S100A8 and Peptic ulcer: In this sense, a previous study that involved the isolation of 38 strains from patients with non-ulcer dyspepsia and 25 from individuals with peptic ulcer showed that cagA was present in 60% of the patients with peptic ulcer (15 out of 25) and in 55% of the patients with dyspepsia (21 out of 38).