Figure 6.

Low numbers of a subset of CD8+ cells (CD8^lo) predict response to adipose-derived mesenchymal stem cell (ASC) therapy and normalize after treatment. CD8+ T cells can be divided into CD8^hi and CD8^lo populations. (A–C): Representative flow cytometry gating scheme for CD8+ and CD8^lo populations for (A) control non-FCGS cat, (B) responder feline chronic gingivostomatitis (FCGS)-affected cat, and (C) nonresponder FCGS-affected cat, including the percent of total lymphocytes that were CD8+, and the percent of CD8+ cells that were CD8^lo. (D): Summary of CD8^lo percentages of CD8+ cells based on flow cytometry gates described in (A–C) for all cats in the study. Responder cats had a lower percentage of CD8^lo cells before ASC treatment than at 6 months after (multiple comparisons 2-way analysis of variance, p < .05). (E): Comparison of the percent of CD8+ cells that were CD8^lo in responder and nonresponder groups before ASC treatment for use as a biomarker to predict response to treatment. Responders had a lower percentage of CD8+ cells that were CD8^lo than nonresponders (unpaired t test, p = .04).