CD4 and systemic lupus erythematosus: The content difference in immunoprofiling between patients with SLE and healthy controls (HCs) can characterise the dysregulation of the immune response.7 As compared with HCs, patients with SLE have lower percentages of the natural killer (NK) cell, dendritic cell (DC), regulatory cells and CD4+/CD8+ T-cell ratios (attributed to CD4 lymphocytopaenia) and higher percentages of B cells, double-negative T cells and regulatory CD4+ T cells.8–14 These alterations may be potential targets for monitoring the treatment efficacy of SLE disease activity.