CD4 T cell measurements in the management of antiretroviral therapy-A review with an emphasis on pediatric HIV-infected patients

Abstract

The measurement of both the percentage (in pediatric patients aged less than 5 or 6 years) and the absolute number of circulating CD41 T cells remains the single most important parameter for establishing prognosis and determining when to treat HIV-1 infected infants. The predictive power of CD41 T cell measurements in HIV-1 infected individuals has resulted in robust guidelines from numerous agencies on the use of CD41 T cell measurements ranging from pretreatment evaluations to the initial assessment and monitoring of therapeutic responses and treatment failures. The increase in availability of HIV-1 antiretroviral drugs in resource limited setting has led to the urgent need to develop systems and technologies for the accurate and cost-effective measurement of CD41 T cells. The establishment of standardized guidelines for antiretroviral therapy (including CD4 testing) along with significant advancements in the development of structured access to health care, centralized CD4 testing programs, improved quality assurance programs, and inexpensive CD4 measurement technologies are making CD4 testing more universally available. Recent evidence suggests that a CD4/CD8 ratio of less than 1 may provide a reliable marker of presumptive HIV-1 infection in HIV-1 exposed infants. This review will summarize the current guidelines for the use of CD4 testing in HIV-1 infected infants and the potential for the CD4:CD8 ratio to be used as a surrogate of HIV-1 infection in resource limited settings. q

Validation of a Single-Platform, Volumetric, CD45-Assisted PanLeucogating Auto40 Flow Cytometer To Determine the Absolute Number and Percentages of CD4 T Cells in Resource-Constrained Settings Using Cameroonian Patients' Samples

“…The Senegalese validation used the initial Auto40 version based on primary CD4 gating and focused exclusively on CD4 T cell counting in absolute number (10). However, because the CD4 T lymphocyte percentage is essential for monitoring HIV disease progression in children less than 5 years old (21,35), the primary CD4 gating format of the Auto40 analyzer, which measured only absolute CD4 T cell numbers, was modified by the manufacturer in 2006 to measure the percentage of CD4 T cells. Thus, our observations extend those of the previous study by demonstrating that the updated version of the Auto40 flow cytometer, now based on a PanLeucogating protocol using anti-CD45 and anti-CD4 monoclonal antibodies, is valid for CD4 T cell enumeration not only by absolute number but also by percentage.…”

“…Affordable CD4 T cell counting has gradually become possible by using simple, compact, and robust low-cost new-generation cytometers operating as single-platform volumetric instruments without the use of expensive microbeads (9,20,21). The recently developed Auto40 flow cytometer (Apogee Flow Systems Ltd., Hemel Hempstead, United Kingdom) was originally developed for military applications (10).…”

Reference Values of Lymphocyte Subsets in Healthy, HIV-Negative Children in Cameroon

“…The same has been suggested for early infant diagnosis of HIV in African children younger than 18 months old. This should be done where DNA PCR is not available and where the results of HIV rapid testing can be complicated by maternal antibodies (13,29). These findings show that 4% of Cameroonian children younger than 18 months had a CD4 ϩ / CD8 ϩ ratio of Ͻ1.0.…”

Central memory CD4+ T cells dominate the normal cerebrospinal fluid

“…In specific patients, enumeration of absolute levels of circulating cells and their subsets is of primary importance. F.e., in acquired immune deficiency syndrome (AIDS) absolute counting of CD4 þ T cells in peripheral blood is the major laboratory tool for staging human immunodeficiency virus (HIV) infected patients (10). In candidates for autologous or allogeneic hematopoietic stem cell transplantation, enumeration of absolute levels of circulating CD34…”