Accordingly, in healthy controls, the presence of ubiquitin tag involves a suppressive mechanism when it is bound to a molecule with a dual role in inflammatory signaling, such as MPO, which might be diminished in the context of systemic autoimmune diseases, such as SLE, explaining the shift towards Th1 and Th17 in CD4+ cells in patients and the tolerogenic role in controls, diminishing the activation and proliferative responses. Here, CD4 is linked to systemic lupus erythematosus.