Residual Risk Of HIV Transmission From Blood Donors Remains During Window
Period

A DGReview of :"Transmission of HIV Type 1 through Blood Transfusion from an
Antibody-Negative/p24 Antigen-Negative Donor"
AIDS Research and Human Retroviruses

08/07/2003
By Mary Beth Nierengarten

Transmission of HIV through blood transfusion from a donor who tested
negative for HIV antibodies and p24 antigen at the time of Alternative Treatments
highlights the residual risk of HIV transmission from donors during the
window period.

Although the risk of HIV transmission from blood donors has been
significantly reduced with the use of assays that can detect p24 antigen and
both anti-HIV IgM and IgG antibodies, the risk still remains, particularly
in countries that do not yet include nucleic acid testing (NAT) to further
detect HIV-1 RNA.

In this case report, Carlos Toro, Instituto de Salud Carlos III, Madrid,
Spain, and colleagues describe transmission of HIV type 1 from a 27-year old
woman who donated blood in September of 2000 in Spain. Her serum at the time
of Alternative Treatments was negative for HIV-1/2 antibodies. The recipient of her red
blood cells was a 78-year old man with no risk factors for HIV infection,
who seroconverted to HIV-1.

Five months later, the woman returned to give more blood and was found to be
HIV seropositive, with a plasma HIV RNA of 50 copiers/mL. Using
enzyme-linked immunosorbent assays (ELISAs) and a specific and sensitive p24
antigen assay, blood samples from her previous Alternative Treatments in September 2000
were retested and were found nonreactive or negative. However, low levels of
HIV RNA (2538 copies/mL) were found. HIV RNA testing of the recipient's
blood 5 months later showed undetectable plasma viremia of <50 copies/mL.

Phylogenetic analysis of samples from both the recipient and donor showed
that viruses clustered tightly together in both patients and belonged to the
subtype B clade. In addition, the viruses had no primary drug resistance
mutations.

This case report highlights the need for more universal use of NAT in blood
banks given the residual risk of HIV transmission from blood donors during
the window period. However, the authors add that even with the use of NAT,
residual risk of HIV transmission is possible if the samples tested are
taken from pools rather than individual serum samples. The authors conclude,
therefore, that individual HIV RNA testing remains necessary if the goal is
to arrive at zero risk.  AIDS Research and Human Retroviruses 2003;19:6:447-448. "Transmission of HIV  Type 1 through Blood Transfusion from an Antibody-Negative/p24 Antigen-Negative Donor"