Question about reticulin (sp?)

I was thinking about yesterdays appointment and something the consultant said.

He explained that after 12 months on the drug, you would need a bone marrow test to ensure that the level of scarring/reticulin wasn't too high. While he was explaining this, he said tnat non-TIP people start off with a level of 0-1, whilst people with ITP normally start off with a level of 1-2. Why is this? What is ITP doing that is producing scarring in the bone marrow? I thought it was mostly an antibody issue, so why would it affect bone marrow like that? He seemed to imply that the increased reticulin was present in ITP patients that had never received any treatment as well as those that had.

Sorry, been thinking too hard!

Thanks, Ali

Bad typing - sorry, I meant non-ITP people not non-TIP people!

I had read that that was a theory but that it hadn't held up on examination. And this report says..

"In a study of bone marrow biopsy specimens from healthy subjects analyzed using the modified Bauermeister scheme, which grades the degree of reticulin/collagen on a scale from 0 to 4, 19% were found to be grade 0 (no reticulin fibers), 76% were grade 1 (occasional fine fibers), 5% were grade 2 (fine fibers throughout section), and none was grade 3 (diffuse fiber network, scattered coarse fibers) or grade 4 (same as grade 3 but with areas of collagenization [positive trichrome stain]). In a retrospective analysis of bone marrow biopsies from 40 patients with ITP (no prior treatment with TPO mimetics), the distribution of reticulin grades was similar to healthy subjects: 38% were grade 0, 50% were grade 1, 13% were grade 2, and none was grades 3 or 4.

bloodjournal.hematologylibrary.org/content/114/18/3748.full

Maybe your doctor is ultra cautious but with romiplostim they check the blood film every time they take blood in order to check for odd shaped cells. They can tell from that if the marrow needs looking at. They don't do biopsies routinely.

It might be interesting to ask about it as a question to be answered at the conference to see what the latest thinking is. I believe you can email questions to Shirley at the Association now.

Edited post to add that the theory was that it was the high number of megakaryocytes that caused the reticulin formation. I think the theory has fallen somewhat because they now know that ITP doesn't really cause a greater number of megakaryocytes to be made.

Have been reading the online info on Nplate and it says..

"Increased bone marrow reticulin is believed to be a result of TPO receptor stimulation, leading to an increased number of megakaryocytes in the bone marrow, which may subsequently release cytokines. Increased reticulin may be suggested by morphological changes in the peripheral blood cells and can be detected through bone marrow biopsy. Therefore, examinations for cellular morphological abnormalities using peripheral blood smear and complete blood count (CBC) prior to and during treatment with romiplostim are recommended."

www.medicines.org.uk/EMC/medicine/23117/SPC/Nplate+with+Reconstitution+Pack/