Response group: (a) percentages of CD66b+ neutrophils in the peripheral blood of patients with active CD (n =15) before and after IFX treatment; (b) expression of CD66b mRNA in the peripheral blood neutrophils from patients with active CD (n =15) before and after IFX treatment by qRT-PCR; (c) expression of CD66b mRNA in intestinal mucosa from patients with active CD (n = 13) before and after IFX treatment by qRT-PCR; (d) immunohistochemical staining of CD66b in the intestinal mucosa of active CD (n = 10) before and after IFX treatment; and (e) expression of S100A8, (f)
S100A9, and (g) MPO in the intestinal mucosa of patients with active CD (n = 13) before and after IFX treatment.
Myeloid-related proteins (MRP), also called S100A8 (MRP8) and
S100A9 (MRP14), are two calcium-binding proteins linked to innate immunity, and they are expressed in neutrophils and monocytes.
The masses of the 2
S100A9 proteins (13152 and 12 689 Da) corresponded to a form missing the N-terminal methionine and an added acetylation of threonine 2, and a form missing the 1st 5 N-terminal residues and an added acetylation of serine 6, as reported elsewhere (21).
Calprotectin, a heterocomplex of the two calcium-binding proteins S100A8 and
S100A9, is one of the most common skin-derived AMPs [41].
S100A9 belongs to a large [Ca.sup.2+]-binding protein family, which has a wide range of functions.
Furthermore, as exercise does not increase calprotectin levels in neutrophils [6], the likely source is skeletal muscle, since S100A8 and
S100A9 mRNA rates increase in skeletal muscle during exercise [16].
HDM-DP, as an allergen from our environment, could induce the secretion of myeloid-related protein 8 (MRP8, S100A8) and MRP14 (
S100A9).
Human S100A8 and
S100A9 were purchased from Bachem AG.
Abbreviations SEM: Scanning electron microscopy TEM: Transmission electron microscopy MPO: Myeloperoxidase Lf: Lactoferrin NGAL: Neutrophil gelatinase-associated lipocalin GAPDH: Glyceraldehyde-3-phosphate dehydrogenase S100A8,
S100A9: The S100 calcium-binding proteins, known also as calgranulins A and B or myeloid-related proteins MRP8 and MRP14, or cystic fibrosis antigen S100A8/A9: Calprotectin MMP-9: Matrix metalloproteinase 9 or gelatinase B, 92 kDa HNP 1-3: Human neutrophil peptides 1-3 or defensins CAP37: Cationic antimicrobial protein 37 LPS: Lipopolysaccharide from Salmonella enterica serovar Typhimurium fMLP: N-Formylmethionyl-leucyl-phenylalanine PMA: Phorbol 12-miristate 13-acetate CDT: Clostridium difficile binary toxin.