Our finding that IL-27 signaling plays an important role in the formation of IL-10-producing Tfh cells during persistent viral infection, coupled to our observation that IL10+IL21+Tfh cells predominately form during chronic but not acute LCMV infection (Fig. 2), prompted us to investigate whether potential differences in IL-27 availability exists between these two respective infections. The gene discussed is IL10; the disease is viral infectious disease.