Figure 7: MS-associated IL2RA risk alleles augment GM-CSF-producing T_H cells.

(a) Ex vivo surface expression of IL-2Rα on naive T_H cells from healthy individuals with a protective (G/G or A/G) or risk IL2RA genotype (A/A) at rs2104286, determined by flow cytometry (protective n=14, rs2104286 n=25). Data are combined from >3 independent experiments. (b) Sorted naive T_H cells were activated in vitro (αCD3) in the presence of 10 ng ml⁻¹ IL-2 and then analysed for GM-CSF expression by flow cytometry on day 5 (protective n=10, rs2104286 n=16). Data are combined from >3 independent experiments. (c) Naive T_H cells were sorted according to IL-2Rα expression and then activated (αCD3) for 5 days in the presence of 10 ng ml⁻¹ IL-2 (n=10). Data are combined from two independent experiments. (d) PBMCs from healthy individuals were analysed ex vivo (without previous in vitro culture) for the frequency of GM-CSF⁺, IFN-γ⁺ and IL-17A⁺ memory T_H cells (protective n=31, rs2104286 n=46). (e) Individuals with rs2104286 protective alleles were further analysed for ex vivo GM-CSF expression with regard to rs12722489 (protective n=28, rs12722489 n=14). (f) Ex vivo frequency of GM-CSF⁺ T_H cells with regard to HLA-DRB1*15:01 alleles (HLA-DRB1*15:01⁻ n=58, HLA-DRB1*15:01⁺ n=15). Data are combined from >3 independent experiments. (g,h) Purified T_H cells were cultured in the presence of 0–10 ng ml⁻¹ IL-2 (no αCD3) for 4 days. Shown are the frequency of GM-CSF⁺ and IFN-γ⁺ T_H cells at 10 ng ml⁻¹ IL-2 (protective n=28, rs2104286 n=40, g) and the frequency of GM-CSF⁺ T_H cells at IL-2 concentrations from 0 to 10 ng ml⁻¹ (protective n=30, rs2104286 n=34, h). (i) Gene-dosage effect of rs2104286 on the frequency of GM-CSF⁺ T_H cells, cultured as in g and h, assuming a linear gene–phenotype relation (G/G n=5, A/G n=33, A/A n=45). Data are combined from >3 independent experiments. Each symbol represents a single individual. (a–g) lines represent the median, (h,i) error bars show mean±s.e.m.