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Abstract: PO1480

Clinicopathological Characteristics and Long-Term Prognosis of Monoclonal Immunoglobulin Light Chain-Associated Fanconi Syndrome

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

  • Li, Jiaying, Peking Union Medical College Hospital, Dongcheng-qu, Beijing, China
  • Shi, Xiaoxiao, Peking Union Medical College Hospital, Dongcheng-qu, Beijing, China
  • Xia, Peng, Peking Union Medical College Hospital, Dongcheng-qu, Beijing, China
  • Chen, Limeng, Peking Union Medical College Hospital, Dongcheng-qu, Beijing, China
Background

Monoclonal immunoglobulin light chain associated Fanconi syndrome (LC-FS) is a rare disease which involved the proximal tubules. As most of the cases came from western countries, we aimed to analyze the clinicopathological characteristics of Asian LC-FS and its long-term prognosis.

Methods

From January 1998 to February 2019, 26 patients who were diagnosed with both FS and monoclonal gammopathy in Peking Union Medical College Hospital were enrolled. Their clinicopathological and follow-up records were retrospectively reviewed.

Results

At diagnosis, the mean age of the 26 Asian LC-FS patients was 54.7±14.7 years, with females accounting for 57.7 %. The underlying malignancies included monoclonal gammopathy of renal significance (MGRS, n=14, 53.8%), multiple myeloma (MM, n=10, 38.5%), Waldenstrom macroglobulinemia (WM, n=1) and primary plasma cell leukemia (PPCL, n=1). The most common symptoms were fatigue (95.7%), ostealgia (88.5%) and nocturia (61.1%). Their mean eGFR was (68.0 ± 26.4) ml/min/1.73m2, with different degrees of proximal tubular dysfunctions, including normoglycemic glycosuria (88.0%), hyperphosphaturia (84.2%), aminoaciduria (84.0%), hypouricemia (80.8%), hypophosphatemia (80.8%), RTA (73.1%), and hypokalemia (42.3%). For kidney pathology, some specific features of LC-FS were observed in proximal tubular cells, including k deposition, intracellular crystalline formation and increased lysosomes. A total of 13 patients received chemotherapy, which mainly included bortezomib-based (n=6) and melphalan-based (n=2) regimens. Renal response was achieved in 58.3% cases which was accompanied by the hematological response, and tubular response was acquired in 66.7% cases. The k-LC FS patients presented with more common hypophosphatemia and hyperphosphaturia than the λ-LC group, and no differences were shown in treatment responses between these two groups. Compared to the primary Sjogren’s syndrome associated FS patients with increased immunoglobulin G, LC-FS patients had more severe proteinuria, a higher prevalence of ostealgia, and less hypokalemia.

Conclusion

Asian LC-FS patients had mild renal function disorder, with more common hypophosphatemia and hyperphosphaturia in κ-LC patients than in λ-LC patients. The chemotherapy could improve renal function, which was related well to the hematological response.

Funding

  • Private Foundation Support