Moreover, when incubated with lupus patient's peripheral blood lymphocytes (PBLs), P140 generated secretion of high levels of regulatory cytokine IL-10 in cell cultures without proliferation of CD4+ T cells, suggesting that P140 (and not the non-phosphorylated analogue, which induces CD4+ T cell proliferation) possesses specific immunomodulatory functions on lupus T cells [4]. Here, CD4 is linked to systemic lupus erythematosus.