A recent cohort study found that plasma levels of sPD-1 and sPD-L1 were correlated with the severity and activity of the disease and also had an important role in predicting future relapses in AQP4-IgG+ NMOSD, which may help guide prompt and targeted therapy.
Neuromyelitis optica spectrum disorder (NMOSD) is described as an autoimmune disorder associated with aquaporin 4-immunoglobulin G (AQP4-IgG) in the majority of cases. Immune modulation in NMOSD is related to programmed death-1 (PD-1) and programmed death ligand 1 (PD-L1). The soluble forms of PD-1 and PD-L1, known as sPD-1 and sPD-L1, are abnormally expressed in various autoimmune disorders, such as systemic sclerosis and systemic lupus erythematosus, which is indicative of their role in immunomodulation.
This study aimed to assess the relationship between relapse and status of AQP4-IgG+ NMOSD and plasma levels of sPD-1 and sPD-L1. The findings of this study are published in the journal Annals of Clinical and Translational Neurology.
Baseline Characteristics
The study included a total of 66 AQP4-IgG+ participants, with 26 in the remission phase (remission-NMOSD group) and 40 in the attack phase (attack-NMOSD group). The control group included 28 healthy individuals. The male-to-female ratio of the study participants was 7:59. The median age of the participants was 45 (32.3–55) years, and the median duration of disease was 27.7 (6.5–69.4) months. At baseline, the attack-NMOSD group had significantly lower complement 3 (C3) levels compared to the remission-NMOSD group.
Levels of sPD-1 and sPD-L1 in AQP4-IgG+ NMOSD
The attack-NMOSD group had significantly higher levels of sPD-1 and sPD-1/sPD-L1 ratio compared to the control and remission-NMOSD groups. Compared to the control group, the attack-NMOSD group and the remission-NMOSD group had higher concentrations of interleukin-6 (IL-6) and the attack-NMOSD group had higher levels of IF-10 and interferon-γ (IFN- γ). During the attack phase, the study participants demonstrated a decrease in IL-10 and an increase in sPD-1/sPD-L1 ratios and sPD-1 levels.
Correlation of sPD-1/sPD-L1 and sPD-1 With Cytokines
There was a positive correlation between sPD-L1 and sPD-1 in the attack-NMOSD group, whereas IL-6 and IL-5 were positively correlated with sPD-L1 and sPD-1 levels in the attack-NMOSD and remission-NMOSD groups. IFN-γ was positively correlated with sPD-1 levels in the healthy controls. Levels of sPD-L1 and sPD-1 were also positively related to tumor necrosis factor α (TNF-α).
Clinical and Predictive Value of sPD-L1 and sPD-1 in AQP4-IgG+ NMOSD
The levels of sPD-L1 and sPD-1 were found to have a positive correlation with the clinical indicators of AQP4-IgG+ NMOSD. These included the Expanded Disability Status Scale (EDSS) score, segments of spinal cord involvement, and the number of attacks. In the attack-NMOSD group, a higher sPD-1/sPD-L1 ratio predicted the risk of relapse within 2 years.
Source:
Liu, J., Shao, X., Fan, J., Wang, Y., Cao, Y., Tan, G., Sugimoto, K., Li, B., & Jia, Z. (2023). Association of plasma sPD‐1 and sPD‐L1 with disease status and future relapse in AQP4‐IgG (+) NMOSD. Annals of Clinical and Translational Neurology. https://doi.org/10.1002/acn3.51964
