To report the long-term outcomes of two NMOSD patients post-transplant from the previous report.

A previous study on non-myeloablative autologous hematopoietic stem cell transplantation (AHSCT) in patients with neuromyelitis optica spectrum disorder (NMOSD) reported seroreversion from AQP4-IgG + to - status and up to five years of remission [Neurology. 2019;93(18):e1732-e1741]. Longitudinal follow-up data beyond five years are lacking, and patients may become lost to follow-up.

We conducted clinical record reviews and measured AQP4-IgG status and cell-killing activity using live AQP4-transfected cells by flow cytometry.

The first patient, a 73-year-old woman diagnosed with NMOSD in January 2010 after presenting with longitudinal extensive transverse myelitis (LETM) and testing positive for AQP4-IgG (titer 100), experienced a LETM relapse in April 2010. After AHSCT in October 2010, her AQP4-IgG seroreverted to negative status, and she remained relapse-free for 12 years. However, she later relapsed with area postrema syndrome, and her AQP4-IgG seroconverted to positive (titer 1000). She made a good recovery following steroid treatment and commenced Eculizumab. The second patient, a 60-year-old woman, experienced multiple episodes of optic neuritis dating back to November 2002, with an AQP4-IgG titer of 1:100 in 2008. Despite receiving rituximab, she had relapses of LETM from 2010-2012. After AHSCT in February 2013, her AQP4-IgG seroreverted to negative status, and she remained relapse-free for 10 years. However, she later relapsed with LETM, and her AQP4-IgG seroconverted to positive (titer >100,000). Unfortunately, she developed pulmonary aspergillosis and passed away in September 2023.

Patients undergoing AHSCT for AQP4+ NMOSD who experience seroreversion (+ to - AQP4-IgG status) and remain attack-free for 10 years or more may eventually seroconvert (- to +) and relapse. This study highlights the necessity for continued clinical and serological surveillance over the long term in NMOSD patients post-AHSCT.