Circulating Treg subpopulation
We first analyzed the frequencies of total Tregs
and activated Tregs in peripheral
blood using FOXP3 intracellular staining in patients with AIN
(Figure 1a ). The frequencies of both total Tregs and activated
Tregs in patients with AIN were significantly lower than those observed
in age-matched control subjects, as shown in Figure 1b (4.49 ±
0.99% vs. 5.87 ± 1.44% and 0.78 ± 0.17% vs. 1.00 ± 0.33%; p =
0.0123 and p = 0.0123, respectively). This result was partly
consistent with those reported in our previous study (9). The low
frequency of total Tregs may be caused by the decrease in activated
Tregs that play an important role in suppressive function to avoid
autoantibody production in autoimmune disease (including AIN).
For the analysis of the TCR repertoire, Tregs were defined as
CD4+CD25+CD127lowT cells substituted for FOXP3 intracellular staining using a flow
cytometer (Figure 1c ). When the frequency of
CD4+CD25+CD127lowTregs was compared between patients with AIN and control subjects, Tregs
in the former group showed a lower frequency than that noted in control
subjects (6.32 ± 1.59% vs. 7.69 ± 1.36%, respectively; p =
0.0113) (Figure 1d ). There was no difference in the frequency
of CD4+CD25− conventional T cells
between patients with AIN and control subjects.