Hyperviscosity in HIV infected children--a potential hazard during intravenous immunoglobulin therapy.

A four year old boy with symptoms of HIV infection and serum IgG of 53.2 g/l had been treated for 16 months with regular infusions of intravenous immunoglobulin (IV IgG). During one such infusion he developed temporary neurological symptoms and signs suggestive of the hyperviscosity syndrome. Serum relative viscosity was raised at 5.0 (normal range 0.42-2.78). Subsequent IV IgG infusions given at a slower rate have been without adverse reactions. In a study of eight HIV infected children including the index case, and 20 children not infected with HIV, serum relative viscosity was significantly raised in the HIV infected children (p less than 0.01; students t-test). Viscosity correlated with total serum IgG, which was raised in all HIV infected children, and with serum IgM. In HIV infected children with very high levels of serum IgG a slow rate of IV IgG infusion should therefore be chosen due to the possibility of hyperviscosity.