IL-2 (Interleukin-2) is a pro-inflammatory Th1 cytokine that promotes the growth and activation of T cells, NK cells, and B cells, playing a key role in immune defense and regulation. Produced by activated T-helper cells, IL-2 strengthens immune responses while also supporting regulatory T cells (Tregs) to prevent autoimmunity. Elevated IL-2 levels often indicate immune activation, autoimmune activity, or chronic inflammation, whereas low IL-2 may reflect immune exhaustion, poor T-cell function, or regulatory imbalance. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-2 serves as a core marker of Th1 immune strength and balance, helping clinicians evaluate whether the immune system is properly activated, overactive, or suppressed.

IL-4 (Interleukin-4) is an anti-inflammatory cytokine that promotes Th2 immune activity and supports antibody production, immune tolerance, and tissue repair. Produced by Th2 cells, mast cells, and basophils, IL-4 helps suppress excessive Th1-driven inflammation. Elevated IL-4 levels are often linked to allergies, asthma, eczema, and parasitic infections, reflecting Th2 dominance and increased antibody activity. Low IL-4 may occur in autoimmune or chronic inflammatory states, where regulatory immune signaling is reduced. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-4 serves as a key marker of anti-inflammatory balance, helping clinicians determine whether a patient’s immune system is tilted toward inflammatory (Th1/Th17) or regulatory (Th2) pathways.

IL-5 (Interleukin-5) is an anti-inflammatory Th2 cytokine that stimulates the production and activation of eosinophils, immune cells involved in allergic reactions, asthma, and defense against parasites. Produced by Th2 cells, mast cells, and ILC2s, IL-5 promotes antibody production and supports mucosal immunity. Elevated IL-5 levels are often seen in allergic diseases, asthma, and eosinophilic inflammation, indicating a Th2-dominant immune response. Low IL-5 may occur in Th1/Th17-driven inflammation or immune suppression, leading to reduced mucosal protection. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-5 serves as a marker of anti-inflammatory and Th2 activity, helping clinicians evaluate whether the immune system is balanced or skewed toward chronic inflammation or allergic hypersensitivity.

IL-6 (Interleukin-6) is a pro-inflammatory cytokine that plays a central role in inflammation, immune defense, and metabolic regulation. Produced by immune and tissue cells, IL-6 triggers the liver’s acute-phase response, supports antibody production, and influences energy metabolism. Elevated IL-6 levels indicate chronic inflammation and are associated with autoimmune disease, metabolic dysfunction, cardiovascular disease, and chronic infection. Persistently high IL-6 can also promote fatigue, tissue damage, and oxidative stress. Low IL-6 may reflect suppressed immune function or reduced inflammatory capacity. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-6 serves as a key marker of systemic inflammation and immune activation, helping clinicians identify chronic inflammatory drivers and guide strategies to restore immune balance.

IL-7 (Interleukin-7) is a cytokine essential for the development, maintenance, and survival of T and B lymphocytes, key players in the body’s adaptive immune system. Produced by stromal and epithelial cells in the bone marrow and thymus, IL-7 helps sustain immune cell balance and readiness. Elevated IL-7 levels often reflect immune activation, lymphocyte depletion, or chronic inflammation, as the body increases IL-7 production to replenish immune cells. High IL-7 can be seen in autoimmune diseases, chronic viral infections, and metabolic or inflammatory disorders, while low levels may indicate immune suppression or impaired bone marrow function. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-7 serves as a key marker of immune activity and adaptive resilience, helping clinicians assess whether the immune system is in a state of activation, recovery, or dysregulation.

IL-8 (Interleukin-8) is a pro-inflammatory chemokine that recruits neutrophils and other immune cells to sites of infection or tissue injury. Produced by immune and epithelial cells, IL-8 helps the body mount an effective inflammatory response, but when chronically elevated, it can contribute to autoimmune disease, metabolic inflammation, and tissue damage. High IL-8 levels are often linked to rheumatoid arthritis, IBD, asthma, chronic infections, and cardiometabolic disorders, reflecting sustained immune activation. Low IL-8 may occur with immune suppression or impaired inflammatory signaling. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-8 is a key indicator of innate immune activity and inflammatory load, helping clinicians identify chronic inflammatory or autoimmune processes and guide personalized strategies for restoring immune balance.

The Immature Reticulocyte Fraction (IRF) measures the percentage of young red blood cells (RBCs) in the bloodstream, indicating the bone marrow's RBC production rate. High IRF suggests active bone marrow response, as seen in recovery from anemia, while low IRF indicates inadequate marrow activity, common in conditions like aplastic anemia. IRF is essential in diagnosing and monitoring red blood cell disorders, differentiating anemias caused by decreased production versus increased destruction. It's also key in evaluating treatment effectiveness, particularly in patients with chronic kidney disease or undergoing chemotherapy. Its inclusion in advanced hematology analyzers underscores its clinical significance in hematologic condition management.

Immature granulocytes (IGs) are precursor white blood cells that appear in the bloodstream during heightened immune responses, particularly in severe infections or inflammatory conditions. Their presence in a complete blood count (CBC) provides valuable diagnostic information about immune system activity.

Immature Granulocytes (%) (IG%) is a value reported on a Complete Blood Count (CBC) with differential that shows how many early-stage infection-fighting white blood cells are circulating in your bloodstream. In healthy adults, immature granulocytes are usually absent or extremely low because they normally stay in the bone marrow until fully mature.

When your body is fighting a bacterial infection, experiencing significant inflammation, or under severe physical stress, the bone marrow may release these cells early. As a result, a high IG% can be an early sign of infection — sometimes appearing before the total white blood cell count rises.

An elevated IG% does not diagnose a specific disease on its own. It must be interpreted alongside symptoms, neutrophil levels, total white blood cell count, and inflammatory markers such as CRP or procalcitonin.

Circulating immature platelets, also known as the immature platelet fraction (IPF), is the term that defines much larger platelets that have been recently released from the bone marrow, presence of which show the thrombopoietic activity of the marrow.

They represent the most recently produced platelets released into the circulation by regenerated BM megakaryocytes. These types of platelets are the analogs of reticulocytes and are similarly large; moreover, they contain elevated amounts of cytoplasmic RNA and decrease in size and RNA content as they age. The number and proportion of immature platelets reflect the rate of thrombopoiesis; the values of these parameters rise and fall concomitantly with the platelet production rate.

The Immature Reticulocyte Fraction (IRF) test is a vital diagnostic tool in the field of hematology, offering crucial insights into the health and functionality of the bone marrow. IRF measures the percentage of immature reticulocytes (young red blood cells) in the blood, providing an early indication of bone marrow response, especially in conditions like anemia. This test is key for diagnosing various types of anemia, assessing bone marrow recovery post-chemotherapy, or monitoring the effectiveness of treatments for conditions affecting red blood cell production.

An immune complex is formed from the binding of an antibody to a soluble antigen. The bound antigen and antibody act as a specific antigen. Immune complexes can be subject to any of a number of responses, which can lead to autoimmune reactivity.

Antibodies Appear: IgA-related renal disease, Mucosal infection, Sjogren’s syndrome

Anti-C1q autoantibodies are indicative for lupus nephritis, but can also be found in other conditions and inflammatory diseases.

Circulating immune complexes can be demonstrated in rheumatic, infectious, and neoplastic diseases, as well as most immunologically mediated illnesses (inflammatory bowel disease, thrombotic thrombocytopenic purpura). Complement is part of the innate immune system. Its major function is recognition and elimination of pathogens. Complement activity plays also an important role in the pathogenesis of systemic autoimmune diseases.

Immunofixation electrophoresis or immunosubtraction capillary electrophoresis identifies the type of immunoglobulin protein(s) present as monoclonal bands on a protein electrophoresis pattern. Typically, this testing determines the presence and type of monoclonal proteins (e.g., IgG kappa).

Immunoglobulin A (IgA), one of the five primary immunoglobulins, plays a pivotal role in mucosal homeostasis in the gastrointestinal, respiratory, and genitourinary tracts, functioning as the dominant antibody of immunity in this role.

Total IgA (Immunoglobulin A), expressed in milligrams per deciliter (mg/dL), is a crucial marker in clinical immunology representing the predominant immunoglobulin class in mucosal secretions and the second most abundant immunoglobulin in serum. This glycoprotein plays a pivotal role in mucosal immunity, offering a primary line of defense against pathogens at mucosal surfaces, including the gastrointestinal, respiratory, and genitourinary tracts. Normal levels of Total IgA in the blood vary based on age and individual health conditions but typically range from 70 to 400 mg/dL in adults.

Immunoglobulin D (IgD) is an antibody isotype that makes up about 1% of proteins in the plasma membranes of immature B-lymphocytes where it is usually coexpressed with another cell surface antibody called IgM.

Remains in the bloodstream to fight bacteria. Functions mainly as an antigen receptor on B cells that have not been exposed to antigens. It has been shown to activate basophils and mast cells to produce antimicrobial factors.

Immunoglobulin E (IgE) is a key antibody in the immune system, crucial for diagnosing and managing allergies. Testing for IgE is important for identifying specific allergens causing allergic reactions, which can range from mild symptoms like sneezing to severe, potentially life-threatening conditions like anaphylaxis. Measuring IgE levels helps in creating personalized treatment plans, including medication and immunotherapy. It's also used to monitor the effectiveness of allergy treatments and assess the severity of chronic conditions like asthma. Elevated IgE levels can indicate broader immune system issues, making it a valuable tool in immunological assessments. With allergies becoming more common, IgE testing is increasingly important in healthcare, aiding in better patient care in allergy and immunology.

In the blood of healthy people, IgE antibodies make up less than 0.001% of all immunoglobulins. These IgE antibodies are key in triggering allergic responses when people sensitive to allergens come into contact with them.

Structurally, IgE resembles other antibodies, having two light chains and two heavy chains. The heavy chains have a special region that determines the antibody's specificity to antigens. Measuring IgE levels is clinically significant mainly because of its role in allergic reactions, even though IgE myeloma is a very rare condition.

Immunoglobulin E (IgE) are antibodies produced by the immune system. 

IgE antibodies are found in the lungs, skin, and mucous membranes. They cause the body to react against foreign substances such as pollen, fungus spores, and animal dander. They are also involved in allergic reactions to milk, some medicines, and some poisons.