Changes

Some types of [[IgG]] antibody are able to directly activate the complement cascade but, in most cases, these antibodies are not able to cause intravascular haemolysis of agglutination and they are therefore described as '''incomplete''' antibodies.  These antibodies act as opsonins and, through their interaction with Fc receptors expressed by cells of the hepatosplenic monocyte-phagocyte system (MPS), they promote the uptake and destruction of the red blood cells to which they are bound. These types of antibody therefore cause '''extravascular haemolysis'''.

Some types of [[IgG]] antibody are able to directly activate the complement cascade but, in most cases, these antibodies are not able to cause intravascular haemolysis of agglutination and they are therefore described as '''incomplete''' antibodies.  These antibodies act as opsonins and, through their interaction with Fc receptors expressed by cells of the hepatosplenic monocyte-phagocyte system (MPS), they promote the uptake and destruction of the red blood cells to which they are bound. These types of antibody therefore cause '''extravascular haemolysis'''.

IMHA may occur as a '''primary''' disease with no apparent cause or it may be '''secondary''' to another systemic insult. Possible secondary causes of IMHA include bacterial and parasite infections (including ''[[Babesia canis]]'' in dogs and ''[[Mycoplasma haemofelis]]'' in cats), adverse drug reactions, neoplasia (especially myeloproliferative and lymphoproliferative disease) and live vaccines, although the association between vaccination and immune-mediated disease remains controversial.   

IMHA may occur as a '''primary''' disease with no apparent cause or it may be '''secondary''' to another systemic insult. Possible secondary causes of IMHA include bacterial and parasite infections (including ''[[Babesia canis]]'' in dogs and ''[[Feline Infectious Anaemia|Mycoplasma haemofelis]]'' in cats), adverse drug reactions, neoplasia (especially myeloproliferative and lymphoproliferative disease) and live vaccines, although the association between vaccination and immune-mediated disease remains controversial.   

The majority of cases of IMHA affect only the circulating red blood cells resulting in a strongly [[Regenerative and Non-Regenerative Anaemias|regenerative anaemia]] as the bone marrow stem cells respond to the disease. In a small number of cases, antibodies are produced that affect the stem cells of the [[Erythropoiesis|erythroid lineage]] in the bone marrow, resulting in a non-regenerative anaemia that still bears many of the same clinical features as IMHA. Although the two diseases have been considered separately in the past, they really represent two ends of a spectrum of immune-mediated disease directed at cells of the erythroid line.   

The majority of cases of IMHA affect only the circulating red blood cells resulting in a strongly [[Regenerative and Non-Regenerative Anaemias|regenerative anaemia]] as the bone marrow stem cells respond to the disease. In a small number of cases, antibodies are produced that affect the stem cells of the [[Erythropoiesis|erythroid lineage]] in the bone marrow, resulting in a non-regenerative anaemia that still bears many of the same clinical features as IMHA. Although the two diseases have been considered separately in the past, they really represent two ends of a spectrum of immune-mediated disease directed at cells of the erythroid line.