This document provides methods and materials involved in assessing immune system profiles. For example, methods and materials for performing flow cytometry to determine the number of CD4+ lymphocytes, CD8+ lymphocytes, regulatory T cells, B cells, NK cells, granulocytes, CD14+HLA-DRlo/neg monocytes, and/or CD86+ monocytes per unit volume (e.g., cells per μL or mL) of whole blood (e.g., fresh, un-manipulated whole blood) obtained from a mammal (e.g., a human) are provided.
