Single-Cell Analysis in Blood Reveals Distinct Immune Cell Profiles in Gouty Arthritis

Gout is a chronic disease caused by monosodium urate crystal deposition. Previous studies have focused on the resident macrophage, infiltrating monocyte, and neutrophil responses to monosodium urate crystal, yet the mechanisms of the potential involvement of other immune cells remain largely unknown. In this study, we enrolled seven gout patients and five age-matched healthy individuals and applied single-cell mass cytometry to study the distribution of immune cell subsets in peripheral blood. To our knowledge, our study reveals the immune cell profiles of gout at different stages for the first time. We identified many immune cell subsets that are dysregulated in gout and promote gouty inflammation, especially those highly expressing CCR4 and OX40 (TNFR superfamily member 4), including CCR4+OX40+ monocytes, CCR4+OX40+CD56high NK cells, CCR4+OX40+CD4+ NK T cells, and CCR4+CD38+CD4+ naïve T cells. Notably, the plasma levels of CCL17 and CCL22, measured by ELISA, increased in the acute phase of gout and declined in the interval. We also found a clue that Th2-type immune responses may participate in gout pathology. Moreover, the subset of granzyme B+ (GZMB+) CD38+ NK cells is positively correlated with serum urea acid level, and another two γδT subsets, GZMB+CD161+ γδT cells and GZMB+CCR5+ γδT cells, are negatively correlated with erythrocyte sedimentation rate. In sum, gouty arthritis is not a disease simply mediated by macrophages; multiple types of immune cell may be involved in the pathogenesis of the disease. Future research needs to shift attention to other immune cell subsets, such as NK cells and T cells, which will facilitate the identification of novel therapeutic targets.