Sputum and serum hydrogen sulfide (H2S) as novel biomarker of asthma

Results H2S levels in induced sputum from severe and nonsevere asthmatic patients were significantly higher than those from healthy subjects but there was no difference between the severe and non-severe group. Serum H2S levels were 10 times higher than in sputum and these were also higher in severe and non-severe asthmatic subjects compared to healthy subjects. There was a positive correlation between sputum and blood H2S levels (r=0.42, p<0.05). Sputum H2S levels were negatively correlated with FEV1 %predicted (r=-0.42, p=0.003), and with reversibility to salbutamol (r= -0.54, p<0.01). There was a correlation between sputum H2S and sputum neutrophils and macrophages, and a negative correlation between sputum H2S and FeNO levels.