Evaluation of inflammatory markers interleukin-6 (IL-6) and matrix metalloproteinase-9 (MMP-9) in asthma

Srilata Puru Naik, Mahesh P A, Jayaraj B S, SubbaRao V. Madhunapantula, Sarah Raeiszadeh Jahromi, Manish Kumar Yadav

Even though IL-6 and MMP-9 are associated with airway inflammation in asthma, there is paucity of data in Indian population. To determine the levels of IL-6 and MMP-9 in the serum of patients suffering from asthma, and correlate with (a) disease severity, as per GINA guidelines; (b) clinical phenotypes; and (c) response to treatment. The levels of IL-6 and MMP-9 were compared between moderate persistent asthma (n = 25), severe persistent asthma (n = 25) and normal controls (n = 30). IL-6 and MMP-9 were measured by ELISA (R&D System, USA &Canada, Inc.) and compared between controls and asthmatics and between groups of different asthma severity, clinical variables, spirometry, and allergen sensitization. Spirometry was repeated after two months of ICS+LABA to assess response to treatment in relation to baseline IL-6 and MMP-9 levels. We observed a significant difference in both IL-6 and MMP-9 levels among asthmatics versus controls (p<0.001), moderate versus severe persistent asthma (p<0.001). A significant negative correlation was observed between MMP-9 and pre bronchodilator FEV1 and FVC, but not with IL-6. There was no association between IL-6 and MMP-9 with asthma duration, total IgE, AEC, number of allergens sensitized and degree of sensitization. No significant correlation (p>0.5) was observed with IL-6 and MMP-9 levels and FEV1 improvement after two months of ICS+LABA. Higher levels of IL-6 and MMP-9 were observed in asthmatics as compared to controls and in severe persistent asthma as compared to moderate persistent asthma, higher levels of MMP-9 was associated with lower lung functions.