Faster, better, quicker ways to fight hidden costs of CD4 counting in HIV/AIDS

Sampling blood for the new CD4 tests.While saving the taxpayer more than 4.5 billion rands, Dr Debbie Glencross has developed a cost effective method for monitoring CD4 count in HIV/AIDS patients. The technology has direct benefits for antiretroviral programmes across the world and in particular for those in remote areas.

No wonder the National Science and Technology Forum gave this mother of three a coveted award for recent research at the end of May. No hospital or clinic can fight AIDS without knowing the all-important CD4 count – the bloodstream's tipping point, the moment when anti retroviral drugs are needed, and a key viral indicator which has to be monitored throughout the patient’s lifespan.

Savings of 76%

Glencross and her team located at the medical school next to Johannesburg General Hospital found a way to accurately measure the CD4 count in white blood cells at savings of 76%. And no, that is not a misprint. Without this breakthrough, chances are that South Africans would still lack a government AIDS drug rollout. Moreover, she's done it by developing a simpler method that can take advantage of the existing equipment - so the health authorities don't have to spend money upgrading or buying new gear.

“The prices of anti-retroviral drugs caused a huge debate,” the Wits lecturer explains. “But people don’t realize that there are huge costs hidden from view in the lab. You only realize what lab costs are if you are on a medical aid and have to pay in.”

Her speciality, flow cytometry, is normally so complicated that it is confined to universities and reference labs. Now medical technologists in all 18 government anti-retroviral drug rollout sites, from Lusikisiki to Rustenburg, Witbank to Umtata are using Glencross’ simpler, standardised version. And their verdict?

“Fantastic!” reports Glencross, who is running site validation studies to monitor the impact of the newly simplified test. “They are loving it. They say they feel so privileged to be doing this.”

Across the Atlantic, the Carribean countries, also hard-hit by AIDS, are using the new technique called PLG CD4.

How the technology works

Dr Glencross explains: "The mainstay and novelty PLG CD4 testing is that this method utilizes the White Cell count as the reference point, a parameter that is generally well quality-controlled. 

Traditionally, CD4 cells are referenced to total lymphocytes, a sub-population of the total white cells, which is notoriously unreliable and generally poorly quality controlled. Several steps are recommended in an attempt to quality control the identification of lymphocytes by flow cytometry, adding significant extra cost to the conventional test."

She says that by simplifying the strategy and referencing the test to all white blood cells, the need for extra steps and extra costs falls away that is required with the traditional CD4 testing.

"The result is the PLG CD4 assay which is much cheaper (more than 75% cheaper) because it needs only one quality control step, whereas up to 5 parameters are required in the conventional CD4 test," she adds. And it is also simpler to perform.

According to Glencross, the technique opens CD4 testing to remote areas which do not have ready access to a CD4 counting service. Due to the nature of the previous method of CD4 testing, blood samples would have to be analysed within 24 hours for an adequate result. Now, with the new test, samples can be analysed up to five days after collection. This means that people in remote areas have access to a CD4 service as long as their samples can be transported to a central testing facility that does PLG CD4 testing.

"The bottom line", says Glencross  "is that antiretroviral treatment programmes need not necessarily be limited to main centres but can include more remote areas because these areas now have access to laboratory CD4 monitoring required when ARV drugs are administered. A much more fair distribution of treatment programmes across all areas of our country."

Technology to benefit African countries

Dr Glencross is also undertaking the ongoing quality control of her revamped technology for the World Health Organisation, assessing around 50 public and private labs inside the country. Then there are the drug rollout programmes in nearby Botswana, Lesotho, Swaziland, Namibia and Zimbabwe, the reference labs from Mozambique and Malawi. But it goes much further up the continent, into Kenya, Uganda, Cameroon, Senegal, Rwanda, Burundi and as far north as Ethiopia. Many labs in Africa have been hammered by budget cutbacks but this easier, cheaper technique gives staff new opportunities to help the people.

“We couldn’t cope with the enthusiasm,” the 42-year-old reveals. “Participation in international programmes costs a fortune so the laboratories generally can't afford to do it. Courier costs to a country like Burundi are around R2,500 a time from South Africa, four times a year, and that's a special deal I negotiated. And there are many other hidden costs, like fees. Countries in Africa cannot afford it. But when I offered a quality programme sponsored by WHO, people jumped at it!”

There are other benefits. The Beckman Coulter diagnostic company will be launching the technology patent for her discovery at a global gathering of thousands of AIDS experts at the International AIDS Conference in July in Bangkok. Because the intellectual property discovery was made here, those lovely royalties will flow back home.

But Glencross doesn’t become rich overnight. Her employer, the National Health Laboratory Services, receives the royalties. And they can’t spend the money on roof repairs or fresh flowers. Glencross helped draft the terms of the contract to make sure that the money is plowed back into the NHLS trust fund for research. Future breakthroughs may well be underwritten by her discovery.

In the meantime, when not monitoring the success of her method, she’s rather busy. It’s not just the seven-month-old baby, the pre-schooler and the eight-year-old at home. It’s not just the teaching and the diagnostics lab.

No, now she’s working with colleague Professor Wendy Stevens on ways to bring down other AIDS lab costs, such as viral load monitoring.

“It’s still prohibitively expensive. Even if you don’t use state of the art technology, viral load monitoring is very, very expensive,” she points out. “We should be doing viral load tests every time we do CD4 tests. By 2008 that’s eight million viral load tests a year. We just don’t have the money. What does the banking ad say? We need to find new ways, faster, better, quicker.”

More information:

Photo courtesy Dr Glencross


PLG = PanLeucogated. Pan means all, leuco refers to white blood cells and gate refers to computer identification of a specific population


June 2004