Abstract
Purpose: :
Macrophages are a major component of cellular components in inflammatory disease. To study the proliferative activity of such macrophages at the site of action, the potential co-immunolocalization of Ki67 with 2 different macrophage markers was investigated in 6 different specimens with various inflammatory conditions.
Methods: :
6 specimens from 6 different patients (2 males, 4 females, age range 16 to 58 years) were examined. Diagnoses were mostly inflammatory in nature but due to varying stimuli, ranging from chalazion over xanthogranuloma to intravascular papillary endothelial hyperplasia. Using immunohistochemistry, reactivity against monoclonal macrophage antibodies CD68 and CD163 was investigated. At the same time, immunoreactivity with Ki67 was tested. All specimens were fixed in paraformaldehyde, and processed routinely for paraffin histology. Prior to immunohistochemistry, sections were stained with Hematoxilin & Eosin and PAS. For conventional immunohistochemistry, the immunoreaction product was visualized using AEC as chromogen. For double labeling, immunofluorescence was used.
Results: :
All lesions revealed numerous cells reacting with CD68 and CD163. Using regular immunohistochemistry, there seemed to be a slightly different distribution pattern with CD68 being more prominent near the center of the inflammatory process. Double labelling also seemed to somewhat distinguish between these two populations but with a great amount of overlap. Double labeling with Ki67 indicated an unequivocal - albeit only moderate - proliferative activity in both CD68- as well as CD163-positive macrophages distributed throughout the lesion. In endogenous granulomatous lesions, CD68-positive cells seemed to colocalize slightly more often with Ki67 compared to CD163-positive cells. Overall, no significant difference in macrophage proliferation was seen between the various disease conditions.
Conclusions: :
In inflammatory conditions, macrophages can proliferate at the site of their activity. However, the evaluation of more specimens is necessary to be able and possibly distinguish between various diseases and/or different macrophage populations.
Keywords: immunohistochemistry • inflammation • pathology: human