Any discovery about the human body or its components helps health professionals to better understand how it works and, therefore, to provide more specific, rapid solutions that cause the least possible suffering for the patient. Investigating at a smaller level is often the key, which is why immunocomplexes have been and continue to be of great clinical utility.
These structures, formed by the union of two components, can give us many answers about the human immune system and its behavior in receiving, analyzing, and eliminating foreign substances or those that should not be in the body. Given their importance, today we will see how useful their analysis can be in laboratories and what their exact function or functions are.
What are immunocomplexes?
As we have mentioned, immunocomplexes are structures formed by the union of two complexes, in this case antigens and antibodies. Both are closely related to the immune system of the human body, as one attacks and the other defends. One is the response to the other, and one of the responses to an external attack on the human body is to fuse both into a single complex.
This interaction helps to neutralize and eliminate foreign substances, such as microorganisms and toxins. The process begins when the immune system detects an antigen and B lymphocytes are activated and become plasma cells, which produce specific antibodies for that external invader. These antibodies have binding sites called paratopes, which recognize and bind to specific sites on the antigen, called epitopes.
The binding between an antibody and an antigen is based on non-covalent interactions, such as hydrogen bonds, Van der Waals forces, ionic bonds, and hydrophobic forces. This interaction can lead to the formation of larger and more complex structures, which would be the immunocomplexes. Their size can range from small compounds, with an antigen bound to an antibody, to large aggregates of several antigens and antibodies bound in a complex network.
They also have the ability to activate the complement system, a set of plasma proteins that facilitate the opsonization and phagocytosis of immunocomplexes, as well as the direct lysis of pathogens. Normally, the body naturally eliminates them through the reticuloendothelial system (including the liver and spleen). Phagocytes, such as macrophages and neutrophils, ingest and degrade immunocomplexes. However, it can also happen that they are not eliminated and end up staying in tissues, causing inflammation and damage. In fact, it is very common for this to lead to diseases such as systemic lupus erythematosus, glomerulonephritis, and vasculitis.
Function
However, immunocomplexes, despite their unwanted presence in the body causing problems, also fulfill a number of very important functions in the immune system. They neutralize pathogens by binding to antigens, preventing viruses, bacteria, and toxins from infecting or damaging the body’s cells. They also mark them for destruction by immune cells such as macrophages and neutrophils. In this way, they help facilitate the process of phagocytosis and their final elimination. They activate the complement system, a set of plasma proteins that help destroy pathogens, promote inflammation, and facilitate the elimination of immunocomplexes.
Their activation and the release of inflammatory mediators by immune cells attracted to the site of the immunocomplexes contribute to generating inflammation, helping to contain and eliminate the infection. They are also capable of eliminating soluble antigens and immune complexes formed with the body’s infected or damaged cells, maintaining homeostasis and preventing tissue damage.
Related Diseases
As mentioned, the accumulation of immunocomplexes in areas where they should not be for too long, such as in tissues, can trigger an inflammatory response and tissue damage. Some of the main diseases related to immunocomplexes are:
Systemic Lupus Erythematosus (SLE)
This autoimmune disease causes immunocomplexes to deposit in various organs, including the skin, joints, kidneys, and central nervous system, causing inflammation and damage.
Glomerulonephritis
This consists of inflammation of the glomeruli in the kidneys caused by an accumulation of immunocomplexes in the glomeruli, leading to complement activation and kidney damage. A specific example is post-streptococcal glomerulonephritis.
Rheumatoid Arthritis
In this autoimmune disease, immunocomplexes deposit in the joints, causing chronic inflammation and damage to the cartilage and bone.
Vasculitis
This consists of inflammation of the blood vessels because immunocomplexes end up in the walls of the blood vessels. Some examples are polyarteritis nodosa and Henoch-Schönlein disease.
Serum Sickness
This occurs when immunocomplexes form in response to the administration of serum or other animal-derived medications. If the body reacts, it can generate fever, skin rashes, arthralgia, and glomerulonephritis.
Cryoglobulinemia
This consists of the formation of immunocomplexes with proteins called cryoglobulins. These complexes deposit in the blood vessels and cause vasculitis, mainly in the skin, joints, nerves, and kidneys.
Subacute Bacterial Endocarditis
Immunocomplexes deposit in the kidneys and other organs, causing glomerulonephritis and other complications.
Type III Allergic Reactions
These include reactions to certain medications and infectious antigens, where the formation of immunocomplexes causes inflammation and tissue damage.
Immunological Tests
Currently, there are laboratory tests capable of evaluating the immune response of a patient in various cases and diseases. These can also help if immunocomplexes have caused any problems, so it is useful to know which are the most common:
Antibody Tests (Serology)
In this type of analysis, three stand out:
- ELISA (Enzyme-Linked Immunosorbent Assay). Used to detect specific antibodies in the blood (HIV, hepatitis B and C, among other viral and bacterial infections).
- Western Blot. Used to confirm positive ELISA results, especially in HIV diagnosis.
- Immunofluorescence. Used to detect specific antibodies in the serum, often for autoimmune diseases.
Antigen Tests
These are currently much more well-known among the general population thanks to their use in rapid diagnostics of infections such as COVID-19 and influenza, detecting the presence of specific pathogen proteins.
Chemiluminescent Immunoassay (CLIA
Used to detect antigens and antibodies in the blood with high sensitivity and specificity. It is also applied in the diagnosis of various infectious and autoimmune diseases.
Cellular Immunity Tests
In this case, the lymphocyte proliferation test should be highlighted, which evaluates their ability to proliferate in response to specific antigens and the interferon gamma release assay (IGRA), used to detect Mycobacterium tuberculosis infections (tuberculosis).
Autoantibody Tests
As in the first case, three tests are worth mentioning:
- ANA (antinuclear antibodies), used for autoimmune diseases such as lupus.
- Anti-dsDNA antibodies, used in the diagnosis of systemic lupus erythematosus.
- Antithyroid antibodies, used to diagnose autoimmune thyroid diseases such as Hashimoto’s disease and Graves’ disease.
Allergy Tests
These tests will be very familiar to people with allergies, as they have likely undergone skin allergy tests, used to detect allergies to various substances, or specific IgE tests, which measure IgE levels for different allergens in the blood.
All these tests are essential in clinical practice for the diagnosis, monitoring, and management of various immunological and infectious conditions. A laboratory like Ambar Lab, capable of performing more than 3000 laboratory tests, can be an indispensable ally in any health-related business.
Clinical Utility
Speaking of clinics, we cannot overlook all the utilities that immunocomplexes can have in this sector, as they can help in:
Disease Diagnosis
The detection of immunocomplexes in serum or tissues can aid in the diagnosis of various diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis, glomerulonephritis, and/or vasculitis.
Activity Evaluation
Quantifying their levels in serum can provide information on the activity of autoimmune and inflammatory diseases to help monitor and adjust treatment.
Prognosis
Sometimes elevated levels of immunocomplexes can be associated with a poorer prognosis in diseases such as lupus and glomerulonephritis. Their analysis and control can help health professionals make better therapeutic decisions.
Monitoring Treatment Response
Changes in immunocomplex levels often reflect the patient’s response to treatment. They can be used to help assess therapeutic efficacy and adjust clinical management if necessary.
Biomedical Research
Immunocomplexes are used in biomedical research to study the pathogenesis of autoimmune, inflammatory, and infectious diseases, as well as to develop and evaluate new therapies.
The detection and quantification of immunocomplexes have great clinical utility in the diagnosis, monitoring, and management of various diseases, as well as in biomedical research to better understand the underlying mechanisms of these conditions and develop better therapeutic approaches.
That is why at Ambar Lab we are more than ready not only to offer you the laboratory tests you are looking for but also support in managing your business and developing new projects. If you have any specific questions or want to start working together, you just need to contact our team so that we can advise you more personally.
