of urinary tract infections. However, for urine sTLR4 levels, no correlations with dipstick results were observed.  In conclusion, these results showed the presence of sTLR2 and 4 in MS patients’ serum and urine, but analysing large number of patients is essential to confirm the value of sTLRs as potential biomarker of disease activity.