TreatmentUpdate57, Vol. 7, No. 3 - March 1995
Sean Hosein

Researchers in Sweden and Tanzania conducted a 3 year study to try and find out factors that might explain why some babies are born without HIV infection. The researchers tested blood from 3,000 mothers and found that roughly 12% were HIV infected. Data analysis relied on information from 255 mothers,138 of whom were infected with HIV, and 117 who were not. The researchers noted CD4+ and CD8+ cells, the HIV protein p24 and beta2-microglobulin ( 2-m). Blood levels of 2-m increase as the immune system weakens in subjects with HIV infection.

* RESULTS

On average about 22% of infants born to infected mothers were also infected. The researchers found that the following factors were linked to infection in the infants:

- higher-than-normal blood levels of 2-m - detectable p24 antigen - low blood levels of CD4+ cells

* 2-M

On average, infants born to women with relatively high blood levels of 2-m (2 mg/litre or greater) had a 34% chance of also being HIV-infected. In women with less than 2 mg/L of 2-m, the chance of giving birth to an infected infant was 14%.

* %CD4+ CELLS

The researchers did not find any statistically significant relations between infected infants and CD4+ cell counts. When they measured the percent of lymphocytes that were CD4+, then low %CD4+ levels were linked to infants being infected. For mothers with %CD4+ cells 20% or less, the chance of an infant being born with HIV infection was about 33%. Mothers who had more than 20% CD4+ cells had a transmission rate of 14%. Among mothers with less than 20% CD4+ cells and blood levels of 2-m greater than 2 mg/L, the rate of transmission was 54%. Although p24 antigen was more commonly detected in blood samples from mothers who transmitted the infection (than in those that didn't), "few mothers had [detectable p24]".

* COTE D'IVOIRE

Another study in C8te d'Ivoire analyzing data from over 600 poor HIV-1 infected women, found that pregnant women had a 25% chance of giving birth to an infected infant. For women with HIV-2, the equivalent figure was 1%.

REFERENCES:

1. Bredberg-Raden U, Urassa W, Urassa E, et al. Predictive markers for mother-to-child transmission of HIV-1 in Dar es Salaam, Tanzania. Journal of Acquired Immunodeficiency Syndromes and Human Retrovirology 1995;8(2):182-187.

2. Adjorlolo-Johnson G, De Cock D, Dkpini E, et al. Prospective comparison of mother-to-child transmission of HIV-1 and HIV-2 in Abidjan, Cote d'Ivoire. Journal of the American Medical Association 1 994;272(6):462-466.

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