Peripheral immune landscape and natural killer-like B cells in human Vogt-Koyanagi-Harada disease.

Vogt-Koyanagi-Harada (VKH) disease is a systemic autoimmune disorder threatening the eyesight. The pathogenic mechanisms and biomarkers reflecting disease severity and predicting treatment response require further exploration. Here, we performed a single-cell analysis of peripheral blood mononuclear cells (PBMC) obtained from eight patients with VKH disease and eight healthy controls to comprehensively delineate the changes in VKH disease. We showed a mixture of inflammation, effector, and exhausted states for PBMCs in VKH disease. Notably, our study implicated a newly identified B cell subset, natural killer-like B cells (K-BC) characterized by expressing CD19 and CD56, was correlated with VKH disease. K-BCs expanded in VKH disease, fell back after effective treatment, and promoted the differentiation of pathogenic T cells. Overall, we mapped the peripheral immune cell atlas in VKH disease and indicated the pathogenic role and potential value in predicting treatment response of K-BCs.