Four-year trends in Helicobacter pylori IgG serology following successful eradication.
OBJECTIVE
Detection of anti-Helicobacter pylori antibodies is accurate in the diagnosis of the infection, and there is a decline in IgG titers after successful eradication. It is not known whether these titers continue to decline during the next 3 to 4 years.


METHODS
Patients had been successfully treated for H pylori with triple therapy (metronidazole, tetracycline, and bismuth subsalicylate) during 1990 and 1991. Those who had frozen serum samples available from that time were contacted to have follow-up serum collected in 1994. A simultaneous [13C]urea breath test was done to confirm H pylori infection status. Serology was determined by quantitative enzyme-linked immunosorbent assay (ELISA) and qualitative immunoassay.


RESULTS
All 29 patients who agreed to participate were free of H pylori infection. They had a mean decrease in H pylori IgG titers of 51% from baseline (P <0.001). Titers remained stable from 1 year to a mean of 3.5 years after therapy (range 2.8 to 4.4). Of the 29 patients, 21 (72%) remained seropositive by ELISA 3.5 years after successful H pylori treatment, and 18 (62%) remained positive by rapid serum immunoassay.


CONCLUSIONS
IgG titers against H pylori plateau at a 50% decrease after therapy. Helicobacter pylori serology, either quantitative or qualitative, will yield false positive results in patients who have previously been treated for H pylori and should not be used to determine infection status in this population.
Department of Medicine, Sinai Hospital, Detroit, Michigan 48235, USA.
A F
AF
Cutler
V M
VM
Prasad
P
P
Santogade
D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged
D007074:Immunoglobulin G