Assessment of mutual relationships between serum protein levels and alpha-1-antitrypsin (AAT) in the faeces of patients with diarrhoea-predominant irritable bowel syndrome (DP-IBS)

Introduction: To this day, no gold standard or laboratory marker for Irritable Bowel Disease (IBS) exists. Low-grade inflammation may disturb gastrointestinal reflexes. Searching for mutual quantitative relationships between acute-phase proteins present in the serum and alpha-1-antitrypsin in the faeces may form a diagnostically typical panel which allows for an objective assessment of low-grade intestinal lesions in the course of IBS. Methods: 26 patients with diarrhoea-predominant IBS (DP-IBS) and 10 healthy subjects were studied. The serum levels of albumin (ALB), alpha-1-antitrypsin (AAT), orosomucoid (OM) and transferrin (TRF) and the AAT concentration in single portions of faeces were determined by the method of radial immunodiffusion. Results: In patients with DP-IBS the increased faecal AAT (range 0-9.33 mg/g of dry faecal mass) and reduced serum TRF concentrations were observed when compared to a healthy control group (p<0.05.) In the serum of patients with DP-IBS with the faecal AAT concentration >1.25 mg/g of dry faecal mass a significant correlation between AAT/ALB and TRF/OM was demonstrated . No correlation was found between the serum proteins and faecal AAT in patients with DP-IBS (p>0.05.). Conclusions: Varied increases in the faecal levels of AAT in patients with DP-IBS indicate that this group is not homogenous. There is an increase in mutual relationships between the levels of different acute-phase proteins in the serum of patients with the increased faecal AAT levels. Searching for a correlation between selected acute-phase proteins present in the serum may be an initial method to differentiate patients with IBS and a marker to detect low-grade inflammatory intestinal lesions. (Clin Exp Med Lett 2009; 50(2):89-92)

Keywords: diarrhoea, irritable bowel syndrome, protein-losing enteropathy, serum proteins