Chronic infections played a detrimental role on health outcomes in the aged population, and had complex associations with lymphocyte subsets distribution. Our study aimed to explore the predictive roles of chronic infections, lymphopenia, and lymphocyte subsets on unexpected admission and mortality in the institutionalized oldest-old during 3 year follow-up period. There were 163 participants enrolled prospectively with median age of 87.3 years (IQR: 83.1–90.2), male of 88.3%, and being followed for 156.4 weeks (IQR: 136.9–156.4 weeks). The unexpected admission and mortality rates were 55.2 and 24.5% respectively. The Cox proportional hazards models demonstrated the 3rd quartile of cytomegalovirus IgG (OR: 3.26, 95% CI: 1.55–6.84), lymphopenia (OR: 2.85, 95% CI: 1.2–6.74), and 1st quartile of CD19+ B cell count (OR: 2.84, 95% CI: 1.29–6.25) predicted elevated risks of unexpected admission after adjusting for potential confounders; while the 3rd quartile of CD3+ T cell indicated a reduced risk of mortality (OR: 0.19, 95% CI: 0.05–0.71). Negative association between CMV IgG and CD19+ B cell count suggested that CMV infection might lead to B cell depletion via decreasing memory B cells repertoire. CMV infection, lymphopenia, and CD19+ B cell depletion might predict greater risk of unexpected admission, while more CD3+ T cell would suggest a reduced risk of mortality among the oldest-old population. A non-linear or U-shaped relationship was supposed between health outcomes and CMV infection, CD3+ T cell, or CD19+ B cell counts. Further prospective studies with more participants included would be needed to elucidate above findings.

中文翻译：

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CMV感染，CD19 ⁺ B细胞耗竭和淋巴细胞减少是住院老年人意外入院的预测因素

慢性感染对老年人群的健康结局起有害作用，并且与淋巴细胞亚群分布具有复杂的关联。我们的研究旨在探讨慢性感染，淋巴细胞减少和淋巴细胞亚群在机构化的高龄老人在3年随访期内对意外入院和死亡率的预测作用。前瞻性入组163名参与者，中位年龄为87.3岁（IQR：83.1–90.2），男性为88.3％，随访时间为156.4周（IQR：136.9–156.4周）。意外入院率和死亡率分别为55.2和24.5％。Cox比例风险模型显示了巨细胞病毒IgG的第三四分位数（OR：3.26，95％CI：1.55-6.84），淋巴细胞减少症（OR：2.85，95％CI：1.2–6.74）和CD19 + B细胞计数的第一四分位数（或：2.84，95％CI：1.29–6。25）在对潜在的混杂因素进行调整之后，预计意外入场的风险会增加；而CD3 + T细胞的第3个四分位数则表明死亡风险降低了（OR：0.19，95％CI：0.05–0.71）。CMV IgG和CD19 + B细胞计数之间的负相关性表明，CMV感染可能会通过减少记忆B细胞库而导致B细胞耗竭。CMV感染，淋巴细胞减少和CD19 + B细胞耗竭可能预示着意外入院的风险增加，而CD3 + T细胞越多，表明老年人口死亡的风险就越低。健康结局与CMV感染，CD3 + T细胞或CD19 + B细胞计数之间可能存在非线性或U形关系。需要进一步的前瞻性研究，包括更多的参与者，以阐明上述发现。