Diffuse Panbronchiolitis - Treatment

Treatment

Macrolide antibiotics, such as erythromycin, are an effective treatment for DPB when taken regularly over an extended period of time. Clarithromycin or roxithromycin are also commonly used. The successful results of macrolides in DPB and similar lung diseases stems from managing certain symptoms through immunomodulation (adjusting the immune response), which can be achieved by taking the antibiotics in low doses. Treatment consists of daily oral administration of erythromycin for two to three years, an extended period that has been shown to dramatically improve the effects of DPB. This is apparent when an individual undergoing treatment for DPB, among a number of disease-related remission criteria, has a normal neutrophil count detected in BAL fluid, and blood gas (an arterial blood test that measures the amount of oxygen and carbon dioxide in the blood) readings show that free oxygen in the blood is within the normal range. Allowing a temporary break from erythromycin therapy in these instances has been suggested, to reduce the formation of macrolide-resistant P. aeruginosa. However, DPB symptoms usually return, and treatment would need to be resumed. Although highly effective, erythromycin may not prove successful in all individuals with the disease, particularly if macrolide-resistant P. aeruginosa is present or previously untreated DPB has progressed to the point where respiratory failure is occurring.

With erythromycin therapy in DPB, great reduction in bronchiolar inflammation and damage is achieved through suppression of not only neutrophil proliferation, but also lymphocyte activity and obstructive mucus and water secretions in airways. The antibiotic effects of macrolides are not involved in their beneficial effects toward reducing inflammation in DPB. This is evident because the treatment dosage is much too low to fight infection, and in DPB cases with the occurrence of macrolide-resistant P. aeruginosa, erythromycin therapy still reduces inflammation.

A number of factors are involved in suppression of inflammation by erythromycin and other macrolides. They are especially effective at inhibiting the proliferation of neutrophils, by diminishing the ability of interleukin 8 and leukotriene B4 to attract them. Macrolides also reduce the efficiency of adhesion molecules that allow neutrophils to stick to bronchiolar tissue linings. Mucus production in the airways is a major culprit in the morbidity and mortality of DPB and other respiratory diseases. The significant reduction of inflammation in DPB attributed to erythromycin therapy also helps to inhibit the production of excess mucus.