aplastic anaemia is an auto-immune, rare (1-4 per million population) life threatening disorder in which the stem cells in bone marrow are destroyed leading to severe anaemia, thrombocytopenia and agranulocytosis (ie. pancytopenia)
more frequent in teenagers and young adult but is also common among the elderly
many have clones of cells (perhaps as an escape mechanism from immune destruction of stem cells) characteristic of paroxysmal nocturnal haemoglobinuria
Rx is generally immunosuppressive drugs, blood transfusions and protection from infections whilst awaiting bone marrow transplant
for allografting (grafting between individuals), the donor's stem cells must be as compatible as possible with those of the recipient to avoid the risk of immunological complications including graft-versus-host disease
parvovirus may cause a short-lived aplastic anaemia as parvovirus binds to P antigen and causes temporary cessation of red cell production which is usually unnoticed as RBC life span is 120 days