CXCL12 and systemic lupus erythematosus: It has been described that peritoneal (Mac-1+CD5+) B1a cells that accumulate in the peritoneal cavity of normal mice under the effect of CXCL12 are hypersensitive to CXCL12 in (NZBxNZW)F1 lupus mice (de la Varga Martínez et al., 2017).