The anti-inflammatory effect of erythromycin and its derivatives, with special reference to nasal polyposis and chronic sinusitis

Macrolides have been used for decades as an important chemotherapeutic agen t in the treatment of infectious diseases. In the last 10 years there has a lso been increasing interest in the interaction between macrolide antibioti cs and the immune system. The aim of this review is to focus on the anti-in flammatory action of erythromycin and its derivatives in the treatment of c hronic sinusitis and nasal polyps. Systematic clinical investigations have been few and to the author's knowledge there have been no placebo-controlle d studies. However there have been, especially from Japan, a number of clin ical reports stating that long-term, low-dose macrolide antibiotics are eff ective in treating chronic sinusitis incurable by surgery or glucocorticost eroid treatment, with an improvement in symptoms varying between 60% and 80 % in different studies. In animal studies macrolides have increased mucocil iary transport, reduced goblet cell secretion and accelerated apoptosis of neutrophils, all factors that may reduce the symptoms of chronic inflammati on. There is also increasing evidence in vitro of the anti-inflammatory eff ects of macrolides. Several studies have shown macrolides to inhibit interl eukin gene expression for IL-6 and IL-8 and also to inhibit the expression of intercellular adhesion molecule essential for the recruitment of inflamm atory cells. There is also evidence in vitro, as well as clinical experienc e, showing that macrolides reduce the virulence and tissue damage caused by chronic bacterial colonization without eradicating the bacteria. The benef it of long-term, low-dose macrolide treatment seems to be that it is, in se lected cases, effective when steroids fail. The exact mechanism of action i s not known, but it probably involves downregulation of the local host immu ne response as well as a downgrading of the virulence of the colonizing bac teria. In the future, placebo-controlled studies should be performed to est ablish the efficacy of macrolides if this treatment is to be accepted as ev idence-based medicine.