What is the role of serology in assessing Helicobacter pylori eradication?
OBJECTIVE
To assess the decline in Helicobacter pylori antibodies after eradication of infection.


METHODS
The H. pylori status was determined at entry (D0) by culture and histology performed on antral biopsies and after eradication treatment at day 42 (day 42) and after 6 months (M6) by the 13C-urea breath test. The EIA kits used to determine the anti-H. pylori antibody titre were HM-CAP (immunoglobulin-G) and PP-CAP (immunoglobulin-A) kits (Enteric Products, Inc.) and Pyloriset EIA-G (Orion Diagnostica).


RESULTS
Ninety-three patients were included. For 82 patients who were successfully treated, no kit was sufficiently accurate at D42 to show eradication. The antibody titre decreased for HM-CAP, PP-CAP and Pyloriset EIA-G by a mean of 35.6%, 41.2% and 64.7% between D0 and M6, respectively. According to the cut-off values defined by the manufacturers, 8.5% (PP-CAP, Pyloriset EIA-G) and 9.7% (HM-CAP) of the patients became H. pylori negative at M6. Using a 25% decrease in antibody titre between D0 and M6 as a threshold for H. pylori eradication, specificity was 100% for HM-CAP, 89.9% for Pyloriset EIA-G and 100% for PP-CAP, whereas the sensitivity was 76.8%, 98.8% and 72%, respectively.


CONCLUSIONS
An antibody titre decrease of 25% at M6 was found to be accurate in confirming H. pylori eradication.
Bergey
B
B
Laboratoire de Bactériologie, Université Victor Segalen Bordeaux 2, Bordeaux, France.
Marchildon
P
P
Peacock
J
J
Mégraud
F
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents; D001944:Breath Tests; D004311:Double-Blind Method; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000188:drug therapy; D016480:Helicobacter pylori; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D054328:Proton Pump Inhibitors; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000592:standards; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D054328:Proton Pump Inhibitors