Pulmonary morbidity improves after autologous stem cell transplantation in POEMS syndrome

Background POEMS syndrome is a plasma cell disorder manifested by Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal gammopathy and Skin changes. Pulmonary morbidity includes restriction, decreased diffusing capacity for carbon monoxide (DLCO), respiratory muscle weakness, abnormal imaging, and pulmonary hypertension. Autologous peripheral blood stem cell transplantation (aPBSCT) is an effective treatment for POEMS syndrome. It is unknown if aPBSCT improves pulmonary morbidity. We hypothesize pulmonary morbidity will improve following aPBSCT.

Methods Retrospective cohort study of POEMS syndrome aPBSCT recipients from 2000 to 2010. Demographic, pulmonary function test (PFT), echocardiogram, cytokine, and imaging data at baseline and after aPBSCT were abstracted. Pre- and post-transplant data were compared using Wilcoxon signed-rank and McNemar's tests.

Results 53 patients met criteria. Median improvements in forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), and total lung capacity (TLC) after transplant were 180, 315 and 350 ml respectively (median follow-up of 1.1 years). DLCO, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) improved by a median of 11, 12.5 and 10% predicted respectively. RVSP and chest imaging also improved. Vascular endothelial growth factor and IL-6 decreased by a median of 334 and 2 pg/ml respectively. All comparisons were statistically significant. Longitudinal data demonstrated stability in FEV₁, MEP, and TLC and continued improvement in FVC, MIP and DLCO on subsequent PFTs (median follow-up 26.5 months).

Conclusion Patients with POEMS syndrome treated with aPBSCT have significant improvement in PFTs, respiratory muscle strength, imaging, and post-transplant IL-6. The improvement in PFTs persists during long-term follow-up.