Our Own Body’s Friendly Fire

Targeted medical attention early on for warm autoimmune hemolytic anemia, a rare form of an autoimmune blood disorder, helps patients manage symptoms

A serious, but treatable condition, warm autoimmune hemolytic anemia (wAIHA) dominates clinical cases of acquired anemias¹. wAIHA occurs when immunoglobulin G autoantibodies form against red blood cells by mistakenly recognizing them as foreign, resulting in hemolysis. The replenishing of red blood cells cannot offset their unwanted depletion under a barrage of friendly fire by our immune system. Insidiously, the autoantibodies responsible for the wreckage work most effectively at normal body temperature.

Just as autoimmunity is not yet fully understand, there are no underlying identifiable causes for wAHIA; rather it develops with other complications, such as lupus, rheumatoid arthritis, or lymphoproliferative disorders like lymphomas, Epstein-Barr virus and Mycoplasma pneumonia. Some medications can also trigger immune responses that contribute to hemolysis. Since these circumstances always leave less intact red blood cells in circulation, the blood’s oxygen carrying capacity is diminishing, triggering anemia. 

Treatment options overall aim at immune suppression and managing anemia symptoms. If the first line of corticosteroid intervention turns out to be insufficient, newer medications like rituximab or azathioprine provide another avenue for dampening immune responses. Removal of the spleen, which clears circulating red blood cells, can also help. Intravenous immunoglobulin (IVIG) therapy may modulate immune activity in severe cases, and blood transfusions can restore red blood cell levels, if anemia is advanced. 

Before any of these options can be evaluated by clinicians, however, blood tests are needed to diagnose wAIHA. The Direct Antiglobulin Test, also called Coomb’s test, checks for the presence of the disease-associated autoantibodies. Unfortunately, this key test at times misses low amounts of these antibodies, giving off false negative results. Unlike for PNH flow cytometry is not yet routinely consulted for confirming wAHIA, though it offers more reliable analytics than the standard Coomb’s test². Therefore, streamlining diagnostic pathways with flow cytometry based-autoantibody detection and quantification can be beneficial for quickly offering treatment options to patients diagnosed with wAHIA.    

References: 
1.    Barcellini W, Fattizzo F. How I treat warm autoimmune hemolytic anemia. Blood, 2021, 137(10):1283-1294. https://doi.org/10.1182/blood.2019003808
2.    Khunger, JM, Pati HP, Mahapatra M, Khunger A. Utilisation of Flow-cytometry in the Diagnosis of Auto Immune Haemolytic Anaemia. Indian J Hematol Blood Transfus, 2018, 35(2):297-303. https://doi.org/10.1007/s12288-018-1017-y