How PMN Cells Contribute to Autoimmune Disorders

In the complex world of autoimmune diseases, a surprising player has attracted the attention of scientists and researchers: PMN cells.

The knowledge of the processes behind autoimmune diseases depends greatly on these mysterious cells, commonly referred to as neutrophils.

Our bodies are protected from hazardous intruders by the immune system, which includes PMN cells.

They can, however, play a significant role in autoimmune disease when they are dysregulated, leading to inflammation and tissue damage.

Exploring the complicated interactions between PMN cells and autoimmune disease increases our understanding of these complex diseases and allows brand-new treatment approaches.

The mystery surrounding PMN cells, their function in autoimmune illnesses, and the potential advantages of studying them for better treatment and diagnosis are all revealed in this article.

What is the function of PMN cells?

White blood cells called PMN cells, sometimes called neutrophils, are an essential component of the immune system’s first line of defense against infections.

They make up between 50 to 70 percent of all circulating white blood cells, making them the most common immune cells in circulation.

Through a process known as phagocytosis, PMN cells’ main function is to get rid of invasive pathogens like bacteria and fungi.

They possess an extraordinary capacity to recognize and absorb harmful bacteria, effectively neutralizing them and preventing further infection.

In addition, PMN cells are important contributors to the inflammatory response.

They rapidly go to the area of an infection or injury when it occurs, directed by chemical signals emitted by injured tissues or other immune cells.

When they arrive, they produce several inflammatory chemicals including cytokines and chemokines that draw other immune cells to the site of the infection or damage [1].

Granules carrying antimicrobial substances are present in PMN cells and help to destroy pathogens.

These granules contain enzymes with strong bactericidal capabilities, such as lysozyme and myeloperoxidase.

While their primary function is host defense, PMN cells also repair and remodel tissue.

They release cytokines and growth factors that aid in the healing of wounds and the reduction of inflammation.

What are autoimmune diseases?

A wide range of conditions known as autoimmune diseases are defined by the immune system’s misguided attack on the body’s own cells, tissues and organs.

The immune system turns on healthy cells rather than external intruders like bacteria or viruses, resulting in persistent inflammation, tissue damage and malfunction.

Common autoimmune diseases

Over 80 autoimmune illnesses are currently recognized, each with a distinct set of symptoms, organs affected and underlying causes.

Some of the common autoimmune diseases are:

• Rheumatoid arthritis

A chronic autoimmune condition mostly affecting the joints is rheumatoid arthritis (RA).

Consistent inflammation in the synovial lining of joints, which results in pain, edema, stiffness and increasing joint damage, is what distinguishes it.

Commonly, RA affects the hands, wrists, feet and knees, however it can occasionally also impact other organs and systems.

• Systemic lupus erythematosus (SLE)

Chronic autoimmune disease Systemic Lupus Erythematosus (SLE) can have an impact on multiple human body parts and systems.

It is characterized by an immune response that is dysregulated, in which the immune system unintentionally targets a variety of healthy tissues, causing tissue damage and extensive inflammation [2].

SLE often appears in women during their reproductive years and mostly affects them.

• Multiple sclerosis (MS)

A persistent neurological condition called multiple sclerosis (MS) is characterized by the immune system incorrectly targeting the coating that protects nerve fibers in the central nervous system (the brain and spinal cord).

The effective transmission of nerve impulses depends on this protective layer, known as the myelin sheath.

Inflammation, demyelination (loss of myelin) and damage to the nerve fibers happen as a result of the immune system’s onslaught.

Despite the fact that its specific cause is still unclear, MS is regarded as an autoimmune disease.

It is thought to be a result of a hereditary and environmental combination.

Young individuals are generally affected by MS, and symptoms frequently start between the ages of 20 and 40.

• Type 1 diabetes

The pancreatic beta cells that produce insulin are destroyed in type 1 diabetes, a chronic autoimmune disease.

It leads to inadequate insulin production, which is a hormone essential for controlling blood sugar levels [3].

It can happen at any age, although type 1 diabetes commonly manifests in childhood or adolescence.

How PMN cells contribute to autoimmune disorders — Photograph: SabrinaBracher/Envato

• Psoriasis

Skin is the main part affected by the chronic autoimmune disease known as psoriasis.

It is characterized by a rapid accumulation of skin cells, which gives rise to plaques, which are thick, red, scaly patches.

The head, lower back, elbows and knees are the most common areas for these plaques to develop, while they can develop anywhere on the body.

Around 2-3% of the world’s population suffers with psoriasis, which can strike at any age.

What is the role of PMN cells in autoimmune diseases?

The immune system’s capacity to differentiate between self and non-self is compromised in autoimmune diseases, causing the body to unintentionally target its own cells and tissues.

Neutrophils, often called polymorphonuclear cells or PMN cells, are now widely acknowledged as important players in the development of autoimmune diseases, despite previously being known for their function in preventing bacterial infections.

Initiation of inflammation

One of the first immune cells to go to areas of tissue injury or inflammation are PMN cells.

Immune complexes, cytokines, and chemotactic signals are just a few of the triggers that might cause PMN cells to become active in autoimmune illnesses.

When these cells are activated, pro-inflammatory cytokines including TNF-, IL-1, and IL-8 are released, which aid in attracting additional immune cells and starting an inflammatory response.

Immune cell recruitment

Other immune cells can be attracted to and recruited to the site of inflammation by PMN cells.

They facilitate the movement and accumulation of immune cells, such as monocytes, dendritic cells and T cells, by releasing chemokines and producing adhesion molecules.

In autoimmune diseases, this immune cell recruitment intensifies the inflammatory response and aids in tissue destruction.

Release of reactive oxygen species (ROS) and enzymes

As a component of its antimicrobial defense mechanisms, activated PMN cells produce reactive oxygen species (ROS) and release enzymes including myeloperoxidase and elastase [4].

However, in autoimmune diseases, these ROS and enzymes can also harm the tissues in the immediate vicinity, resulting in tissue injury and persistent inflammation.

Formation of neutrophil extracellular traps (NETs)

In response to stimuli such as immunological complexes and cytokines, PMN cells can release neutrophil extracellular traps (NETs). DNA, histones and antimicrobial proteins make up NETs, which mainly capture and neutralize pathogens.

As they may include autoantigens and trigger immune reactions against self-components, excessive or dysregulated NET production can contribute to tissue damage in autoimmune disorders.

Modulation of adaptive immune responses

Other immune cells, notably T and B cells, can interact with PMN cells and affect their operation.

They can enhance T cell activation and proliferation, control regulatory T cell differentiation and function, and support B cell activation and the generation of autoantibodies.

How do PMN cells contribute to the progression of autoimmune diseases?

Through a number of processes, PMN cells may assist autoimmune diseases progress.

The prolonged survival and dysregulated activation of these cells in autoimmune diseases can have a negative impact on the course of the disease, despite the fact they are generally known for their function in fighting infections.

Amplification of inflammation

Tumor necrosis factor-alpha (TNF-), interleukin-1 (IL-1) and interleukin-8 (IL-8) are examples of pro-inflammatory cytokines released by PMN cells that help to amplify the inflammatory response.

This ongoing inflammation has the potential to harm tissue and worsen autoimmune conditions.

Tissue damage and organ dysfunction

As a component of its antimicrobial defense system, PMN cells may release reactive oxygen species (ROS) and enzymes including myeloperoxidase and elastase.

However, the overproduction of ROS and the release of these enzymes in autoimmune diseases can result in collateral damage to healthy tissues, which can induce organ malfunction and gradual tissue deterioration [5].

Formation of neutrophil extracellular traps (NETs)

In autoimmune diseases, neutrophil extracellular traps (NETs), which are made of DNA, histones and antimicrobial proteins, can be released by PMN cells.

While NETs are designed to capture and eliminate infections, when they are released in large quantities in autoimmune diseases, they can include autoantigens and trigger autoimmune reactions against self-components, which can lead to tissue damage.

Promotion of autoantibody production

B cell activation and differentiation can be induced through interactions between PMN cells and B cells.

This interaction can result in the development of autoantibodies, which are vital in autoimmune illnesses as they target self-antigens and cause tissue damage and the production of immune complexes.

Induction of cytokine storms

PMN cells may aid in the emergence of cytokine storms in severe autoimmune disease situations.

Pro-inflammatory cytokines are excessively and uncontrollably released during cytokine storms, which can result in systemic inflammation, tissue damage and possibly fatal complications.

Conclusion

The growth and development of autoimmune diseases are significantly influenced by PMN cells.

PMN cells have a role in the development of autoimmune diseases, chronic inflammation and organ dysfunction through dysregulated activation, the production of pro-inflammatory mediators, tissue damage and participation in immunological responses.

It is possible to develop treatments to modify PMN cell activity and reestablish immunological homeostasis by understanding the complex interactions between these cells and autoimmune disorders.

Our understanding will continue to improve as a result of further study in this area, and it will also pave the way for more focused treatments that will help control autoimmune illnesses.

FAQs

What are PMNs in immune system?

White blood cells known as PMNs, or polymorphonuclear cells, are essential to the immune system’s fight against infections. They are the most prevalent kind of white blood cell, and through a process known as phagocytosis, they are in charge of engulfing and eliminating pathogens like bacteria and fungus.

Which PMNs is increased in rheumatoid arthritis?

Neutrophils are a particular subtype of PMNs that increase in rheumatoid arthritis. When it comes to rheumatoid arthritis, the synovial fluid of afflicted joints frequently exhibits an elevated neutrophil count, which contributes to the disease’s inflammatory processes and tissue destruction.

What is the main role of the neutrophils?

Neutrophils’ primary function is to protect the body against infections. Through a process known as phagocytosis, their main job is to engulf and kill pathogens, assisting in the removal of invasive microbes and defending the body against infection.