Significantly decreased platelet serotonin contents were measured in rheumatoid arthritis, systemic lupus erythematosus (SLE), progressive systemic sclerosis, and mixed connective tissue disease. An inverse relationship between platelet serotonin levels and clinical disease activity was observed in both rheumatoid arthritis and systemic lupus erythematosus. SLE patients with multiple organ involvement showed the lowest platelet serotonin values. No correlation was observed between platelet serotonin contents and nonsteroidal antiinflammatory drug treatment, presence of circulating platelet reactive IgG, or the amount of circulating immune complexes. The results are interpreted as indicating platelet release occurring in vivo during inflammatory episodes of the rheumatic disorders investigated.In addition to their role in blood coagulation, platelets have been shown to play an important part as intravascular inflammatory cells (1). Substances such as thrombin, collagen, ADP, prostaglandin endoperox- Supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 5 4 4 3 .

Sonography and NMR imaging of the knee joint make it possible to obtain a visual representation of the thickened synovial membrane occurring in patients with rheumatoid gonarthritis, even before inflammatory deformation is radiologically detectable. Both methods can expose effusions and Baker's cysts. In NMR imaging, an indication of the inflammatory genesis can be obtained from the extended relaxation time T1. Due to the good representation of soft tissues, prognostic evidence may be gained of whether a mainly exudative or proliferative form is present.

In a multicenter placebo-controlled double-blind randomized clinical study, 91 patients with rheumatoid arthritis were given 28 days' treatment with recombinant interferon-gamma (50 micrograms daily for 20 days, then 50 micrograms each second day up to day 28, given by subcutaneous injection). The aim of the study was to provide a methodologically clear demonstration of the efficacy of treatment with interferon-gamma, using criteria that could be handled by statistical tests. Evaluatable documentation was available for 79 patients, of whom 40 were treated with the active compound. The principal criterion for the statistical evaluation of the therapeutic success was improvement of the Ritchie "joint pain index" or Lansbury "joint pain index" by at least 30% within 28 days. The chi-square test showed superiority of the interferon arm over the placebo arm with an error probability of alpha less than 1%. In addition, efficacy of interferon-gamma was demonstrated in respect of practically all parameters investigated. The frequency of side-effects, including febrile reactions, was the same for the active compound and the placebo. During interferon treatment the daily maximum body temperature was raised by 0.3 degrees C on average, but was below 37.2 degrees C at all times.