Serious and sometimes fatal viral (e. g. adenovirus, parainfluenza, hepatitis B, progressive multifocal leukoencephalopathy (PML)), bacterial (including tuberculosis and atypical mycobacterioses, nocardiosis), protozoan (e. g. toxoplasma gondii), and fungal (e. g. rhinocerebral mucormycosis) infections, including those due to reactivation of latent infections have occurred during post-marketing surveillance.