Beta 2-microglobulin amyloidosis: why and how to look for it

Thirty years after the introduction of chronic dialysis into clinical practice, amyloidosis based on the precursor molecule beta 2-microglobulin (beta 2m-A) has emerged as an important complication of end-stage renal disease in patients on renal replacement therapies other than transplantation. For the individual patient, diagnosis of beta 2m-A is important to exclude other treatable causes of the symptoms, initiate symptomatic treatment, prevent possible life-threatening complications, and assign a high priority for transplantation. For the ESRD population as a whole, early specific diagnosis should help to assess the influence of various therapeutic modes on the development and course of beta 2m-A and to guide further the optimization of renal replacement therapy. Besides, sophisticated diagnostic techniques may yield valuable information on underlying pathogenetic mechanisms of beta 2m-A. Morphology, including immunohistochemistry, as the most definitive and specific diagnostic proof must rely on invasive procedures to obtain the appropriate material from clinically affected sites. Clinical assessment and imaging techniques such as x-ray and joint sonography suffer from non-specificity. Scintigraphic imaging of beta 2m-A after injection of radiolabelled beta 2-microglobulin is a non-invasive, specific, and highly sensitive way of diagnosis. Further refinement and more widespread use of this method can be expected to enhance the understanding of beta 2m-A pathogenesis and promote therapeutic and preventive efforts against this complication.