HLA class II antigen associated invariant chain gene expression in malignant lymphoma.

Expression of the gene encoding HLA class II antigen-associated invariant chain was studied in several types of fresh human malignant lymphoma by Northern blot analysis or slot-blot analysis. The invariant chain mRNA levels decreased with the stage of B-lymphocyte differentiation to plasma cells such as in immunoblastic lymphoma (IBL) or multiple myeloma (MM). The invariant chain gene (In-gene) was expressed in diffuse large cell lymphoma (DLCL), while its expression was hardly detected in IBL. It is suggested that the difference in In-gene expression between DLCL and IBL could be useful in distinguishing these two morphologically similar diseases.