Mycosis fungoides and Sezary syndrome are not associated with HTLV‐I infection: an international study

Association between mycosis fungoides (MF), its leukaemic variant Sezary syndrome (SS) and the human T‐cell lymphotropic virus type‐I (HTLV‐I) has been controversial, with the reported incidence of infection varying between 0% and nearly 100%. We studied 127 patients (85 MF, 28 SS, five Sezary cell leukaemia, four lymphomatoid papulosis, and five unspecified cutaneous T‐cell lymphomas (CTCL)) originating from Europe (France, Spain, U.K., Portugal) or from U.S.A. (California) for the presence of HTLV‐I infection markers. HTLV‐I and ‐II serology were performed on 78 patients using standard immunological methods. Reverse transcriptase (RT) assay was also performed in 26 cases using an RT‐PCR‐based method of high sensitivity. Molecular analyses were performed on 215 DNA samples (121 from fresh PBMCs, 26 from PBMCs after short‐term culture and 68 from skin lesions) by PCR amplification using HTLV‐I and ‐II gag, pol, env, pX and LTR specific primers. Immunological tests were negative except for two sera which were indeterminate. PCR with all HTLV‐I and ‐II primer pairs showed negative results in all 215 samples investigated. No RT activity was detected in short‐term PBMC cultures of any of the 26 cases studied. The results of this large study from five different countries clearly indicate that MF and SS are not associated with HTLV‐I infection.