In Vitro: Efalizumab (78 ng/mL-5 mg/mL) induces a leukocytosis and downregulates LFA-1 expression on T cells in the peripheral blood. Efalizumab (78 ng/mL-5 mg/mL) downregulates plate-bound, anti-CD3-stimulated proliferation of PBMC.
In Vivo: Efalizumab shows side effects include bacterial sepsis, viral meningitis, invasive fungal disease and progressive multifocal leukoencephalopathy (PML), a brain infection caused by reactivation of latent JC virus infection.