Candidate serum biomarkers for predictive medicine and disease management of asthma

As proteins are the ultimate effectors of gene expression, we have applied an innovative antibody-based approach to the identification of serum secreted protein markers in pediatric asthma. In this asthmatic population we have analyzed various asthma phenotypes according to: i) asthma severity (persistent mild or persistent moderate); ii) asthma duration (less than 5 years or more); and iii) allergic phenotype (allergic sensitization or not). We have used: i) Milagen's collection of about 100,000 high affinity polyclonal antibodies raised against individual human proteins and their isoforms; ii) Milagen's proprietary matrix protein array technology (MPAT), comprising a multiplex protein immunoassay coupled to a readout and data analysis system. Asthma serum samples (up to 50 per group) and healthy controls were printed on a membrane, and allowed to interact with individual antibodies. Antibody-sample reaction was detected by chemiluminescence, and computer analysis of a CCD-acquired image quantified each spot. Statistical analysis of the data points thus generated, resulted in the selection of antibody panels that specifically recognize differentially secreted markers in asthma. Such antibodies are then used to identify corresponding protein antigens as molecular determinants of asthma. Among them, we have found proteins previously associated with asthma, as well as novel ones. This approach enables us to: i) identify antibodies discriminating intermediate asthma phenotypes, and ii) discover proteins correlating with such phenotypes. These biomarkers offer potential application in prognosis, treatment response, and clinical trial follow-up.