Idiopathic thrombocytopenia purpura ITP

One of the functions of the lymphocytes is to produce agents that stimulate other cells to divide or mature or function in some ways. When they are all taken out by immunologic therapy, their production of interleukins will obviously drop as well. Then, when the interleukins start being produced, one of the cells which will be targeted is the progenitor cells for red cells, granulocytes, monocytes, and platelets. Increases in each of those in the blood stream will occur depending on the time it takes them to mature and platelet mature more slowly than the others.
Second - if you have ITP, then all bets are off on normal recovery. ITP is caused by an antibody which you form against platelets. Any additional platelet that you get from a transfusion will be coated by the same antibody and removed from the system just as your own platelets are removed. Standard therapy for this is either prednisone to stop the production of the antibody or Splenectomy to remove the site which takes the coated but still functional platelets out of the blood stream.
 

Should a platelet count of less than 100 trigger treatment?

Bleeding is unlikely unless the platelets fall to less than 10. We frequently allow patients with chronic ITP to run at around 30 with no treatment. The reason that we are concerned with a low platelet count is because it may be an indication of marrow failure. But there are many reasons for a platelet count of less than 100 in CLL other than marrow failure. ITP is the one that everyone knows about, and if thios can be confidently diagnosed then treatment should be exactly the same as for ITP not associated with CLL, including no treatment if none is indicated. Hypersplenism is another common cause. As the spleen enlarges more and more platelets pool in the spleen. A platelet count that hoovers above and below 100 is often caused by hypersplenism. Artefact is another important cause. When blood is taken into certain anticoagulants (such as EDTA) the platelets may aggregate as the blood cools, and give a spuriously low reading. If there is a small clot in the sample that is unnoticed by the technician this will also give a spuriously low reading. Occasionally, because of mislabelling, entirely the wrong blood sample is analyzed.

Even patients who genuinely have a platelet count of less than 100 may not need treatment. Remember the mantra - we treat patients not blood counts. A wise physician considers the whole patient when deciding on treatment.