Question

An autoimmune disease linked directly to an infectious etiology. a. Psoriasis b. Rheumatoid arthritis c. Alkylosing spondylitis d. Systemic Lupus erythematosus

Short answer

a. Psoriasis b. Rheumatoid arthritis c. Ankylosing spondylitis d. Systemic Lupus erythematosus

Step-by-step solution

Definition of autoimmune disease

An autoimmune disease is a condition where the immune system mistakenly attacks and damages the body's own cells and tissues. In this exercise, we need to identify which of the given diseases is directly linked to an infectious etiology, meaning that the disease is caused by an infection.

Brief overview of each disease

a. Psoriasis: It is a chronic inflammatory skin condition where the immune system attacks skin cells, leading to rapid skin cell turnover, causing red, scaly, and itchy skin plaques. b. Rheumatoid arthritis: It is a chronic inflammatory disease, where the immune system attacks the joints, causing pain, swelling, and can result in joint deformity. c. Ankylosing spondylitis: It is a type of inflammatory arthritis that affects the spine and sacroiliac joints, causing chronic pain, stiffness, and sometimes damage to the affected joints. d. Systemic Lupus erythematosus: It is an autoimmune disease in which the immune system attacks healthy cells and tissues throughout the body, causing inflammation and damage to various organs.

Identify the disease related to infectious etiology

Among the given options: a. Psoriasis: The exact cause of psoriasis is unknown, but it is not directly linked to an infectious etiology. b. Rheumatoid arthritis: The exact cause is unknown, but some studies suggest that an infectious agent may trigger an autoimmune response in some people. However, the etiology is not directly linked to an infectious etiology. c. Ankylosing spondylitis: The cause is unknown, and it is not directly linked to an infectious etiology. d. Systemic Lupus erythematosus: The exact cause is unknown, and it is not directly linked to an infectious etiology. In the given diseases, none of them have a direct causal relationship with an infectious etiology. However, among these options, Rheumatoid arthritis has some suggested link with infectious agents as triggers for the autoimmune response, but this is yet to be confirmed. So, Answer: b. Rheumatoid arthritis (with the caveat that the exact cause is unknown and the link to infectious etiology is not direct or confirmed)

Key concepts

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disorder that primarily affects the joints. It occurs when the immune system mistakenly targets the lining of the joints, called synovium, causing painful swelling that can eventually result in bone erosion and joint deformity.
The disease is symmetric, meaning it often affects both sides of the body, such as both knees or both wrists. Beyond joints, RA can impact other tissues and organs, including the skin, eyes, lungs, heart, and blood vessels.

• Pain and stiffness are common morning symptoms that improve with activity.
• Swollen, warm joints are typical manifestations.
• As the disease progresses, it can lead to reduced range of motion and deformities.

The exact cause of RA is unknown, but genetic and environmental factors play a role. Some research suggests infections could trigger the immune system in genetically predisposed individuals, although no specific infectious agent has been directly linked to the onset of RA.

Infectious Etiology in Autoimmune Diseases

The concept of infectious etiology in autoimmune diseases is intriguing yet complex. It suggests that infections by viruses, bacteria, or other pathogens might trigger the onset of autoimmune diseases in certain individuals. This hypothesis is grounded in the idea that these infectious agents could mimic parts of the body's own cells, leading the immune system to mistakenly attack its own tissues after targeting the infectious agent. This is known as "molecular mimicry."
Furthermore, infections can stimulate the immune system to respond in an overactive manner, priming it to attack body tissues even after the infection is cleared. While direct evidence linking specific infections to autoimmune diseases is scarce, researchers continue to investigate potential causative links.

• Viruses like Epstein-Barr and Hepatitis C have been studied for their roles in autoimmune disorders.
• Pathogenic bacteria could potentially trigger diseases through molecular mimicry mechanisms.

This area remains a key research focus, with ongoing studies seeking to identify which infectious agents, if any, are definitive triggers for autoimmune diseases like rheumatoid arthritis.

Immune System Attack on Body Tissues

Autoimmune diseases are characterized by the immune system mistakenly targeting and attacking the body's own cells and tissues. This happens because the immune system identifies its own cells as foreign invaders, a mistake leading to chronic inflammation and tissue damage.
Typically, the immune system protects the body by detecting and destroying harmful pathogens such as bacteria and viruses. However, in autoimmune diseases, this defense mechanism fails, causing the body to self-destructively attack its own healthy cells.

• This process can affect various parts of the body including skin, joints, organs, and connective tissues.
• It leads to pain, inflammation, tissue destruction, and disruption of normal body functions.

Conditions like rheumatoid arthritis, lupus, and psoriasis are examples where body tissues are attacked, leading to significant symptoms and necessitating medical intervention to control the disease and maintain quality of life.