RT Journal Article
SR Electronic
T1 Calprotectin as a Biomarker for Rheumatoid Arthritis: A Systematic Review
JF The Journal of Rheumatology
JO J Rheumatol
FD The Journal of Rheumatology
SP 760
OP 770
DO 10.3899/jrheum.140628
VO 42
IS 5
A1 Mads Abildtrup
A1 Gabrielle H. Kingsley
A1 David L. Scott
YR 2015
UL http://www.jrheum.org/content/42/5/760.abstract
AB Objective. Calprotectin (myeloid-related protein 8/14), a heterodimeric complex of calcium-binding proteins, is expressed in granulocytes and monocytes. Calprotectin levels are high in synovial tissue, particularly in activated cells adjacent to the cartilage-pannus junction. This systematic review evaluates the use of calprotectin as an indicator of disease activity, therapeutic response, and prognosis in rheumatoid arthritis (RA). Methods. Medline, Scopus, and the Cochrane Library (1970–2013) were searched for studies containing original data from patients with RA in whom calprotectin levels were measured in plasma/serum and/or synovial fluid (SF). We included studies examining associations between calprotectin levels and clinical and laboratory assessments, disease progression, and therapeutic response. There were no restrictions for sample size, disease duration, or length of followup. Results. We evaluated 17 studies (1988–2013) with 1065 patients enrolled; 11 were cross-sectional and 8 had longitudinal designs with 2 studies reporting cross-sectional and longitudinal data. Systemic and SF levels of calprotectin were raised in RA. There was a wide range of levels and marked interstudy and intrastudy variability. Calprotectin levels were high in active disease and were particularly high in rheumatoid factor (RF)-positive patients. Levels fell with effective treatment. Longitudinal data showed that calprotectin was a significant and independent predictor of erosive progression and therapeutic responses, particularly in patients who received effective biological treatments. Conclusion. SF calprotectin levels are high, suggesting there is substantial local production by inflamed synovium. Blood calprotectin levels, though highly variable, are elevated in active RA and fall with effective therapy. High baseline calprotectin levels predict future erosive damage.