Seroreactivity to 19.5-kDa antigen in combination with absence of seroreactivity to 35-kDa antigen is associated with an increased risk of gastric adenocarcinoma.
BACKGROUND
Only a minority of those infected with Helicobacter pylori will develop gastric cancer. Stratification of H. pylori strains based on carcinogenic potential will provide a basis for selective surveillance and eradication therapy. We studied the anti-H. pylori antibody profile in Asian patients with gastric adenocarcinoma to identify any H. pylori antigen that may be associated with an increased or decreased risk of gastric carcinoma.


METHODS
A case-control study comparing the seroprevalence of antibodies with various H. pylori antigens in Singaporeans with gastric adenocarcinoma and the normal Singaporean population was carried out using both conventional immunoglobulin (Ig) G enzyme-linked immunosorbent assay (ELISA) and Western blot immunoassay.


RESULTS
The seroprevalence among 44 gastric adenocarcinoma cases (70.5% males, mean age 66.7 +/- 13.5 years) and 261 controls (49.8% males, mean age 61.5 +/- 4.1 years) was 90.9% vs. 50.2% by IgG ELISA. In the H. pylori-positive male population, those suffering from gastric adenocarcinoma had significantly lower seroreactivity to the 35-kDa antigen compared with asymptomatic controls (p =.0198, OR = 3.79, 95% CI 1.24-11.61). Seropositivity to the 19.5 kDa antigen was also found to be associated with the presence of gastric adenocarcinoma in Singaporean males (p =.022, OR = 4.17, 95% CI 1.22-14.28). A 'high-risk' phenotype consisting of absence of a band at 35-kDa in combination with the presence of a band at 19.5-kDa was significantly associated with the presence of gastric adenocarcinoma (p =.002, OR = 3.7, 95% CI 1.6-8.6).


CONCLUSIONS
Stratification of H. pylori strains based on their potential for carcinogenesis, such as those strains that are seropositive for the 19.5 kDa antigen and seronegative for the 35-kDa antigen, may provide a basis for selective eradication of H. pylori infection and future vaccine development.
Chua
Tju Siang
TS
Division of Gastroenterology, Department of Medicine, Changi General Hospital, Singapore.
Fock
Kwong Ming
KM
Chan
Yiong Huak
YH
Dhamodaran
Subbiah
S
Sim
Chee Seng
CS
Ng
Tay Meng
TM
Teo
Eng Kiong
EK
D000230:Adenocarcinoma / Q000276:immunology / Q000382:microbiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology*; D015153:Blotting, Western; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016481:Helicobacter Infections / Q000276:immunology / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D012846:Singapore / Q000453:epidemiology; D013274:Stomach Neoplasms / Q000276:immunology / Q000382:microbiology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial