Please explain How ATG works

[pvinod]

hi all, my 4 years daughter suffering from Aplastic Anemia since April 2010. We have taken the ATG on December 2010. my confusion is how ATG treat AA. On day 1 when ATG start her lymphocytes goes around just 11% and nutrophils increase 44%. but as day pass lymphocytes grow back now around 95%. Cyclosporine is continuing right now.

so how ATG works. My confusion is before ATG lymphocytes are 95% and after ATG it also 95%. so what is the role of ATG?

[Karenish]

In very layman terms, I think the ATG enters the system and the rogue T cell/s bands his/her army to attack this and leave your bone marrow alone, then the cyclosporine jumps in and suppresses your immune system thus rendering the rouge Tcell/s without the troops i.e. army is squished. (this is why we become vulnerable to bugs). ATG then leaves the system by the usual method, (toileting etc) and the cyclosporine keeps the big army suppressed while your bone marrow (stem cells) recovers and starts producing your own blood stuff.
Hopefully then you slowly reduce the cyclosporine and either go into full remission on partial. Not sure what stops the rogue T cells from returning...maybe someone a bit more knowlegeable can help with that one?

[Hopeful]

Hi pvinod,

I think that you should bring up your daughter's high lymphocyte count with her doctor. There may be something else going on that is not associated with Aplastic Anemia or ATG. It may be the sign of another infection or illness.

To give you a feel for lymphocyte percentages...
My lab has a normal percentage (for adults) as 26-46%.
Pre-ATG, my lymphocyte % was high (up to 67%).
During ATG, it dropped to 7%.
A week later, it was back in the normal range and has stayed there except when I am sick. This is despite being on Cyclosporine.

Be persistant with the doctors to see what else may be going on! Her situation sounds unusual.

[Greg H]

pvinod,

Hopeful has experience with this, so I second her recommendation that you be persistent with her doctors.

I did find this on the AA&MDS website:

ATG and Lymphocytes
Why would an aplastic anemia (or MDS) patient receiving ATG have high lymphocyte count if ATG is supposed to suppress lymphocytes?

Until the patient responds, which may take 2-6 months it is very common that the only surviving white blood cells are lymphocytes. The lymphocyte count usually drops somewhat after ATG therapy, but it is not long before it comes back up. It is important to remember that there are many different types of lymphocytes such as T-cells, B-cells, and natural killer cells. In patients who respond to ATG, the lymphocyte count also rises but the sub-set of "bad" T-lymphocytes that cause the aplastic anemia does not. You can't tell by doing a CBC the type of lymphocytes that are coming back (i.e. good B-cells and good T-cells that protect from infection vs. the "bad" T-cells). This is a very difficult thing to test for even in academic laboratories. Most patients, including the approximately 75% who respond to ATG, have this same pattern of lymphocytes after ATG therapy is given. ATG is not intended to kill all lymphocytes, just the overactive ones that cause marrow aplasia.

That text was taken from this page (http://www.aamds.org/aplastic/disease_information/qa_library/immunosuppressive_th/): (http://www.aamds.org/aplastic/disease_information/qa_library/immunosuppressive_th/)

So it seems it is not unusual for the lymphocyte count to be high, but the 95% you cite does sound very high indeed.

Good luck to you and your daughter.

Greg