CD4 and systemic lupus erythematosus: PB γδ T cells in general, and Vγ9+ γδ T cells and TNFα/IL-17-secreting CD4-CD8− γδ T cell subsets, in particular, were decreased in SLE compared to HCs, but the numbers of the γδ T cell subsets reached levels similar to those of HCs in responders, but not in non responders, to therapy.