Effectiveness of antiinflammatory therapy in patients with interstitial lung diseases using reassay of biomarker mucin 3EG5

Aim. To investigate a potential of a new marker of activity of interstitial pulmonary diseases (IPD) - mucin 3EG5 - in monitoring of effectiveness of the antiinflammatory therapy. Materials and methods. Serum mucin antigen 3EG5 (glycolyl-sialylated glycop rotein) was assessed with sandwich immunoassay constructed using a monoclon al antibody 3E1.2 (Medical Innovations, Australia) and affinity-purified po lyclonal antibody G5 (Xema, Russia) against total mucin antigen family. The level of serum 3EG5 was studied in 16 IPD patients (9 had idiopathic pulmo nary fibrosis and 7 - chronic hypersensitivity pneumonitis) before and afte r 6 months of immunosuppressive therapy. By changes in pulmonary function t ests during 6 months of steroid treatment all the patients were divided int o two group: responders (a 15% increase in FVC, 20% increase in DLCO and re duction in the PA-aO2 of 5 mm Hg) and nonresponders (worsening or insignifi cant changes in these indices). Results. In responders (n = 7) after treatment serum levels of 3EG5 fell fr om 230 +/- 97 to 88 +/- 40 units/ml (p < 0.01). In nonresponders serum 3EG5 was not different before and after therapy: 249 +/- 153 and 247 +/- 170 un its/m, although in this group two patients with unchanged lung function sho wed a significant decrease in 3EG5, so the accuracy of changes in serum 3EG 5 to reflect response to therapy was 88%. There was a significant differenc e between the posttreatment levels of 3EG5 of the two groups of patients (p = 0.03). Conclusion. Successive measurements of serum mucin 3EG5 may be used for mon itoring of the response to immunosuppressive therapy in IPD patients.