Basophil involvement in lupus nephritis: a basis for innovation in daily care

Lupus nephritis (LN) affects a large proportion of patients with systemic lupus erythematosus (SLE). LN can lead to end-stage renal disease depending on when it is diagnosed and on the adequacy of the treatment administered to the patient based on the class of LN. Determination of the class and activity of LN is only possible by histological analysis of kidney biopsies. In this context, the development of non-invasive early diagnostic tools for determining the class of LN and biomarkers predicting the response to treatment would greatly benefit patients with SLE. Basophils, which are one of the rarest types of circulating leucocytes, are well-established effectors of allergic and parasitic diseases. Recent advances in the understanding of the immune regulatory role of basophils in several auto immune conditions, including SLE and LN, have demonstrated their involvement in the amplification of auto-antibody production and LN pathogenesis in both human SLE and lupus-like mouse models. The present review summarizes the currently available literature describing dysregulation of basophil counts, basophil activation status and basophil activating factors in patients with SLE and the involvement of basophils in the pathogenesis of SLE. We also discuss the potential utility of these biological and immunological parameters as diagnostic and prognostic biomarkers, used alone or in combination with other known SLE and LN activity biomarkers. Finally, considering basophils as contributors to the disease, they may also constitute a future treatment target for the management of SLE and LN.