Speculative model of unfavorable peroxiredoxin 4 translocation. Intracellular peroxiredoxin 4 (Prx4) is localized in the endoplasmic reticulum where it switches between dimer and pentadimeric decamer structure . A potential decameric structure has been proposed for extracellular Prx4 circulating in the blood . A 'good outcome', that is, an improvement of or a protection against pathological processes, could be achieved by high cellular Prx4 levels. Low endogenous Prx4 serum levels, corresponding to non-secreted high intracellular Prx4 levels, imply a non-serious disease course. Accordingly, decreased intracellular Prx4 levels or elevated endogenous serum levels of the enzyme are indicative of 'adverse outcome', that is, a more severe disease course or a higher mortality rate.