A biomarker is a characteristic that is measured and evaluated as an indicator of a normal biologic or pathologic process or pharmacologic responses towards a therapeutic intervention (definition by the NIH). Biomarkers can be detected and measured in parts of the body like the blood, urine, or tissue and can involve specific cells, molecules, genes, gene products, enzymes, or hormones. Biomarkers are of crucial importance in modern medicine for risk assessment and disease prevention, early diagnosis, drug target identification, drug response, and so forth. Although the term biomarker is relatively new, biomarkers have been used for considerable time. For example, body temperature is a well-known biomarker for fever, serum levels of C-reactive protein (the most performed assay in hospital laboratories) are a marker for inflammation, and glucose levels are used as therapeutic readout for controlling diabetes.

Biomarkers for childhood diseases are, due to ethical restrictions, small populations, and limited sample volumes, less available. Mostly they are extrapolated from adult populations or animal models. Insight and progression of complex paediatric diseases, in particular inflammatory diseases, can benefit from establishment and validation of a comprehensive set of biomarkers. For this special issue we take particular interest in manuscripts that describe biomarkers in immune-mediated childhood diseases based on three topics: first methodologies to detect biomarkers in pediatric patients, second sharing new insight for diagnosis and therapeutic interventions, and third translation of known biomarkers to pediatrics. Potential topics include, but are not limited to:

• Methods for biomarker discovery:
  • Biomarker imaging in pediatrics
  • Cells as biomarkers in pediatrics
  • Proteins as biomarkers in pediatrics
• Biomarkers for diagnosis and therapeutic interventions:
  • Biomarkers for diagnosis of (rare) pediatric diseases
  • Biomarkers for monitoring therapeutic interventions (e.g. sepsis, viral infections, and autoimmunity)
• Translation of biomarkers to pediatric patients:
  • Translation of biomarkers from adult disease
  • Translation of biomarkers from (adult) animal models

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/mi/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: