The Immunocompromised Host

Questions and Answers

Which type of immunodeficiency is characterized by genetic deficiencies leading to gaps in the immune system's defenses?

Secondary immunodeficiency

Primary immunodeficiency (correct)

Autoimmune disorder

Acquired immunodeficiency

What is the typical consequence of deficiencies in early complement components in the immune response?

Enhanced phagocytosis

Improved adaptive immunity

Increased Staphylococcal infections (correct)

Increased susceptibility to viral infections

What gene defect is commonly associated with Chronic Granulomatous Disease?

Failure to produce T cells

Inability to form superoxide (correct)

Reduced complement action

Inability to synthesize antibodies

Which condition is a known risk factor for secondary immunodeficiency?

Splenectomy Signup and view all the answers

In the context of immunodeficiencies, what impact do anti-rejection drugs after transplants have?

Suppress immune function Signup and view all the answers

Which syndrome is characterized by a deficiency in all three types of lymphocytes?

Severe Combined Immunodeficiency (SCID) Signup and view all the answers

What is the main consequence of genetic defects affecting phagocytic cell function?

Predisposition to bacterial infections Signup and view all the answers

The loss of late components of the complement system primarily increases susceptibility to which type of infections?

Neisseria infections Signup and view all the answers

Which factor is NOT typically associated with primary immunodeficiencies?

Excessive exercise Signup and view all the answers

What primary deficiency is characteristic of defects in complement components?

Failed activation of the complement cascade Signup and view all the answers

What type of immunity primarily involves the function of antibodies to combat pathogens?

Humoral immunity Signup and view all the answers

Which of the following is a classic feature of inflammation?

Rubor (redness) Signup and view all the answers

What is indicated by a non-resolving patchy pneumonia in a healthy young adult with a history of a viral infection?

Secondary immunodeficiency Signup and view all the answers

Which type of immunodeficiency is typically congenital and includes disorders like Severe Combined Immunodeficiency (SCID)?

Primary immunodeficiency Signup and view all the answers

Which immune response is characterized by immediate, non-specific action against pathogens?

Innate immunity Signup and view all the answers

Why may a patient with lymphoma and a history of prior malignancies require careful observation after a dog bite?

Because of their potentially compromised immune response Signup and view all the answers

What role does macrophage play in the immune response?

They induce cell death of infected or malignant cells Signup and view all the answers

What is an example of a secondary immunodeficiency?

HIV/AIDS Signup and view all the answers

In a post-kidney transplant patient, why might the effectiveness of antibiotics be questioned when an infection is present?

Because of the patient's use of anti-rejection medications which may affect immune response Signup and view all the answers

What type of infections are patients with T cell deficiencies most susceptible to?

Viral infections, especially from the herpes family Signup and view all the answers

What is a common consequence of using corticosteroids in immune-compromised patients?

Impaired migration of PMN and reduced T lymphocyte counts Signup and view all the answers

Which group of primary immunodeficiencies tends to be associated with recurrent bacterial infections?

B cell deficiencies Signup and view all the answers

What effect does chemotherapy have on the immune system?

Inhibits cell division and reduces blood cell regeneration Signup and view all the answers

What is a key characteristic of secondary or acquired immunodeficiencies?

They can result from infections or medications Signup and view all the answers

What is the result of the maternal immunity wearing off in infants with genetic immunodeficiencies?

Increased susceptibility to fungal and viral infections Signup and view all the answers

What impact does tacrolimus have on post-transplant patients?

Suppresses immune response leading to higher infection risk Signup and view all the answers

Which of the following best describes the immune response in patients receiving corticosteroid therapy?

Reduced ability to migrate to sites of infection Signup and view all the answers

What underlying condition is most likely to cause neutropenia after chemotherapy?

Interference with cell division of blood cells Signup and view all the answers

What is the typical immune infection pattern observed in individuals who suffer from both B cell and T cell deficiencies?

Increased incidence of fungal, bacterial, and viral infections Signup and view all the answers

Study Notes

Innate and Adaptive Immunity

Innate immunity includes non-specific defenses that act immediately upon infection.
Adaptive immunity is characterized by a trained immune system that learns and remembers specific pathogens.

Immunodeficiency States

Immunodeficiencies categorized as primary (genetic) and secondary (acquired).
Primary immunodeficiencies arise from genetic defects leading to gaps in immune defenses, often resulting in inadequate pathogen response.
Secondary immunodeficiencies can occur due to infections, medication (chemotherapy/steroids), surgery (splenectomy), and external factors like poor nutrition or pregnancy.

Genetic Deficiencies Impacting Immunity

Complement Deficiencies:
- Lack of complement components disrupts the immune cascade.
- Early component deficiencies increase susceptibility to Staphylococcal and Streptococcal infections.
- Late component deficiencies lead to heightened risk of Neisseria infections.
Phagocytic Cell Function Defects:
- Impairments lead to bacterial infections.
- Example: Chronic Granulomatous Disease affects the ability to kill ingested pathogens, particularly Staphylococci.
Lymphocyte Function Deficiencies:
- Conditions like Subacute Combined Immune Deficiency (SCID) result in non-functional immune systems due to issues in B cells, T cells, or NK lymphocytes.
- Patients typically present with fungal and viral infections once maternal immunity wanes.
- Live vaccines may trigger severe disease in these patients.

B Cell deficiencies primarily increase vulnerability to bacterial infections.
T Cell deficiencies cause higher susceptibility to viral infections (especially herpes), intracellular bacteria, and fungi.

Secondary/Acquired Immunodeficiencies

Chemotherapy:
- Affects lymphocytes, inhibiting cell division and reducing neutrophil (PMN) levels, leading to increased infection risk post-treatment.
Corticosteroids (e.g., prednisone, dexamethasone):
- Suppress inflammation by impairing PMN and macrophage function, reducing T lymphocyte counts, resulting in higher risks of viral, bacterial, and fungal infections.
Post-Transplant Immunosuppression:
- Agents like cyclosporin A and tacrolimus reduce T cell function, increasing vulnerability to infections due to T cell deficiency.

Classic Features of Inflammation

Rubor (redness)
Calor (heat)
Tumor (swelling)
Dolor (pain)

Importance of Immune Status

Patient immune status can dramatically influence clinical presentations and treatment approaches.
Examples illustrating the effect of immune status on clinical expectations:
- Kidney transplant patients may respond poorly to standard antibiotics due to immunosuppression.
- Non-resolving pneumonia in healthy individuals may suggest underlying HIV/AIDS.
- Frequently hospitalized children for pneumonia may indicate primary immunodeficiency.

Summary of Key Immune Concepts

Innate immunity encompasses immediate, non-specific responses, while adaptive immunity involves a trained response to specific pathogens.
Understanding immunodeficiencies aids in identifying potential complications and tailoring treatment approaches effectively.

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Description

This quiz explores the fundamental concepts of innate and adaptive immunity. It highlights the differences between non-specific defenses and the trained responses of the immune system. Additionally, it covers immunodeficiency states, including primary and secondary forms.