Evaluating the total lymphocyte count (TLC) as a substitute for CD4 cell count in the follow up of AIDS patients. / Relação entre contagem total de linfócitos e contagem de células T CD4+ em pacientes soropositivos para HIV.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

CD4 count is the major surrogate marker for defining the best time to start antiretroviral therapy in HIV infected patients, as well as for defining the duration of prophylaxis against opportunistic infection. Its high cost, however, limits the use of this technique in resource-limited settings. Total lymphocyte count (TLC) has been evaluated as a substitute marker for CD4 count. The objective of this study is to evaluate the capability of TLC to be used as a substitute marker for CD4 count in order to detect patients who need prophylaxis against opportunistic infection (CD4 <200 cells/mm3), and those with CD4 <350 cells/mm3 (Brazilian limit to define AIDS). We evaluated TLC and CD4 of 1174 HIV-infected patients, in HUPES, from May/2003 to September/2004. CD4 counts were performed by flow cytometry, and TLC by an automated hematological counter. A total of 1510 subjects were evaluated. The CD4 count range was 4 to 2531 cells/mm3), and the TLC range 300 to 6200 cells/mm3. The best TLC limit to estimate a CD4 <200 cells/mm3 was ≤ 1700 cells/mm3 (SE= 76.3%; SPE= 65.2%, NPV= 93.1%), but the PPV was only 31.1%. The same findings were observed for the limit of <350 cells/mm3, but we find a worst sensitivity (SE= 59.4%, SPE= 96.6%, PPV= 57.3% and NPV= 79.4%). Altogether, these results indicates that although a statistical correlation exists between TLC and the CD4+ T cell count, the TLC is not a good predictor of the CD4+ T cell count. TLC would not be a safe marker for a CD4+ T cell count in HIV-infected patients, but could be used as an surrogate to monitoring the need to perform CD4 cell count.

ASSUNTO(S)

imunologia celular imunologia tlc aids hiv cd4 cd4 tlc

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