PLoS ONE (Jan 2013)

Evaluating total lymphocyte count as a surrogate marker for CD4 cell count in the management of HIV-infected patients in resource-limited settings: a study from China.

  • Jieqing Chen,
  • Wei Li,
  • Xiaojie Huang,
  • Caiping Guo,
  • Ran Zou,
  • Qiuying Yang,
  • Hongwei Zhang,
  • Tong Zhang,
  • Hui Chen,
  • Hao Wu

DOI
https://doi.org/10.1371/journal.pone.0069704
Journal volume & issue
Vol. 8, no. 7
p. e69704

Abstract

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OBJECTIVE: To evaluate the correlation of total lymphocyte count (TLC) and CD4 cell count and the suitability of TLC as a surrogate marker for CD4 cell count of HIV-infected patients in China. METHODS: Usefulness of TLC as a surrogate marker for a CD4 cell count <350 cells/mm(3) for HIV-positive patients in China was evaluated by 977 pairs of TLC and CD4 cell count from 977 outpatients. The result was then validated by a literature review which was conducted on 9 relevant articles. Further investigation using the 977 pairs of TLC and CD4 cell count data was done to determine a TLC threshold for predicting a CD4 cell count <500 cells/mm(3). Correlation and receiver operating characteristic (ROC) analysis were performed for both CD4 cell counts, and the sensitivity and specificity were computed. RESULTS: Good correlation was noted between TLC and CD4 count (r = 0.60, 95% CI, 0.56-0.64). TLC obtained a relatively high diagnostic performance (area under ROC curve, 0.80) for predicting a CD4 cell count <350 cells/mm(3), with a sensitivity of 0.65 (95% CI, 0.61-0.68) and a specificity of 0.80 (95% CI, 0.75-0.85) at the TLC threshold of 1570 cells/mm(3). The literature review suggested that for a CD4 cell count <350 cells/mm(3), the optimal TLC threshold was 1500 cells/mm(3), which was similar to the figure presented in this observational study. As for predicting a CD4 cell count <500 cells/mm(3), TLC obtained a high diagnostic performance (area under ROC curve, 0.82) as well with a sensitivity of 0.70 (95% CI, 0.67-0.73) and a specificity of 0.80 (95% CI, 0.73-0.87). CONCLUSIONS: When considering the antiretroviral therapy for HIV-infected Chinese individuals, total lymphocyte count can be considered as an inexpensive and easily available surrogate marker for predicting two clinically important thresholds of CD4 count of 350 cells/mm(3) and 500 cells/mm(3).