A potential role for this population in the pathogenesis of lupus was first suggested by the observation that lupus-prone mice with a homozygous point mutation in the Roquin gene, demonstrated expansion of their Tfh population, and subsequently supported by demonstration of similar expansions in MRLlpr and BXSB/Yaa lupus-prone mice [4]. The gene discussed is RC3H1; the disease is systemic lupus erythematosus.