Interleukin-6 positive follicular hyperplasia in the lymph node of a patient with rheumatoid arthritis.

We examined interleukin-6 production in the hyperplastic lymph node of a 77-year-old male rheumatoid arthritis patient with lymphadenopathy. The interleukin-6 production of the lymph node was observed by both immunohistological staining and in vitro culture. The results suggest that interleukin-6 plays a significant pathogenic role in the etiology of the lymphadenopathy seen in many rheumatoid arthritis patients.