164 Progressive multifocal leukoencephalopathy (PML) following autologous periph- eral blood stem cell transplantation for multiple myeloma

A 67-year-old man presented with unilateral weakness and reduced dexterity four months after autolo- gous peripheral blood stem cell transplantation for multiple myeloma. The progressed over the following months, accompanying cognitive sensory symptoms. Brain MRI showed numerous hyper- intense T2 lesions within subcortical white matter of both cerebral hemispheres suggestive demy- elination, progressing rapidly on interval imaging. His CSF tested positive JC virus, diagnostic PML. This diagnosis was unexpected as patient did not appear to be significantly immunocompromised PML is extremely rare in patients Treatment progressive multifocal leukoen- cephalopathy via restoring immune function; our no reversible cause immuno-suppression present. At time patient’s treatments had been shown effective against clinical trials. However, last year pembrolizumab BK virus specific T-cell therapy have demonstrated efficacy published trials, offering new hope patients. Clinicians should consider a when assessing neurological symptoms signs treatment myeloma other haematological conditions, particularly efficacious can now given if diagnosed early. [email protected]