Scientists at the Institute of Molecular Biology and Biotechnology (IMBB-FORTH) and the University of Crete, together with collaborators from Greece, Europe, the USA, and India, have discovered a novel role of albumin, the most abundant protein in human blood, in protecting against a rare and often deadly fungal infection called mucormycosis. The study is published Nature.

Mucormycosis is a rapidly progressing infection caused by Mucorales fungi and is associated with high mortality rates. The disease appeared extensively in India following the second wave of COVID-19 in 2021, a development that may be linked to the suppression of albumin production due to inflammation, according to the research findings. Mucormycosis, also known as “black fungus,” occurs when fungal spores are inhaled or when they invade the body through a wound. These pathogens secrete a potent toxin that kills the surrounding tissue, causing the skin to turn black, sometimes within a few hours, and it has a mortality rate that can reach up to 50%. Mucorales fungi are commonly found in the environment, but healthy individuals do not develop the disease. It has been observed that the disease occurs more frequently in cases of weakened immune system, malnutrition, and diabetes.

The researchers found that patients with the disease have significantly lower levels of albumin than those with other fungal diseases. Importantly, hypoalbuminemia, emerged as the strongest predictor of poor clinical outcomes of patients with mucormycosis across multiple continents.

The study further demonstrated that albumin potently and selectively stops the growth of Mucorales fungi among a broad range of human bacterial and fungal pathogens. The removal of albumin from blood samples of healthy individuals led to the unrestricted growth of mucormycetes. In addition, mice lacking albumin were specifically vulnerable to mucormycosis, while administration of albumin restored resistance to disease following infection.