IL9 and inflammatory skin disease: Neither calprotectin nor IL-9 encoding transcripts have been previously identified in transcriptional studies comparing IgAV with normal skin and different inflammatory skin diseases.18 Calprotectin comprises over half of the soluble cytoplasmic protein content of neutrophils; is also expressed by activated keratinocytes, macrophages, and endothelial cells; and is released by secretion or cell death.