The present invention is directed to in vitro methods to predict the presence of inflammation, gene IRG1 or protein encoded by IRG1 in a subject by determining presence of itaconic acid in a biological sample isolated from the subject. The invention is also directed to methods to predict the ability of a subject to produce itaconic acid under inflammation by determining the presence IRG1 in a biological sample. The invention is also related to pharmaceutical composition to initiate production of itaconic acid in a subject for preventing or treating inflammation, or bacterial infection.
