Decreased Fecal Calprotectin Levels in Cystic Fibrosis Patients After Antibiotic Treatment for Respiratory Exacerbation

Objectives: In all patients with cystic fibrosis (CF), gastrointestinal (GI) tract CF transmembrane conductance regulator dysfunction occurs early in life. The identical pathophysiological triad of obstruction, infection, and inflammation causes disease of the airways and in the intestinal tract (CF enteropathy). Mucus accumulation within GI tract is a niche for abnormal microbial colonization, leading to dysbiosis. Fecal calprotectin (FC) is a neutrophil cytosolic protein released during apoptosis and necrosis and reflects inflammatory status. Systemic antibiotic treatment for pulmonary exacerbations has been shown to improve systemic inflammatory markers and serum and sputum calprotectin. Antibiotic treatment aimed at pulmonary complaints may improve GI tract inflammatory status. We hypothesized that high levels of FC present during pulmonary exacerbation are due, in part, to multiorgan dysbiosis and thus should diminish with systemic antibiotic treatment. Methods: This prospective pilot study enrolled 14 patients with CF, with no current GI symptoms. FC levels and lung function were measured at the beginning and end of systemic antibiotic treatment. Results: Compared to preantibiotic treatment baseline values, end of treatment FC levels declined significantly after antibiotic treatment, P = 0.004 and similarly, there was significant improvement in forced expiratory volume in 1 second, P = 0.002. Conclusions: High levels of FC during respiratory exacerbation may reflect a systemic exacerbation rather than solely pulmonary. Antibiotic treatment lowered the FC levels possibly by its impact on the intestinal microbiome.