Detection of human T-lymphotropic virus-like particles in cultures of peripheral blood lymphocytes from patients with mycosis fungoides.

Because of seronegativity and absence of a leukemic phase in most patients with mycosis fungoides, a role for the human T-lymphotropic virus type I (HTLV-I) in this disease has remained tenuous. Virus particles are not seen in fresh isolates of skin or blood lymphocytes and the malignant cells (Sézary cells) have been difficult to culture. The availability of growth factors and biomolecular techniques have prompted a renewed attempt to find evidence of virus infection in these patients. We report here the successful culture of blood lymphocytes of 17 patients with mycosis fungoides and 1 patient with the Sézary syndrome. The cells of 2 additional patients failed to grow after 4-6 weeks in vitro. Ultrastructural analysis of the cultures showed an abundance of HTLV-like particles in the specimens of 18 of the 20 patients. Preliminary immunohistochemical studies carried out with various antisera directed against HTLV-I and the polymerase chain reaction utilizing a probe for a conserved region of the pol gene of HTLV-I were positive on only a portion of the specimens. Although definitive characterization of this organism awaits further analysis, it seems likely that circulating lymphocytes of all patients with mycosis fungoides harbor a virus that morphologically resembles HTLV-I.