Kidney Involvement in Light Chain Amyloidosis

Systemic amyloidoses are complex diseases caused by the misfolding of autologous protein. Immunoglobulin light chain (AL) amyloidosis is caused by usually small plasma cell clone synthesizing light chains undergoing conformational changes that lead to their aggregation and deposition in tissues. Although the presence of heart involvement is the most important prognostic determinant, the kidney is involved in 70% of patients. Renal involvement results in significant morbidity, and renal failure limits the therapeutic options. The clinical presentation of kidney involvement is characterized by nephrotic syndrome and progressive renal failure. Diagnosis relies on the identification and accurate typing of amyloid deposits at the abdominal fat pad aspirate or with renal biopsy. Refined diagnostic and staging systems based on biomarkers have helped in assessing prognoses and evaluating responses to therapy, which has considerably improved the management of these conditions. In addition, the availability of novel, more powerful drugs targeting different steps in the pathogenic cascade of AL amyloidosis has created a favorable environment for a long-awaited improvement in the treatment of this disease.