Prolonged Immunosuppression in Relapsed, Refractory Multiple Myeloma Leading to Cerebral Toxoplasmosis and Progressive Multifocal Leukoencephalopathy

Toxoplasmosis and progressive multifocal leukoencephalopathy (PML) are both uncommon conditions and occur following reactivation of the toxoplasma parasite and John Cunningham virus, respectively. The prevalence of these conditions became more frequent with the HIV epidemic as a result of the profound T-cell immunosuppression (AIDS) caused. More recently, however, with prolonged and intense immunosuppression, increased numbers of cases are being detected. These include unforeseen side effects of more targeted therapies (eg, PML development with natalizumab, an alpha 4-integrin inhibitor). Given the rarity of these infections coupled with unanticipated adverse effects of newer hematologic therapies, there is no guidance on clinical surveillance or risk-stratification of these patients. We present a case of 2 unusual adverse effects of immune suppression - cerebral toxoplasmosis and PML, diagnosed sequentially in a patient with 12 years' treatment for multiple myeloma, illustrating the importance of physician vigilance. Crown Copyright (C) 2019 Published by Elsevier Inc. All rights reserved.