Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine and a pivotal regulator of the immune response implicated in the pathogenesis of various acute and chronic inflammatory diseases. In 1993, D-dopachrome tautomerase (D-DT) was discovered during an investigation of melanogenesis. The tertiary structure of D-DT is remarkably similar to MIF, identifying D-DT as the only known eukaryotic MIF homologue discovered to date. Despite D-DT’s intriguing similarities to the very well studied MIF, there have been very few reports on the biological functions and mechanisms of action of D-DT. This dissertation aimed at the functional characterization of D-DT in biological and pathophysiologic conditions.