Schacker Timothy W, Brenchley Jason M, Beilman Gregory J, Reilly Cavan, Pambuccian Stefan E, Taylor Jodie, Skarda David, Larson Matthew, Douek Daniel C, Haase Ashley T
Department of Medicine/Infectious Diseases, University of Minnesota, MMC 250, 516 Delaware Street, Minneapolis, MN 55455, USA.
Clin Vaccine Immunol. 2006 May;13(5):556-60. doi: 10.1128/CVI.13.5.556-560.2006.
The organized structure of lymphatic tissues (LTs) constitutes a microenvironment referred to as a niche that plays a critical role in immune system homeostasis by promoting cellular interactions and providing access to cytokines and growth factors on which cells are dependent for survival, proliferation, and differentiation. In chronic human immunodeficiency virus type 1 (HIV-1) infection, immune activation and inflammation result in collagen deposition and disruption of this LT niche. We have previously shown that these fibrotic changes correlate with a reduction in the size of the total population of CD4+ T cells. We now show that this reduction is most substantial within the naïve CD4+ T-cell population and is in proportion to the extent of LT collagen deposition in HIV-1 infection. Thus, the previously documented depletion of naïve CD4+ T cells in LTs in HIV-1 infection may be a consequence not only of a decreased supply of thymic emigrants or chronic immune activation but also of the decreased ability of those cells to survive in a scarred LT niche. We speculate that LT collagen deposition might therefore limit repopulation of naïve CD4+ T cells with highly active antiretroviral therapy, and thus, additional treatments directed to limiting or reversing inflammatory damage to the LT niche could potentially improve immune reconstitution.
淋巴组织(LTs)的组织结构构成了一种被称为生态位的微环境,它通过促进细胞间相互作用以及提供细胞赖以生存、增殖和分化的细胞因子和生长因子,在免疫系统稳态中发挥关键作用。在慢性人类免疫缺陷病毒1型(HIV-1)感染中,免疫激活和炎症会导致胶原蛋白沉积并破坏这种LT生态位。我们之前已经表明,这些纤维化变化与CD4+T细胞总数的减少相关。我们现在表明,这种减少在初始CD4+T细胞群体中最为显著,并且与HIV-1感染中LT胶原蛋白沉积的程度成正比。因此,先前记录的HIV-1感染中LTs内初始CD4+T细胞的耗竭可能不仅是胸腺迁出细胞供应减少或慢性免疫激活的结果,也是这些细胞在瘢痕化的LT生态位中存活能力下降的结果。我们推测,LT胶原蛋白沉积可能因此会限制高效抗逆转录病毒疗法对初始CD4+T细胞的再填充,因此,针对限制或逆转对LT生态位的炎性损伤的额外治疗可能会潜在地改善免疫重建。