[Macro-AST and myeloma: An incidental association?]

Abstract

Introduction: Macro-AST is recognized as a classical aetiology of isolated and persistent increase of serum aspartate aminotransferase (AST) levels. Macro-AST are high molecular weight complexes associating AST and a macromolecule, often an immunoglobulin. Although those macroenzymes of unknown pathogenesis are usually non-pathogenic, association with several diseases, including autoimmune diseases and liver diseases has been described.

Case report: We report here the case of a 45-year-old patient with previously normal liver enzymes in whom an AST elevation and an IgA monoclonal gammopathy were discovered concomitantly. Following the diagnosis of multiple myeloma, we could evidence in the patient's serum a complex between AST and the monoclonal IgA. AST levels course followed closely the progression of monoclonal gammopathy.

Conclusion: This is the first report demonstrating a clear link between macro-AST and a monoclonal gammopathy.

Keywords: Antigen-antibody complex; Aspartate aminotransferase; Aspartate aminotransférase; Complexe antigène-anticorps; Immunoglobulin; Immunoglobuline monoclonale; Macro-ASAT; Macro-AST; Multiple myeloma; Myélome multiple.