Hematopoietic stem cell transplantation for uncommon immune-mediated neurological disorders: A literature review.

Background: Chronic inflammatory demyelinating polyneuropathy (CIDP), stiff-person syndrome (SPS), neuromyelitis optica spectrum disorders (NMOSD) and severe refractory myasthenia gravis (MG) are immune-mediated neurological diseases that severely affect patients' functionality and quality of life, with a considerable percentage undergoing relapse or not responding to conventional treatment options. Autologous hematopoietic stem cell transplantation (auto-HSCT) has emerged as a potential second-line treatment alternative.

Methods: We performed a literature review in PubMed/Medline, EMBASE, Web of Science and Cochrane Library from inception to September 2021 of reported cases and studies of CIDP, SPS, NMOSD and MG that underwent HSCT as a treatment option.

Results: A total of 173 patients who underwent HSCT were found, including 32 patients described in case reports and 60 in a phase 2 clinical trial with CIDP, 29 patients with SPS, 42 patients with NMOSD and 10 patients with refractory MG. Complete remission was documented in 68/92 patients with CIDP, 13/29 with SPS and 10/10 with MG. From the NMOSD cases, 24/42 were relapse-free at last follow-up, with 13/33 having negative anti-AQ4 antibodies after HSCT. From all the included studies, only 8/173 patients received an allogeneic HSCT, 4/8 after a failed auto-HSCT. All showed clinical improvement and disease remission.

Conclusion: HSCT has the potential to induce long-term remission in patients with CIDP, NMOSD, SPS or MG with adequate safety and tolerability. Collaboration between centers is needed to implement larger, homogeneous prospective studies, focusing on immunological correlates of favorable long-term response.