HTLV-1-LIKE PARTICLES AND HTLV-1-RELATED DNA-SEQUENCES IN AN UNAMBIGUOUS CASE OF SEZARY-SYNDROME

An unambiguous case of Sezary syndrome associated with the presence of unusual retroviral infection markers is described. The blood smear sh owed 15% typical Sezary cells but also tare atypical lymphocytes with convoluted nuclei, evocative of characteristic adult T-cell leukemia ( ATL) flower cells. However, the patient did not present any clinical o r biological manifestations of ATL, and human T-cell leukemia virus ty pe 1 (HTLVI)serology was consistently negative. After being cultured f or 4 months, peripheral blood mononuclear cells (PBMC) produced typica l type C retrovirus-like particles with budding forms strongly ressemb ling HTLV-1 virions. The producer cells did not express HTLV-l-specifi c antigens detectable by indirect immunofluorescence (IIF). Southern b lotting of uncultured PBMC DNA, submitted to digestion with the restri ction enzymes Pstl and Sad, and hybridized with a full genomic HTLV-I probe, showed the presence of specific homologous sequences, absent in all of the healthy donor control PBMC DNAs. These HTLV-l-like sequenc es presented a restriction enzyme pattern distinct from that of the HT LV-1 prototype genome and of other HTLV-1 proviruses studied up to now . Polymerase chain reaction (PCR) with highly conserved HTLV-1 derived pol and env primers was consistently negative with the patient's DNA. All these results taken together suggest that our patient carries a r etroviral agent partially homologous to, but probably different from H TLV-1. The possibility is discussed that this type of retroviral agent might be associated with a subtype of cutaneous T-cell lymphoma (CTCL ) represented by a typical Sezary syndrome with a very low percentage of ATL-like flower cells in the blood smear.