CD4 and systemic lupus erythematosus: In conditions of disrupted gut mucosal integrity, such as those found in SLE, bacteria translocate through the intestinal barrier triggering the activation and migration of CX3CR1+ cells, such as dendritic cells or macrophages, toward drain lower intestinal tract lymph nodes.46 These cells additionally present antigens to naïve CD4+ T lymphocytes, leading to T cell priming.