Year : 2013 | Volume
: 12 | Issue : 4 | Page : 232--235
The role of polymerase chain reaction in early diagnosis of human immunodeficiency virus infection in infants
Christopher S Lukong1, Edourd D Tshimwanga2, Anita Y Mfuh3,
1 Department of Surgery, Paediatric Surgery Unit, Usmanu Danfodiyo University, Sokoto, Nigeria
2 Department of Outpatient, Baptist Hospital Mutengene, South west Province, Cameroon, Nigeria
3 Department of Nursing Sciences, Ahmadu Bello University, Zaria, Nigeria
Christopher S Lukong
Department of Surgery, Usmanu Danfodiyo University Teaching Hospital, Sokoto
Background: The prevalence of human immunodeficiency virus (HIV) infection is rising in Sub- Saharan Africa. The various indirect tests readily available have not been helpful in neonatal and early infant diagnosis of the disease. Polymerase chain reaction (PCR) is a direct test that can be used in these groups of children. Early infant diagnosis is important in achieving good outcome in the management of HIV infection. The aim of this article was to examine the role of PCR in the evaluation HIV-infected infants, with a view to achieve early diagnosis, early treatment, and good outcome.
Materials and Methods: This was a prospective review of 174 infants delivered by HIV-infected mothers in a rural hospital from January 2007 to September 2008. The blood samples of the patients were collected and subjected to PCR analysis for detection of viral antigen. Two samples were collected, the first at 6 weeks and the second 6 weeks after that. The results were recorded, collated, and analyzed using SPSS version 17.
Results: There were 174 infants, 100 boys, and 74 girls. The age range was 6-8 weeks (median 6 weeks). PCR was positive for both the samples in 12 (6.9%) infants. PCR was negative in both samples in 162 (93.1%) infants. All infants who were negative in the first sampling were found to be negative in the second sampling as well. None of the infant was positive for only one sample. Analysis of 12 positive infants revealed that 5 (2.9%) infants were placed on anti-retroviral drugs, 3 (1.7%) infants were not placed on anti-retroviral drugs because of low CD+ count, and 1 (1.0%) infant was lost to follow-up, while 3 (1.7%) infants died from sepsis.
Conclusion: PCR has a role as a direct test in early diagnosis of HIV infection in infancy, particularly where the other direct test are not readily available.
|How to cite this article:|
Lukong CS, Tshimwanga ED, Mfuh AY. The role of polymerase chain reaction in early diagnosis of human immunodeficiency virus infection in infants.Ann Afr Med 2013;12:232-235
|How to cite this URL:|
Lukong CS, Tshimwanga ED, Mfuh AY. The role of polymerase chain reaction in early diagnosis of human immunodeficiency virus infection in infants. Ann Afr Med [serial online] 2013 [cited 2020 Sep 26 ];12:232-235
Available from: http://www.annalsafrmed.org/text.asp?2013/12/4/232/122692
HIV infection has assumed a serious health hazard in Sub-Saharan Africa as well as the world at large. There are about 34 million people worldwide living with HIV infection, with 68% in Sub-Saharan Africa.  The infection has been on the increase, with 2.7 million new infections recorded in 2011.  About 2 million children less than 15 years are living with HIV infection, 90% of them in Sub-Saharan Africa. It is estimated that 3,90,000 new infections were recorded in this group in 2010.  The mortality from this infection is high, with an average of 270,000 child deaths recorded in the 2010 WHO statistics. 
The diagnosis of HIV infection in children less than 15 years is not reliable using indirect test such as ELISA. This is because of the circulating maternal antibodies as a result of vertical transmission from mother to child. The diagnosis is better made with direct test that detect the agent or the antigenic substance of the HIV virus. These direct tests are often not readily available in facility limited environments. The consequence is diagnosis conundrum, leading to late presentation, poor evaluation, and poor treatment outcome.
Among the direct tests, PCR technology is an immunological test that identifies the viral antigenor antigenic body. It was found to be useful in early infant diagnosis of HIV infection. ,,] This is because, in this technology, any small amount of antigen present is picked and proliferated so that it can be assayed.
The aim of this article was to highlight the role of PCR in the evaluation HIV-infected infants, with a view to achieving early diagnosis, early treatment, and good outcome.
Materials and Methods
This study was conducted in Baptist Hospital Mutengene, a rural hospital in southwest Cameroon.
Mutengene is a cosmopolitan junction town in the southwest province of Cameroon. Its inhabitants are mainly plantation workers, most of them from the northwest province of Cameroon.
This study was a prospective analysis of infants born to HIV-infected mothers in our hospital from January 2007 to September 2008.
Infants delivered by HIV-positive mothers, who tested positive to HIV by ELISA test.
Infants with clinical features of HIV infection, who tested positive to the rapid ELISA HIV screening.
A cohort of mothers attending antenatal clinic in our centre were all counseled and tested for HIV infection by ELISA. Those who tested positive and delivered in our centre were randomly selected, and their infants were tested for HIV infection by rapid ELISA. The infants who tested positive with ELISA were recruited for the study. The other group of infants recruited included those who presented to our clinic with clinical features of HIV infection and tested positive to rapid ELISA. All infants who satisfied the above inclusion criteria were recruited for the study. Their mothers were precounseled and verbal consent was obtained before the blood samples were collected from the infants.
The first sample from the infant age 6-8 weeks (median 6 weeks) was collected, tested for HIV by subjecting it to the PCR, and results recorded on a structured proforma. The second sample was collected 6 weeks later, analyzed similarly, and results recorded on the proforma. The blood samples were also analyzed for full blood count, CD+ count, urea, and electrolytes. The results of the other investigations together with the demographic data of the infants were recorded on the proforma. Data was extracted from the proforma and analyzed SPSS version 17.0.
There were 174 infants within the study period: 100 boys and 74 girls.
The median age was 6 weeks (range 6-8 weeks). Twelve infants (6.9%) were positive at the first and second sampling that was tested by PCR and 162 (93.1%) tested negative for both samples tested by PCR. None of the infants tested positive for only one sample. The analysis of the 12 infants who tested positive with the PCR revealed that 5 (2.9%) infants were placed on anti-retroviral drugs, 3 (1.7%) infants were not placed on anti-retrovrial drugs due to low CD+ count, 1 (1.0%) infant was lost to follow-up, and 3 (2.9%) infants died from sepsis. Of the 162 infants who were PCR-negative and ELISA-positive, 30 (17.2%) infants seroconverted by rapid ELISA test 6 weeks after cessation of breast milk. None of the 12 infants who were positive with PCR, seroconverted. The CD+ count range was 36-452 cells/nl (median 181 cells/nl).
The HIV infection and its end-stage disease AIDS has become a major pandemic in recent times. The morbidity and mortality rates from HIV type 1 infection has remained high in African continent. , Despite the fact that children are vulnerable in Sub-Saharan Africa, the pediatric HIV diagnostic facilities are limited. Therefore, most children are diagnosed late or not at all. Late diagnosis accounts for poor outlook of HIV in children in these settings. Also, 95% of infants get the infection through vertical transmission from mother to child and 5% get it by other means. 
The various indirect tests such as ELISA, which assess antibodies, are not reliable in children. This is because the maternal antibodies continue to circulate in the child for up to age 1 year and sometimes beyond. 
The direct tests that assay the antigen or the antigenic component of the virus are more reliable and preferred in infants and children. Such direct tests include PCR, western blot, and viral culture.  Viral culture are often time consuming, require a biosecurity secluded laboratory, and sometimes results in low sensitivity. 
The PCR was used in the study and found to be useful in our setting. This assertion corroborated with reports that found PCR useful in similar settings. ,,,,, Twelve (6.9%) infants tested positive with the PCR and were therefore diagnosed as having HIV infection. This figure is higher than the global prevalence of 5.0% for Sub-Saharan Africa.  The test was conducted at a median age of 6 weeks. This was appropriate as some studies have demonstrated that the antigen load peaks after 28 days of life. ,,,
Thirty (17.2%) infants out of 162 were found to have seroconverted 6 weeks after cessation of breast milk. Most of the children were aged 6-12 months, with a few aged 18-24 months. This fact further explains the weakness of indirect serological test in diagnosis of HIV infection in infants and children. Following the diagnosis, 5 were placed on ART, 3 had good CD4 levels and were not on drugs, 3 died before commencement of the drugs, and 1 was lost to follow-up. The mortality in the study was 3 (1.7%), mainly due to sepsis. Low immunity is common in this age group, and may contribute to mortality.
Generally mortality from this disease has improved with introduction of anti-retroviral therapy (ART). These drugs have been noted to suppress viral replication, delay disease progression, and thereby reduce mortality. 
Five (2.9%) infants on ART drugs were found to be growing and developing well at 6 months of follow-up.
In conclusion, PCR is a useful tool for early diagnosis of HIV infection in infants and children, especially in a facility limited setting. Early diagnosis and early treatment may confer a good outcome.
We recommend the use of PCR in the sub region to enable early detection and prompt treatment of HIV infection in infants. This will help to curb the menace from this dreaded pandemic.
We are grateful to Dr. Palmer for providing the PCR facility.
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