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

Stefan Cordes, Morie A. Gertz, Francis K. Buadi, Yi Lin, Martha Q. Lacy, Prashant Kapoor, Shaji K. Kumar, Arleigh McCurdy, Angela Dispenzieri, David Dingli, Suzanne R. Hayman, William J. Hogan, Rajiv K. Pruthi

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.