New biomarkers of Crohn's disease: serum biomarkers and development of diagnostic tools

Crohn's disease (CD) is a complex and heterogeneous inflammatory disorder that is part of inflammatory bowel diseases. Its diagnosis is performed on clinical presentation and results of radiography, endoscopy and histological findings. New noninvasive diagnostic biomarkers are needed to allow rapid and accurate CD discrimination. Blood-derived biomarkers correlating with disease activity, supported by genetic evidences and valid for all CD patients subtypes are still missing. Hence, no biomarkers and no related diagnostic tests are recommended or used alone for CD diagnosis in clinical practice. This review describes diagnosis tests based on the detection/quantification of specific acute-phase reactant proteins, enzymes and derived antibody response developed by inflammatory bowel disease patients for pathogens or symbiotic flora determinant, as well as autoantibodies. Their power as diagnostic tools is discussed, as well as new high-throughput techniques, such as microarrays and proteomics, for the discovery of new CD clinical biomarkers and for the development of specific CD diagnostic tests. Some rapidly evolving nanotechnologies, mathematical analysis and bioinformatics methods are also mentioned to highlight their importance for further accurate CD diagnosis.