Figure 4b showed the cluster analysis on the significantly upregulated genes of C1QB, C1QC, C2, HIST1A2BB, HIST1H3G, HIST1H4L, HLA-DPA1, IL10, FCGR1A, FCGR1B, CTSG, and ELANE. Validation experiments confirmed that these genes were upregulated in the PBMCs of SLE patients (Fig. 4c). The gene discussed is C2; the disease is systemic lupus erythematosus.