Immunoglobulin M

and Eva Rudolf-Müller, doctor

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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Medical professionals refer to a certain class of antibodies as immunoglobulin M (IgM). Five individual IgMs assemble into a larger structure - a so-called pentamer. Read here which functions the immunoglobulin M fulfills in the body's defense and in which cases the IgM level in the blood is increased or decreased.

What are the tasks of immunoglobulin M?

Similar to immunoglobulin G, immunoglobulin M recognizes characteristic surface structures (antigens) of pathogens and thus marks them for certain leukocytes, which then kill the germs. In addition, the IgM are the strongest activator for the complement system. This is a cascade-like activation of various proteins that are part of the immune system and that remove non-specific foreign substances in the body.

Normal values for immunoglobulin M

The IgM levels are measured in the blood serum. Depending on age and gender, the following IgM normal ranges apply:

age	masculine	Female
up to 12 months	37-140 mg / dl	40 - 150 mg / dl
1 to 2 years	41-160 mg / dl	47-180 mg / dl
3 to 4 years	43-160 mg / dl	52-190 mg / dl
5 to 6 years	45 - 170 mg / dl	56-210 mg / dl
7 to 8 years	47-180 mg / dl	60-220 mg / dl
9 to 10 years	48-180 mg / dl	62-230 mg / dl
11 to 12 years	49-180 mg / dl	65 - 240 mg / dl
13 to 14 years	50-180 mg / dl	66 - 250 mg / dl
15 to 16 years	50-190 mg / dl	68 - 260 mg / dl
17 to 18 years	51-190 mg / dl	68 - 260 mg / dl
from 19 years	40-230 mg / dl	40-230 mg / dl

When is the immunoglobulin M decreased?

An immunoglobulin M deficiency exists from values below 40 mg / dl in adults; for children, a lower lower limit applies depending on their age. The IgM deficiency can occur congenitally or as a concomitant symptom or consequence of an acquired underlying disease. For example, the following diseases are associated with an increased loss of the body's own immunoglobin M:

Nephrotic syndrome (loss of protein in the urine, increased blood fat content and edema)
Burns
Exudative enteropathy (loss of protein via the intestinal tract due to watery diarrhea

Other diseases, however, inhibit the formation of IgM antibodies, for example:

Monoclonal gammopathy (excessive production of other antibody classes, which suppresses IgM production)
Therapeutic measures that suppress the immune system (radiation therapy, chemotherapy or the administration of other immunosuppressive drugs)

When is the immunoglobulin M increased?

An increased IgM value can be found, for example, at the beginning of an infection. This can be caused by viruses (such as rubella, mumps, chickenpox) or bacteria (such as chlamydia). IgM is thus the first antibody that is formed during an initial infection. A chronic infection also shows increased IgM levels in the acute episode. Other causes for the increase of immunoglobulin M in the blood serum are: