Early Infant Detection of HIV

The Human Immunodeficiency Virus (HIV) has affected millions of people worldwide, more especially in sub-Saharan Africa. The number of infections that occurred in infants in 2014 was estimated at 220, 000. Out of this, approximately ninety mine percent of the infections in infants are acquired in the pre-partum period, during labour and breastfeeding. Such infections are called mother-to-child transmission of HIV, sometimes called vertical transmission of HIV. Because of the high risk of death before the age of 2years among HIV-infected infants and given the availability of paediatric antiretroviral treatment in many resource limited settings, WHO recommends that national programmes should establish the capacity to provide early virologic testing of infants for HIV. Thus, in concordance with this, the article will spell out every nitty-gritty on early infant detection of HIV and the role the medical laboratory scientist plays in the detection of the virus.

Among the numerous methods available for detection and diagnosis of the HIV in infants, WHO recommends that, Polymerase Chain Reaction (PCR) of Deoxyribonucleic acid (DNA) on whole blood or dried blood spot is the ideal. The Polymerase Chain reaction was invented in 1985 by Kary B. Mullis and allowed scientist to make millions of copies of a scarce sample of DNA. Research conducted by Owens and Dr. Mark Holodniy in the May 1 issues of the Annals of Internal Medicine and the journal of the American Medical Association stipulated that PCR of RNA on plasma or DBS or ultra-sensitive p24 antigen on plasma or DBS (WHO, 2010) is the alternative to detect HIV in infants. The HIV RNA detection provides the information on the virological status and the same used to monitor the response to treatments. Since HIV is an RNA virus, once inside the host CD4 cell, the RNA is converted to DNA and combines with the hosts DNA to form a proviral DNA. This is because the HIV proviral DNA is integrated in the cell’s genome and so detection of cell-associated HIV DNA within the peripheral blood mononuclear cell (PBMC) by PCR is the most sensitive for establishing the virus infection. The repository points of the provirus are the Dried blood spots (DBS).

The DBS was later standardized, commercially available microwell plate amplification and detection kit to detect HIV-1 DNA using Amplicon HIV-1 DNA version 1. 5 and this was based on these steps: sample preparation, PCR amplification of target DNA using HIV-1 specific complementary primers, hybridization of the amplified products to oligonucleotide probes specific to the target and the detection of the probe-bound amplified products by colorimetric determination. Furthermore, Enzyme immunoassay (EIA) is a common immunological technique that has that has been adapted for the detection of the HIV antibodies. Most EIA have a high sensitivity and specificity and are able to detect HIV-1/ HIV-2 and HIV variants. More advances have proved to the fore, the combination of p24Ag EIAs with traditional EIAs allowing for simultaneous detection of HIV antigen and antibodies. The EIA require sophisticated equipment, and are technically demanding; automatic pipettes, incubators, washers, readers and constant supply of electric power must be available and as such requires the medical laboratory scientist to validate the test results. More so, HIV RNA methods can detect a wide range of viral subtypes of the virus in which a viral load confirmatory test be done to determine the clinical status of infants. But the accurate detection of the HIV is not the role of a mere health care professional but the absolute role of a Medical Laboratory Scientist. The predicted workload and the frequency and number of specimens to be tested at a given period are vital for accurate knowledge of a medical Laboratory Scientist. Having highly accurate tests does not necessarily guarantee reliable laboratory results. Many processes are involved from the time of collection of specimen and transportation, tested until the results are reported during which errors can occur. Thus, ongoing Quality Assurance within the context of the laboratory quality system, both internally and externally, is essential. Medical Laboratory Scientists need regular communication about the performance of tests to improve and ensure appropriate performance. Well-defined standard operating procedures (SOPs), following nationally defined and validated testing algorithms, are essential for optimal use of all laboratory-based testing.

In a nutshell, the early detection of the HIV using polymerase chain reaction on the nucleotide sequence of DNA coupled with RNA HIV assay test is paramount to the health status of infants. Inadequate number of medical laboratory scientists dedicated to the provision of EIA services for the ever-increasing workload should also be of great concern. The emerging phenomenon of false positive result being received for some infants may be attributed to procedure challenges during sample collection and processing. The less quality assurance systems associated with equipment and testing processes. All these is the absolute role of the medical laboratory scientists and as such must be held in high esteem.