Immunity in the Progeroid Model of Cockayne Syndrome: Biomarkers of Pathological Aging

Abstract

Cockayne syndrome (CS) is a rare autosomal recessive disorder that affects the DNA repair process. It is a progeroid syndrome predisposing patients to accelerated aging and to increased susceptibility to respiratory infections. Here, we studied the immune status of CS patients to determine potential biomarkers associated with pathological aging. CS patients, as well as elderly and young, healthy donors, were enrolled in this study. Complete blood counts for patients and donors were assessed, immune cell subsets were analyzed using flow cytometry, and candidate cytokines were analyzed via multi-analyte ELISArray kits. In CS patients, we noticed a high percentage of lymphocytes, an increased rate of intermediate and non-classical monocytes, and a high level of pro-inflammatory cytokine IL-8. In addition, we identified an increased rate of particular subtypes of T Lymphocyte CD8+ CD28- CD27-, which are senescent T cells. Thus, an inflammatory state was found in CS patients that is similar to that observed in the elderly donors and is associated with an immunosenescence status in both groups. This could explain the CS patients' increased susceptibility to infections, which is partly due to an aging-associated inflammation process.

Keywords: Cockayne syndrome; immunosenescence; inflammaging; progeroid syndrome.

Figure 1

Box plots of CBC values in 14 CS patients aged (7–12 years) and in different groups of healthy donors (N = 40 [1–6 years]; N = 36 [7–12 years]; N = 24 [13–17 years]; N = 49 [18–25 years]; N = 73 [26–40 years]; N = 66 [41–60 years]; N = 57 [61–75 years]; and N = 52 [76–95 years]). The results are presented as individual values with mean ± SD. The difference in mean values between the different groups was determined using the Tukey test. N = number of subjects. Asterisks indicate statistical significance: * (p ≤ 0.05); ** (p ≤ 0.01); *** (p ≤ 0.001); **** (p ≤ 0.0001).

Figure 2

Cytokine levels in CS patients (N = 6 cases, 5 to 8 years) and in healthy donors (N = 3 [7–12 years]; N = 3 [71–85 years]). Sera were collected and analyzed by a Multi-Analyte ELISArray kit for 12 cytokines. Only cytokines/chemokines above the absorbance value of the negative control were considered. Results are shown based on duplicates for each sample. The difference in mean values between the different groups was determined using the Kruskall–Wallis test. N = number of subjects. Asterisks indicate statistical significance: * (p ≤ 0.05).

Figure 3

Lymphocyte subset percentages in CS patients (N = 4 [5–8 years]) and healthy donors (N = 4 [18–29 years]; N = 7 [30–45 years]; N = 12 [46–65 years]). (a) CD4+ CD3+ LT; (b) CD4+ CD28+ CD27+ LT; (c) CD4+ CD28− CD27− LT; (d) CD8+ CD3+ LT; (e) CD8+ CD28+ CD27+ LT; (f) CD8+ CD28− CD27− LT. Percentages of the different TCD4 and TCD8 subsets were analyzed by flow cytometry. Statistical analysis was performed using the Kruskal–Wallis test. Lines represent the medians, and each dot represents a donor. N = number of subjects. Asterisks indicate statistical significance * p < 0.05, ** p < 0.01. A dashed horizontal line at 0% serves as the cutoff value, indicating the threshold for defining the groups used for subsequent statistical analysis.

Figure 4

LB and NK cell phenotyping: Percentages in CS patients (N = 4 [5–8 years]) and in three groups of healthy donors (N = 4 [18–29 years]; N = 7 [30–45 years]; N = 12 [46–65 years]). (a) CD19+ CD20+ LB; (b,c) NK subsets, assessed by flow cytometry. Statistical analysis wasthe performed using the Kruskal–Wallis test. Lines represent the medians, and each dot represents a donor. N = number of subjects.

Figure 5

Monocyte subsets phenotyping. Percentages of monocyte subsets in CS patients (N = 4 [5−8 years]) and in three healthy donor groups (N = 4 [18−29 years]; N= 7 [30−45 years]; N = 12 [46−65 years]). (a) Classical monocytes; (b) intermediate monocytes; (c) non-classical monocytes. Percentages of studied cells analyzed by flow cytometry. Statistical analysis was performed using the Kruskal–Wallis test. N = number of subjects. Asterisks indicate statistical significance: ** (p ≤ 0.01); *** (p ≤ 0.001); **** (p ≤ 0.0001).