The mRNA abundance of cytokines (IL-1α, IL-1β, IL-8, IL-10, TNF-α, TGF-β) and enzymes (5-LO, iNOS) was measured prospectively in blood leukocytes from 34 dogs with severe leptospirosis and acute kidney injury, including 22 dogs with leptospirosis-associated pulmonary hemorrhages. This evidence concerns the gene TGFB1 and leptospirosis.