Question

People born without a thymus would have which of the following laboratory derangements? A. Low lymphocyte count B. Low immunoglobulin titer C. High immunoglobulin titer D. High interferon concentrations

Short answer

A. Low lymphocyte count

Step-by-step solution

- Understand the role of the thymus

The thymus is an organ located in the upper chest that plays a crucial role in the development of the immune system, particularly in the maturation of T-lymphocytes (T-cells).

- Identify the immune cells affected

Since the thymus is essential for T-cell development, individuals without a thymus will have impaired T-cell production.

- Analyze the options

Review the given options to determine which one involves T-cells affected by the absence of the thymus. Note that T-cells are a type of lymphocyte.

- Select the correct answer

Given the role of the thymus in T-cell development, individuals without a thymus will have a low lymphocyte count because T-cells are a part of the lymphocyte population.

Key concepts

T-lymphocytes

T-lymphocytes, or T-cells, are a type of white blood cell essential for the immune system. They originate from the bone marrow but mature in the thymus. There are several types of T-cells, each with a unique role:

• Helper T-cells: They assist other immune cells by releasing cytokines.
• Cytotoxic T-cells: These directly kill infected cells.
• Regulatory T-cells: They help maintain immune tolerance and prevent autoimmune diseases.
• Memory T-cells: They quickly respond to previously encountered antigens.

Without the thymus, T-cell production is severely compromised. This impacts the body's ability to combat infections and diseases. The thymus provides an environment for T-cells to mature and differentiate; without it, immature T-cells cannot become functional. This leads to a weakened immune system.

immune system development

The immune system is a network of cells, tissues, and organs working together to defend the body against harmful invaders. The thymus is crucial in the early stages of immune system development. In a fetus and young children, the thymus is highly active. It produces T-cells that are essential for the adaptive immune system. This part of the immune system adapts to new threats the body encounters. During puberty, the thymus starts to shrink, and its activity decreases because the body has already produced a sufficient number of T-cells. However, the thymus's role in early immune development cannot be underestimated. Without it, an individual's immune system cannot develop properly, leading to vulnerability to infections and diseases. This impacts overall health and longevity.

Lymphocyte count

Lymphocytes are a type of white blood cell critical for the immune response. They include B-cells, T-cells, and natural killer cells. T-cells, produced with the help of the thymus, play a vital role in this count. A normal lymphocyte count indicates a healthy immune system. Conversely, a low lymphocyte count can mean immunodeficiency. This is often seen in people without a thymus since T-cell production is hampered.

• Complete Blood Count (CBC): A test used to measure lymphocyte levels.
• Normal Range: Typically between 1,000 to 4,800 lymphocytes per microliter of blood in adults.

Lymphocyte counts can vary based on factors like age, stress, and illness. Monitoring lymphocyte levels helps diagnose and manage various immune disorders. It also provides insight into overall immune system health.