This study aims to evaluate the association between peripheral blood T follicular helper (Tfh) cells and Roquin-1 expression, and to explore their correlation with the clinical features of neuromyelitis optica (NMO).

Tfh cells, which aid B cells in antibody production, are increasingly recognized for their role in NMO pathogenesis. However, the clinical relevance of protein alterations and functional changes within Tfh cells remains to be determined.

We enrolled 71 NMO patients in this study, comprising 37 in the acute phase and 34 in remission, along with 53 healthy controls. Clinical characteristics, MRI lesion counts in the spinal cord or brain, Expanded Disability Status Scale (EDSS) scores, CD4+ T cell Roquin-1 mRNA expression levels, and the proportion of peripheral blood Tfh cells were recorded and analyzed for both the NMO and control groups.

In the acute phase, Roquin-1 mRNA expression was reduced, while in remission phase, it was increased compared to healthy controls. The proportion of Tfh cells (CXCR5+PD-1+) was higher in NMO patients than in controls, and there was a negative correlation between Tfh cells proportions and Roquin-1 mRNA expression levels (R²=0.3885, p<0.0001). EDSS score was negatively correlated with Roquin-1 mRNA levels in CD4+ T cells (R²=0.3059, p<0.0001) and positively correlated with proportion of Tfh cells (R²=0.3737, p<0.0001). However, the number of MRI lesions in the NMO group was no significant correlation correlated with the relative expression level of Roquin-1 mRNA (R²=0.0856, P=0.0126) and the proportion of Tfh cells (R²=0.0779, P=0.0175).

Roquin-1 expression correlates with the clinical progression of NMO and appears to play a protective role in autoimmunity. This role may be mediated through the modulation of Tfh cell differentiation, affecting the interaction between Tfh and B cells, and thus influencing the pathogenesis of NMO.