Lymphocyte Subsets Are Associated with Disease Status in Neuromyelitis Optica Spectrum Disorders

<b><i>Objective:</i></b> At present, studies on lymphocytes are mostly conducted on CD19⁺ B cells and CD27⁺ B cells in neuromyelitis optica spectrum disorders (NMOSDs), but the exact changes in lymphocyte subsets (CD19⁺ B cells, CD3⁺ T cells, CD4⁺ Th cells, CD8⁺ Ts cells, the CD4⁺/CD8⁺ ratio, and NK [CD56+ CD16] cells) have rarely been studied. This study aimed to assess lymphocyte subset changes in patients with NMOSD. <b><i>Methods:</i></b> We performed a cross-sectional study of consecutive patients with acute NMOSD (<i>n</i> = 41), chronic NMOSD (<i>n</i> = 21), and healthy individuals (<i>n</i> = 44). Peripheral blood samples were obtained upon admission, and lymphocyte subsets were analyzed by flow cytometry. Levels of lymphocyte subsets among 3 groups were compared and its correlation with the length of spinal cord lesions was analyzed. <b><i>Results:</i></b> The levels of peripheral blood CD19⁺ B cells were significantly higher in patients with acute and chronic NMOSD than in healthy controls (HCs) (17.91 ± 8.7%, 13.08 ± 7.562%, and 12.48 ± 3.575%, respectively; <i>p</i> &#x3c; 0.001) and were positively correlated with the length of spinal cord lesions in acute NMOSD (<i>r</i> = 0.433, <i>p</i> &#x3c; 0.05). The peripheral blood CD4⁺/CD8⁺ ratio was significantly lower in patients with acute NMOSD and chronic NMOSD than in HCs (1.497 ± 0.6387, 1.33 ± 0.5574, and 1.753 ± 0.659, respectively; <i>p</i> &#x3c; 0.05), and the levels of peripheral blood NK (CD56+ CD16) cells were significantly lower in patients with acute and chronic NMOSD than in HCs (13.6 ± 10.13, 11.11 ± 7.057, and 14.7 [interquartile range = 9.28], respectively; <i>p</i> &#x3c; 0.01). <b><i>Conclusions:</i></b> The levels of certain subsets of peripheral blood lymphocytes are associated with disease status in NMOSD.