Journal de recherche en immunologie muqueuse

Abstrait

Intestinal Mucosal Immunity against Polioviruses in Adolescent and Adult Populations: A Community Based Cross-sectional Study in India

Mohammad Ahmad, Tapan Dhole, Abhishek Kunwar, Rakesh Vishwakarma, Gopal Krishna Soni, Lalitendu Mohanty, Raman Sethi and Sunil Bahl

Introduction: It is known that the intestinal mucosal immunity against polioviruses wanes with time. Polio free nations risk importation of polioviruses from polio endemic countries and outbreaks of circulating vaccine derived polioviruses. Waning intestinal mucosal immunity against polioviruses in elderly age groups may facilitate setting up of poliovirus transmission, especially in post OPV switch periods. This study assessed the level of intestinal mucosal response among adolescents and adult populations in the high-risk states for poliovirus transmission in India.

Methods: 1200 subjects in two age groups (15-19 years-exposed to multiple doses of OPV and 30-39 yearsmore exposed to wild polioviruses but almost no OPV) were enrolled in two states of India; Uttar Pradesh and Rajasthan. Subjects were challenged on day-0 and stool samples were subsequently collected on days 7 and 14.

Results: Against expectation, the study found significantly better intestinal mucosal response in the adult (30-39 years) age group compared to adolescents (15-19 years) for poliovirus type 1 and 2. Type-3 showed similar mucosal response in both groups. Residents in Uttar Pradesh, a traditional high-risk state for poliovirus transmission showed better mucosal response compared to those in Rajasthan; significantly so for type-2.

Conclusion: Adult population in high-risk states in India, which was more exposed to wild polioviruses but received almost no OPV doses in past, showed better intestinal mucosal response than the adolescent group which received more OPVs but lesser exposure to wild polioviruses. Despite waning mucosal immunity in the younger population, elderly groups in India have better mucosal immunity, probably induced by infection to wild polioviruses, earlier on, in their life.