cmv neg vs irradiated PRBC

[mollyredone]

Hello all! I am being re-introduced to blood bank after being out of a hospital setting for 20 years! I'm loving gel cards!

My question is regarding irradiated vs leukoreduced vs CMV negative PRBCs. Somewhere in my wanderings on the net, I'm not sure if it was this forum or not, I thought I read that irradiated PRBCs were considered to be equal to CMV negarive PRBCs. Does anyone have any references stating this or refuting this?

TIA

Mari

[Malcolm Needs ☆]

Hello all! I am being re-introduced to blood bank after being out of a hospital setting for 20 years! I'm loving gel cards!

My question is regarding irradiated vs leukoreduced vs CMV negative PRBCs. Somewhere in my wanderings on the net, I'm not sure if it was this forum or not, I thought I read that irradiated PRBCs were considered to be equal to CMV negarive PRBCs. Does anyone have any references stating this or refuting this?

TIA

Mari

Hi Mari,

Welcome back to the sanity of blood transusion!

I think that you will find that what equates to CMV- blood is leukodepleted blood.

This is because the virus is carried in leukocytes.

It is true that leukodepletion will remove most of the CMV, BUT, and it is quite a big but, not every unit is tested to see whether full leukodepletion has actually taken place or not; there could be a dud filter in the batch. This, nevertheless, will take out sufficient leukocytes in most cases that the minimum number of viral particles to cause an infection is reached, and theblood will still be suitable in most cases. However, when the recipient is immunocompromised, either by immunosuppressive drugs (such as in the case of a stem cell transplant) or is immunoimmature (such as in the case of an IUT), one should not take the risk of giving leukodepleted blood (just in case), and in suchcircumstances it is wise to give leukodepleted, CMV- blood (tested by PCR, rather than the older testing regimes).

Of course, in the case of an IUT, the blood should also be irradiated, and this, in itself, may give some protection, as the DNA/RNA of the viral particle will also be disrupted by the irradiation (be it gamma or X-ray).

Hope that helps.

Malcolm

:fingerscr:fingerscr:fingerscr:fingerscr:fingerscr

[mollyredone]

Thanks, Malcom! I knew I could count on you! We have increased our standard holding of irradiated PRBCs due to more oncology patients and doctor requests, but don't really deal with baby problems...they get shipped to someplace better!

Mari

[Malcolm Needs ☆]

Ah, but the irradiation is different, especially for oncology patients!

The irradiation may indeed render the cells, effectively, CMV negative, but the real reason for the irradiation for such patients is to render any viable T lymphocytes non-viable, to prevent potential transfusion associated graft versus host disease (TA-GvHD).

Edited October 25, 2010 by Malcolm Needs
Spelling - yet again!

[vilma_mt]

a lot of hospitals here in the US acknowledges that leukodepletion reduces risk of CMV infection. Irradiation on the other hand is still used to prevent GVHD. In the the event that there's an emergent need of transfusion and no available irradiated products available, no one should hesitate transfusing non-irradiated products. There are drugs available to prevent and treat GVHD.

Here's a copy of AABB statement regarding Leukoreduced blood and CMV.

STATEMENT OF THE AMERICAN ASSOCIATION OF BLOOD BANKS BEFORE THE BLOOD PRODUCTS ADVISORY COMMITTEE ON THE EFFECT OF LEUKOREDUCTION ON CMV TRANSMISSION THROUGH BLOOD TRANSFUSION

SEPTEMBER 19, 1997

Presented by Roger Y. Dodd, PhD

Mid-Atlantic District Representative to the AABB Board of Directors

The AABB is the professional society for almost 8,500 individuals involved in blood banking and transfusion medicine. It also represents more than 2,200 institutional members including community and Red Cross blood collection centers, hospital based blood banks, and transfusion services as they collect, process, distribute, and transfuse blood and blood components. Our members are responsible for virtually all of the blood collected and more than 80 percent of the blood transfused in this country. Throughout its 50-year history, the AABB’s highest priority has been to maintain and enhance the safety of the nation’s blood supply.

The AABB appreciates the opportunity to comment on the effect of leukoreduction on CMV transmission through blood transfusion. Over the past year, an ad hoc committee of the Association has reviewed the issue in detail and has reported that both retrospective and prospective data support the conclusion that the leukocyte reduction level currently accepted for the reduction of alloimunization to HLA molecules (that is, to fewer than 5 X 106 per transfused component) reduces transfusion-transmitted CMV to a level at least equivalent to that observed with the use of CMV-seronegative components. The data supporting this conclusion reflected a number of different studies, encompassing a variety of technical approaches to leukocyte reduction. These studies are reviewed in some detail in AABB’s Association Bulletin #97-2, dated April 23, 1997, and entitled “Leukocyte Reduction for the Prevention of Transfusion-Transmitted Cytomegalovirus (TT-CMV).†A copy of the Association bulletin has been provided to committee members.

The AABB therefore endorses the use of leukoreduced components as a measure to reduce the risk of transmission of CMV to susceptible patients. The Association encourages the use of procedures which can be performed in a fashion which assures that current Standards for leukoreduction are consistently achieved.

[Yanxia]

What about the irradiation to prevent CMV infection? Is this effective?

[vilma_mt]

Ah, but the irradiation is different, especially for oncology patients!

The irradiation may indeed render the cells, effectively, CMV negative, but the real reason for the irradiation for such patients is to render any viable T lymphocytes non-viable, to prevent potential transfusion associated graft versus host disease (TA-GvHD).

Irradiation "kills" the wbcs but does not remove it from the blood. CMV lives in white blood cells and the virus is transmitted thru wbcs. I have yet to find a literature that says irradiation kills the virus.

Leukoreduction does not prevent GVHD since there is still a small amount of "viable" wbcs and this small amount of wbc can wreak havoc in an immunocompromised patient.

[SMW]

Actually irradiation does not "kill" the white cells--just destroys their mitotic capability so they cannot divide and reproduce and therefore engraft in the host. Think of Granulocyte products that are transfused to patients. These products are irradiated but the granulocytes are still able to function following transfusion. The doses of irradiation used for blood products are not high enough to kill viruses or bacteria so irradiation cannot be used in lieu of testing for these agents.

[Yanxia]

Actually irradiation does not "kill" the white cells--just destroys their mitotic capability so they cannot divide and reproduce and therefore engraft in the host. Think of Granulocyte products that are transfused to patients. These products are irradiated but the granulocytes are still able to function following transfusion. The doses of irradiation used for blood products are not high enough to kill viruses or bacteria so irradiation cannot be used in lieu of testing for these agents.

Thank you SMW. I think you explain this question very well.

[profbaud]

As Malcolm stated, if seronegative blood products are not available, using leukoreduced products is second best for reducing the chance of a CMV infection. We had a patient receive 50 units of leukoreduced blood before the doctor decided to do an allogenic stem cell transplant and he tested her for CMV IgG antibodies. I was truly surprised when it came back negative. Leukoreduction works!

As to irradiation, this prevents graft vs host disease and is necessary for patients receiving blood from first degree family members, BMT or HSCT or intrauterine transfusions.

[L106]

Nice explanation, SMW. Thanks!