May

11

2022

Warm Autoimmune Hemolytic Anemia

By William Aird

Low power view of a peripheral smear from a patient with warm autoimmune hemolytic anemia shows three populations of erythrocytes: 1) normal red cells, 2) small, hyperchromic red cells with loss of central pallor, and 3) large blue-purple-stained polychromatic cells (10x).
Low power view of a peripheral smear from a patient with warm autoimmune hemolytic anemia shows three populations of erythrocytes: 1) normal red cells, 2) small, hyperchromic red cells with loss of central pallor, and 3) large blue-purple-stained polychromatic cells (10x).
Spherocytes (blue arrows) with loss of central pallor, and polychyromaopnic cells (one shown with black arrow) in a patient with warm autoimmune hemolytic anemia (100x, oil).
Spherocytes (blue arrows) with loss of central pallor, and polychyromaopnic cells (one shown with black arrow) in a patient with warm autoimmune hemolytic anemia (100x, oil).

Red cell morphology in warm AIHAComments
Spherocytes
Definition/description Spherocytes are round, thicker and more densely staining than normal and lack central pallor. Typically appear slighter smaller than normal red cells.
Mechanism of formationOccurs as a consequence of membrane loss, resulting in decreased surface area: volume ratio.
Other red cell phenotypes
PolychromatophiliaPolychromatophilic cells appear slightly larger than normal red cells and their color is slightly more basophilic (blue-purple). They represent reticulocytes, reflecting the bone marrow response to anemia.
HistoryFrench investigators reported the presence of hemolysins in the sera of patients with hemolytic anemia as early as 1908. The direct Coombs (antiglobulin) test was introduced in 1945 and in 1946 was used to definitely diagnose idiopathic acquired hemolytic anaemia in 5 patients who demonstrated spherocytosis on their peripheral smear.
Source/authorWilliam Aird
ReferencesLancet. 1946;1(6405):812-4.
AIHA, autoimmune hemolytic anemia

Stay Updated

If you are interested in getting the latest articles from The Blood Project, enter your name and email

  • This field is for validation purposes and should be left unchanged.