Detection of RNA complementary to herpes-simplex virus in mononuclear cells from patients with Behçet's syndrome and recurrent oral ulcers.

Viral DNA probes were used in in-situ hybridisation to detect the complementary RNA in mononuclear cells from the blood of normal subjects and patients with Behçet's syndrome and recurrent oral ulcers. Hybridisation of 125I-labelled DNA probes was detected by means of autoradiography and quantitated with a video image-analysis technique. Hybridisation between herpes-simplex virus type 1 (HSV-1) DNA and the complementary RNA in mononuclear cells was significantly greater in 10 of 20 patients with Behçet's syndrome than in controls. Consistently, mononuclear cells from fewer patients showed significant hybridisation with the HSV-2 probe, and the grain counts were also lower. Control DNA probes from adenovirus 2, bacteriophage lambda, and Micrococcus lysodeikticus did not show significant hybridisation. Further separation of the patients into the four types of Behçet's syndrome revealed that mononuclear cells in 8 of 10 patients with the ocular or arthritic types showed significant hybridisation of RNA to the HSV-1 DNA probe, compared with 2 of 10 patients with the mucocutaneous or neurological types. Mononuclear cells from 4 of 8 patients with minor but not major aphthous ulcers also showed significant RNA hybridisation to HSV-1 DNA. The results suggest that at least part of the HSV genome is present and transcribed in peripheral-blood mononuclear cells--probably lymphocytes--of patients with the ocular and arthritic types of Behçet's syndrome and minor aphthous ulcers. The immunopathogenesis of these diseases might therefore be associated with HSV-1.