From the Guidelines
CD3+ CD4+ T helper/inducer cells play a crucial role in the adaptive immune system, coordinating immune responses by activating B cells for antibody production and cytotoxic T cells for cellular immunity. These cells are critical components of the immune system, and their proper functioning is essential for maintaining immune homeostasis. According to the most recent study 1, regulatory CD4+ T cells, a subset of CD3+ CD4+ T cells, are essential for preventing excessive inflammation and maintaining self-tolerance.
Key Functions of CD3+ CD4+ T Cells
- Coordinating immune responses by activating B cells for antibody production
- Activating cytotoxic T cells for cellular immunity
- Maintaining immune homeostasis and self-tolerance
- Preventing excessive inflammation
Clinical Significance of CD3+ CD4+ T Cells
- Low CD4+ counts (below 500 cells/μL) may indicate immune suppression, as seen in HIV infection, certain medications, or other immunodeficiency disorders
- Extremely low counts (below 200 cells/μL) in HIV patients indicate significant immunocompromise and risk for opportunistic infections
- The CD4:CD8 ratio is also important, with normal values typically between 1.0 and 4.0
Reporting CD3+ CD4+ T Cells
- CD3+ CD4+ T helper/inducer cells should typically be reported as a percentage of total lymphocytes and as an absolute count (cells/μL), with normal values generally ranging from 500-1600 cells/μL or 30-60% of total lymphocytes, though reference ranges may vary slightly between laboratories 1. A comprehensive report should include both the percentage and absolute count of CD3+CD4+ cells, along with the CD4:CD8 ratio for proper clinical interpretation.
From the Research
CD3+ CD4 T Helper/Inducer Cells
- CD3+ CD4 T helper/inducer cells, also known as CD4+ T cells, play a central role in orchestrating the immune response and are involved in various immune processes, including infection, chronic inflammation, autoimmune diseases, and carcinogenesis 2, 3, 4, 5
- These cells can be subdivided into different subsets, including Th1, Th2, Th17, Treg, and Tfh cells, each with unique cytokine profiles and functions 2, 3, 5
- Th1 cells produce IFN-γ, IL-2, and TNF-α, and are involved in type 1 immune responses to intracellular pathogens 2, 3
- Th2 cells produce IL-4, IL-5, and IL-13, and are involved in type 2 immune responses to extracellular pathogens 2, 3
- Th17 cells produce IL-17 and IL-22, and are involved in type 3 immune responses to extracellular pathogens 2, 3
- Treg cells express Foxp3 and regulate immune responses to maintain immune cell homeostasis and prevent immunopathology 2, 3
- Tfh cells produce IL-21 and help B cells produce corresponding antibodies 3
Functions of CD4+ T Cells
- CD4+ T cells are essential for the development and activation of B cells and CD8+ T cells 5
- They play a crucial role in the control and clearance of infections 5
- CD4+ T cells are involved in the pathogenesis of autoimmune diseases, such as multiple sclerosis (MS) 4
- Memory CD4+ T cells are complex and less well understood, but are thought to play a critical role in immunity and autoimmune diseases 4