Scientists uncover specific immune cells driving inflammation, paving way for targeted treatments

Scientists have identified immune cells that drive inflammation in the human body, which could pave the way for safer and more targeted treatments for chronic inflammatory and autoimmune diseases.

The human blood consists of three major types of cells – red blood cells, white blood cells and platelets. White blood cells are the body’s primary immune defence system and help fight off infections by bacteria, viruses and parasites.

According to scientists, the key players are neutrophils, constituting 60-70 per cent of the white blood cells. They engulf and clear the pathogen, release chemicals called cytokines that summon other cells to the site of infection and clear cellular debris once the infectious agent is no longer present.

However, when these cells become overactive or remain in the body for long periods, they can cause inflammation, leading to diseases such as fatty liver, rheumatoid arthritis, lupus and even severe cases of Covid.

“Neutrophils play a critical role in various patho-physiological conditions. However, their therapeutic targeting has been challenging due to the associated risk of infections. Therefore, identifying disease-associated neutrophil populations is essential for targeted strategies,” the study, published recently in Cell Reports, an international peer-reviewed journal, states.

A team of scientists from CSIR’s Central Drug Research Institute, led by Dr Sachin Kumar and his team at CSIR-CDRI, provides fresh insights into the role of neutrophils.  Their research shows that not all neutrophils are equal.

A sub-group of neutrophils live longer and are far more aggressive in causing inflammation. These cells are especially abundant in the liver and tend to appear in both short-term and long-term inflammatory conditions, including certain severe disorders. While certain types of regular neutrophils help to fight off infection, the “rouge” neutrophils that persist are associated with more tissue-damaging behaviour.

The researchers used advanced techniques, including high resolution microscopy and cell sorting, to closely study these cells. They observed that inflammatory signals and metabolic stress such as poor liver health can cause regular neutrophils to transform into rouge neutrophils.

These cells were also found to store more lipids and fats inside them, hinting that their activity could be influenced by changes in fat metabolism. The researchers found that when the rogue protein on these cells was blocked, the harmful effects like tissue damage and excess inflammation were reduced, suggesting that it is not just a marker, but may play an active role in driving inflammation.

The study uncovers a distinct subpopulation of neutrophils with unique functional attributes that distinguish them from conventional neutrophils. “By establishing their presence and relevance in inflammatory settings, our findings significantly advance the understanding of neutrophil heterogeneity and function,” the researchers said.