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,[1] 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.
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.
[3] Nevertheless, what is known is, those with idiopathic cold agglutinin disease are susceptible to having or developing mild clonal bone marrow disorder.
D-L antibodies, typically IgG, are characterized by targeting against red blood cells' on-surface antigens called "P".
[citation needed] 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),[11][12] which can block blood vessels and cause a variety of health problems[12] including inflammation and organ damage.
Therefore, cryoglobulins don't produce hemolysis effect, however its serious complications such as systemic inflammatory or neoplastic disorders can in turn lead to anemia.