Refractory anaemia

Pathohysiologically, this orderly sequence of events can be disrupted due to an inherited deficiency of the enzyme called chelatase or, more importantly, acquired from a wide variety of toxins such as lead or drugs frequently used in treating tuberculosis. An increasing awareness is that preleukaemia or the myelodysplastic syndrome may result in a refractory anaemia with ringed siderob-lasts. 

Pathophysiologically, there is a macrocytic anaemia with megaloblastic haematopoiesis that occurs in the face of normal folate and vitamin B12 and is refractory to therapeutic trials of these two nutrients. Patients are characterized as having a preleukaemic syndrome, which is currently regarded by many as a neoplastic process arising in the haematopoietic stem cells that is analogous to early acute myeloblas-tic leukaemia. 

Treatment of chronic iron overload, e.g. haemochro-matosis, patients who are transfusion-dependent due to chronic haemolytic anaemias, thalassaemia and refractory anaemias with transfusional iron overload (siderosis). The goal of therapy is the reduction and maintenance of body iron stores at normal or near-normal levels to avoid the tissue damage associated with iron overload. 

Patients with transfusion siderosis require a long-term programme of chelation therapy. In patients who are transfusion-dependent from infancy (thalassaemia major, congenital refractory anaemia) chelation therapy is commenced after 10-20 transfusions at about 3 years of age. In older patients with acquired transfusion-dependent anaemias chelation is commenced after 20 transfusions or when the serum ferritin is 2-3 times the upper limit of normal. 

Walsh CE, Liu JM, Anderson SM, et al. A trial of recombinant human interleukin-I in patients with severe refractory aplastic anaemia. Br J Haematol 1992 80 106-110. 

Ahrens N, Kingreen D, Seltsam A, Salama A. Treatment of refractory autoimmune haemolytic anaemia with anti-CD (rituximab). Br J Haematol 2001 114 244-245. 

Red cell Fe utilization labelled red cells disappearance (----) measured simultaneously by LSC in a patient with refractory anaemia. Net activity + 1 S.D. 

Bargetzi MJ, Gluckman E, Tichelli A et al. (1995). Recombinant human interleukin-3 in refractory severe aplastic anaemia a phase I/II trial. British Journal of Haematology, 91 306-12. 

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