Calprotectin more accurately discriminates the disease status of rheumatoid arthritis patients receiving tocilizumab than acute phase reactants
José Inciarte-Mundo, Virginia Ruiz-Esquide, Maria Victoria Hernández, Juan D Cañete, Sonia Raquel Cabrera-Villalba, Julio Ramirez, Jordi Yagüe and Raimon Sanmarti. - Rheumatology. 2015 Aug 4. doi:pii: kev251. [Epub ahead of print]
Calprotectin is a member of the S100 protein family that has strong pro-inflammatory effects that reflect local ongoing inflammation rather than systemic response, due to its release at local inflammation sites. High calprotectin levels have been found in SF and serum from RA patients and correlate with disease activity. This study analysed the accuracy of calprotectin compared to acute phase response in discriminating the clinical disease status of RA patients receiving TCZ. A clinical assessment to project DAS28-ESR, SDAI and CDAI was performed on 33 patients from the Immunology Department Hospital Clinic at the University of Barcelona.
Findings from this study show that calprotectin has a strong correlation with all composite disease and composite joint indices, while CRP and ESR were only moderately correlated to DAS28-ESR and not correlated with SDAI or CDAI. Calprotectin levels were able to distinguish between patients in remission or with low disease activity, despite the recognized reduction in acute phase response observed after TCZ treatment, independently of serum trough TCZ levels. The small sample size is a limitation of the study that make the exact effects of TCZ on serum calprotectin levels difficult to ascertain.