LUM and glycogen storage disease VI: Another mechanism of lumican-mediated regulation of the inflammatory response isrelated to its interaction with MAC-1 (αM/β2) and LFA-1 (αL/β2),125 the two major cell surface integrins of polymorphonuclear (PMN)leukocytes (Fig. 3).125 By binding to both integrins, lumican promotes PMN leukocyte migration.125 PMN leukocytes are crucial regulators in inflammatory and autoimmune diseases.134 PMN trafficking toward the sites of inflammation is an initial phase ofinflammatory diseases.127