Cheap and Quick CD4 Test

posted: 17/02/2009

A rapid and inexpensive test to check the immune system of people living with HIV/AIDS for the developing world is now a step closer. Imperial College in London has just been given a $7.3m grant from the Bill & Melinda Gates Foundation.

If successful, the test would improve healthcare workers' ability across the globe to determine the best treatment for people with HIV.

The CD4 Initiative  at Imperial College was set up to develop an easy to use point-of-care test, costing around $2, that can rapidly measure the numbers of CD4 cells in a person's blood, without using electronics or mechanical parts.

Having enough CD4 cells is critical in anyone's immune system and HIV gradually reduces their number. When the number of CD4 cells fall too low, people become more and more vulnerable to HIV-related illness. Below a CD4 of 200, illnesses become highly probable. In the UK treatment typically starts at around the 350 level to prevent this illhealth.

CD4 counts are a vital measure

Healthcare workers rely on a CD4 count when making decisions about treatment for HIV and when this should begin. The new test would mean people and nurses would find out within minutes if they should start the HIV treatment.

Imperial's academic and industrial partners in the CD4 Initiative  have worked since 2007 to devise the new test. USA and Australian teams have already developed three prototypes, one of which will be chosen to be manufactured and mass produced in 2010.

Finger-prick blood sample is enough

The new test will work with a finger-prick blood sample and will have a simple read-out. One of the new prototypes is similar to a home pregnancy test.

The majority of people with HIV in the developing world do not get CD4 tested often or at all, because it is expensive and requires a lab and specially trained staff. Where testing facilities do exist, it is often too difficult for people in rural areas to reach them. For those who are tested, it can take weeks to obtain results.

source

Delaying Treatment Costs

posted: 14/01/2009

Researchers have now found that the immune systems of people who start HIV treatment at CD4 cell counts below 350 don’t recover as well as people who started HIV treatment at the recommended 350 level.

For some time now it has been recommended that people should start HIV treatment when the CD4 cell count is around 350. Starting treatment then rather than waiting until your CD4 cell count is lower, not only reduces the risk of developing HIV-related illnesses, but also reduces the risk of some other serious illnesses as well, for example heart, kidney, and liver disease as well as some cancers.
 

This research finding - that the immune systems of people who start HIV treatment at CD4 cell counts below 350 don’t recover as well - is true even when people had a good rise in their CD4 cell count following treatment.
 

The researchers found that the immune systems of people who started treatment with a CD4 cell count below 350 were similar to older people's.
As a person ages, the ability of the immune system to produce new CD4 cells falls. This partly explains why older people are more likely to get serious infections and cancers.
 

The researchers say this adds even more weight to starting treatment at CD4 cell counts around 350 and they suggest that just monitoring CD4 cell counts isn’t enough to assess the health of the immune system of people with HIV. Another useful test could include looking at the ratio of CD4 to CD8 cells.
 

Some can't start soon enough

But many people cannot start HIV treatment when their CD4 cell count is at 350. The main reason for this in the UK is late diagnosis of HIV. About one in three people who have HIV in this country don’t know they have HIV. Many people only have their HIV diagnosed when they are already ill because of HIV and have a low CD4 cell count.
 

And it’s a huge global issue as well – most people in resource-limited countries don’t start HIV treatment until their CD4 cell count is around 100.

Therefore the researchers suggest that new treatments to restore the immune system are needed for people who start treatment later than is recommended.

Source