Thus, CD28−/− MRL-lpr mice show milder disease [3], OX40:OX40L interaction may contribute to T follicular helper (Tfh) activation in SLE patients [4], while the CD40:CD40L axis seems to be able to promote B cells class switching in SLE murine model [5]. This evidence concerns the gene TNFRSF4 and systemic lupus erythematosus.