MP NHM CHO-2024 (Shif…: The main type of immune cells targeted by HIV is

MP NHM CHO-2024 (Shift-1)

Applied Microbiology & Infection control

Easy

Appeared in: MP NHM CHO-2024 (Shift-1)

Explanation

The Human Immunodeficiency Virus (HIV) has a strong affinity for CD4 receptors, which are most prominently found on the surface of T helper cells.
T helper cells (a subset of T cells) are the primary host for HIV replication.
The virus enters these cells, replicates, and ultimately destroys them.
The progressive depletion of CD4+ T cells is the central feature of HIV disease, leading to severe immunodeficiency.
This destruction of T cells cripples the adaptive immune system, making the body vulnerable to opportunistic infections and cancers.

Option A: B cells are responsible for producing antibodies (humoral immunity). They are not the primary cells infected by HIV, although their function is impaired due to the lack of signaling support from T helper cells.
Option C: Natural Killer (NK) cells are part of the innate immune system and do not have the CD4 receptor that HIV uses to enter its main target cells.
Option D: While macrophages can be infected by HIV (as they also express CD4, but at lower levels) and act as a viral reservoir, the defining characteristic of AIDS is the catastrophic decline in CD4+ T cells, not macrophages.

Visual 1: Diagram - A diagram illustrating the HIV virion with its gp120 surface protein binding to the CD4 receptor and a coreceptor on a T helper lymphocyte, showing the process of viral entry.
Visual 2: Graph - A line graph showing the typical course of HIV infection over time, plotting the inverse relationship between viral load (increasing) and CD4+ T cell count (decreasing).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of HIV and its primary target immune cells as background academic context rather than a clinical decision trigger.
Monitoring the CD4+ T cell count is a critical nursing responsibility in managing patients with HIV. It determines the stage of the disease, risk for opportunistic infections, and when to initiate antiretroviral therapy (ART) or prophylactic medications.
Patient safety is paramount. A low CD4 count (below 200 cells/mm³) indicates severe immunocompromise (AIDS), requiring the nurse to implement neutropenic precautions and educate the patient on avoiding sources of infection.
What if? If a patient's CD4 count drops to 180 cells/mm³, the nursing priority shifts from routine monitoring to active prevention of opportunistic infections like Pneumocystis jirovecii pneumonia (PJP), for which prophylaxis (e.g., with trimethoprim-sulfamethoxazole) is indicated.

How to Approach the Question

First, identify the core of the question, which is asking for the 'main' or 'primary' target of a specific pathogen (HIV).
Recall knowledge about the pathophysiology of HIV. The name 'Human Immunodeficiency Virus' itself points to its effect on the immune system.
Access specific knowledge about virology: HIV is a retrovirus that targets cells with CD4 receptors.
Evaluate the options based on this key fact. Which of the listed immune cells is famously known for its CD4 receptor and its role in HIV infection?
T cells, specifically T helper cells, are the classic CD4+ cells. This makes them the most likely answer.
Eliminate other options: B cells, NK cells, and Macrophages are not the primary target whose destruction defines the progression to AIDS, even if some (like macrophages) can be infected.

Concept Tested & Keywords

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E6 Microbiology Applied AnjuDhir 3e Part 2 p. 223-224