HTLV-I in neurological diseases

The human lymphotropic retrovirus type I (HTLV-I) has been recently associated with neurological diseases. Antibodies against HTLV-I were found in the sera and in the CSF of patients affected by Tropic Spastic Paraparesis (TSP), diffused in tropical areas such as Caraibi, south America, Seychelles. A similar clinical pattern was found in Japan and was named Human myelopathy (HAM). The virus was isolated from mononuclear cells either of the peripheral blood, and of the CSF. Molecular studies have shown that the "neurotropic" HTLV-I is similar to that associated to T cell leukemia. In vitro studies have shown that tumoral and fetal astroglial cells are susceptible to HTLV-I entry. Actually after 7 days, cells exposed to HTLV-I showed the virus core protein p19 together with an high expression of class II antigens and a disorganization of the GFAP. Multiple sclerosis (MS) has also been associated with HTLV-I infection, on the basis of finding antibodies against HTLV-I in the sera and in the CSF of some patients. However the presence of HTLV-I genome detected by PCR analysis within mononuclear cells from peripheral blood lymphocytes of MS patients is still a controversial question. The aim of the present review is to critically analyze the role of a lymphotropic retrovirus in demyelinating diseases.