Anti-inflammatory effects of pre-seasonal Th1-adjuvant vaccine to Parietaria judaica in asthmatics

BACKGROUND The ultra-short course pre-seasonal allergy vaccine, containing appropriate allergoids with the adjuvant monophosphoryl lipid A (MPL), may be effective in treating allergic symptoms. OBJECTIVE To explore the timing of the immunological responses to the pre-seasonal allergy vaccine. METHODS Four subcutaneous injections of the active product (Pollinex Quattro) were administered to 20 Parietaria-sensitive intermittent asthmatics (M/F: 12/8; age: 48 ± 10 years; FEV(1)% predicted: 108% ± 12%) during the 6 weeks prior to the start of the pollen season. Exhaled breath condensate (EBC) was collected immediately before the first and immediately after the last injections (t(1) and t(2)), during the pollen season (t(3)) and after (t(4)) the pollen season. EBC was analyzed to determine the levels of pH and 8-isoprostane. Ten Parietaria-sensitive asthmatics served as the untreated control group at t(1) and t(2). RESULTS Measured pH levels were 7.64 ± 0.33 at t(1), 7.67 ± 0.23 at t(2), 7.72 ± 0.34 at t(3), and 7.82 ± 0.34 at t(4) (P = 0.049 vs baseline). 8-isoprostane levels were significantly lower than baseline at each visit (mean difference from baseline, for t(2): -0.77 pg, P = 0.031; for t(3): -0.92 pg, P = 0.010; for t(4): -0.70 pg, P = 0.048). In the control group, pH levels were 7.73 ± 0.26 at baseline and did not change after 6 weeks (7.79 ± 0.25, P = 0.33). Similarly, the concentrations of 8-isoprostane in the control group were not different from those of the study group at baseline (P = 0.86), and the levels remained unchanged after 6 weeks (P = 0.58). CONCLUSION These findings show that the ultra-short course of vaccine adjuvated with MPL acutely reduces the degree of airway inflammation, as expressed by markers of oxidative stress, and suggest that this reduction is maintained during and after the pollen season.