Heterogeneity of immunoglobulin G response to Helicobacter pylori measured by the unweighted pair group method with averages.

The heterogeneity of the immune response to Helicobacter pylori has always been noticed but has never been evaluated by obtaining a quantitative measure. For this purpose, sera were tested by enzyme-linked immunosorbent assay, and 207 positive serum specimens were subsequently tested by immunoblotting. The presence or absence of six specific bands was noted. The homology of the different profiles of bands was measured by calculating the Dice coefficient, and a dendrogram was constructed. Thirty-four profiles were found, with each profile containing from 1 to 43 serum specimens. At a level of 72% similarity, 115 of the serum specimens studied fell into eight profiles. At a level of 48% similarity, 186 of the serum specimens studied fell into 22 profiles. The difference in immunoblot profiles was probably linked to the host immune response, but infection with strains carrying different antigens cannot be ruled out.