Secretoneurin, a Novel Neuropeptide, Is a Potent Chemoattractant for Human Eosinophils

Neural expression and increased lavage fluid levels of secretoneurin in seasonal allergic rhinitis

Secretoneurin is a neuropeptide potentially involved in migration of eosinophils, monocytes, and dendritic cells. Whether secretoneurin is present in the human airway mucosa and whether it is released at ongoing allergic airway inflammation is currently unknown. In patients with allergic rhinitis, we have explored the occurrence of secretoneurin in nasal mucosal biopsies and lavage fluids before and during natural allergen exposure. Immunohistochemical analysis revealed an abundance of nerves displaying secretoneurin immunoreactivity, which were distributed predominantly around blood vessels and submucosal glands. A majority of nerve fibers containing vesicular acetylcholine transporter, tyrosine hydroxylase, calcitonin gene-related peptide, and vasoactive intestinal peptide were also secretoneurin-immunoreactive, indicating a localization of secretoneurin in cholinergic, adrenergic, and sensory nerves. Lavage fluid levels of secretoneurin were increased at allergen exposure (p < 0.01-0.05). Levels of secretoneurin did not correlate with eosinophil cationic protein (rho = 0.1, p = 0.7). We conclude that secretoneurin has a widespread occurrence in nasal mucosal nerves of patients with seasonal allergic rhinitis and that increased nasal lavage fluid levels of secretoneurin may characterize ongoing allergen exposure. These data favor a role of secretoneurin in the local traffic of immune cells in human airway mucosa.

Differential Chemokine Expression in Tissues Involved by Hodgkin’s Disease: Direct Correlation of Eotaxin Expression and Tissue Eosinophilia

Hodgkin’s disease (HD) is a lymphoid malignancy characterized by infrequent malignant cells surrounded by abundant inflammatory cells. In this study, we examined the potential contribution of chemokines to inflammatory cell recruitment in different subtypes of HD. Chemokines are small proteins that are active as chemoattractants and regulators of cell activation. We found that HD tissues generally express higher levels of interferon-γ–inducible protein-10 (IP-10), Mig, RANTES, macrophage inflammatory protein-1 (MIP-1), and eotaxin, but not macrophage-derived chemotactic factor (MDC), than tissues from lymphoid hyperplasia (LH). Within HD subtypes, expression of IP-10 and Mig was highest in the mixed cellularity (MC) subtype, whereas expression of eotaxin and MDC was highest in the nodular sclerosis (NS) subtype. A significant direct correlation was detected between evidence of Epstein-Barr virus (EBV) infection in the neoplastic cells and levels of expression of IP-10, RANTES, and MIP-1. Levels of eotaxin expression correlated directly with the extent of tissue eosinophilia. By immunohistochemistry, IP-10, Mig, and eotaxin proteins localized in the malignant Reed-Sternberg (RS) cells and their variants, and to some surrounding inflammatory cells. Eotaxin was also detected in fibroblasts and smooth muscle cells of vessels. These results provide evidence of high level chemokine expression in HD tissues and suggest that chemokines may play an important role in the recruitment of inflammatory cell infiltrates into tissues involved by HD.