Detection of nonspecific immunohistochemical response caused by tissue necrosis and the presence of metallic wear debris

Tissues retrieved during revision arthroplasty (n=25) were processed for routine immunohistochemical techniques to localize the presence of bone resorbing cytokines (IL-1 and IL-6), and to identify areas of significant necrosis and metallic deposition. Tissues were processed and embedded according to standard laboratory techniques. Several slides were prepared for each tissue sample taken. Several sequential slides were stained for Hematoxylin and Eosin to demonstrate cell type. Other slides of the same tissues were processed for localization of cytokines, IL-1 and IL-6. To identify specific cytokine reactions, the tissues were first blocked with proteins to ensure that all. The results revealed that there were several locations on the tissues that appeared highly reactive for cytokines IL-1 and IL-6. However, some of these areas turned out to be nonspecific when compared with negative controls and the Hematoxylin and Eosin stained slides. Areas of extreme necrosis or where metal debris was presence demonstrated sites of nonspecific reactivity. Areas of necrosis have a high nonspecific affinity for antibodies and these areas of necrosis can be demonstrated on the Hematoxylin and Eosin sections, and should be avoided in determining the amount of specific cellular reactivity. In addition, new immunohistochemical techniques use cobalt ions as enhancers of peroxidase response, in areas on slides labeled as negative controls where metallic debris was trapped, there was an increase in nonspecific positive reactivity. These factors must be carefully controlled in determining true cellular responses that causes resorption of bone and implant failure