Is β2-microglobulin-related amyloidosis of hemodialysis patients a multifactorial disease? A new pathogenetic approach

Purpose: β2-microglobulin amyloidosis (Aβ₂M) is one of the main long-term complications of dialysis treatment. The incidence and the onset of Aβ₂M has been related to membrane composition and/or dialysis technique, with non-homogeneous results. This study was carried out to detect: i) the incidence of bone cysts and CTS from Aβ₂M; ii) the difference in Aβ ₂M onset between cellulosic and synthetic membranes; iii) other risk factors besides the membrane. Methods: 480 HD patients were selected between 1986 to 2005 and grouped according to the 4 types of membranes used (cellulose, synthetically modified cellulose, synthetic low-flux, synthetic high-flux). The patients were analyzed before and after 1995, when the reverse osmosis treatment for dialysis water was started at our center, and the incidence of Aβ₂M was compared between the two periods. Routine plain radiography, computer tomography (CT) and nuclear magnetic resonance imaging (MRI) as well as electromyography were used to investigate the clinical symptoms. Results: Bone cysts occurred in 29.2% of patients before 1995 vs. 12.2% after 1995 (p2M. Conclusions: The findings that the inflammatory status as well as low albumin and the residual GFR of the uremic patient are predictive of Aβ₂M lesions suggests that Aβ₂M has a multifactorial origin rather than being solely a membrane- or technique-related side effect.