Figure 1. Interleukin-3 associates with human RRMS and exacerbates spinal cord inflammation, demyelination, and EAE.

(A) Left panel - IL-3 amount in the CSF of male and female unaffected control subjects and patients with RRMS. Right panel - Baseline CSF IL-3 amount in male and female non-converters and patients who converted to MS diagnosis over a 2 year follow up (n=29 controls, 36 RRMS patients, 28 non-converters, 22 converters; Mann–Whitney U-tests).

(B) Il3 gene expression in the spinal cord in WT EAE mice at disease peak and naive mice (n=4-5 mice/group; Mann–Whitney U-test).

(C) Schematic diagram of the experimental design. EAE was induced in WT and Il3^−/− mice by administering myelin oligodendrocyte glycoprotein (MOG_35-55) peptide emulsified in complete CFA by subcutaneous injection on day 0 and PTX by intraperitoneal injections on days 0 and 2. Mean clinical disease scores and corresponding AUC analysis of WT and Il3^−/− mice over the course of 21 dpi (n=10 mice/group; two-way ANOVA and Mann–Whitney U-test).

(D) Representative histological sections of 4 mice per group and quantification of demyelinated area in diseased spinal cords from WT and Il3^−/− mice stained for myelin by Luxol fast blue and counterstained with Cresyl Echt Violet Solution at disease peak. Scale bars represent 500 μm for overview images and 100 μm for the inset images (n=4 mice/group; two-way ANOVA and Mann–Whitney U-test).

(E) Quantification of CD45⁺ leukocyte numbers in the blood, spleen and bone marrow of WT and Il3^−/− mice at the disease peak (n=5 mice/group).

(F) Quantification of leukocyte subsets in the spinal cord of WT and Il3^−/− mice at the disease peak (n=5-7 mice/group; Mann–Whitney U-tests).

(G) qPCR analysis of chemokine transcript expression in the spinal cord of healthy and EAE WT and Il3^−/− mice (n=4-5 mice/group; one-way ANOVA).

Mean±s.e.m., *p<0.05, **p<0.01, ***p<0.001.

CSF, cerebrospinal fluid; RRMS, relapsing remitting multiple sclerosis; AU, arbitrary units; IL-3, interleukin-3; WT, wildtype; EAE, experimental autoimmune encephalomyelitis; CFA, Freund’s adjuvant; PTX, pertussis toxin; MOG, myelin oligodendrocyte glycoprotein; AUC, area under the curve; dpi, days post immunization.

See also Figures S1 and S2.