Cold antibody

Cold sensitive antibodies (CSA) are antibodies sensitive to cold temperature. Some cold sensitive antibodies are pathological and can lead to blood disorder. These pathological cold sensitive antibodies include cold agglutinins, Dnotath-Landsteniner antibodies, and cryoglobulins which are the culprits of cold agglutinin disease, paroxysmal cold hemoglobinuria in the process of Donath-Landsteiner hemolytic anemia, and vasculitis, respectively. Cold sensitive antibodies (CSA) are antibodies sensitive to cold temperature. Some cold sensitive antibodies are pathological and can lead to blood disorder. These pathological cold sensitive antibodies include cold agglutinins, Dnotath-Landsteniner antibodies, and cryoglobulins which are the culprits of cold agglutinin disease, paroxysmal cold hemoglobinuria in the process of Donath-Landsteiner hemolytic anemia, and vasculitis, respectively. Cold agglutinins are antibodies, typically immunoglobulin M (IgM), that are acquainted with and then binding the antigens on red blood cells, typically antigens 'I' or 'i' on the RBC surface, in the environment in which the temperatures are lower than normal core body temperature and, thus, ends up leading to agglutinations of the red blood cells and hemolysis reaction occurring outside the vessels (extra-vessels), resulting in anemia without hemoglobinuria in ordinary cases. Cold agglutinins can cause two pathological conditions, that are, primary cold agglutinin disease (CAD) and secondary cold agglutinin syndrome (CAS), both of which are sole two subtypes of cold agglutinin disease. Primary cold agglutinin disease is idiopathic, meaning the phenomenons of agglutinations of the red blood cells and hemolysis reaction occurring outside the vessels are absent from any underlying cause. Nevertheless, what is known is, those with idiopathic cold agglutinin disease are susceptible to having or developing mild clonal bone marrow disorder. Secondary cold agglutinin syndrome refers to cold agglutinin disease that is identified to be caused by viral infection, autoimmune disorder, lymphoid malignancy, or any other underlying disease. Cold agglutinins (CA) are autoantibodies that agglutinate RBCs with a temperature optimum of 3-4 °C but may also act in a warmer environment, depending on the thermal amplitude of the CA. If the thermal amplitude exceeds 28–30 °C, the CA will be pathogenic. Low-affinity CA also occurs in many healthy individuals; these nonpathogenic CA are polyclonal, have low thermal amplitude, and are present in low titers, not higher than 256 and usually lower than 64. More than 90% of pathogenic CA are of the IgM class and these IgM macromolecules can be pentameric or hexameric. Donath-Landsteiner antibodies share similarities with cold agglutinin disease in recognition and connection of the antigens on the red blood cells' surface in the presence of relatively lower temperatures compared to core body temperature. Yet, the place where the hemolysis taking place differentiates between D-L antibodies and cold agglutinin. D-L antibodies rather fix complement system which result in hemolysis in vessels (intra-vessels). Blood vessels are pathways carrying living-required elements to reach everywhere inside the body through circulation. This explains why the clinical manifestations of hemolysis caused by D-L antibodies are in line with representations of hemoglobinemia and hemoglobinuria. D-L antibodies, typically IgG, are characterized by targeting against red blood cells' on-surface antigens called 'P'. The pathophysiology of Donath-Landsteiner hemolytic anemia has been entitled as paroxysmal cold hemoglobinuria. Cryoglobulins are abnormal antibodies that only dissolve/disappear at temperature higher than 37 °C (99 °F) and form solid or gel-like immune complexes in presence of the environment under 37 °C (99 °F), which can block blood vessels and cause a variety of health problems including inflammation and organ damage.