Lymphoma associated antigen (LAA)--a unique biomarker for lymphomas

A lymphoma associated antigen (LAA) isolated from pooled lymph nodes of confirmed Hodgkin's and non-Hodgkin's lymphomas has been purified and characterized. Using a xenogenic rabbit anti-serum, enzyme-linked immunosorbent assay (ELISA) and RIA were developed for LAA. LAA was detected in the sera of all confirmed lymphomas, the test being negative for normals, for patients with benign lymphadenitis and various other types of cancers. Except for a very few false positive results, no false negative was observed. LAA was identified in urine, CSF, saliva and gastric juice of a few lymphoma patients, and the test proved to be of diagnostic potential, as for a few patients it had a lead time of a few months over the histological diagnosis. In order to render the LAA test more precise and specific, monoclonal antibodies were generated by both in vitro and in vivo immunization procedures. Seven monoclonals were generated, viz. 7D6, 7D2, 7G2, 7C5, 6G2, 23B7 and 23G11, which exhibited cytoplasmic staining of frozen sections of malignant lymphoid tissues of B cell derived non-Hodgkin's lymphomas. Two of these monoclonal antibodies, 7D6 and 23B7, revealed strong cytoplasmic staining of frozen sections, impression smears and cytospin specimens of B cell non-Hodgkin's lymphomas. The reactivity was very weak or negative for T cell lymphomas. The test was negative for Hodgkin's disease and controls. These results were confirmed by dot blotting, immunoprecipitation and immunofluorescence study. By ELISA with a sensitivity of 15 ng/ml, serum LAA levels for lymphomas were in the range 72-1250 ng/ml. LAA could not be detected in the sera of normals and controls.(ABSTRACT TRUNCATED AT 250 WORDS)