Characteristics of enrolled subjects
A total of 39 patients with PD and 26 age- and gender-matched HCs were recruited. The demographic and clinical characteristics of the subjects are described in Table 1. There were no significant differences in age, gender, or body mass index (BMI) between the PD and HC groups. Compared to the patients in the early PD group, patients in the middle-advanced PD group had a significantly increased disease duration, H-Y stage, UPDRS-III score, and NMSS score (P<0.05).
Table 1 Demographic and clinical characteristics of enrolled PD patients and HCs.
|
HCs
|
PD patients
|
Early PD patients
|
Middle-advancedPD patients
|
Number
|
26
|
39
|
28
|
11
|
Age (years)
|
60.77±6.77
|
61.49±5.79
|
61.71±5.98
|
60.91±5.47
|
Gender (male/female)
|
13/13
|
20/19
|
16/12
|
4/7
|
BMI (kg/m2)
|
24.09±2.34
|
23.92±2.96
|
23.84±2.59
|
24.10±3.88
|
Disease duration (years)
|
-
|
3 (1-8)
|
3 (1-6)
|
8 (3-10)*
|
Hoehn-Yahr stage
|
-
|
1.5 (1-3)
|
1.25 (1-1.5)
|
3 (3-3)*
|
UPDRS-III score
|
-
|
19 (14-28)
|
16 (12-20)
|
35 (26-47)*
|
NMSS score
|
-
|
48.18±25.44
|
42.79±20.43
|
61.91±32.29 *
|
Data are shown as mean±standard deviation or median (interquartile range). BMI, body mass index. *P<0.05 between the early PD and middle-advanced PD groups.
Altered frequencies of cTfh, cTfr and B cells in PD patients
According to the expression patterns of PD-1 and CD25/CD127, CD4+CXCR5+ cells in the peripheral blood were classified as cTfh (CD4+CXCR5+PD-1+) cells and cTfr (CD4+CXCR5+CD25hiCD127low) cells. Compared to that in HCs, the percentage of CD4+ T cells among lymphocytes was slightly lower in PD patients, but this difference was without statistical difference (32.60% (27.60%–41.95%) vs 35.65% (26.50%–48.4%), P>0.05, Fig. 2A). The percentage of cTfh cells among CD4+ T cells was significantly higher in PD patients than in HCs (3.68% (2.64%–5.70%) vs 1.94% (1.32%–2.99%), P<0.0001, Fig. 2B). However, there was no significant difference between the early PD group and middle-advanced PD group (P>0.05, Fig. 2E). The percentage of cTfr cells among CD4+ T cells appeared to be lower in PD patients than in HCs, but the difference was without significant difference (1.05% (0.62%–1.54%) vs 1.3% (0.63%–1.90%), P>0.05, Fig. 2C).
In our study, we also found that the percentage of CD19+ B cells among PBMCs was significantly lower in PD patients than in HCs (5.35% (4.13%–9.38%) vs 8.68% (5.61%–12.93%), P=0.014, Fig. 2D). However, similar to cTfh cells, no significant difference was found between the early PD group and middle-advanced PD group (P>0.05, Fig. 2F).
Correlations of cTfh percentage, cTfr percentage, and cTfh/cTfr ratio with clinical symptoms
No significant correlations were found between the percentages of cTfh cells or cTfr cells in PD patients with patients' age, disease duration, disease severity (UPDRS-III score), or nonmotor symptoms (NMSS) (P>0.05, Fig. 3 A-D). However, the cTfh/cTfr ratio in PD patients was significantly higher than that in HCs (P<0.0001, Fig. 3E). Although the correlation of the cTfh/cTfr ratio and NMSS in PD patients showed no statistical significance (P=0.058, Fig. 3F), a significant negative correlation was observed after adjustment to remove an abnormal value (P=0.016).
Serum concentrations of IL-4, IL-10, IL-21, and TGF-β in PD patients
CBA measurements showed that the serum concentrations of IL-4, IL-10, IL-21, and TGF-β did not differ significantly between PD patients and HCs (P>0.05, Fig. 4A-D).
Correlations of serum IL-4, IL-10, IL-21, and TGF-β concentrations with clinical symptoms
We also performed correlation analyses to identify significant associations between serum IL-4, IL-10, IL-21, and TGF-β concentrations and clinical symptoms. The results showed no significant correlations between serum IL-4, IL-10, and TGF-β concentrations in PD patients and patients' age, disease duration, disease severity (UPDRS-III score), and nonmotor symptoms (NMSS) (P>0.05). However, significant positive correlations were found between the serum IL-21 concentration and H-Y stage (r=0.356, P=0.026, Fig. 4E) as well as UPDRS-III score (r=0.347, P=0.030, Fig. 4F).