The aim of the study was to characterize the demographic, clinical, and prognostic features of Chinese patients with acute transverse myelitis (ATM). The clinical data from ATM patients in a demyelinating disease database were analyzed retrospectively. Sixty-seven ATM patients with a follow-up duration longer than 2 years were identified. The frequency of neuromyelitis optica-related ATM (NMO-ATM) was high in our cohort (40.3%). Recurrent ATM (R-ATM), with a female predominance, was common in total idiopathic ATM (69.0%, 20/29). In R-ATM with longitudinally extensive spinal cord lesions (LESCLs), the high seropositivity of NMO-IgG, spinal cord lesions mostly involved the central gray matter and severer long-term disability were similar to NMO-ATM. In RTM without LESCLs, low seropositivity of NMO-IgG, preferentially involvement of the peripheral white matter and relative better neurological recovery were consistent with multiple sclerosis-related ATM (MS-ATM). The transition rates to MS in patients with acute partial transverse myelitis (APTM) and acute complete transverse myelitis (ACTM) were not significant (16.7 vs. 6.3%, P = 0.753), while LESCLs (OR = 11.4, P = 0.028) were significantly correlated with transition to NMO. The presence of LESCLs was the only variable showing a higher risk for reaching Rankin 3 (hazard ratio: 2.5, 95% CI: 1.0-6.1). Chinese patients with ATM had demographic, clinical, and prognostic features different from those in Western populations. Idiopathic R-ATM, common in Chinese, is a heterogeneous entity that shares partial clinical, spinal MRI and prognostic features with MS-ATM and NMO-ATM. The length of spinal cord lesion, rather than APTM/ACTM, may be a prognostic factor associated with clinical outcome and long-term disability in our population.

Our results indicate a reduced serum level of CysC in patients with relapsing NMOSD and an increased level in remission. Further studies on the role of CysC in NMOSD are warranted.