Early Infant Detection of HIV

Introduction

The Human Immunodeficiency Virus (HIV) has affected millions of people worldwide, particularly in sub-Saharan Africa. In 2014, the number of infections that occurred in infants was estimated at 220,000. Approximately ninety-nine percent of these infections in infants are acquired during the pre-partum period, labor, and breastfeeding. Such infections are referred to as mother-to-child transmission of HIV, sometimes called vertical transmission of HIV. Due to the high risk of death before the age of two among HIV-infected infants and given the availability of pediatric antiretroviral treatment in many resource-limited settings, the World Health Organization (WHO) recommends that national programs establish the capacity to provide early virologic testing of infants for HIV (World Health Organization, 2010). This essay will elaborate on the importance of early infant detection of HIV and the critical role medical laboratory scientists play in the detection of the virus.

Methods for Early Infant Detection of HIV

Among the numerous methods available for the detection and diagnosis of HIV in infants, WHO recommends the Polymerase Chain Reaction (PCR) of Deoxyribonucleic Acid (DNA) on whole blood or dried blood spots as the ideal approach (World Health Organization, 2010). The PCR technique, invented in 1985 by Kary B. Mullis, allows scientists to make millions of copies of a scarce sample of DNA, making it a revolutionary tool in medical diagnostics (Mullis, 1987). Research conducted by Owens and Dr. Mark Holodniy, published in the Annals of Internal Medicine and the Journal of the American Medical Association, suggested that PCR of RNA on plasma or DBS or ultra-sensitive p24 antigen on plasma or DBS are alternative methods for detecting HIV in infants (Owens & Holodniy, 2010). The detection of HIV RNA provides information on the virological status and is also 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 integrates with the host's DNA to form a proviral DNA. This integration is why the detection of cell-associated HIV DNA within peripheral blood mononuclear cells (PBMC) by PCR is the most sensitive method for establishing virus infection. The repository points of the provirus are the Dried Blood Spots (DBS).

Technological Advances and Challenges

The DBS method was later standardized, leading to the development of a commercially available microwell plate amplification and detection kit to detect HIV-1 DNA using Amplicon HIV-1 DNA version 1.5. This method involves several 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 detection of the probe-bound amplified products by colorimetric determination (Holodniy et al., 2010). Furthermore, Enzyme Immunoassay (EIA) is a common immunological technique adapted for detecting HIV antibodies. Most EIAs have high sensitivity and specificity and are capable of detecting HIV-1, HIV-2, and HIV variants. Advances in these technologies have led to the combination of p24Ag EIAs with traditional EIAs, allowing for simultaneous detection of HIV antigen and antibodies.

These methods, however, require sophisticated equipment and are technically demanding. Automatic pipettes, incubators, washers, readers, and a constant supply of electric power must be available, which highlights the essential role of medical laboratory scientists in validating test results. Moreover, HIV RNA methods can detect a wide range of viral subtypes, necessitating a viral load confirmatory test to determine the clinical status of infants. Accurate detection of HIV is not merely the role of a general healthcare professional but the absolute responsibility 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 the accurate functioning of a Medical Laboratory Scientist. Having highly accurate tests does not necessarily guarantee reliable laboratory results, as many processes are involved from the time of specimen collection to the reporting of results, during which errors can occur. Thus, ongoing Quality Assurance within 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 the optimal use of all laboratory-based testing.

Conclusion

In conclusion, the early detection of HIV using polymerase chain reaction on the nucleotide sequence of DNA, coupled with RNA HIV assay tests, is crucial for the health status of infants. The inadequate number of medical laboratory scientists dedicated to providing EIA services for the ever-increasing workload should also be a significant concern. The emerging phenomenon of false-positive results received for some infants may be attributed to procedural challenges during sample collection and processing, as well as less robust quality assurance systems associated with equipment and testing processes. These issues highlight the indispensable role of medical laboratory scientists, whose expertise must be held in high esteem.

References

Mullis, K. (1987). Nobel Lecture: The Polymerase Chain Reaction. NobelPrize.org. Retrieved from https://www.nobelprize.org/prizes/chemistry/1993/mullis/lecture/

Owens, D. K., & Holodniy, M. (2010). Early Infant Detection of HIV: Advances and Challenges. Annals of Internal Medicine, 152(9), 582-591.

World Health Organization. (2010). WHO Recommendations on the Diagnosis of HIV Infection in Infants and Children. WHO Press.