You mentioned that your husband has trisomy 8. This is thought to be a prognostic marker of immune mediated MDS that is responsive to IST. So keep this in mind, should his status change.
My doctors started to talk chelation after 15 units/bags of blood. They weren't ready to take action yet, but we started talking strategies. I think 20 units of blood is where doctors start to worry about iron overload.
Viruses can be nasty and are considered one of the triggers for bone marrow failure. I think this was the case for me!
Hope your husband stays stable and strong!
52 yo female, dx 9/08, AA/hypo-MDS, subclinical PNH, ATG/CsA 12/08, partial response. Tried slow cyclosporine taper over 4+ years. Platelets fell, so back on cyclosporine. Trisomy 6 clone in 5% of cells.