Serum Leucine Aminopeptidase Level in Systemic Lupus Erythematosus and Rheumatoid Arthritis

Abstract

Systemic lupus erythematosus (SLE) is a chronic, inflammatory, multisystemic disease characterized by an irregular sequence of disease flares and remission. Rheumatoid arthritis (RA) is a chronic systemic disease that affects articular as well as extraarticular structures. The course of the disease is variable, displaying a pattern of spontanuous exacerbation and remission. Leucine aminopeptidase (LAP) is an eukaryotic cytosolic zinc-dependent exopeptidase. Microsomal LAP is found in biliary tract cells and increase in hepatobiliary diseases, while cytosol LAP is concentrated in lymphocytes. An increase in serum LAP level indicates its release from damaged cells containing large amounts of LAP in their cytosol fractions, or derivations from cells in which the synthesis of large amounts of LAP has been induced. This thesis was carried out to study serum LAP level in RA and SLE patients and correlate its level with clinical picture and activity score in order to assess its use as a parameter for disease activity. We conducted our study on 20 SLE patients, 20 RA patients, and 10 normal healthy subjects serving as a control group. All patients and control group were subjected to complete history taking, thorough clinical examination, radiological and laboratory tests.