Other soluble activation markers, such as intercellular adhesion molecule (ICAM)-1 [22], IL-2 receptor [23], neopterin [24], [25], beta 2-microglobulin [24] and IP-10 in blood [26] and urine [27], have also been shown to increase during infection and to decrease with treatment (reviewed in [21]), but none appear to display the predictive power of HO-1 demonstrated here. Here, B2M is linked to infection.