TNF and progressive multifocal leukoencephalopathy: In 2010, Crouser et al. showed that lymphocyte counts can increase in sarcoidosis patients treated with antibodies directed against tumor necrosis factor alpha,40 whereas infliximab treatment itself has been discussed as a risk factor for PML development.41 In our cohort, we decided to initiate a systemic corticosteroid treatment in all patients that were previously naive to immunosuppressants.