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clone size
Hey SAA Mom. I have been reading a lot lately. Karin (mother of my kids) has had PNH for 23 years and has a clone size of 39% (granulocytes are missing either CD55 or CD59 or both i.e. are PNH granulocytes). In my reading I saw a set of slides with an "incidence of thrombosis versus time chart", and the cut off point was 50% (the two charts were very different with much larger incidence of thrombosis if clone size >= 50%). I have also read that PNH is thought to be a response to AA in some cases. AA involves an autoimmune response involving T-cells. T-cells are activated and attack the stem cells from the marrow (T-cells come from stem cells too). PNH stem cells are more resistant to T-cell attack so even though PNH causes other problems (red blood cells are attacked by the complement system and don't live so long) at least there are *some* cells from the AA marrow. Karin is now showing signs of AA (pancytopenia) and needing RBC and platelet transfusions. We have had some early (just 10 days taking it so far) success with Papaya Leaf extract which is a sort of herbal Anti-Thymocyte Globulin but less toxic. There may be a less toxic treatment for AA (Phase II trial NCT00229619) using Rituximab a monoclonal antibody (mab) that attacks B cells which may be stimulating the T cells involved in AA. A case study with a patient with AA/PNH found it virtually eliminated the PNH clone. So there is hope of less drastic treatments for your son's condition.
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