The proportion of all T cells that are CD8 cells.

CD8 cells are also called cytotoxic T-lymphocytes. They help fight cancer and germs that live inside your cells (intracellular pathogens).

The CD8 percentage is sometimes more reliable than the absolute count of CD8 because it tends to vary less.

CD15s expression (LAD 2), as part of a Leukocyte Adhesion Deficiency (CD15s, CD18) panel from Quest Diagnostics, plays a critical role in diagnosing Leukocyte Adhesion Deficiency Type II (LAD II). This condition is a rare genetic disorder that affects the immune system's ability to function properly. In healthy individuals, CD15s (also known as sialyl-Lewis X) is a specialized molecule present on the surface of white blood cells (leukocytes) that facilitates their adhesion, or sticking, to blood vessel walls during inflammation or infection. This process is essential for the immune response, as it allows leukocytes to exit the bloodstream and enter affected tissues to combat pathogens.

CD16, also known as FcγRIII, refers to a cluster of differentiation molecule found on the surface of various immune cells, including natural killer cells, neutrophils, monocytes, macrophages, and certain T cells. CD16 has been identified as two different receptors: FcγRIIIa (CD16a) and FcγRIIIb (CD16b). These receptors participate in signal transduction and are involved in antibody-dependent cellular cytotoxicity (ADCC), which is a process where immune cells target and destroy cells coated with specific antibodies.

CD16, also known as FcγRIII, refers to a cluster of differentiation molecule found on the surface of various immune cells, including natural killer cells, neutrophils, monocytes, macrophages, and certain T cells. CD16 has been identified as two different receptors: FcγRIIIa (CD16a) and FcγRIIIb (CD16b). These receptors participate in signal transduction and are involved in antibody-dependent cellular cytotoxicity (ADCC), which is a process where immune cells target and destroy cells coated with specific antibodies.

CD1656 are an important NK (Natural killer) cell subset.

- NK cells are best known for killing virally infected cells, and detecting and controlling early signs of cancer. As well as protecting against disease, specialized NK cells are also found in the placenta and may play an important role in pregnancy.

- Natural killer T (NKT) cells represent a specialized T-cell population that is distinct from conventional T cells. They express an invariant T-cell receptor (TCR) that recognizes self and bacterial glycosphingolipid antigens presented by the MHC class I-like molecule, CD1d.

- Human natural killer (NK) cells can be subdivided in several subpopulations on the basis of the relative expression of the adhesion molecule CD56 and the activating receptor CD16. 

- NK cells serve an important role in host defense against viral infections, as well as tumor surveillance. They are also a component of the adaptive immune response through cytokine production.

- NK cell functions are governed by a balance between activating receptors and inhibitory receptors.

The marker "CD18 Expression (LAD 1)" on a Leukocyte Adhesion Deficiency (CD15s, CD18) panel from Quest Diagnostics is a crucial test for diagnosing Leukocyte Adhesion Deficiency Type 1 (LAD-1), a rare genetic disorder. In this condition, CD18, a protein that is part of a complex necessary for white blood cells (leukocytes) to adhere to and migrate through blood vessel walls during an immune response, is either missing or malfunctioning. CD18 expression is vital because it facilitates the process by which white blood cells exit the bloodstream to reach sites of infection, inflammation, or injury.

The CD19 antigen (aka B-lymphocyte antigen CD19 or Cluster of Differentiation 19) plays an important role in clinical oncology. It’s a protein found on the surface of B-cells, a type of white blood cell.

The CD19 antigen (aka B-lymphocyte antigen CD19 or Cluster of Differentiation 19) plays an important role in clinical oncology. It’s a protein found on the surface of B-cells, a type of white blood cell.

CD19+CD27+IgM+IgD+ refers to a specific subset of B cells characterized by the expression of the cell surface markers CD19, CD27, IgM, and IgD. These markers help categorize B cells into different subsets based on their developmental stage and function.

In this context, the percentage of CD19+CD27+IgM+IgD+ cells (% of CD27+) likely refers to the proportion of B cells with this specific phenotype within the total CD27+ B cell population. It represents a subset of memory B cells with unique characteristics.

Naive B cells CD19+CD27-CD21-CD38- are a specific subset of B cells with distinct surface marker characteristics:

• CD19+: This marker indicates that these cells express the CD19 antigen, which is commonly found on B cells.

• CD27-: The absence of CD27 expression suggests that these B cells are not memory B cells. CD27 is typically expressed on memory B cells.

• CD21-: The absence of CD21 expression may indicate that these B cells have reduced levels of complement receptor 2 (CR2), which can affect their ability to respond to complement-mediated signals.

• CD38-: The absence of CD38 expression suggests that these B cells have lower levels of CD38, which is involved in various B cell functions, including activation and differentiation.

Naive B cells, characterized as CD19+CD27-IGM+IGD+, are a subset of B cells that have not yet encountered an antigen. Here's a breakdown of their characteristics:

• CD19+: This marker signifies that these cells express the CD19 antigen, which is a common B cell marker.

• CD27-: Naive B cells lack CD27 expression. CD27 is a marker used to distinguish between memory B cells and naive B cells. The absence of CD27 indicates that these B cells have not undergone the differentiation and class-switching that typically occurs in memory B cells.

• IGM+ and IGD+: Naive B cells express both IgM and IgD immunoglobulin isotypes on their surface. IgM and IgD are B cell receptors and are important for antigen recognition. Naive B cells carry both to allow them to respond to a wide range of antigens effectively.

CD20 is a critical surface marker predominantly expressed on B lymphocytes from the late pre-B cell stage to memory B cells, absent on pro-B cells and plasma cells. The CD20+ % marker measures the proportion of B cells expressing CD20, aiding in disease monitoring, treatment assessment, and immune status evaluation. Abnormal levels can indicate conditions like chronic lymphocytic leukemia, non-Hodgkin lymphoma, or immunodeficiencies and are pivotal in tracking the efficacy of anti-CD20 therapies such as rituximab. Normal CD20+ % ranges vary, typically 5-15% of total lymphocytes or 95-100% when expressed as a percentage of CD19+ B cells. Deviations should be interpreted alongside other markers (e.g., CD19, CD22) and clinical context to guide diagnosis and treatment.

CD20 is a cell surface protein primarily expressed on the surface of B-cells, a type of white blood cell involved in the immune response. The CD20 molecule plays a critical role in the development, differentiation, and function of B-cells, which are responsible for producing antibodies. It acts as a calcium channel, helping regulate the flow of calcium ions into the cell, a process essential for B-cell activation and immune function. CD20 is not expressed on early B-cell precursors or on plasma cells, which means its expression is limited to specific stages in B-cell maturation.

Because CD20 is highly expressed on the surface of mature B-cells, it has become an important biomarker in diagnosing and treating various B-cell-related diseases, particularly B-cell non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). These cancers are characterized by an abnormal proliferation of B-cells, and CD20 serves as a target for therapies designed to eliminate these malignant cells. Rituximab, an anti-CD20 monoclonal antibody, was one of the first therapeutic agents to target this protein, marking a significant advance in cancer treatment.

CD3+ cells are all T-lymphocytes, which includes both CD4+ and CD8+ lymphocyte cells.

This figure is rarely used for making treatment decisions.

CD3+/CD4+ % refers to the percentage of T-helper cells (a subtype of white blood cells) among all T-lymphocytes (T cells) in your blood. This marker is often measured as part of an immune panel using flow cytometry, especially in contexts involving immune system monitoring, such as HIV, autoimmune conditions, or immunodeficiency assessments.

Understanding the Components

• CD3+ T cells: Represent all mature T lymphocytes, a key part of the adaptive immune system.

• CD4+ T cells: A subset of CD3+ cells, often called T-helper cells, which coordinate immune responses by signaling other immune cells.

• CD3+/CD4+ %: The percentage of total T cells that are CD4+. This gives insight into the relative balance of helper T cells within the T cell population.

CD3+/CD4+, Abs stands for the absolute count of CD4+ T-helper cells within the total population of CD3+ T cells in the blood. This marker measures the exact number of helper T cells per microliter (μL) of blood, rather than just their percentage. It is a key indicator of immune system function, especially in the context of infections like HIV, immune deficiencies, and chronic inflammatory conditions.

The biomarker CD3+/CD4-/CD8- identifies a unique subset of T lymphocytes that express the CD3 surface protein but lack both CD4 and CD8 co-receptors. These cells are often referred to as double-negative T cells (DN T cells) due to their absence of CD4 and CD8 expression. DN T cells represent a small fraction of the total T cell population in peripheral blood, typically accounting for less than 5% of T cells.

The biomarker CD3+/CD4-/CD8- identifies a unique subset of T lymphocytes that express the CD3 surface protein but lack both CD4 and CD8 co-receptors. These cells are often referred to as double-negative T cells (DN T cells) due to their absence of CD4 and CD8 expression. DN T cells represent a small fraction of the total T cell population in peripheral blood, typically accounting for less than 5% of T cells.