Inhaled vasoactive intestinal peptide exerts immunoregulatory effects in sarcoidosis

This clinical study published in the American Journal of Respiratory and Critical Care Medicine evaluated the immunoregulatory effects of inhaled VIP in 20 patients with active pulmonary sarcoidosis, a chronic inflammatory granulomatous disease. Patients received VIP by nebulization for 4 weeks, with bronchoalveolar lavage (BAL) collection before and after treatment for detailed immunological analysis.

The results demonstrated significant immunoregulatory effects in the pulmonary compartment. There was a marked reduction in TNF-alpha production by BAL cells, a central cytokine in the pathogenesis of sarcoidosis. Simultaneously, an increase in regulatory T cells (Tregs) was observed in the BAL, indicating active promotion of local immune tolerance.

• The reduction in TNF-alpha was accompanied by decreases in other pro-inflammatory cytokines
• The increase in CD4+CD25+FoxP3+ Tregs suggests modulation of the Th1/Treg balance
• Pulmonary function parameters showed a trend toward improvement
• The treatment was well tolerated, with no significant adverse events

This study is particularly relevant for demonstrating that VIP, beyond its known vasodilatory properties, exerts clinically measurable immunoregulatory effects when administered via inhalation. The ability to promote Tregs in inflamed pulmonary tissue suggests therapeutic potential not only for sarcoidosis, but for other immune-mediated pulmonary diseases, such as asthma and interstitial lung disease.