ITGAL and psoriasis: Recently it has occasionally been observed in patients treated with biologic drugs such as natalizumab (Tysabri) which is an alpha-4-beta-1 integrin inhibitor approved for the treatment of relapsing remitting MS and Efalizumab which is an immunosuppressive recombinant-humanized IgG1 monoclonal antibody that binds to human CD11a, used in psoriasis therapy.