Blood levels of pro-inflammatory factors and collagen type II in patients with MPS and normal control. (a) EGF, (c) IL-1β, (e) IL-6, (g) TNF-α, (i) MIP-1α, (k) MMP-1, (m) MMP-2, (o) MMP-9 and (q) Collagen type II levels in patients with MPS II. (b) EGF, (d) IL-1β, (f) IL-6, (h) TNF-α, (j) MIP-1α, (l) MMP-1, (n) MMP-2, (p) MMP-9 and (r) Collagen type II levels in patients with MPS IV. *p < .05 vs normal control group. #p < .05 vs MPS IVA untreated patients.