Georas, Steve N.

Abstract Macrophage inflammatory protein (MIP-1α), a member of the CC chemokine subfamily, has been shown to attract T cells and monocytes in vitro and to be expressed at sites of inflammation. Although the in vitro activities of MIP-1α have been well documented, the in vivo biological activities of MIP-1α in humans have not been studied. To address this, we challenged human subjects by intradermal injection with up to 1000 pmol of MIP-1α and performed biopsies 2, 10, and 24 h later. Although no acute cutaneous or systemic reactions were noted, endothelial cell activation, as indicated by the expression of E-selectin, was observed. In agreement with its in vitro activity, monocyte, lymphocyte, and, to a lesser degree, eosinophil infiltration was observed, peaking at 10–24 h. Surprisingly, in contrast to its reported lack of in vitro neutrophil-stimulating activity, a rapid infiltration of neutrophils was observed in vivo. This neutrophil infiltration occurred as early as 2 h, preceding the appearance of other cells, and peaked at 10 h. Interestingly, we found that neutrophils in whole blood, but not after isolation, expressed CCR1 on their cell surface. This CCR1 was thought to be functional as assessed by neutrophil CD11b up-regulation following whole-blood MIP-1α stimulation. These studies substantiate the biological effects of MIP-1α on monocytes and lymphocytes and uncover the previously unrecognized activity of MIP-1α to induce neutrophil infiltration and endothelial cell activation, underscoring the need to evaluate chemokines in vivo in humans.

Abstract Interleukin-2 (IL-2), a product of activated T-cells, is now being used in a number of protocols for cancer immunotherapy. In one stem cell transplantation protocol for breast cancer, IL-2 is used together with interferon- γ (IFN- γ ) and cyclosporine to stimulate a graft-versus-tumor response and improve the likelihood of a prolonged remission. We present the case of a patient who developed peripheral eosinophilia, perihilar infiltrates, and hypoxemia after autologous stem cell transplantation and the use of recombinant IL-2 and IFN- γ. Histologic analysis of transbronchial lung biopsies demonstrated a few eosinophils within the bronchial submucosa. Immunostaining using antibodies directed against eosinophil major basic protein (MBP), however, revealed massive extracellular deposition of this toxic granule protein throughout the lung parenchyma. IL-2 therapy is well known to induce a peripheral eosinophilia and to be associated with the capillary leak syndrome characterized by weight gain, edema, and oliguria. The findings noted in this case report suggest that the eosinophil activation that accompanies immunologic therapy with IL-2 can result in direct toxicity to the lung and a localized vascular leak syndrome. This syndrome should be considered in the differential diagnosis of pulmonary infiltrates that occur acutely after bone marrow transplantation with cytokine augmentation.