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B-lymphocytes carrying IgM in the blood
Medical expert of the article
Last reviewed: 04.07.2025
Normally, the relative amount of B-lymphocytes carrying IgM in the blood of adults is 3-10%, the absolute amount is 0.07-0.17×10 9 /l.
B-lymphocytes carrying IgM are humoral immunity cells responsible for the synthesis of antibodies. They are formed in the red bone marrow and accumulate mainly in the peripheral lymphoid organs. Peripheral blood contains only 3-10% of their total number. After antigens are bound by the surface IgM receptors of B-lymphocytes, the latter are activated and prepared for DNA synthesis and division. Growth factors (IL-4) are necessary for the proliferation of B-lymphocytes, and IL-5 and IL-6 (factors determining the differentiation of B-lymphocytes) are necessary for the formation of immunoglobulin-producing plasma cells.
The ratio of populations in the general pool of B-lymphocytes is of great importance in assessing humoral immunity. A violation of the ratio is characteristic of humoral immunity deficiency.
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