SCD and irritable bowel syndrome: Recently, some authors tried to correlate the circulating levels of LPS, the LPS coreceptor soluble cluster of differentiation (sCD), monocyte chemoattractant protein 1 (MCP 1), intestinal fatty acid binding protein (IFABP), and calprotectin with the symptom scores calculated by the IBS Severity Scoring System, but they failed in identifying any associations [25].