Lymphocyte numbers need to be quite tightly regulated. It is generally assumed that lymphocyte production and survival rates increase homeostatically when lymphocyte numbers decrease. This widely-accepted concept is largely based on experiments in mice. In humans, lymphocyte reconstitution usually occurs very slowly, which challenges the idea that density dependent homeostasis aids recovery from lymphopenia. Using in vivo deuterium labelling, we quantified lymphocyte production and survival rates in patients who underwent an autologous hematopoietic stem cell transplantation (autoHSCT). We indeed found that the production rates of most T-cell and B-cell subsets in autoHSCT-patients were 2 to 8-times higher than in healthy controls. These increased lymphocyte production rates went hand in hand with a 3 to 9-fold increase in cell loss rates, and both rates did not normalize when cell numbers did. This challenges the concept of homeostatic regulation of lymphocyte production and survival rates in humans.

中文翻译：

---

自体造血干细胞移植后独立于细胞密度的淋巴细胞生成和丢失率增加

淋巴细胞数量需要严格控制。通常认为，当淋巴细胞数量减少时，淋巴细胞的产生和存活率会稳态增加。这个被广泛接受的概念主要基于小鼠实验。在人类中，淋巴细胞重建通常非常缓慢，这挑战了密度依赖性体内稳态有助于从淋巴细胞减少中恢复的观点。使用体内氘标记，我们量化了接受自体造血干细胞移植（autoHSCT）的患者的淋巴细胞产生和存活率。我们确实发现，autoHSCT患者中大多数T细胞和B细胞亚群的生产率比健康对照组高2至8倍。这些增加的淋巴细胞生成率与细胞丢失率提高3到9倍密切相关，而当细胞数量改变时，两个比率均未正常化。这挑战了人类淋巴细胞生产和存活率的体内调节的概念。