Idiotype identity in a MALT-type lymphoma and B cells in Helicobacter pylori associated chronic gastritis.
BACKGROUND
To investigate the mechanisms triggering MALT-lymphoma development, we examined the occurrence of normal B cells in lymphoid tissue and chronic gastritis with the same idiotype as an IgA-positive MALT lymphoma.


METHODS
Lymphoma idiotype IgA was produced by monoclonal human antibody technology. Against this idiotype a murine monoclonal antibody 27/165 with anti-idiotypic (alpha Id) specificities was raised, and applied immunohistochemically to identify the non-neoplastic precursor B cells in non-neoplastic human tissues.


RESULTS
alpha Id 27/165 reacted exclusively with the IgA expressing MALT lymphoma but not with 20 other MALT-type gastric lymphomas nor with 26 nodal lymphomas and was not reactive with normal and inflamed lymph nodes. alpha Id 27/165 immunoreactivity was also absent from MALT of different mucosal sites but was readily encountered on a substantial number of lymphocytes and plasma cells in 95% cases of chronic gastritis associated with Helicobacter pylori (H.p.). The target antigen of the lymphoma IgA was found to be a common antigen of IgA and IgM plasma cells of MALT but not a constituent of bacteria commonly involved in the pathogenesis of gastritis.


CONCLUSIONS
The distinct binding of alpha Id 27/165 to only reactive mucosal B cells is a first direct evidence for the evolution of MALT-type lymphoma from chronic gastritis. Since the target antigen of the lymphoma IgA has been found to be an autoantigen of MALT plasma cells it is suggested that this MALT-type lymphoma may have arisen after triggering by an autoimmune response resulting from H.p.-induced gastritis.
Greiner
A
A
Pathologisches Institut, Julius Maximilian Universität Würzburg, Deutschland.
Marx
A
A
Heesemann
J
J
Leebmann
J
J
Schmausser
B
B
Müller-Hermelink
H K
HK
D000911:Antibodies, Monoclonal / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D005753:Gastric Mucosa / Q000276:immunology; D005756:Gastritis / Q000276:immunology*; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000145:classification / Q000276:immunology*; D008297:Male
D000911:Antibodies, Monoclonal; D007130:Immunoglobulin Idiotypes