Successful Autologous Hematopoietic Stem Cell Transplant in Glycine Receptor Antibody-Positive Stiff Person Syndrome: A Case Report

BACKGROUND AND OBJECTIVES:To describe a case of glycine receptor (GlyR) antibody-positive stiff person syndrome (SPS) treated with autologous hematopoietic stem cell transplant (aHSCT). METHODS:This was a multicenter collaboration for the treatment of a single patient who underwent aHSCT as part of a clinical trial (NCT00716066). To objectively assess the response to transplantation, several clinical outcome measures were evaluated pretransplant and up to 18 months post-transplant, including modified Rankin Score (mRS), stiffness index, Hauser Ambulation Score (HAS), hypersensitivity index, timed 25-foot walk, and Montreal Cognitive Assessment. RESULTS:After transplant, the patient achieved sustained clinical improvement evidenced across various clinical scales, including mRS, stiffness index, HAS, and 25-foot walk time. DISCUSSION:aHSCT represents a promising treatment option for SPS, including for GlyR-positive patients. In addition, this case represents the need to validate and standardize best clinical outcome measures for patients with SPS. CLASSIFICATION OF EVIDENCE:Class IV; this is a single observational study without controls.