Seroprevalence of Helicobacter pylori infection in patients with lymphoma

To determine the Helicobacter pylori (HP) seroprevalence in patients with non-Hodgkin's lymphoma (NHL) and other hematological conditions. Sera were collected from 444 patients with NHL, Hodgkin's disease (HD), lymphoproliferative disorders (LPD), myeloproliferative disorders (MPD), and other hematological conditions. HP seropositivity was determined by ELISA and the results were compared among diagnostic groups HP seropositivity was observed in 168/444 (38%) of the total population. Higher seropositivity rates were associated with increasing age (p=0.001), and country of birth outside the USA and Canada (p=0.0001). Among the diagnostic groups, patients with NHL demonstrated the highest frequency (43%) and those with HD, the lowest frequency (20%; p=.026) of HP seropositivity. The differences among diagnostic groups remained statistically significant after controlling for country of birth (p<0.05), but not after controlling for patient age at diagnosis. The HP seroprevalence of G1 NHL was 55% compared to 40% for non-G1 NHL (p=NS). The highest rate of HP seropositivity (67%) occurred in gastric MALT lymphoma patients, although this did not reach statistical significance compared to the non MALT group (50%) due to small sample size. In conclusion, the rate of HP seropositivity in patients with MALT lymphoma in the USA appears to be lower than in Europe. Helicobacter pylori does not appear to be an important factor in other types of NHL of the G1 tract or elsewhere. Studies of HP prevalence should be controlled for country of birth as well as for age.