Autologous stem cell transplantation in immunoglobulin light chain amyloidosis with factor X deficiency.

Acquired factor X deficiency and associated haemorrhage can be consequences of immunoglobulin light chain amyloidosis. There are limited data on the safety and efficacy of autologous stem cell transplant (ASCT) on factor X deficiency. We retrospectively reviewed immunoglobulin light chain amyloidosis patients with factor X levels below 50%, not on chronic anticoagulation who underwent ASCT at the Mayo Clinic, Rochester, Minnesota, USA, between April 1995 and December 2011. Twenty-seven of 358 patients (7.5%) met study criteria. Median pre-ASCT factor X was 36% (range: 2-49%). The most frequent and severe bleeding complications occurred in patients with factor X levels below 10%. Peri-procedural prophylaxis included activated recombinant factor VII, fresh frozen plasma and platelet transfusions. Steady-state post-ASCT factor X levels were determined in 12 patients. Post-ASCT factor X levels increased in 100% of patients, with median factor X improvement of +32% (range: +8 to +92%). About 46.2% of patients were no longer factor X deficient after ASCT. The degree of improvement in factor X levels was correlated with an improvement in markers of renal involvement by amyloid. Improvement in factor X correlated with an improvement in the degree of total serum protein (ρ = 0.54; P = 0.04) and proteinuria (ρ = -0.54; P = 0.04). Our findings support the decision to offer ASCT to factor X-deficient patients as both appropriate and efficacious.