HIV患者外周血CD4+/CD25hi/CD127low调节性T细胞的表达及临床意义

目的探讨感染人类自身免疫缺陷病毒（HIV）患者抗病毒治疗前后外周血CD4+/CD25hi/CD127low调节性T细胞的表达情况及临床意义。方法选择符合HIV诊断标准、接受抗病毒治疗超过3个月的64例患者,采用高效抗逆转录病毒治疗（HARRT）,分别于治疗前、治疗3个月后采用流式细胞术检测外周血CD4+/CD25hi/CD127low调节性T细胞和CD4+T细胞的表达情况,并与80例健康体检者（对照组）比较。结果与对照组比较,HIV患者CD4+/CD25hi/CD127low调节性T细胞绝对计数及百分比显著降低,差异有统计学意义（P＜0.01）。HIV患者的CD4+/CD25hi/CD127low调节性T细胞绝对计数和CD4+T细胞呈正相关（P＜0.01）;HIV患者治疗3个月后CD4+/CD25hi/CD127low调节性T细胞均有升高,与治疗前的差异均有统计学意义（均P＜0.01）。根据年龄将患者分为18~30岁、31~45岁、＞45岁,各年龄段患者治疗后CD4+/CD25hi/CD127low调节性T细胞绝对计数分别是治疗前的4.28倍、3.00倍、2.00倍。结论 HIV患者外周血CD4+/CD25hi/CD127low调节性T细胞的表达与病毒的感染、清除有关;外源性药物可升高调节性T细胞的表达。     

多元协方差分析用于艾滋病疗法的选择

目的:优化HAART药物治疗方案,提高治疗效果,为广大患者和医生选择艾滋病的疗法提供科学的依据.方法:以CD4细胞数的增加值作为体现治疗效果的因变量,治疗时间和初始治疗CD4细胞数为协变量,通过四组疗法分组进行多元协方差分析。结果:患者治疗效果的差异主要是由于治疗方法和治疗时间以及初始治疗cd4值的差异所致;四种疗法的疗效总体上差异显著,满足完备性条件和显著性条件的疗法疗效优劣顺序是:M4>M2≈M3≈M1.结论:多元协方差分析用于艾滋病疗法的选择对实际工作有积极的指导意义.     

基于三次样条插值的艾滋病治疗模型

基于数学建模提供的艾滋病治疗方案中的实验数据,依据病人的初始CD4状态,将实验数据分类筛选,采用一维三次样条插值法描绘各类病人服药时间与病情的关系图形,进而由图形确定最佳治疗终止时间;并建立了CD4与时间的函数关系模型,借助于性价比函数进行疗效、价格的综合比较分析,此模型解法对最佳治疗方案的选择提供了有力依据.     

线性混合模型用于艾滋病疗效预测和疗法选优

为探究线性混合效应模型在艾滋病疗效预测和疗法选优中的应用。利用美国艾滋病医疗试验机构ACTG的193A研究中的一组非平衡重复测量数据,以logcd4为体现疗效的因变量,年龄、性别为固定效应,建立截距和治疗时间的斜率随受试者随机变化且其期望值因疗法不同的线性混合效应模型,用SAS软件中mixed过程求解并预测。通过疗法对截距和治疗时间斜率期望值的影响选择最优疗法。结果表明模型有非常好的拟合和预测效果,疗法4为最优疗法。本研究为专业医生进行艾滋病疗效的预测和疗法选优提供了科学依据和方法。     

放疗前后食管癌患者红细胞免疫功能和T淋巴细胞亚群的变化

目的 研究放疗前后食管癌患者红细胞免疫功能及T 淋巴细胞亚群的变化。方法 以68 例食管癌患者为研究对象（病例组）,另外选取健康献血者40 例作为对照组。以流式细胞仪检测病例组患者放疗前、接受6 周放疗后及对照组血清中T细胞亚群水平,使用受体黏附法检测红细胞免疫功能。结果 病例组患者治疗前红细胞免疫功能、血清T 细胞亚群水平均显著低于对照组（均P＜0.05）,红细胞免疫复合物花环（RBC-ICR）高于对照组（P＜0.01）;放疗后1 周,病例组的CD4＋T 细胞比例、肿瘤红细胞花环（DTER）、红细胞C3b 受体花环（RBC-C3bRR）进一步下降,而CD8＋T 细胞比例明显升高,CD4＋/CD8＋比值降低;同放疗前比较均有统计学差异（均P＜0.05）;放疗后3 个月病例组CD4＋T 细胞比例、DTER、RBC-C3bRR 逐步升高,而CD8＋T 细胞比例及RBC-ICR逐渐下降,CD4＋/CD8＋比值升高,同放疗前及放疗后1 周比较均有统计学差异（均P＜0.05）。结论 食管癌患者红细胞免疫功能及T 淋巴细胞亚群水平低下,放疗刚结束时,细胞免疫抑制作用为主导,放疗结束3 个月后,红细胞免疫功能逐渐改善、T淋巴细胞亚群逐渐恢复。放疗可有效减少肿瘤负荷,改善患者红细胞免疫及T 淋巴细胞功能。     

一类带有治愈率的HIV感染的CD4＋T细胞模型的动力学性质

本文主要介绍一类带有治愈率的HIV感染的CD4 T细胞模型的动力学性质,同时证明了如果基本再生数R0＜1,HIV感染消失;如果R0＞1,HIV感染持续.然后进行数值模拟,给出了地方性平衡点E·全局稳定的参数域,得到了地方性平衡点E·不稳定时周期解存在.     

基于线性混合模型的艾滋病最佳治疗时机选择

本文利用美国艾滋病医疗试验机构ACTG的193A研究中的一组非平衡重复测量数据。以log(cd4+1)为体现疗效的因变量,年龄、性别为固定效应,治疗时间和滞后治疗时间为随机效应,同时考虑疗法对疗效的影响引入其与治疗时间的交互效应,建立线性混合效应模型。用SAS软件求解。再通过建立以治疗时间斜率随机效应为因变量初始logcd4为解释变量的回归模型判断艾滋病最佳治疗时机。结果表明,当初始cd4为185个/mm~3时治疗时机最佳,即为无症状感染的晚期.与美国DHHS推荐的小于200个/mm~3一致,却更为科学和精确。本研究对艾滋病治疗的临床实践具有重要的指导意义。     

CARA效用函数下美式期权的定价

考虑当期权持有者的效用为CARA效用函数U(x)=-e<'-λx>时的关式期权定价问题.运用最优停止理论得到其在有限离散时间金融市场模型下的最佳实施期,并给出相应美式期权的定价公式.     

随机终止的非平稳折扣半马氏决策规划

半马氏决策规划(SMDP)提出至今讨论了时齐模型{S,A,,,p,T V}和非时齐模型{＆:A。,rt。,P。;T,。,Vn},后者的元素中至少有一个与决策周期数。有关.在实际问题中还有元素全部或部分与时间因子有关的模型,我们称之为非平稳模型.SMDP的目标函数也仅讨论决策周期数有限和无限这两种情形,但有时还要考虑时间段K到上系统的最优控制.这里T为系统的终止时间,可是随机的.我们称这种问题为随机终止的。本文讨论随机终止的非平稳折扣SMDP.     

艾滋病治疗综效的评价和预测

本文利用美国艾滋病医疗试验机构ACTG的临床试验小组193A研究中的一组数据为样本,以10g(cd4+1)和治疗费用作为艾滋病治疗综效评价的指标,对疗法一的不同患者相同治疗时间的综合评价值平均得到平均治疗综效周时间序列,在此基础上建立ARIMA(3,1,1)模型,并做15周的外延预测。结果表明,模型有非常好的拟合和预测效果,治疗费用使欠发达地区的治疗综效有明显的下降趋势,约在第45周后直线下降,说明患者的病情此时得以很好的控制。     

关于一个脉冲用药的HIV免疫模型的研究

对一个脉冲用药的HIV免疫模型进行研究,发现在用药间隔足够小时,预防抗化剂的脉冲使用通过使T细胞水平无限接近于未被感染的免疫水平来保持个体的免疫功能,并且文中进一步给出这个合适的用药间隔估计.这对指导AIDS治疗临床实践具有参考意义.     

A Delayed HIV Infection Model with the Homeostatic Proliferation of CD4+ T Cells

Acta Mathematicae Applicatae Sinica, English Series - In this paper, we investigate a delayed HIV infection model that considers the homeostatic proliferation of CD4+ T cells. The existence and...     

The role of CD4 T cells in immune system activation and viral reproduction in a simple model for HIV infection

CD4 T cells play a fundamental role in the adaptive immune response including the stimulation of cytotoxic lymphocytes (CTLs). Human immunodeficiency virus (HIV) which infects and kills CD4 T cells causes progressive failure of the immune system. However, HIV particles are also reproduced by the infected CD4 T cells. Therefore, during HIV infection, infected and healthy CD4 T cells act in opposition to each other, reproducing virus particles and activating and stimulating cellular immune responses, respectively. In this investigation, we develop and analyze a simple system of four ordinary differential equations that accounts for these two opposing roles of CD4 T cells. The model illustrates the importance of the CTL immune response during the asymptomatic stage of HIV infection. In addition, the solution behavior exhibits the two stages of infection, asymptomatic and final AIDS stages. In the model, a weak immune response results in a short asymptomatic stage and faster development of AIDS, whereas a strong immune response illustrates the long asymptomatic stage. A model with a latent stage for infected CD4 T cells is also investigated and compared numerically with the original model. The model shows that strong stimulation of CTLs by CD4 T cells is necessary to prevent progression to the AIDS stage.     

Games of stopping with infinite horizon

We consider two-person zero-sum games of stopping: two players sequentially observe a stochastic process with infinite time horizon. Player I selects a stopping time and player II picks the distribution of the process. The pay-off is given by the expected value of the stopped process. Results of Irle (1990) on existence of value and equivalence of randomization for such games with finite time horizon, where the set of strategies for player II is dominated in the measure-theoretical sense, are extended to the infinite time case. Furthermore we treat such games when the set of strategies for player II is not dominated. A counterexample shows that even in the finite time case such games may not have a value. Then a sufficient condition for the existence of value is given which applies to prophet-type games.     

Stability of HIV/HTLV-I co-infection model with delays

In this paper, we formulate a within-host dynamics model for HIV/HTLV-I co-infection under the influence of cytotoxic T lymphocytes (CTLs). The model incorporates silent HIV-infected CD4⁺T cells and silent HTLV-infected CD4⁺T cells. The model includes two routes of HIV transmission, virus to cell (VTC) and cell to cell (CTC). It also incorporates two modes of HTLV-I transmission, horizontal transmission via direct CTC contact and vertical transmission through mitotic division of Tax-expressing HTLV-infected cells. The model takes into account five types of distributed-time delays. We analyze the model by proving the nonnegativity and boundedness of the solutions, calculating all possible equilibria, deriving a set of key threshold parameters, and proving the global stability of all equilibria. The global asymptotic stability of all equilibria is established by utilizing Lyapunov function and LaSalle's invariance principle. We present numerical simulations to justify the applicability and effectiveness of the theoretical results. In addition, we discuss the effect of HTLV-I infection on the HIV dynamics and vice versa.     

Global properties of a class of HIV infection models with Beddington–DeAngelis functional response

In this paper, the global properties of a class of human immunodeficiency virus (HIV) models with Beddington–DeAngelis functional response are investigated. Lyapunov functions are constructed to establish the global asymptotic stability of the uninfected and infected steady states of three HIV infection models. The first model considers the interaction process of the HIV and the CD4 ⁺ T cells and takes into account the latently and actively infected cells. The second model describes two co‐circulation populations of target cells, representing CD4 ⁺ T cells and macrophages. The third model is a two‐target‐cell model taking into account the latently and actively infected cells. We have proven that if the basic reproduction number R₀ is less than unity, then the uninfected steady state is globally asymptotically stable, and if R₀ > 1, then the infected steady state is globally asymptotically stable. Copyright © 2012 John Wiley & Sons, Ltd.