Differential central nervous system responses following single and multiple recombinant interleukin-2 infusions.

The effects of systemic recombinant human interleukin-2 (rIL-2) infusion on cerebrovascular permeability to an endogenous circulating macromolecule, immunoglobulin G (IgG), were assessed in rats after single and multiple rIL-2 infusions. Ultrastructural detail of the cerebral vasculature and the related brain parenchyma was also examined for rIL-2-related changes following single and multiple infusions. Animals examined 6 and 24 h after a single rIL-2 infusion exhibited moderately increased permeability to IgG that was not observed in those animals examined 6 h after 5 days of rIL-2 infusion. Alterations of cerebrovascular morphology were evident as early as 6 h after a single infusion and were accompanied by occasional axonal degeneration and demyelination. Such structural changes persisted, becoming more widespread after 5 days of rIL-2 infusion, at which time they were associated with other neuronal as well as glial alterations.