Fecal Calprotectin, Gut Inflammation and Spondyloarthritis

Gut inflammation is closely related to spondyloarthritis (SpA) pathophysiology. Fecal calprotectin has been used to measure the degree of gut inflammation. The phenotype of SpA may change according to studied population.

To study the fecal calprotectin levels in a sample of SpA in Brazilian patients and its relationship with epidemiological, clinical and treatment variables as well as with the macro and microscopic degree of gut inflammation.

Eighty five SpA patients were studied for epidemiological and clinical features, functional and inflammatory indexes and fecal calprotectin levels measured using a ELISA kit. Colonoscopy with intestinal biopsies were performed in 39 of them. At time of colonoscopy a second calprotectin level was done after suspension of at least 3 weeks of used anti-inflammatory nonsteroidal drugs (NSAIDs).

Fecal calprotectin levels were higher in Ankylosing Spondylitis (AS) patients (p <0.0001) and in those with axial involvement (p = 0.002). No relationship was found with SpA inflammatory and functional parameters (all p = ns). After suspension of NSAIDs, a drop in fecal calprotectin levels was observed (from median levels of 215.0-76.0 μg/g; p = 0.01). In the colonoscopy, 33.3% had macroscopic signs of inflammation and these patients had higher calprotectin (p = 0.009) than others. Microscopic examination showed that all patients had lymphoplasmacytic infiltrate and eosinophilic infiltrate; epithelial erosion was present in 27.2%.

Patients with ankylosing spondylitis and axial forms of diseases have higher fecal calprotectin levels. Patients with all types of SpA have microscopic inflammatory changes in the gut.