Allogeneic BK Virus-Specific T Cells for Progressive Multifocal Leukoencephalopathy

Researchers at Houston's M.D. Anderson Cancer Center report on the results of an experimental treatment administered to three immunocompromised patients with progressive multifocal leukoencephalopathy (PML).

Researchers at Houston's M.D. Anderson Cancer Center report on the results of an experimental treatment administered to three immunocompromised patients with progressive multifocal leukoencephalopathy (PML). The fact that the JC virus underlying PML is genetically similar to the BK virus, which causes nephritis and cystitis in patients after stem cell transplantation, gave the team reason to believe that PML patients might respond to T cells designed to combat BK virus. In two patients, infusion of BK virus-specific T cells was followed by clearing of the JC virus from cerebrospinal fluid and alleviation of clinical symptoms and evidence of PML. JC viral load was reduced in the third patient, and her symptoms stabilized until she died—which was 8 months after the first infusion of BK T cells. The findings from this proof-of-principle study suggest that third-party–produced, "off-the-shelf," partially HLA-matched, BK virus–specific T cells may be a viable therapy for PML. Additional large-scale trials are warranted to determine the success rate, durability, and longer-term adverse events associated with this intervention.