CRP and irritable bowel syndrome: Fulfilling IBS Rome IV criteria with moderate to severe IBS, BMI 18.5-38kg/m2, age18-70 years, hemoglobin 120-160g/L, transglutaminase immunoglobulin A <7 U/ml, C-reactive protein <5 mg/L, thyroid stimulating hormone <4 mU/L, systolic/ diastolic blood pressure ≤160/≤105 mmHg