Definition of Organ Involvement and Treatment Response in Primary Systemic Amyloidosis (AL): A Consensus Opinion from the 10th International Symposium on Amyloid and Amyloidosis.

Introduction Previously, specific criteria for recognizing organ involvement and defining response in amyloid (AL) had minimal utility. However, new therapies directed at the plasma cell, including conventional dose chemotherapy, myeloablative chemotherapy, and agents directed at disruption of fibril structure are regularly being used to treat patients. Currently criteria for response and organ involvement differ from institution to institution, making it difficult to directly compare outcomes. Outcomes are directly related to the number of organs involved with amyloid and accurate definition as to what constitutes organ involvement are more than an academic exercise. Thirteen leaders in the field were invited to submit institutional criteria from which the current guidelines were developed.

Results The panel drew up consensus guidelines for the following questions: What is required for a diagnosis of amyloidosis?, differentiating systemic from localized amyloidosis, How is amyloidosis characterized as AL type?, Definitions of organ involvement, Criteria for organ response (heart, kidney, liver, nerve and soft tissue) and organ progression, hematologic response criteria (including utilization of the newly developed immunoglobulin nephelometric free light chain assay) and Definitions for progressive disease both hematologic and organ based.

Conclusion Defining organ involvement and response criteria, both hematologic and organ-based for amyloidosis AL has always been challenging. The thirteen members of the consensus panel have defined criteria proposed to be used worldwide by physicians who treat patients with this disease and to permit uniform reporting criteria of treatment-related outcomes. In the future integration of new imaging techniques, as well as serum biomarkers such as serum troponin and brain naturetic peptide will further define the definitions of organ involvement and response.