Long-term effects of the growing population of HIV-treated people in Southern Africa on individuals and the public health sector at large are not yet understood. This study proposes a novel 'ratio' model that relates CD4+ T-cell counts of HIV-infected individuals to the CD4+ count reference values from healthy populations. We use mixed-effects regression to fit the model to data from 1,616 children (median age 4.3 years at ART initiation) and 14,542 adults (median age 36 years at ART initiation). We found that the scaled carrying capacity, maximum CD4+ count relative to an HIV-negative individual of similar age, and baseline scaled CD4+ counts were closer to healthy values in children than in adults. Post-ART initiation, CD4+ growth rate was inversely correlated with baseline CD4+ T-cell counts, and consequently higher in adults than children. Our results highlight the impacts of age on dynamics of the immune system of healthy and HIV-infected individuals.

中文翻译：

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南非 HIV 感染儿童和成人接受 ART 的长期免疫结果的机制模型

南部非洲接受艾滋病毒治疗的人数不断增长对个人和整个公共卫生部门的长期影响尚不清楚。本研究提出了一种新的“比率”模型，该模型将 HIV 感染者的 CD4+ T 细胞计数与健康人群的 CD4+ 计数参考值联系起来。我们使用混合效应回归将模型拟合到来自 1,616 名儿童（ART 开始时的中位年龄为 4.3 岁）和 14,542 名成人（ART 开始时的中位年龄为 36 岁）的数据。我们发现，与成人相比，儿童的标度承载能力、相对于 HIV 阴性个体的最大 CD4+ 计数和基线标度 CD4+ 计数更接近于健康值。ART 开始后，CD4+ 生长速率与基线 CD4+ T 细胞计数呈负相关，因此成人高于儿童。我们的研究结果强调了年龄对健康和 HIV 感染者免疫系统动态的影响。