MSU crystal deposition contributes to inflammation and immune responses in gout remission.

As a prominent feature of gout, monosodium urate (MSU) crystal deposition induces gout flares, but its impact on immune inflammation in gout remission remains unclear. Using single-cell RNA sequencing (scRNA-seq), we characterize the transcription profiling of peripheral blood mononuclear cells (PBMCs) among intercritical remission gout, advanced remission gout, and normal controls. We find systemic inflammation in gout remission with MSU crystal deposition at the intercritical and advanced stages, evidenced by activated inflammatory pathways, strengthened inflammatory cell-cell interactions, and elevated arachidonic acid metabolic activity. We also find increased HLA-DQA1 classic monocytes and PTGS2 monocytes in advanced gout and overactivated CD8 T cell subtypes in intercritical and advanced gout. Additionally, the osteoclast differentiation pathway is significantly enriched in monocytes, T cells, and B cells from advanced gout. Overall, we demonstrate systemic inflammation and distinctive immune responses in gout remission with MSU crystal deposition, allowing further exploration of the underlying mechanism and clinical significance in conversion from intercritical to advanced stage.