| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1990: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
It is well recognized that viral infections may induce autoantibodies. In 1986, Salahuddin et al isolated a new herpes group virus called HHV-6, from patients with immunodeficiency. Because this virus primarily infects T lymphocytes, the infections of the virus could be involved in the pathogenesis of autoimmune disease such as connective tissue diseases (CTD).
Therefore, we studied on the association of HHV-6 infections with CTD.
Antibody titers against HHV-6 were measured in sera from 66 patients with CTD, using indirect immunofluorescence (IF) assay and neutralization test. The geometric mean titer of IgG and IgM class anti-HHV-6 antibodies were significantly higher than in normals. Titers of neutralizing antibodies to HHV-6 also showed the same significant difference. However, antibodies against other herpes group viruses, such as herpes simplex virus, EB virus or cytomegalovirus, were not correlated with the titers against HHV-6.
Titers of anti-nuclear RNP antibody correlated significantly with those of IgG class anti-HHV-6 antibody. On the contrary, there were no significant correlations between titers of anti-DNA or SS-A antibodies and those of anti-HHV-6 antibody.
Our observations suggest that elevated anti-HHV-6 antibody is not the result of polyclonal B cell activation, which is a characteristic feature of CTD. It was also suggested that there may be an immunologic cross reactivity between HHV-6 antigens and nuclear RNP antigens.
Isolations of HHV-6 were attempted from peripheral blood monnuclear cells, salivary fluids, and tissue homogenates of skin biopsies of patients with CTD. However, no HHV-6 was isolated so far. Detections of HHV-6 DNA by polymerase chain reaction method are needed for further investigation.
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