Omega-3 fatty acids and ankylosing spondylitis

We've all been told, I think, about the anti-inflammatory benefits of omega-3 fatty acids, but now there's a clinical study about their efficacy against ankylosing spondylitis (see also). It turns out that while relatively low doses of omega-3 accomplished little, disease activity was reduced among those taking high doses. (High and low doses mean 4.55 g and 1.95 g per day, respectively. The omega-3 doses came from marine sources; I wonder if it matters.)