PTPRC and Alzheimer disease: Extracellular IVIg was also detected in CD45+ splenocytes using flow cytometry analyses, with a mean fluorescence index (MFI) of 28.2 ± 1.2 for 12-month-old treated 3xTg-AD mice compared to 7.5 ± 0.3 for untreated controls (Figure 1C).