The 2016 and 2017 World Health Organization (WHO) guidelines provide guidance on the diagnosis of human immunodeficiency virus (HIV) infection, the care of people living with HIV, and the use of antiretroviral (ARV) drugs for treating and preventing HIV infection.
While these guidelines recommend lifelong antiretroviral therapy (ART) regardless of CD4 cell count (“treat all policy”) and analysis of viral load (VL) as the preferred monitoring approach, they also provide clear guidance on the indispensable role of CD4 in assessing baseline risk of disease progression—particularly for individuals presenting with advanced disease—decisions regarding starting and stopping prophylaxis for opportunistic infections (OIs), and prioritization decisions regarding ART initiation in settings where universal treatment is not possible.CD4 cell count measurement may also be important for people who are failing ART.
1. CD4 BASELINE TESTING
CD4 cell count testing at baseline for all people living with HIV
The 2017 WHO guidelines point out that CD4 cell count testing at baseline for all people living with HIV remains important, because relying on clinical staging alone risks missing substantial numbers of people living with HIV with severe immune suppression.1In a study from Kenya, Malawi, Uganda, and Zimbabwe, almost half the people with CD4 count <100 cells/µl were classified as having WHO clinical stage 1 or 2 disease.1 Hence, identifying people with advanced HIV disease who are eligible for elements of a package of care requires CD4 cell count testing.1
All patients entering or re-entering care should receive a CD4 test at treatment baseline and as clinically indicated for patients who are unstable or with advanced HIV disease.2
2. IDENTIFICATION OF ADVANCED HIV DISEASE
Definition of advanced HIV disease
People presenting with advanced HIV disease are at high risk of death. The 2017 WHO guidelines define advanced HIV disease as follows:3
- For adults and adolescents, and children older than five years, advanced HIV disease is defined as CD4 cell count <200cells/µl or WHO stage 3 or a 4 event.
- All children younger than five years old with HIV are considered as having advanced HIV disease.
- A severely immunosuppressed adult is defined as having a CD4 cell count <50cells/µl.
Advanced HIV disease package of care
People with advanced HIV disease are defined as those presenting to care with a CD4 count below 200 cells/µl or WHO disease stages 3 and 4. The package of care for these people should include the following:5
- Rapid initiation of ART (once the risk of immune reconstitution inflammatory syndrome [IRIS] is ruled out);
- Systematic screening for Cryptococcus antigen;
- Screening and treatment for tuberculosis (TB) or isoniazid preventive treatment (IPT) as indicated;
- Screening for toxoplasmosis and Co-trimoxazole (CTX) prophylaxis; and
3. LABORATORY & DIAGNOSTIC SERVICES
Effective laboratory and diagnostic services
Even in settings with full access to viral load testing, CD4 cell count testing capability will continue to be needed as part of HIV programs for baseline risk and other clinical assessments. Depending on the context, as the transition to viral load monitoring from CD4 count testing for initiation and monitoring progresses, programs may wish to consider centralizing the continued use of CD4 count testing.17
Follow this space in MLO’s January 2019 Special Feature to continue Beckman Coulter Life Sciences’ “Twelve Steps to CD4 Testing.”
1. World Health Organization (2017): Guidelines for managing advanced HIV disease and rapid initiation of antiretroviral therapy, page 6.
2. World Health Organization (2017): What’s new in treatment monitoring: Viral load and VCD4 testing Information Note WHO/HIV/2017.22, page 1.
3. World Health Organization (2017): Guidelines for managing advanced HIV disease and rapid initiation of antiretroviral therapy, page v.
4. World Health Organization (2017): Guidelines for managing advanced HIV disease and rapid initiation of antiretroviral therapy, page 2.
5. World Health Organization (2016): Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection; recommendations for a public health approach – 2nd ed., page 241.
17. World Health Organization (2016): Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection; recommendations for a public health approach – 2nd ed., pages 295-297.