CCL4 and irritable bowel syndrome: Furthermore, the average fecal concentrations of MCP-1 and MIP-1β were 149.6 pg/ml and 85.6 pg/ml, respectively (healthy volunteers), 305 pg/ml and 170.4 pg/ml, respectively (ID-IBS), 235.9 pg/ml and 145.9 pg/ml, respectively (PI-IBS).