Rapid stereology based quantitative immunohistochemistry of dendritic cells in lymph nodes: A methodological study

This study was done to arrive at a fast and reliable protocol for assessmen t of fractional volumes of immunohistochemically stained dendritic cells in lymph nodes. Twenty axillary lymph nodes of patients with locally advanced breast cancer were immuno-histochemically stained with an S100 antibody. F ractional volumes of dendritic cells were assessed by stereology based quan titative immunohistochemistry using an interactive video overlay system inc luding an automated microscope. The gold standard percentage of dendritic c ells was the fractional volume of S100 stained cells in 500 fields systemat ically spread over the whole lymph node. Then, in a computer simulation, di fferent sample sizes (1-200 fields of vision) were tested and the coefficie nt of variation (CV) for each sample size was calculated. The CV dropped wi th increasing sample size. A sample size of 100 fields of vision appeared t o be optimal. Intra- and interobserver reproducibility appeared to be good (correlation coefficients of 0.95 and 0.86, respectively) when re-analyzing the cases with the established protocol. In conclusion, a fast and reliable assessment of the fractional volume of d endritic cells in lymph nodes is possible with semi-automated quantitative immuno-histochemistry. This method will form the base for further clinical studies into the immunological response in lymph nodes of patients with loc ally advanced breast cancer.