Background: Immunoglobulin light chain (AL) amyloidosis can be treated with high-dose melphalan and autologous stem cell transplantation (HDM/SCT). Risk factors for infections may include hyposplenism, hypogammaglobulinemia, treatment-related neutropenia, melphalan-induced mucositis, and nosocomial exposures.
Methods and design: A review of 493 patients with AL amyloidosis undergoing treatment with HDM/SCT from August 1994 to August 2009 was performed. The objectives were to determine the rate and types of infections following HDM/SCT, to identify factors associated with microbiologically documented infections, and to assess the contribution of infections to all-cause treatment-related mortality (TRM; defined as deaths within 100 days of SCT).
Results: Microbiologically documented infections after HDM/SCT occurred in 24% (n = 119) of patients. TRM was 10% (n = 48) overall, and 21% (n = 25) in patients who had a documented infection. Thus, the relative risk of TRM in a patient with a documented infection was 3.42 (95% confidence interval [CI] 2.02-5.79). Infections were caused by gram-positive bacteria in 51%, anaerobic bacteria in 16%, gram-negative bacteria in 13%, and fungi in 9% of cases. Serum creatinine >2 mg/dL was associated with increased risk of post-SCT infection (38% vs. 21%, P = 0.0007) with an odds ratio of 2.27 (95% CI 1.40-3.68). No significant association for infection was found for age, gender, cardiac involvement, prior steroid therapy, dose of melphalan, multiorgan involvement, days to neutrophil engraftment, or dose of CD34 + cells infused.
Conclusion: Serum creatinine >2 mg/dL is a risk factor for infections in patients with AL amyloidosis undergoing HDM/SCT. The relative risk of TRM in a patient with a documented infection was increased >3-fold. A broad spectrum of infections, similar to that in other SCT patients, is seen in this population in the early post-SCT period.
© 2012 John Wiley & Sons A/S.