Immunoglobulins of type M (IgM), or type M antibodies, are one of several types of antibodies in our body and play an important role in the first stages of the immune response. Their characteristic structure resembles a snowflake and allows for the binding of several antigens simultaneously with high efficiency. What is the correct IgM result? What are the standards? What does high IgM mean, and what does low IgM mean?
M type immunoglobulins (IgM)or M type antibodies are immune proteins produced by cells of the immune system - plasma cells, which are a type of B lymphocytes. IgM antibodies are produced as the first of the antibodies when it comes into contact with various chemical molecules (antigens) that the immune system considers foreign. Antigens can be fragments of bacteria, viruses, fungi, food, pollen, and in some situations even your own tissues.
Type M immunoglobulins (IgM) - role in the body
IgM antibodies make up about 10 percent. of all types of antibodies and are produced first in the immune response. IgM antibodies act specifically because they are always directed against a specific antigen.
However, compared to IgG antibodies, they are much less specific, because their role is to quickly neutralize the threat. This is possible thanks to the unique structure, the so-called snowflake, which means that one IgM antibody can bind several antigen molecules at the same time.
Over time, IgM antibodies are replaced with IgG antibodies. Prolonged production of IgM antibodies may occur in conditions of chronic contact with the antigen, e.g. in chronic infections.
IgM antibodies have the ability to form immune complexes with antigen molecules and to activate the complement system very strongly compared to IgG antibodies. The complement system is a grouping of proteins that causes inflammation in the body.
This is to neutralize the antigen and remove it safely from the body. Cells of the immune system, such as macrophages and neutrophils, have receptors on their surface that bind to IgM antibody fragments, allowing them to absorb them and break down immune complexes through phagocytosis.
Type M immunoglobulins (IgM) - specific and total
AntibodiesIgM can be divided into total and specific. Specific IgM antibodies are produced throughout life after contact with a variety of antigens. Testing specific IgM antibodies is of particular importance in the diagnosis of infectious diseases. All specific IgM antibodies in the body constitute the pool of total IgM antibodies.
Type M immunoglobulins (IgM) - indications for the test
The level of immunoglobulin M (IgM) antibodies is tested when there is a suspicion:
- primary and secondary immunodeficiencies
- Waldenström's macroglobulinemia
- infectious diseases, e.g. Lyme disease, herpes
- parasitic invasions, e.g. lamblia, ascariasis
- hematological cancers, e.g. multiple myeloma, lymphomas
Type M immunoglobulins (IgM) - Lyme disease
Testing specific IgM (preferably including IgG) can be important information regarding bacterial, viral, fungal and parasitic infections. An example is the diagnosis of Lyme disease, in which the assessment of the level of IgG and IgM antibodies is used. IgM antibodies appear early in the course of infection, and their elevated levels will indicate the initial or chronic stage of the infection.
Immunoglobulin type M (IgM) - what is the test?
In laboratory tests, we can assess the concentration of both total and specific IgM. Both tests can be performed with venous blood, as well as in the cerebrospinal fluid or synovial fluid in specific indications.
The concentration of specific IgM antibodies is most often determined by enzyme immunoassay methods (eg ELISA test) or immunofluorescence methods. Immunonephelometric and immunoturbidimetric methods are routinely used to determine total IgM antibody concentrations.
Worth knowingImmunoglobulin type M (IgM) - norm
The reference range for total IgM is age dependent and is:
- 1-7 days: 0.04-0.21 g / l
- 8 days-2 months: 0.045-0.21 g / l
- 3-5 months: 0.21-0.51 g / l
- 6-9 months: 0.21-0.89 g / l
- 10-15 months: 0.21-1.04 g / l
- 16-24 months: 0.39-1.54 g / l
- 2-5 years; 0.3-1.12 g / l
- 5-10 years: 0.36-1.98 g / l
- 10-14 years: 0.5-2.13 g / l
- 14-18 years: 0.44-1.13 g / l
- over 18 years: 0.53-3.44 g / l
Immunoglobulin type M (IgM) - results. What does low level mean?
Decreased IgM levels can be caused by:
- Congenital selective immunodeficiencies, e.g. isolated IgM deficiency
- protein loss syndrome
- immaturity of the immune system, e.g. in infants andtoddlers
- non-IgM myeloma
- extensive burns
- malnutrition
Immunoglobulin type M (IgM) - results. What does elevated level mean?
Too high IgM level may be caused by:
- hyper-IgM syndrome
- inflammation
- initial or chronic stage of infection
- liver diseases, e.g. cirrhosis
- autoimmune diseases, e.g. rheumatoid arthritis
- hematological diseases, e.g. Waldenström's macroglobulinemia
Immunoglobulin type M (IgM) - cold agglutinin disease
Cold agglutinin disease is a very rare autoimmune disease characterized by the presence of IgM antibodies against the blood group AB0 antigens (anti-A and anti-B isoagglutinins), which cause red blood cells to clump and break down (haemolysis).
However, this only occurs at low temperatures (28-31 ° C). That is why the symptoms of the disease, such as dizziness, headache, pallor, jaundice, dark urine are very often noticed only in the winter.
Cold agglutinin disease can be diagnosed by performing an antiglobulin test (Coombs test), which is usually positive in these people. These same antibodies are also responsible for the clumping of red blood cells in people who have had the wrong blood group transfused.
References
- Swiecicki P.L. et al. Cold agglutinin disease. Blood 2013,15,122 (7), 1114-21.
- Paul W.E. Fundamental immunology, Philadelphia: Wolters Kluwer / Lippincott Williams & Wilkin 2008, 6th edition.
- Laboratory diagnostics with elements of clinical biochemistry, a textbook for medical students edited by Dembińska-Kieć A. and Naskalski J.W., Elsevier Urban & Partner Wydawnictwo Wrocław 2009, 3rd edition
- Internal diseases, edited by Szczeklik A., Medycyna Praktyczna Kraków 2010
Karolina Karabin, MD, PhD, molecular biologist, laboratory diagnostician, Cambridge Diagnostics Polska A biologist by profession, specializing in microbiology, and a laboratory diagnostician with over 10 years of experience in laboratory work. A graduate of the College of Molecular Medicine and a member of the Polish Society of Human Genetics. Head of research grants at the Laboratory of Molecular Diagnostics at the Department of Hematology, Oncology and Internal Diseases of the Medical University of Warsaw. She defended the title of doctor of medical sciences in the field of medical biology at the 1st Faculty of Medicine of the Medical University of Warsaw. Author of many scientific and popular science works in the field of laboratory diagnostics, molecular biology andnutrition. On a daily basis, as a specialist in the field of laboratory diagnostics, he runs the content department at Cambridge Diagnostics Polska and cooperates with a team of nutritionists at the CD Dietary Clinic. He shares his practical knowledge on diagnostics and diet therapy of diseases with specialists at conferences, training sessions, and in magazines and websites. She is particularly interested in the influence of modern lifestyle on molecular processes in the body.