Distribution of Epstein-Barr virus in systemic rheumatic disease (rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis) with associated lymphadenopathy: a study of 49 cases.

Among systemic rheumatic diseases (SRDs), lymphadenopathy is frequently found in patients with rheumatoid arthritis (RA) and systemic lupus erythematous (SLE). Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs) may occur in patients following methotrexate therapy for RA and dermatomyositis (DM). However, little is known about the distribution of EBV in reactive LPDs in patients with SRDs who had no history of methotrexate therapy. We analyzed 49 such patients (SLE=25, RA=23, DM=1) for the presence and distribution of EBV+ cells using Epstein-Barr virus (EBV)-encoded small RNA (EBER) specific in situ hybridization. A positive signal for EBERs was identified in 9 (SLE=5, RA=4) (18%) of 49 cases, and 3 main distribution patterns of EBER+cells could be delineated: pattern A, more than 500 EBER-positive cells were located in the germinal centers as well as interfollicular area (SLE=2); pattern B, EBER + cells were located in a few germinal centers (RA=2); and pattern C, up to 100 EBER+ cells were located in the interfollicular area (SLE=3, RA=2). Recent EBV infection may be a cause of lymph node lesion in only 2 cases of patients with pattern A. However, the pathognomonic significance of pattern B and pattern C EBER + cell distribution patterns still remains unclear. Our study indicates that the underlying immune deficits of patients with SRDs may also play an important role in the development of EBV-associated LPDs in SRDs, as previously suggested by several authors.