Serum calprotectin as a marker of autoimmunity activation in rheumatologic diseases

Calprotectin is a heterodimer formed by two proteins, S100A8 and S100A9, which are mainly produced by activated monocytes and neutrophils. The role of calprotectin in the pathogenesis, diagnosis and monitoring of rheumatic diseases has attracted a high attention in the last years. According to modern data, circulating serum calprotectin can be considered as a marker of the inflammatory process due to neutrophil activity. An association between its high level and some severe manifestations of autoimmune diseases, such as glomerulonephritis and pulmonary fibrosis, has been found. Also, of interest is its potential role as a target for drug therapy, an indicator of prognosis of therapeutic response to treatment. This article reviews the key biological functions of calprotectin that may be involved in the pathogenesis of rheumatologic diseases, presenting its potential use as a biomarker of these pathologies.