IKZF2 and systemic lupus erythematosus: The optimal cut-off for Helios+ percentages in TFH cells was 2.45%, with a sensitivity of 97.87% and specificity of 56.67%, while the optimal cut-off for Helios+ percentages in TFR cells was 49.5% to distinguish SLE from HCs, with a sensitivity of 89.36% and specificity of 43.33% (Supplementary Table 2).