OBJECTIVETo study the significance of cytokine IL-1α and S100β expression in formation and evolution of different types of plaques in Alzheimer's disease.

METHODSThirty-four autopsy cases of Alzheimer's disease encountered during the period from 1982 to 2008 were retrieved from the archival files of Department of Pathology, Beijing Hospital. Tissue blocks were taken from hippocampus for dual immunostaining for IL-1α/Aβ and S100β/Aβ.

RESULTSImmunohistochemical studied for IL-1α/Aβ and S100β/Aβ delineated four different types of senile plaques: diffuse non-neuritic plaques, diffuse neuritic plaques, dense-core neuritic plaques and dense-core non-neuritic plaques. The numbers of IL-1α-positive microglias and S100β-positive astrocytes associated with diffuse neuritic plaques were (7.29 ± 3.04) per mm(2) and (6.49 ± 2.20) per mm(2), respectively. In contrast, the numbers of IL-1α-positive microglias and S100β-positive astrocytes associated with diffuse non-neuritic plaques, dense-core neuritic plaques and dense-core non-neuritic plaques were (3.24 ± 1.53) per mm(2) and (4.14 ± 1.77) per mm(2), (2.09 ± 1.37) per mm(2) and (2.25 ± 0.83) per mm(2), and (1.38 ± 0.90) per mm(2) and (0.58 ± 0.36) per mm(2), respectively. The numbers of IL-1α-positive microglias and S100β-positive astrocytes associated with diffuse neuritic plaques were significantly higher than those of the other three types of plaques (P < 0.05).

CONCLUSIONThe IL-1α-positive microglias and S100β-positive astrocytes may be of certain significance in transformation of diffuse non-neuritic plaques to diffuse neuritic plaques in Alzheimer's disease.