HIV Staging Based on CD4 Count Should Consider Patient Ethnicity
Originally published by Reuters Health, January 14, 2002
DELHI (Reuters Health) — According to a report from South India, CD4 T lymphocyte counts in both normal and HIV-infected individuals are lower in Indians than in Caucasians, and may necessitate using lower cut-off values for starting antiretroviral treatment.
The US Centers for Disease Control and Prevention (CDC) classification based on CD4 counts are used to monitor the progress of HIV infection and make decisions on initiating treatment, Dr. Sandeep Ramalingam writes in the December issue of National Medical Journal of India. However, the use of these cut-off values in populations with naturally lower CD4 values may result in initiation of antiretroviral treatment earlier than required, leading to increased costs of treatment, he asserts.
Dr. Ramalingam and colleagues from the Christian Medical College and Hospital in Vellore, Southern India, evaluated the total white cell counts, lymphocyte counts and the CD4 and CD8 lymphocyte subsets in 79 HIV-positive and 104 HIV-negative healthy controls using the standard automated methods.
The researchers noted that the CD4 count among normal Indian adults was 799 cells/microliter. This was near the Chinese mean of 785 cells/microliter and significantly lower than normal values of 1013 cells/microliter cited in studies from North America. The CD4/CD8 ratio observed in the present study of 0.94 was closer to the Chinese and Ethiopian values, but was lower than the ratio of 1.36 reported by studies of North American populations.
The investigators classified the HIV-infected individuals into three groups, according to CDC classification guidelines: asymptomatic HIV-positive patients, symptomatic but without AIDS, and patients with AIDS. Their CD4 cell counts were 454.4 cells per microliter, 254.4 cells per microliter and 168 cells per microliter, respectively.
"The mean CD4 count among normal south Indians is significantly lower than that in the western population and parallels that of the Chinese," the researchers write. The CD4 count was less than 500 per microliter in more than 10% of the HIV-negative individuals, they note.
"The differences in counts could be because of genetic, nutritional or environmental factors," Dr. Ramalingam told Reuters Health.
While recommending larger longitudinal studies to establish the CD4 levels in Indian populations, Dr. Ramalingam added that there could be variations in CD4 counts between various regions of India.
"If this trend is proven in the longitudinal study, a lower CD4 cut-off value to classify individuals as having symptomatic HIV or AIDS may need to be established," the researchers conclude.
