HP and infection: Our hypothesis related to the influence of the microbiome on response to treatment seems to be supported by two other factors: age and the history of frequent infections, which independently of zonulin were negative predictors (OR = 1.09, p = 0.047; 95% CI 1.00 − 1.18, OR = 8.63, 95% CI 1.43 − 52.21, p = 0.019, respectively).