Role of MDSCs in SLE is still controversial
MDSCs are the myeloid precursors of dendritic cells, macrophages, and
granulocytes 81, 82. They play a regulatory role81, 83, 84 in the immune system by suppressing T cell
proliferation 82, secreting regulatory cytokines85, and inducing T cell apoptosis86. Recent research has indicated that MDSCs can
enhance the expansion of the regulatory B cells, both in vivo andin vitro 87. However, the role that MDSCs play
in SLE has not yet been thoroughly deciphered.
Some researchers believe that MDSCs can promote the progression of
lupus, based on the evidence that MDSCs accumulate in many organs in SLE
and chronic inflammation conditions 88. MDSCs have
been shown to significantly decrease the differentiation of CD4+ T cells
to Th1 and to suppress the secretion of TNF-α, IL-6, and IFN-γ83. Simultaneously, when accumulated, MDSCs have the
potential to differentiate into macrophage and dendritic cells, in
response to inflammatory cytokines, such as TNF-α, IL-6, and IFN-γ89, 90; these have been found to be significantly
increased in SLE 91.
Macrophage
and dendritic cells have also been regarded to positively contribute to
the pathogenesis of SLE 92, 93. Previous research has
also demonstrated that the transfer of MDSCs into lupus mice
significantly ameliorates the symptoms of SLE, including preventing
autoantibody secretion and relieving renal tissue injuries87. Simultaneously, the infusion of MDSCs has been
shown to decrease follicular helper T cells, Th1 cells, and Th17 cells
in the spleens of lupus mice. MDSCs have also been found to enhance the
expansion of the regulatory B cells and their frequency via inducible
nitric oxide synthase 87.