8 topics with a brief review: definitions, key facts, and classroom questions.
This section is dedicated to immune system disorders, where defense mechanisms either critically weaken or mistakenly begin attacking the body's own tissues. We will examine two fundamental groups of pathologies: immunodeficiencies and autoimmune diseases.
The first part presents the classification of primary (congenital) and the causes of secondary (acquired) immunodeficiencies. The second half of the section covers in detail the mechanisms and markers of severe autoimmune processes: systemic lupus erythematosus (SLE), rheumatoid arthritis, Sjögren's syndrome, and systemic vasculitis.
In seminars and exams, instructors most often demand that you clearly name the components of the immune system affected in a specific immunodeficiency (T-cell, B-cell, or phagocytosis). For autoimmune pathologies, it is critically important to know specific diagnostic markers—for example, antinuclear antibodies in SLE or rheumatoid factor in arthritis. Pay special attention to pathogenesis: understanding the mechanisms of tissue damage will save you from having to memorize symptoms by rote.
What is the main difference between primary and secondary immunodeficiencies?
Primary immunodeficiencies are always caused by genetic mutations and are inherited. Secondary ones develop after birth under the influence of external factors (viruses, radiation, toxins) in the absence of initial genetic defects.
What immunogram parameters are typical for Bruton's disease?
There is a marked decrease in IgG and B lymphocytes, a complete absence of plasma cells and immunoglobulins A and M. The T-cell link remains normal.
What is the main difference between secondary and primary immunodeficiency?
In secondary immunodeficiency, there are no genotype disruptions. The immune system was initially formed and functioned normally, but malfunctioned later in life; this condition is potentially reversible.
What is the difference between a systemic and an organ-specific autoimmune disease?
In an organ-specific disease, the immune system attacks only one specific organ (e.g., the thyroid gland). In a systemic disease, autoantibodies target antigens found in many tissues throughout the body (as in systemic lupus erythematosus).
Which visual sign is considered most characteristic of SLE?
A pathognomonic sign is a specific reddish rash on the face, the shape of which resembles the silhouette of a butterfly's wings.
What triggers the hyperproduction of immunoglobulins in rheumatoid arthritis?
Polyclonal activation of B lymphocytes occurs. This leads to the excessive production of antibodies, including rheumatoid factor.
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