Macrolides can be clinically effective in chronic
rhinosinusitis (CRS). However, little is known about how these drugs affect pathophysiological features of CRS in vivo. In the present study, patients with CRS were subjected to long-term treatment with
clarithromycin. Nasal lavages with and without
histamine (40 and 400 microg ml(-1)) were carried out prior to and late into the treatment period.
Histamine was included as a tool to produce plasma exudation, a process known to move free cellular products from the mucosal tissue into the airway lumen thereby enriching nasal surface liquids with such products.
Interleukin-8 (IL-8),
myeloperoxidase (MPO),
eosinophil cationic protein (ECP), alpha(2)-macroglobulin and
fucose were monitored as indices of pro-inflammatory
cytokine production, neutrophil and eosinophil granulocyte activities, plasma exudation and mucinous secretion, respectively.
Clarithromycin reduced the lavage fluid levels of
IL-8 at the low-dose
histamine observation (P<0.001). There was a trend towards reduced MPO by the treatment, whereas ECP was significantly reduced at the low-dose
histamine observation (P<0.05). alpha(2)-Macroglobulin was reduced by
clarithromycin (saline lavages) (P = 0.05), whereas
fucose was unaffected. The exudative responsiveness to high-dose
histamine was significantly reduced by the treatment (P<0.05). Furthermore, significantly lower levels of
fucose were observed at the low-dose
histamine observation (P<0.01). We conclude that long-term
clarithromycin treatment likely exerts an anti-inflammatory effect in CRS.