0807 Intravenous immunoglobulin (IVIG) for immune haemolysis and hyperbilirubinaemia

In Rh immune haemolysis in the newborn, maternal sensitization results (usually) in anti-D antibodies crossing the placenta into the foetal circulation and attaching to Rh antigen on foetal red cells which then form rosettes on macrophages in the reticuloendothelial system, especially in the spleen. These antibody-coated RBCs are lysed by lysosomal enzymes released by macrophages and natural killer lymphocytes, a process that is independent of the activation of the complement system. IVIG is an immuno-modulating agent that has multiple activities. These include modulation of complement activation; suppression of idiotypic antibodies; saturation of Fc receptors on macrophages; and suppression of various inflammatory mediators, including cytokines, chemokines, and metalloproteinases. The Fc region of IgG facilitates interaction with and signalling through Fc receptors on phagocytes, B cells, and other cells and with Fc-binding plasma proteins (eg, components of the complement system). Given the underlying mechanism/s of haemolysis in Rh disease and the range of actions of IVIG it is not clear exactly where and how IVIG would act to reduce the severity of hyperbilirubinaemia in this situation, but results of several studies show that it does. Recent studies have not been from the US or UK but from Saudi Arabia, Turkey and Germany, perhaps indicating that Rh disease is being kept under control , alternatively the US and UK have not fully endorsed IVIG for this purpose. With the exception of one recent (but small) study that indicated that IVIG was not effective for ABO-disease and was associated with late onset anaemia, results have been positive of both Rh and ABO disease. IVIG is given when the rate of rise of bilirubin is >0,5mg per hour or when exchange levels have been reached. Treatment has usually been with multiple doses (0.5g/Kg to 1.0g/Kg) together with phototherapy, with a control group only getting the latter. Results have fairly consistently shown fewer exchange transfusions, lower bilirubin peaks and shorter hospital stay.

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Saudi Med J 2006; 27: 1827-30
J Mat Fetal Neonatal Med 2004; 16: 163-6
J Trop Pediatr 2001; 47: 50-3