Neutropenia and complement activation after infusion of high dose intravenous immunoglobulin [Neutropenia e attivazione complementare ad opera di immunoglobuline endovena ad alte dosi]

Background. The objective of our study is to investigate on the possible links between complement activation induced by IVIG and transitory neutropenia observed after infusion of immunoglobulins. Materials and methods. We studied 12 infusions of IVIG in patients affected with CVID (Common Variable Immuno Deficiency). Patients were treated in the Department of Internal Medicine of the "S. Eugenio " Hospital of Rome, according to the Consensus Report of 2000. During each infusion samples of blood were drawn as follows: pre-infusion, 25%, 50%, 75% and post-infusion. In every sample we measured different parameters: C3, C4, CH50 and the number of neutrophils. Results. A statistically significant relation among the reduction of neutrophils, the consumption of complement proteins and the activity of the complement system (measured by means of CH50) was found. There is a dramatic reduction of neutrophils and of complement fractions even after only 25% of the dose of immunoglobulins infused (P < 0,0001). Thereafter values remain low and tend to increase after the infusion was completed.