Immunoblot analysis of sera in uncomplicated typhoid fever & with typhoid ileal perforation.

BACKGROUND & OBJECTIVE Ileal perforation is a serious complication of typhoid fever. The exact reasons for the development of perforation in only a few of those infected with Salmonella Typhi is unknown, and it is likely that immunological factors are involved. Therefore we undertook this study to compare the antibody profile in patients with uncomplicated typhoid fever with those having ileal perforation by immunoblotting. METHODS Two groups of patients were included in the study. Group II comprised patients with uncomplicated typhoid fever (n=47), and group I with typhoid ileal perforation (n=33). The flagellar (H), lipopolysaccharide (LPS) and outer membrane protein (OMP) antigens of Salmonella Typhi were extracted and used to test patient sera for antibodies by immunoblotting RESULTS Immunoblotting using S. Typhi antigens enabled the detection of S. Typhi antibodies in the two groups of patients. A significant difference was seen in the response of these two groups of patients with respect to antibodies to flagella, lipopolysaccharide and outer membrane proteins. Antibodies to flagella were more pronounced among patients with uncomplicated typhoid fever, while anti-OMP antibodies were significantly associated with typhoid ileal perforation. INTERPRETATION & CONCLUSION A comparison of antibodies in patients with uncomplicated typhoid fever and with ileal perforation revealed the differences in the antibody profiles of the two groups. Our study suggests that the difference in antibody response may in some way play a role in the pathogenesis of typhoid ileal perforation which can also potentially be exploited to develop suitable diagnostic tests.