Differences in intestinal humoral immunity between healthy volunteers fromUK and Bangladesh

Background/aims Intestinal morphology has been shown to vary geographically . The impact of this variation on gut mucosal humoral immunity is not well- studied, The technique of peroral whole-gut lavage (WGL) with nonabsorbable cleansing fluid can be utilized for the study of gut immune responses in h ealth and disease. In this study, the WGL technique was employed to compare various gut humoral immune parameters in healthy volunteers from Dhaka in Bangladesh and Edinburgh, UK. Methods Eleven healthy individuals tall male, age range 18-32) from Dhaka a nd 12 healthy individuals (4 male and 8 female, age range 23-48) from Edinb urgh underwent WGL with a polyethylene glycol electrolyte-based solution dr unk at a rate of 1 l/h, The first clear effluent was collected and processe d. An ELISA technique was used to measure total immunoglobulins (A, M and G ) and antibodies to bacterial lipopolysaccharide (LPS: endotoxin) ovalbumin and eotaxin, Immunoturbimetry and radioimmunoassy techniques were used to measure protein (albumin and alpha -1 antitrypsin) and eosinophil cationic protein (ECP), respectively, in WGL fluid (WGLF). Results The total IgA, ECP and eotaxin concentrations in WGLF from the Dhak a group were significantly higher than those of the Edinburgh group (P < 0. 03, P < 0.002 and P < 0.005 respectively). The IgA antibody level against t he core oligosaccharide of bacterial LPS from several Gramnegative species was significantly higher in the Dhaka group compared to the Edinburgh group (P < 0.0001), Similarly, there was generally higher level of IgA antibody response against the various different LPS core structures of Escherichia c oll in the Dhaka group, in particular significantly higher against R1, R3 a nd R4 LPS cores (P < 0.02, P < 0.03 and P < 0.01 respectively) compared to the Edinburgh group. in contrast to antibacterial antibodies, the IgA and I gM antibodies against ovalbumin were significantly lower in the Dhaka group (P < 0.001 and P < 0.003, respectively) compared to the Edinburgh group. Conclusions This study on gut mucosal humoral immunity from two geographica lly distinct populations suggests that place of residence influences gut mu cosal humoral immunity. This difference in stimulation of humoral immunity of the gut might explain different rates of inflammatory bowel diseases in developing and developed countries, and also provides a major challenge for the development of mucosally presented vaccine worldwide.