Detection of J chain in lymphomas and related disorders.
Lymph node specimens from 125 patients with malignant lymphomas and related disorders were studied by immunoperoxidase procedure for the presence of intracytoplasmic immunoglobulin (CIg) and J chain CIg staining was present in 22/24 cases of lymphoplasmacytic-lymphoplasmacytoid lymphomas, and in 10/10 cases of extramedullary plasmacytomas and myelomas. In the majority of these cases J chain could be demonstrated in plasmacytoid or neoplastic plasma cells. In 21/36 cases of immunoblastic lymphomas, intracytoplasmic Ig staining was present. In only two of the 36 cases were the lymphomatous cells stained positively for J chain. J chain was not detected in other lymphomas such as lymphocytic lymphomas, follicular lymphomas, lymphoblastic lymphomas or in Reed-Sternberg cells or hairy cells. J chain was demonstrated in mature plasma cells and immunoblastic cells in hyperplastic lymph nodes, and in angioimmunoblastic lymphadenopathy. These findings show that J chain is not detectable in all B cell lymphomas even in the presence of CIg synthesis, irrespective of class.