Cytokine expression in advanced human atherosclerotic plaques: dominance of pro-inflammatory (Th1) and macrophage-stimulating cytokines.
The atherosclerotic lesion contains large numbers of macrophages and T lymphocytes. This suggests that a cellular immune response may take place in the lesion, and oxidized lipoproteins, heat shock proteins, and micro-organisms have been implied as candidate antigens. However, the effector mechanisms elicited by this response have been largely unclear. We have therefore analyzed endarterectomy specimens by immunohistochemistry and reverse transcription-PCR to detect immune cytokines produced by immunocompetent cells of the advanced human plaque. The pro-inflammatory T cell cytokines, interleukin-2 and interferon-7, were found in a large proportion of plaques (IL-2 in 50% and interferon-gamma in 30% of plaques by immunohistochemistry and mRNA for both cytokines in 70% of plaques by PCR). In contrast, interleukin-4 and interleukin-5 were rarely observed (both cytokines in 10% of plaques by immunohistochemistry, mRNA for interleukin-4 in 10% and for interleukin-5 in 40% by PCR). This demonstrates the presence of a predominantly pro-inflammatory, Th1-type T cell response in atherosclerosis. This conclusion was further supported by the expression of the pro-inflammatory cytokine, interleukin-1 by plaque macrophages and endothelial cells. In addition, the chemokine interleukin-8 and the macrophage differentiation-stimulating cytokine, granulocyte-monocyte colony stimulating factor, were observed in plaque tissues, suggesting that the micro-environment promotes monocyte recruitment and macrophage differentiation. Occasional eosinophils and B cells were, however observed, which is compatible with a microheterogeneity within the lesion. Finally, the anti-inflammatory and fibrogenic cytokines, transforming growth factor-beta1-3 and its carrier protein, latent TGF-beta binding protein, were found in large amounts in all plaques. Together, these results show that a pro-inflammatory, Thl type cellular immune response takes place in the atherosclerotic plaque. The balance between pro-inflammatory and anti-inflammatory cytokines may be decisive for the progression of the lesion.
Frostegård
J
J
Department of Medicine, Karolinska Hospital, Karolinska Institute, Stockholm, Sweden.
Ulfgren
A K
AK
Nyberg
P
P
Hedin
U
U
Swedenborg
J
J
Andersson
U
U
Hansson
G K
GK
D001161:Arteriosclerosis / Q000378:metabolism* / Q000473:pathology; D002352:Carrier Proteins / Q000032:analysis; D016207:Cytokines / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D018836:Inflammation Mediators / Q000032:analysis*; D007371:Interferon-gamma / Q000032:analysis; D007378:Interleukins / Q000032:analysis; D008264:Macrophages / Q000378:metabolism / Q000473:pathology / Q000502:physiology; D016133:Polymerase Chain Reaction; D018417:Th1 Cells / Q000378:metabolism / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D002352:Carrier Proteins; D016207:Cytokines; D018836:Inflammation Mediators; D007378:Interleukins; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma