CD8

Dr. Candotti said it appears from all of David's tests (I think we have exhausted all the available testing methods for WAS) that there is only one piece of information that would "make" or "break" his diagnoses of David having X-linked Thrombocytopenia or WAS. Yes, there is a difference between XLT and WAS.

The one piece of David's immune system that is not normal is his CD8 cells (Killer T-cells). There is a reduced (not absent) response to ConA. The Dr. said they could normalize between now and when David is two years old. Around 2 years of age, children's immune systems begin to normalize. If they do not normalize, this could be a hint that David has an immune deficiency. Otherwise, he has normal overall immunity.

The CD8 cells are also called killer T-cells. They stem out from the Thymus. They handle such intracellular pathogens as viruses and parasites such as tuberculosis. They also secrete molecules known as lymphokines, which are chemical messengers that direct the activity of B-cells, other T-cells and other parts of the immune system. The message the lymphokines carry, is in the chemical interleukins, which activate certain immune cells. Since the T-cells have an important role in secreting lymphokines, and David has a T-cell defiency (at this given time), he would not have the lymphocytes to circulate through the body's vascular and lymphatic systems patrolling for foreign antigens, thus he may eventually succumb to lymphoma or leukemia. Those CD8 cells are very important!

David will have a blood draw (it's been months since the last one was done) next week at Stanford. He will then see the Immunologist, Dr. David Lewis and the Hematologist, Dr. Bertil Glader to review the results. The blood draws are going to test: CMV status (for the bone marrow transplant), CBC, immunoglobulins, and lymphocyte mitogen proliferation.