Correlation Between Total Lymphocyte Count and CD4 Lymphocyte Count in Children Infected with HIV

Chezhiyan, M (2006) Correlation Between Total Lymphocyte Count and CD4 Lymphocyte Count in Children Infected with HIV. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION: As of the end of 2003, an estimated 42 million people worldwide - 38.6 million adults and 3.2 million children younger than 15 years - were living with HIV/AIDS. Approximately 70 percent of these people (29.4 million) live in Sub-Saharan Africa; another 17 percent (7.2 million) live in Asia (1).Worldwide, approximately twelve of every 1000 adults aged 15 to 49 are HIV-infected. In Sub-Saharan Africa, about 9 percent of all adults in this age group are HIV-infected. In 4 African countries, the prevalence of HIV infection among adults aged 15 to 49 exceeds 30 percent (1) .Approximately 50 percent of adults living with HIV/AIDS worldwide are women. An estimated 5 million new HIV infections occurred worldwide during 2003; that is, about 14,000 infections each day. More than 95 percent of these new infections occurred in developing countries. In 2003, approximately 2,000 children under the age of 15 years, and 6,000 young people aged 15 to 24 years became infected with HIV every day. In 2003 alone, HIV/AIDS-associated illnesses caused the deaths of approximately 3.1 million people worldwide, including an estimated 610,000 children younger than 15 years.: The first HIV case in India was reported in 1986 in Tamil Nadu. The estimated number of adults living with HIV/AIDS by end of 2003 is 50 lakhs of which children form 1.2 lakhs and women 1.9 lakhs. Indian statistics reveal the high HIV prevalence states in India to be Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Nagaland and Manipur where HIV infection has crossed 1% or more in antenatal women. The national HIV prevalence in adult population is 0.9%. Pediatric AIDS threatens much of the progress made in child survival in developing countries over the past 10 to 15 years. It is estimated that more than 8 lakhs of new pediatric infections are acquired, world wide, every year mostly through maternal foetal transmission. AIM OF THE STUDY: 1.PRIMARY OBJECTIVE: To study the correlation between total lymphocyte counts and CD4 lymphocyte counts of children belonging to stages I , II and III of WHO staging for AIDS. 2.SECONDARY OBJECTIVE: To establish arbitrary cut off values of total lymphocyte counts that correspond to CD4 counts less than 500/mm3 in the age group 2 – 5 years and less than 200/ mm3 in 6 – 12 years age group. DISCUSSION: CD4 lymphocyte are the principal targets of HIV and progressive decline of these cells over time takes place in HIV infection. CD4 T lymphocyte count is a useful indicator of disease progression and is widely used to determine points at which prophylaxis against opportunistic infections should be instituted and also for monitoring response to HAART. However owing to the high cost and need for specialized equipment and wide spread and routine use of CD4 count in the management of HIV infection has not been possible. There is a need for simpler ,cheaper surrogate markers to monitor HIV disease progression especially in resource limited settings such as ours. WHO guidelines now recommends that immune categorization and initiation of HARRT be based on clinical indicators in association with basic laboratory tests like total lymphocyte counts and hemoglobin. Though reports suggesting that total lymphocyte counts is a reliable surrogate marker of immune status in adults no such study is available where children with HIV are concerned. This study aimed at finding out any correlation that exists between total lymphocyte counts and CD4 T cell counts if any and also strength of any such correlation. Previous studies have also attempted a similar correlation between total lymphocyte counts and CD4 lymphocyte counts in adults. The correlation obtained between TLC and CD4 counts in the studies as follows. Beck et al(38) from Newcastle general hospital in London found an correlation of 0.76 between CD4 and total lymphocyte counts in the whole group of patients. Rysst et al(42) from Bloem fontein in South Africa observed a correlation of 0.704 between total lymphocyte counts and CD4 counts. Kumaraswamy et al(34) discovered a correlation of 0.744 in 650 samples.This was an Indian study in adults. Motasim Badri et al (40)in his study of 26 patients in somerset should a correlation of 0.61. Speech et al in a large study involving 1451 patients between the ages 24-62 years found a correlation of 0.72. All the above studies have been conducted in adults. The situation in children regarding such a correlation in more complex and there have been very few studies conducted in children in this aspect. CONCLUSION: Correlation coefficient obtained for the whole group of patients between total lymphocyte count and CD4 count was 0.812. Correlation was strong in all age groups but strongest in the in the 6-12 years age group. Strength of correlation is comparable with that obtained in previous adult studies. Correlation coefficient was also strong in the various subgroups of patients based on WHO staging (stage I-R =0.887 ; Stage II R=0.843; Stage III R=0.712). We have shown that a TLC of 3500 cells / mm3 in children, 1-5 years of age and 1500 cells / mm3 in those aged 6 - 12 years correlates with a CD4 count of <500 cells / mm3 and 200 cells / mm3 respectively, with a sensitivity and specificity between 78 - 86%. TLC can be used as a surrogate marker of immune status in resource poor settings such as ours instead of CD4 lymphocyte counts. Surrogate markers such as hemoglobin which is another easily available investigation, in most health care centre, even in resource restricted settings, need to be evaluated further. A correlation coefficient combining the total lymphocyte count and hemoglobin can be more useful than either of the two, both for predicting CD4 lymphocyte count and also the cut off values for initiating HAART.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Correlation ; Lymphocyte Count ; CD4 Lymphocyte Count ; Children Infected ; HIV
Subjects: MEDICAL > Paediatrics
Depositing User: Ravindran C
Date Deposited: 19 Apr 2018 06:07
Last Modified: 19 Apr 2018 06:07

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