[Circulating interferon in patients with systemic lupus erythematosus. A prospective study]

The serum levels of interferon (IFN) were measured in 31 patients with systemic lupus erythematosus (SLE). Among the 31 patients, 8 (25%) showed IFN in the sera: in 4 patients IFN titers of 16 U/ml, and in the other 4 patients titers of greater than or equal to 32 U/ml became detectable. Whereas antibodies to native DNA (nDNA) were present in 6 of the 8 IFN positive patients, anti-nDNA antibodies were only positive in 6 of the 23 IFN negative individuals (p less than 0.002). Eight months after the first search for IFN in the patients' sera, 6 of the 8 IFN positive patients showed reduced IFN serum levels and one each had an increased or stable IFN titer. A good correlation between IFN titers and both the anti-nDNA antibody titers and the disease activity was observed. However, there were patients with active disease, high anti-nDNA titers but no IFN in the serum

Effect of Head-Down Tilt Bedrest (10 Days) on Lymphocyte Reactivity

Immunological responses of six healthy males to 10 days of headdown tilt bedrest (HDT) were assessed. Lymphocyte responsiveness was severely reduced immediately before, during, and immediately after the HDT, even though the lymphocyte numbers did not change. By contrast, delayed-type hypersensitivity was not affected. No dramatic changes were found in WBC counts and lymphocyte subpopulations, with the only exception of natural killer (NK) cells which transiently decreased immediatley after HDT. Plasma cortisol levels were elevated above normal immediately before and during the HDT. The data suggest that the mitogenic response of lymphocytes was affected by psychological and fluid shift stress. These results are compared with data obtained during and after spaceflight. We conclude that the stress of HDT induces changes in immunological responsiveness that are strikingly similar to those arising from the stress of spaceflight