Could IL-1β, IL-6, IFN-γ, and sP-selectin serum levels be considered as objective and quantifiable markers of rheumatoid arthritis severity and activity?

Among the tested molecules, only IL-6 positively correlated with the DAS28 score. Thus, we postulate that next to C-reactive protein and the erythrocyte sedimentation rate, also IL-6 could be clinically relevant and possibly reflects RA activity. Because recently the IL-6 concentration can be determined in applied in vitro diagnostic tests, it presents us with the possibility to test this protein as a marker of RA activity in routine laboratory practice.

Serum IL-1β, IL-6, IFN-γ, and sP-selectin concentrations were measured using ELISA kits.

Serum IL-1β, IL-6, IFN-γ, and sP-selectin concentrations were measured using ELISA kits.

The concentrations of all molecules tested, except for IL-1β, were significantly different from the control group. Univariate logistic regression analysis indicated that their levels significantly influenced the likelihood of RA diagnosis. Differences between IL-1β, IL-6, IFN-γ, and sP-selectin concentrations dependent on the disease activity assessed on the basis of the DAS28 score, as well as the severity of the disease assessed based on the Steinbrocker classification, were not observed. IL-6 positively correlated with the DAS28 score. Conclusions: Among the tested molecules, only IL-6 positively correlated with the DAS28 score. Thus, we postulate that next to C-reactive protein and the erythrocyte sedimentation rate, also IL-6 could be clinically relevant and possibly reflects RA activity. Because recently the IL-6 concentration can be determined in applied in vitro diagnostic tests, it presents us with the possibility to test this protein as a marker of RA activity in routine laboratory practice.