Иммунологический тест определения холодовых агглютининов при гемолитических анемиях

The cold agglutinins test (also referred to as cold autoantibodies or cold‑reacting antibodies) assesses serum for antibodies that bind erythrocytes at low temperatures and activate complement, resulting in hemolysis. The assay aids in diagnosing cold agglutinin disease, a form of autoimmune hemolytic anemia driven by cold‑reactive antibodies, and helps distinguish cold‑mediated from warm antibody hemolysis. Results can also direct evaluation for secondary causes of cold agglutinins, including Mycoplasma pneumoniae infection, infectious mononucleosis, legionellosis, systemic autoimmune disorders, and lymphoproliferative malignancies such as chronic lymphocytic leukemia and Waldenström macroglobulinemia.

Autoimmune hemolytic anemias arise when immune tolerance fails and antibodies are formed against self red blood cells. Warm autoantibodies react optimally at 37 °C, whereas cold autoantibodies bind best at approximately 4–18 °C. Functionally, antibodies may behave as hemolysins, which lyse cells, or as agglutinins, which promote red cell clumping. Cold agglutinin disease represents a relatively uncommon subset of immune hemolysis, accounting for about 20% of autoimmune hemolytic anemia cases. It can be idiopathic—seen more often in older adults (60–80 years)—or secondary. Secondary forms occur in children and young adults, frequently in the setting of Mycoplasma pneumoniae infection, infectious mononucleosis, or legionellosis, and may accompany systemic autoimmune conditions such as systemic lupus erythematosus and rheumatoid arthritis. In older individuals, cold agglutinins commonly associate with lymphoproliferative disorders, including chronic lymphocytic leukemia and Waldenström macroglobulinemia. Cold agglutinins are most often IgM, although mixtures of immunoglobulin classes can occur. These antibodies attach to erythrocyte membranes at low temperature and fix complement, culminating in formation of the membrane attack complex and complement‑mediated injury with pore formation and cell destruction. As a laboratory marker of cold‑mediated hemolysis, detection of antibodies that agglutinate erythrocytes during low‑temperature incubation is informative. A contemporary approach uses a gel agglutination method: donor red cells are suspended in a neutral gel within microtubes, patient serum is added, and the mixture is incubated at 2–8 °C. After centrifugation, nonagglutinated red cells pass through the gel to form a compact pellet, whereas agglutinated cells are retained at the gel surface or within the gel matrix.