Muscle damage induced by isotretinoin.

The absence of antibody to HTLV-I and HIV in patients with multiple sclerosis from France and similar findings in Italian patients (L ChiecoBianchi et al, personal communication) argue against these viruses having a role in the development of multiple sclerosis. Furthermore, the negative results in patients from the French West Indies, an area endemic for HTLV-I, strengthen the lack of a serological association between HTLV-I and multiple sclerosis. Epidemiologically, the geographical distributions of multiple sclerosis and HTLV-I are quite different. Areas endemic for HTLV-I are mainly south western Japan, the Caribbean regions, and central Africa, countries where multiple sclerosis is virtually absent. In Japan the prevalence of infection with HTLV-I has a north-south gradient but that of multiple sclerosis does not.5 Furthermore, HTLV-I is not endemic north of 400 latitude, either in Europe or in America, which are known as high risk areas for multiple sclerosis. If epidemiological data suggest that there is an association between multiple sclerosis and an infectious agent, probably viral, then a retrovirus other than HTLV-I and HIV might be responsible.