Sequential Clinical Changes Following Autologous Mesenchymal Stem Cell Therapy in a Patient With Concurrent Huntington's Disease and Ankylosing Spondylitis: A Case Report

Huntington's disease (HD) and ankylosing spondylitis (AS) are genetically and pathophysiologically distinct conditions, and their concurrent management may present a complex clinical challenge. A case is reported of a 35-year-old man with genetically confirmed HD and concurrently diagnosed AS, treated with autologous mesenchymal stem cell (MSC) therapy over three consecutive monthly sessions (50 million MSCs per session, total 150 million administered, intravenous and epidural routes). Validated disease-specific assessments were performed at each visit by the treating neurologist before the cell administration of that day: the Unified Huntington's Disease Rating Scale motor score (UHDRS motor), the Bath Ankylosing Spondylitis Functional Index (BASFI), and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Three serial assessments captured changes from baseline (cumulative dose 0) through cumulative doses of 50 million and 100 million MSCs, after which the third (final) dose was administered without subsequent reassessment. Over the two-month observation period, UHDRS motor score declined from 19 to 2, BASFI from 4.0 to 1.0 (with a transient increase to 8.5 at the second visit), and BASDAI from 2.0 to 1.0. No serious short-term adverse events were observed during the active treatment period. Given the single-patient design, concurrent pharmacotherapy, unblinded assessment, absence of objective biomarkers, and absence of post-third-dose assessment, causal attribution to MSC therapy cannot be established. The observation is presented as hypothesis-generating and warrants further investigation under controlled conditions.