Distinct B-cell clonal bands in Helicobacter pylori gastritis with lymphoid hyperplasia

Helicobacter pylori (Hp)-associated gastritis is a risk factor for gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Clonal B-cell population s are present in both reactive and neoplastic MALT tissue, thus limiting th eir usefulness in the evaluation of gastric lymphoid infiltrates in endosco pic biopsy specimens. The aim of this study was to identify the presence of clonal B-cell populations in Hp-gastritis with MALT and to assess their us efulness in distinguishing reactive from malignant infiltrates. Routinely f ixed paraffin-embedded blocks from 20 patients with Hp-gastritis with lymph oid hyperplasia were analysed for B-cell clonality by a semi-nested polymer ase chain reaction (PCR) using FRIII/LJH and FRIII/VLJH primers for amplifi cation of the VDJ region of the immunoglobulin heavy chain gene, The histop athological findings were evaluated according to a previously published sco ring system, Immunohistochemistry was performed by the labelled streptavidi n-biotin technique using the following primary antibodies: CD45, CD45RO, CD 3, CD20, and cytokeratin, The histopathological findings were diagnostic of Hp-chronic active gastritis (grade 2, n=17; grade 3, it = 3), Scattered in traepithelial B-cells,cere present in all cases and non-destructive lymphoe pithelial lesions in one grade 3 case. Amplifiable DNA was obtained from al l samples. Clonal bands were observed in ten (7/17 grade 2 and 3/3 grade 3 lesions) and polyclonal smears in ten cases (all grade 2), The clonal bands were often (n=6) associated with a background polyclonal smear and were no t reproducible from deeper sections (n = 10) or another paraffin block (n = 1), while the clonal bands in control low-grade MALT lymphomas were not as sociated n with a background smear and n ere reproducible from deeper secti ons, None of the patients has developed lymphoma to date (follow-up 21-44 m onths). In conclusion, B-cell clonal bands are common in H. pylori-gastriti s with lymphoid hyperplasia, The irreproducibility of these bands is a usef ul feature in favouring a reactive process, Copyright (C) 2000 John Wiley & Sons, Ltd.