Eight patients suffering from severe rheumatoid arthritis were treated
with high-dose human immunoglobulin. Doses of 500 mg/kg were administ
ered intravenously in the morning on 4 consecutive days. Improvement o
f arthritic symptoms was indicated by a significant decrease of the Ri
tchie index, the number of swollen joints, and the duration of morning
stiffness as well as an increase of grip strength. The improvement la
sted up to 4 months. In 2 patients the disease activity increased agai
n after 4 weeks. Investigations of laboratory parameters demonstrated
a significant reduction of the acute-phase response. Parallel investig
ations of immunological parameters revealed a decrease of Il-6 levels
in the sera. Therefore, we suggest a decreased activation status of th
e monocyte-macrophage system and T cells as a possible mode of action
of high-dose immunoglobulin therapy in rheumatoid arthritis.