Ab0176 Serum Calprotectin Levels Measured by Chemiluminescence Immunoassay as an Inflammation Biomarker in Rheumatoid and Psoriatic Arthritis in Relation to Other Biochemical and Disease Activity Parameters

Background: Several studies reported correlation among ELISA serum calprotectin (cCLP) levels, biochemical inflammatory parameters and disease activity in rheumatoid (RA) and psoriatic (PsA) arthritis. Recently, a chemiluminescence immunoassay (CLIA) for fecal CLP was successfully adapted to measure cCLP. Objectives: To assess CLIA cCLP levels as inflammatory and activity marker and to study its relation with other biochemical parameters in RA and PsA patients. Methods: Eighty-eight subjects were studied: 1) RA patients treated with disease modifying drugs (DMARD) with low or no activity by common clinical indexes (rRA=11), 2) RA patients candidate to start treatment with biological DMARD (aRA=23), 3) PsA patients treated with DMARD with low or no activity by common clinical indexes (rPsA=11), 4) PsA patients candidate to start treatment with biological DMARD (aPsA=10) and 5) non-disease controls (n=33). Disease activity scores were DAS28 (RA) and DAPSA (PsA). Different serum and plasma inflammatory parameters were also analyzed. Statistical GraphPadv7.0S and SPSSv26 programs were used. Results: cCLP concentrations were significantly increased in aRA and aPsA vs controls, as well as in aRA vs rRA. cCLP levels were directly correlated with other biochemical inflammatory parameters (erythrocyte sedimentation rate, C-reactive protein, Serum Amyloid-A), and DAS28 activity index in RA groups. Area under curve (AUC) of 0.66 (p=0.047) and 0.92 (p<0.0001) were obtained for cCLP to classify active/remission RA and PsA patients, using a ROC analysis with DAS28 and DAPSA indexes, respectively. Conclusion: In RA and PsA patients, cCLP is a suitable inflammation biomarker, well correlated with other biochemical inflammatory parameters and the disease activity degree. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.