Brain volume loss (BVL) is commonly observed after high-dose immunosuppression and autologous hematopoietic cell transplantation (HDIT/HCT) for treatment of multiple sclerosis (MS). To better understand the mechanisms of underlying BVL associated with this treatment, we characterized the time courses of whole-brain (WB), grey-matter (GM) and white-matter (WM) volume loss in relapsing-remitting MS (RRMS) patients who received BEAM-based HDIT/HCT.
We used Jacobian integration to measure MRI-based WB, GM and WM volume changes up to 5 years after transplant in twenty-four RRMS participants who underwent BEAM-based HDIT/HCT. Using a two-piecewise mixed-effects model, we estimated the short-term (baseline to 1 year) and long-term (beyond 1 year) rates of BVL after HDIT/HCT. We also compared the rates based on the presence of gadolinium-enhancing lesions at baseline, and the maintenance of event-free survival during follow-up.
On average, accelerated short-term BVL of -1.37% (SE: 0.21), -0.86% (SE: 0.28) and -2.18% (SE: 0.26) occurred in WB, GM and WM, respectively. Baseline T1-weighted MRI WM lesion volume was a significant predictor in the WB (short-term) and the WM (short-term and long-term). The average rates of BVL after the initial acceleration were -0.22%/y (SE: 0.10), -0.13%/y (SE: 0.11) and -0.36%/y (SE: 0.11) in the WB, GM and WM, respectively. Participants with gadolinium-enhancing lesions at baseline had significantly higher short-term rates of GM (-1.56% vs. -0.27%, p = 0.01) and WB volume loss (-1.94% vs. -0.81%, p = 0.006) at 1 year follow-up as compared to those without gadolinium-enhancing lesions. WM volume loss was not significantly different (-2.59% vs. -1.66%, p = 0.16). Participants who maintained event-free survival had similar rates of BVL compared to those who did not.
BVL may accelerate for months after HDIT/HCT. However, over the long-term, adequate HDIT/HCT may reduce BVL rates to those similar to normal aging at the WB level.

Copyright © 2021. Published by Elsevier B.V.