Tue Sep 3, 2013, 09:53 PM
There was a recent trial at the NIH using Rituximab for various diseases including 3 people with moderate AA (neutrophils < 1.2.10^9 / Liter). 2 out of 3 had partial response. Paper not published yet. Main side effect was cytokine release syndrome (symptoms of fever without elevated temperature, as far as I can gather) in 73% of patients. I have seen a couple of case studies where Rituximab has caused PNH to go into remission. A paper by Dr Hillmen at Leeds says PNH remission is almost always associated with immuno-suppression. Rituximab is an unusual immuno-suppression regime in that it targets intermediate B-cells (it is an anti-CD20 monoclonal antibody). Since marrow cells are inhibited by T-cell attack the suggestion is that the B-cells present antigens to the T-cells and keep the process going. Without intermediate B-cells the T-cell auto-immune attack stops and the marrow gets to work as it should. Since in the marrow PNH cells are more resistant to T-cell mediated apoptosis (cell death) than normal cells once the T-cell attack goes away the PNH cells lose their selective advantage. After Rituximab treatment intermediate B-cells take about 40 weeks to come back, and sometimes they have lost the memory of the bone marrow injury. Anyway, Karin is hoping to try Rituximab some day and is registering with the NIH. Note - am not sure they have such a trial (AA/PNH) but best to get registered in case. Has anyone had any luck with Rituximab??