Integrin, alpha L (antigen CD11A (p180), lymphocyte function-associated antigen 1, alpha polypeptide), also known as ITGAL, is a human gene which functions in the immune system. It is involved in cellular adhesion and costimulatory signaling. It is the target of the drug efalizumab. Synonyms: Monoclonal CD11a antibody, Anti-CD11a antibody, LFA1a antibody.