NFKB1 and systemic lupus erythematosus: PELI1 (encoding Pellino1) is a TLR3‐inducible negative regulator of noncanonical NF‐κB, and the expression of PELI1 was negatively correlated with disease severity.24, 25 In our stratification, PELI1 was not significantly underexpressed in any SLE clusters, but was upregulated in C3 and C4, possibly induced for NF‐κB regulation (Figure 4e).