Successful Reduced Intensity Stem Cell Transplant in a Patient with Myeloproliferative Neoplasm/Myelodysplastic (MPN/MDS) Overlap Syndrome Diagnosed with West Nile Virus Encephalitis.

Abstract

West Nile Virus (WNV) infections are associated with high morbidity and mortality rates in transplant recipients. Limited information exists regarding the management of WNV in the peri-transplant period. The optimal duration of time for delaying transplantation remains unclear. We describe the first successful case of a patient diagnosed with WNV encephalitis in the pre-transplant period who subsequently underwent successful reduced intensity conditioning (RIC) HSCT. Our patient initially presented with low grade fevers, malaise, cough and fatigue a fortnight before planned HSCT for myelodysplastic syndrome (see Figure). Chest X-ray and respiratory tract PCR were negative. As Colorado is endemic for WNV, a WNV nucleic acid amplification test (NAAT) was sent and returned positive. WNV IgM in blood was positive (6.22), WNV IgG was negative (0.70), WNV serum reverse transcriptase polymerase chain reaction (RT-PCR) was negative. A week later he was admitted with high-grade fevers, rigors, retro-orbital headaches and confusion. Exam was unrevealing. Magnetic Resonance Imaging of brain did not show encephalitis. Cerebrospinal fluid IgG was negative (0.7), CSF WNV RNA PCR was negative. One week following discharge both WNV serum IgM (7.45) and WNV IgG (2.21) were positive. Given concerns for possible WNV encephalitis, decision was made to delay HSCT and monitor for neuroinvasive disease. He improved with resolution of fever and neurological symptoms and 1.5 months after initial presentation underwent RIC Matched Unrelated Donor (MUD) Allogeneic peripheral blood HSCT. Conditioning regimen involved fludarabine and melphalan. Post-transplant, he was on methotrexate and tacrolimus for graft versus host disease prophylaxis. On Transplant Day + 10, WNV serum IgM was positive at 4.31, WNV IgG positive at 4.12; however, serum WNV RNA PCR were reported negative. He engrafted on Transplant Day +18, bone marrow biopsy from day +28 revealed 100% donor cells. At day +100, there was no evidence of relapse of WNV infection.