Persistent high HTLV-1 proviral load in a patient with complete remission of Adult T-cell leukemia/lymphoma (ATL)

ATL is a highly aggresive lymphoproliferative disorder caused by HTLV-1. While HTLV-1 proviral load increase with progression of the disease, changes following therapy in ATL have not been well characterized. We present a case of ATL in complete remission with persistent high HTLV-1 proviral load.

A 49-year-ol man was diagnosed as HTLV-1 carrier after a blood donation in 2004. He was born in Buenos Aires, a non-endemic area of Argentina. Four years later, he was diagnosed with T-cell lymphoma but rapidly blast cells were observed in peripheral blood and it was classified as T-cell leukemia . Chemotherapy was started in November 2008 and reached complete remission after 6 cycles. In May 2009, Interferon and zidovudine was started as maintainance therapy. HTLV-1 proviral load were log10 5.5 copies/10⁶ PBMCs and log10 5.3 copies/10⁶ PBMCs in September 2009 and December 2009, respectively. Due to persistent high proviral load, the therapy was changed to pegylated interferon, tenofovir and lamivudine (3TC). Proviral load levels were also high at 4 and 14 months on treatment (log10 5.45 copies/10⁶ PBMCs and log10 5.35 copies/10⁶ PBMCs, respectively).

With the combination of interferon and reverse transcriptase inhibitors for more than one year, the patient is in complete remission, 27 month after the diagnosis, despite the fact that he never even attained reduction of HTLV-1 proviral load.