CXCL12 and asthma: In this study, we used RNA-Seq to identify differences between the transcriptomes of ASM derived from fatal asthma and non-asthma donors to vitamin D treatment, and we also specifically examined four cytokines (i.e. CCL2, CCL13, CXCL12, IL8) whose expression differed between fatal asthma- and non-asthma-derived ASM at baseline and with vitamin D treatment.