CONTENTS:


What is the Role of T Cells in ITP

blood cells illustration1

Specialized cells, known as CD8 T-cells, that are isolated from active ITP patients can destroy platelets under specific in vitro circumstances.  Researchers have found that T-cells also can directly damage and destroy megakaryocytes, the precursor of platelets, in the bone marrow. In some ITP patients, there can be a large expansion and activation of a subset of T-cells called CD8 T-cells. These cells were also shown to release chemicals that immune cells use to destroy other cells.1 ITP patients not only had more activated T-cell clones than healthy controls, but these T-cells were more activated in patients with refractory disease and activity decreased when platelet counts rose in response to treatment.

One important question that arose was whether the activity of CD8 T-cells in ITP patients is directed specifically to platelets. T-cells that were isolated from ITP patients were able to attach well onto the platelet layer, which indicated that T-cells in ITP can directly interact with platelets. Dr. Cooper concluded her talk with the remark that currently no ITP therapy focuses on targeting CD8 T-cells. However, if T-cells were to become a therapeutic target, it is important to first investigate whether T-cell-mediated disease is predominant only in patients with refractory disease, or if T-cells are involved from the beginning.


References:

  1. CD8 T cells https://ash.confex.com/ash/2022/webprogram/Paper166348.html


Comments from PDSA Medical Advisors:

These are exciting findings as they point to a better understanding of how ITP develops or persists and suggest a potential new therapeutic target that may be especially pertinent in refractory patients. While exciting and with clinical implications, the findings must be considered preliminary, as the observations were made under special circumstance that might be the same but might differ from what happens in the clinical setting.

 


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