Clinical features of patients with immunoglobulin light chain amyloidosis (AL) with vascular-limited deposition in the kidney

Abstract

In the kidney, immunoglobulin light chain amyloidosis (AL) can be deposited in vascular-limited AL (V-AL) or diffuse (D-AL) pattern. These patterns are associated with different clinical presentations. A nested case study was performed to describe these differences. V-AL was defined by the vascular-limited deposits. Cases were matched for age, sex and date of renal biopsy. There were 12 cases of V-AL (mean age 61 ± 11 years) and 24 cases of D-AL. Median follow-up was 26 months for V-AL and 38 months for D-AL, P = 0.14. Lambda was more common in D-AL (83.3%) than V-AL (50%, P = 0.04). Cardiac function was similar between the two groups. V-AL patients presented with lower renal function (serum creatinine = 2.1 versus 1.3 mg/dL, P = 0.02; estimated glomerular filtration rate 31 versus 59 mL/min/1.73m(2), P = 0.01 and creatinine clearance 38.5 versus 64 mL/min/1.73m(2), P = 0.02, respectively). Proteinuria was low grade in V-AL [0.4 (0.09-0.98) g/day] compared to nephrotic range in D-AL patients [8.0 (0.2-22) g/day, P < 0.001]. Stem cell transplantation was performed on 62.5% of the D-AL but on only 25% of the V-AL, P = 0.08. Median survival was longer in patients with D-AL (77.2 months) versus V-AL (40.6 months, log-rank P = 0.02). Our study found that V-AL patients presented with more severe renal insufficiency and less proteinuria than D-AL. There was a preference for λ light chain in the D-AL that was not noted in the V-AL. Patients with D-AL in this study had a longer median survival but most of them were stem cell transplantation candidates.