The immune system has been thoroughly analyzed as regards to its components and function by using a very successful "reductionist" approach, but its overall functioning principles cannot easily be predicted by studying the properties of its isolated components because they strongly rely on and arise from the interactions among these numerous constituents. Systems immunology represents a different approach for the integrated comprehension of the immune system structure and function based on complex systems theory, high-throughput techniques, as well as on mathematical and computational tools.[1]