HETEROGENEITY OF EPSTEIN-BARR-VIRUS INFECTION IN ANGIOIMMUNOBLASTIC LYMPHADENOPATHY TYPE T-CELL LYMPHOMA

To investigate the relationship of Epstein-Barr virus (EBV) and angioi mmunoblastic lymphadenopathy with dysproteinemia, we performed DNA ana lysis using the polymerase chain reaction (PCR), Southern blot, in sit u hybridization, and immunohistochemical analysis of lymph nodes in fi ve patients who were followed up and biopsied more than once. In the c ourse of the disease, nodal architecture diminished, cellular atypia w orsened, and clear cells increased in number. In the DNA analysis of t he receptor genes, the clonal population increased in number. EBV nucl eic acid sequences were found by either PCR or in situ hybridization i n all examined nodes. The number of EBV-positive cells varied widely a mong the cases and throughout the course of the disease in the same pa tients. The analysis of EBV terminal repeats or lymphocyte-determined membrane antigen genes showed polyclonal populations of EB-infected ce lls. EBV-positive cells possessed intermediate- to large-sized nuclei, and the cells with large nuclei, especially, expressed latent membran e protein of EBV. These large cells varied in number among the cases. Double-labelling immunohistochemistry/in situ hybridization studies de monstrated that most of the EBV-positive cells expressed B-cell antige n (CD20). The presence of EBV seems to be associated with the selectiv e defects of the immune system, rather than with the direct pathogenes is of angioimmunoblastic lymphadenopathy.