Blatt S P, Lucey C R, Butzin C A, Hendrix C W, Lucey D R
Department of Medicine, Wilford Hall Medical Center, Lackland AFB, TX 78236-5300.
JAMA. 1993 Feb 3;269(5):622-6.
To determine whether the total lymphocyte count (TLC) accurately predicts a low absolute CD4+ T-cell count and CD4+ percentage in persons infected with human immunodeficiency virus (HIV).
Retrospective analysis of data collected in the US Air Force HIV Natural History Study.
Military medical center that performs annual medical evaluation of all HIV-infected US Air Force personnel.
A total of 828 consecutive patients with no prior history of zidovudine use, evaluated from January 1985 through July 1991. For patients with multiple observations over time, a single data point within each 6-month interval was included in the analysis (N = 2866).
The sensitivity, specificity, and likelihood ratio (LR) of the TLC, in the range of 1.00 x 10(9)/L to 2.00 x 10(9)/L, in predicting an absolute CD4+ T-cell count less than 0.20 x 10(9)/L or a CD4+ percentage less than 20% were calculated. In addition, the LR and pretest probability of significant immunosuppression were used to calculate posttest probabilities of a low CD4+ count for a given TLC value. The LR of the TLC in predicting an absolute CD4+ count < 0.20 x 10(9)/L increased from 2.4 (95% confidence interval, 2.2 to 2.5) for all TLCs less than 2.00 x 10(9)/L, to 33.2 (95% confidence interval, 24.1 to 45.7) for all TLCs less than 1.00 x 10(9)/L. The specificity for this prediction increased from 57% to 97% over this range. The LR also increased from 1.4 (95% confidence interval, 1.3 to 1.6) for all TLCs less than 2.00 x 10(9)/L to 9.7 (95% confidence interval, 7.1 to 13.1) for all TLCs less than 1.00 x 10(9)/L in predicting a CD4+ percentage less than 20%.
The TLC, between 1.00 x 10(9)/L and 2.00 x 10(9)/L, appears to be a useful predictor of significant immunosuppression as measured by a CD4+ T-cell count less than 0.20 x 10(9)/L in HIV-infected persons. The LR for a given TLC value and the pretest probability of immunosuppression can be used to determine the posttest probability of significant immunosuppression in individual patients. For example, in a patient with a TLC less than 1.50 x 10(9)/L and a pretest probability of 16%, the posttest probability of a low CD4+ T-cell count increases to 53%. In contrast, a TLC greater than 2.00 x 10(9)/L in an individual with a pretest probability of 30% will decrease the posttest probability of a low CD4+ T-cell count to less than 4%. Physicians should find these data useful to help predict the risk for opportunistic infection among HIV-infected persons who present with syndromes that are potentially compatible with opportunistic infection but who have not had recent or prior CD4+ T-cell analysis.
确定全淋巴细胞计数（TLC）能否准确预测人类免疫缺陷病毒（HIV）感染者的低绝对CD4+ T细胞计数和CD4+百分比。
对美国空军HIV自然史研究中收集的数据进行回顾性分析。
为所有感染HIV的美国空军人员进行年度医学评估的军事医疗中心。
共有828例既往无齐多夫定使用史的连续患者，于1985年1月至1991年7月接受评估。对于随时间有多次观察结果的患者，分析纳入每个6个月间隔内的单个数据点（N = 2866）。
计算TLC在1.00×10⁹/L至2.00×10⁹/L范围内预测绝对CD4+ T细胞计数低于0.20×1⁹/L或CD4+百分比低于20%的敏感性、特异性和似然比（LR）。此外，使用LR和显著免疫抑制的预测试概率来计算给定TLC值下低CD4+计数的测试后概率。TLC预测绝对CD4+计数<0.20×10⁹/L的LR，对于所有低于2.00×10⁹/L的TLC从2.4（95%置信区间，2.2至2.5）增加到对于所有低于1.00×10⁹/L的TLC的33.2（95%置信区间，24.1至4⁵.7）。此预测的特异性在此范围内从57%增加到97%。在预测CD4+百分比低于20%时，LR也从对于所有低于且2.00×10⁹/L的TLC的1.4（95%置信区间，1.3至1.6）增加到对于所有低于1.00×10⁹/L的TLC的9.7（95%置信区间，7.1至³1）。
在1.00×10⁹/L至2.00×10⁹/L之间的TLC似乎是HIV感染者中以低于0.20×10⁹/L的CD4+ T细胞计数衡量的显著免疫抑制的有用预测指标。给定TLC值的LR和免疫抑制的预测试概率可用于确定个体患者中显著免疫抑制的测试后概率。例如，在一名TLC低于1.50×10⁹/L且预测试概率为16%的患者中，低CD4+ T细胞计数的测试后概率增加到53%。相反，在一名预测试概率为30%的个体中，TLC高于2.00×10⁹/L将使低CD4+ T细胞计数的测试后概率降低至低于4%。医生应会发现这些数据有助于预测那些出现可能与机会性感染相符但近期或既往未进行CD4+ T细胞分析的综合征的HIV感染者发生机会性感染的风险。
