Anti-Liver/Kidney Microsomal Antibody (Anti-LKMA)

Anti-liver-kidney microsome antibody,LKMA positive autoimmune chronic active hepatitis may be detected early in life, present different clinical patterns, and is frequently associated with extrahepatic autoimmune manifestations . The antigen recognized by LKMA has been identified as a protein with an ,M, of 50 kD, present in a higher concentration in smooth than in rough microsomes. This 50-kD protein is an integral membrane protein exposed on the cytoplasmic side of the microsomal membrane. These properties are typical of the cytochromes, a family of hemeprotein monooxygenase isozymes present in large amounts in hepatocytes. It was recently shown that LKMA crossreacts with two methylcholantrene-inducible isozymes ofcytochrome P450 on dot-blot analysis, suggesting that the antigene, present in noninduced microsomes, has some common epitopes with these P450 isozymes and could be a constitutive form of cytochrome P450 .