Question

Which of the following is a genetic disease that results in almost no adaptive immunity due to lack of B and/ or T cells? a. agammaglobulinemia b. severe combined immunodeficiency c. HIV/AIDS d. chronic granulomatous disease

Short answer

Severe combined immunodeficiency (SCID) is the genetic disease that results in almost no adaptive immunity due to a lack of B and/or T cells.

Step-by-step solution

Understanding the Disease Conditions

First, understand that the question is asking for a genetic disease that leads to a significant deficit in adaptive immunity, which involves a lack or dysfunction of B cells and/or T cells. Each option given corresponds to a different immunological condition that impacts the immune system differently.

Analyzing Each Option

Analyze each condition listed to determine which one is characterized by a near-complete absence of adaptive immunity. Agammaglobulinemia affects B cells, HIV/AIDS impairs both B and T cells over time but is not primarily a genetic disease, and chronic granulomatous disease affects neutrophil function.

Identifying the Correct Disease

Identify that severe combined immunodeficiency (SCID) is indeed a genetic disorder that results in the severe impairment of both B and T cells which are crucial for adaptive immunity. Thus, SCID fits the description given in the question.

Key concepts

Adaptive Immunity

To understand severe combined immunodeficiency (SCID), it's essential to first grasp the concept of adaptive immunity. Adaptive immunity is the part of the immune system that develops throughout our lives. Unlike innate immunity, which we are born with, adaptive immunity is acquired as we are exposed to pathogens.

Adaptive immunity involves highly specialized cells, namely B cells and T cells, that recognize and remember specific pathogens. B cells are responsible for producing antibodies, while T cells are divided into different types, with some killing infected host cells and others helping regulate immune responses.

The adaptive immune system is crucial for long-term protection against diseases because it can remember previous encounters with pathogens, making subsequent responses faster and more effective. When there are defects in B and T cells, as with SCID, an individual's ability to fight infections is greatly compromised.

Genetic Diseases in Immunology

There are numerous genetic diseases that affect the immune system, and understanding these can provide insight into how delicate the balance of immune function is. A genetic disease in immunology is an inherited condition that can lead to abnormalities in the immune system's structure and/or function.

Some conditions, like agammaglobulinemia, primarily affect B cell production or function. Others may interfere with different components of the immune system. For a disease to be considered a genetic disorder within the realm of immunology, the root cause must stem from genetic anomalies, which can include mutations, deletions, or duplications of DNA sequences.

This is different from conditions acquired through infection, lifestyle, or environmental factors, which can also impair immune functionalities but are not inherited. The exercise improvement advice here is to ensure that students differentiate between inherited and acquired conditions when discussing genetic diseases in immunology.

Immunodeficiency Disorders

Immunodeficiency disorders are a group of conditions that weaken the immune system's ability to fight off infections and other diseases. They can be primary, which are present at birth and often due to genetics, or secondary, which are acquired after birth due to factors like infections or chemotherapy.

Severe Combined Immunodeficiency (SCID) is a primary immunodeficiency that is classified as a genetic condition. It results in the inadequate function or absence of T cells and B cells. SCID can manifest in multiple forms depending on the genetic mutation involved, with some forms affecting the adaptive immune system more severely than others.

It is known for its severity because individuals with SCID are vulnerable to repeated and persistent infections that would typically be prevented by a healthy immune system. Treatment for SCID often includes stem cell transplantation or gene therapy to correct the underlying genetic defect and restore immune system function. It is crucial for students to understand that these disorders are not just a simple inconvenience but can be life-threatening without proper management and treatment.