[Regulation and therapeutic modulation of T-lymphocytes adhesion]

LFA-1, Mac-1, and p150,95 are leukocyte adhesion proteins called beta 2 integrins. LFA-1 is expressed at the surface of all leukocytes. A rare disease caused by mutations of the gene encoding the integrin beta 2 subunit is characterized by defective expression of these leukocyte adhesion molecules. Affected individuals have profound immune deficiency with severe bacterial infections for which the only effective treatment is bone marrow transplantation. These patients are unable to reject a transplant from only partially "Human Leucocyte Antigen" (HLA) compatible donors. In vivo studies have demonstrated decreased transplant rejection after injection of anti-LFA-1 antibodies to patients with other immune deficiencies. Simultaneous administration of an anti-CD2 antibody that blocks the second major pathway of lymphocyte adhesion can be expected to reduce even further the rate of rejection episodes.