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.

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.

The CD3-/CD16+CD56+ (%) test is a sophisticated diagnostic assay crucial in the field of immunology, offering invaluable insights into the functioning of the body’s immune system. This test specifically measures the percentage of natural killer (NK) cells, identified by the absence of CD3 and the presence of CD16 and CD56 markers, in the total lymphocyte population. NK cells are a vital component of the innate immune system, playing a key role in the body’s first line of defense against tumors, virally infected cells, and in modulating immune responses. The CD3-/CD16+CD56+ (%) test is pivotal in evaluating various immune conditions, including autoimmune diseases, chronic viral infections, and certain cancers.

The "CD3-/CD16+CD56+ (Absolute)" marker is a crucial measure for evaluating the absolute count of Natural Killer (NK) cells in your blood. NK cells are a vital type of lymphocyte, which is a category of white blood cells that play a key role in your body's first line of defense in its immune response. These cells are unique because they lack the CD3 marker, a characteristic typically found on T cells, and instead, are identified by the presence of CD16 and CD56 markers.

Understanding the absolute count of NK cells, rather than just their percentage among lymphocytes, provides a clearer picture of how equipped your immune system is to combat infections and potentially cancerous cells. NK cells are essentially the body’s natural surveillance system, capable of destroying cells that have become infected or have undergone malignant transformation, without the need for prior activation.

The marker "CD3/CD8/CD45RO" is used in immunological studies to identify and characterize a specific subset of T cells known as memory T cells. CD3 is a marker found on all T cells, indicating their role in the immune system, while CD8 is present on cytotoxic T cells, which are responsible for directly killing infected or cancerous cells. CD45RO is a marker that distinguishes memory T cells from naive T cells; it indicates that these cells have previously encountered an antigen and are primed for a faster and more efficient response upon re-exposure.

The marker "CD3/gamma-delta" on a T Cell Monitoring & Activation panel refers to a unique subset of T cells known as gamma-delta T cells. These cells are characterized by their T-cell receptor (TCR) composition, which includes a gamma chain and a delta chain, distinguishing them from the more common alpha-beta T cells, which have alpha and beta chains in their TCRs. Gamma-delta T cells are a critical component of the immune system, bridging the gap between innate and adaptive immunity. Unlike conventional alpha-beta T cells, gamma-delta T cells can recognize antigens without the need for presentation by major histocompatibility complex (MHC) molecules, allowing for a rapid response to a wide range of pathogens, including bacteria, viruses, and tumors.

The CD4 cells are Helper T-cells expressing both CD3 and CD4.

CD4 T-cells levels are a criterion for categorizing HIV-related clinical conditions by CDC's classification system for HIV infection. The measurement of CD4 T-cell levels has been used to establish decision points for initiating P. jirovecii prophylaxis, antiviral therapy and to monitor the efficacy of treatment. The Public Health Service (PHS) has recommended that CD4 T-cell levels be monitored every 3 to 6 months in all HIV-infected persons.

During HIV infection, antiviral therapy is often initiated when the absolute CD4 count drops below 500 cells/µL. When the absolute CD4 count drops below 200 cells/µL, therapeutic prophylaxis against PCP and other opportunistic infections may be initiated. When the absolute CD4 count drops below 100 cells/µL, prophylaxis against Mycobacterium avium complex is recommended.

This test looks at the ratio of two important types of white blood cells in your blood.

Lymphocytes are a type of white blood cell in your immune system. This test looks at two of them, CD4 and CD8.

CD4 cells lead the fight against infections. CD8 cells can kill cancer cells and other invaders.

This test looks at the ratio of two important types of white blood cells in your blood.

Lymphocytes are a type of white blood cell in your immune system. This test looks at two of them, CD4 and CD8.

CD4 cells lead the fight against infections. CD8 cells can kill cancer cells and other invaders.

This test looks at the ratio of two important types of white blood cells in your blood.

Lymphocytes are a type of white blood cell in your immune system. This test looks at two of them, CD4 and CD8.

CD4 cells lead the fight against infections. CD8 cells can kill cancer cells and other invaders.

The CD4/CD8 ratio is a critical marker of immune system health. It measures the balance between CD4+ T-helper cells and CD8+ cytotoxic T cells, two major subtypes of T lymphocytes. These cells play complementary roles in immune defense:

• CD4+ T-helper cells coordinate immune responses by activating other immune cells.
• CD8+ cytotoxic T cells directly attack infected or cancerous cells.

The ratio is calculated by dividing the absolute count of CD4+ cells by that of CD8+ cells, and it provides insight into the state of immune regulation, activation, and balance.