S100A8 and MALT lymphoma: However, based on the limited number of clinical strains tested here, a direct relationship between the contents of virulence factors (CagA, VacA and UreA in particular) and the severity of diseases caused by these clinical H. pylori strains was not observed, as strains 13,223 and 11,749, which were isolated from patients with much more severe diseases, MALT lymphoma and gastric adenocarcinoma grade III B, respectively, did not contain CagA and VacA (or produced much less) in both bacteria and the corresponding OMVs generated.