Single-cell transcriptomic analysis has revealed significant immune cell infiltration in the bladder mucosa of IC/BPS patients, including Th1-polarized CD4+ T cells, reduced regulatory T cells (Tregs), imbalanced M1/M2 macrophage ratios, and abnormal B cell activation (8, 9). The gene discussed is CD4; the disease is Bartsocas-Papas syndrome 1.