Immune Reconstitution following Myeloablative Allogeneic Hematopoietic Stem Cell Transplantation: The Impact of Expanding CD28negative CD8+ T Cells on Relapse

AbstractAllogeneic stem cell transplantation has become standard therapy for hematologic malignancies through the positive immunologic graft-versus-leukemia effect. Initial immune recovery relies on peripheral expansion of infused T cells, which switch to a memory-like phenotype. This study prospectively investigated whether changes in subset composition precedes complications after myeloablative HLA-matched transplantation for hematologic malignancies. Of 80 allograft recipients, 18 were still free of clinical complication throughout 395 to 1564 days of follow-up. Compared with this complication-free subgroup, patients who developed chronic graft-versus-host disease (cGVHD) without relapsing recovered similar numbers of circulating T cells with predominance of CD8+ T cells lacking CC-chemokine receptor-7 and CD28 expression throughout the first year after transplantation. Conversely, poor CD8+ T cell recovery with diminished numbers of CD28neg CD8+ T cells (∼1/4th of that of relapse-free patients) preceded occurrence of malignant relapse. In multivariate analysis, lower CD28neg CD8+ T cell counts by day 60 postallograft were associated with a greater risk of subsequent relapse (hazard ratio [HR] 0.33; 95% confidence interval [CI]: 0.14-0.76; P = .01). Enumeration of CD28neg CD8+ T cells in patients could assist in predicting risk of relapse and help build an algorithm for accelerating the immune recovery by reducing the immunosuppressive treatment and considering the introduction of preemptive donor lymphocyte infusions

Interleukin-7 Regulates Adipose Tissue Mass and Insulin Sensitivity in High-Fat Diet-Fed Mice through Lymphocyte-Dependent and Independent Mechanisms

Although interleukin (IL)-7 is mostly known as a key regulator of lymphocyte homeostasis, we recently demonstrated that it also contributes to body weight regulation through a hypothalamic control. Previous studies have shown that IL-7 is produced by the human obese white adipose tissue (WAT) yet its potential role on WAT development and function in obesity remains unknown. Here, we first show that transgenic mice overexpressing IL-7 have reduced adipose tissue mass associated with glucose and insulin resistance. Moreover, in the high-fat diet (HFD)-induced obesity model, a single administration of IL-7 to C57BL/6 mice is sufficient to prevent HFD-induced WAT mass increase and glucose intolerance. This metabolic protective effect is accompanied by a significant decreased inflammation in WAT. In lymphocyte-deficient HFD-fed SCID mice, IL-7 injection still protects from WAT mass gain. However, IL-7-triggered resistance against WAT inflammation and glucose intolerance is lost in SCID mice. These results suggest that IL-7 regulates adipose tissue mass through a lymphocyte-independent mechanism while its protective role on glucose homeostasis would be relayed by immune cells that participate to WAT inflammation. Our observations establish a key role for IL-7 in the complex mechanisms by which immune mediators modulate metabolic functions

A single injection of IL-7 protects SCID mice from HFD-induced obesity but not from glucose intolerance and WAT inflammation.

<p>(<b>A</b>) Body weight and perigonadal WAT and BAT masses of SCID male mice fed during 15 weeks with SD or HFD (white bars; PBS/SD, hatched bars; IL-7/SD, grey bars; PBS/HFD, black bars; IL-7/HFD); (<b>B</b>) Intraperitoneal glucose tolerance test at 6 weeks of diet feeding (white bars; PBS/SD, hatched bars; IL-7/SD, grey bars; PBS/HFD, black bars; IL-7/HFD); (<b>C</b>) Expression levels of macrophage (Emr1/F4-80, CD68) and inflammation (TNFα, MCP-1, Nos2) markers in perigonadal WAT, after 15 weeks of diet feeding, using real-time quantitative PCR (white bars; PBS/SD, hatched bars; IL-7/SD, grey bars; PBS/HFD, black bars; IL-7/HFD). Data are expressed as means ± SEM of 8 PBS/SD mice, 6 PBS/IL-7 mice, 3 PBS/HFD mice and 9 IL-7/PBS mice. ^#<i>p</i><0.05, ^##<i>p</i><0.01, ^###<i>p</i><0.001, HFD <i>vs</i> SD within the same injection group; ^*<i>p</i><0.05, ^***<i>p</i><0.001, IL-7 injection <i>vs</i> PBS injection in the same diet group.</p

A single injection of IL-7 reduces WAT inflammation during C57BL/6 HFD feeding.

<p>Real-time quantitative PCR analysis of the perigonadal white adipose tissue from C57BL/6 mice after a unique injection with PBS or IL-7, 16 weeks after SD or HFD feeding. (<b>A</b>) Expression levels of macrophages (Emr1/F4-80, CD68) and B-cells (CD19, CD20) markers; and (<b>B</b>) expression levels of inflammatory markers (TNFα, MCP-1 and Nos2). Data are expressed as means ± SEM of 7 to 9 mice per group (white bars; PBS/SD, hatched bars; IL-7/SD, grey bars; PBS/HFD, black bars; IL-7/HFD). ^#<i>p</i><0.05, ^##<i>p</i><0.01, ^###<i>p</i><0.001, HFD <i>vs</i> SD within the same injection group; ^*<i>p</i><0.05, ^**<i>p</i><0.01, ^***<i>p</i><0.001, IL-7 injection <i>vs</i> PBS injection within the same diet group.</p

A single injection of IL-7 protects high-fat diet-fed C576BL/6 mice from obesity and glucose intolerance.

<p>(<b>A</b>) Body weight at 16 weeks of diet feeding (white bars; PBS/SD, hatched bars; IL-7/SD, grey bars; PBS/HFD, black bars; IL-7/HFD); (<b>B</b>) An i.p. glucose tolerance test was performed after 5 weeks of diet feeding (grey squares-continuous line; PBS/SD, grey triangles-dotted line; IL-7/SD, black squares-continuous line; PBS/HFD, black triangles-dotted line; IL-7/HFD); (<b>C</b>) Masses of perigonadal WAT, inguinal SCAT and interscapular BAT at 16 weeks of diet feeding (white bars; PBS/SD, hatched bars; IL-7/SD, grey bars; PBS/HFD, black bars; IL-7/HFD); Data are expressed as means ± SEM of 7 to 9 mice per group. ^#<i>p</i><0.05, ^##<i>p</i><0.01, ^###<i>p</i><0.001, HFD <i>vs</i> SD within the same injection group; ^*<i>p</i><0.05, ^**<i>p</i><0.01, IL-7 injection <i>vs</i> PBS injection in the same diet group.</p

The IL-7 receptor is mostly expressed in the stromal vascular fraction of C57BL/6 adipose tissue.

<p>Expression levels of the mRNA of the IL-7 receptor subunits (IL-7Rα; black bars, γ_c; grey bars) (<b>A</b>) and IL-7 (<b>B</b>) in different insulin sensitive tissues and in adipose tissue fractions isolated from three C57BL/6 male mice, using quantitative PCR. The insulin receptor mRNA levels are shown as control (spotted bars). Thymus was used as a positive control for the expression of IL-7 and IL-7R.</p

Reduced white adipose tissue mass and insulin sensitivity in IL-7 overexpressing mice.

<p>(<b>A</b>) Perigonadal WAT mass in transgenic mice and control animals. Results are expressed as mean ± SEM of 7 WT mice (white bars) and 8 Tg IL-7 mice (black bars). (<b>B</b>) Adipocyte diameter distribution of 3 WT (white circles) and 3 Tg IL-7 (black circles). (<b>C</b>) Ratio of total triglycerides to total DNA (in pg/ng). Results are expressed as mean ± SEM of 3 WT mice (white bars) and 5 Tg IL-7 mice (black bars). (<b>D</b>) Glucose tolerance test: Blood samples for glucose level determination were taken from each individual animal. Results are expressed as mean ± SEM of 5 WT (white circles) and 5 Tg IL-7 (black circles). (<b>E</b>) Insulin tolerance test: Glycaemia were individually measured at the indicated times. Data are presented as mean percentage of basal glycemia (t = 0 min) from average value ± SEM from 5 WT (white circles) and 5 Tg IL-7 (black circles). (<b>F & G</b>) <i>In vivo</i> hyperinsulinaemic-euglycaemic clamps were performed using [3-³H] glucose and 2-deoxy-D-[1-¹⁴C] glucose (2DG) for the estimation of whole body glucose fluxes (<b>F</b>) and tissue glucose uptake (<b>G</b>), respectively. The uptake of glucose was determined in one red fiber-type of muscle (<i>Soleus</i>, S), one white fiber-type of muscle (<i>Tibialis anterior</i>, TA), inguinal SCAT, perigonadal WAT, and brown adipose tissue (BAT). Results are expressed as the mean ± SEM of 5 WT (white bars) and 5 Tg IL-7 (black bars). Statistically significant differences between the groups are indicated as <b>^*</b><i>p</i><0.05 and <b>^**</b><i>p</i><0.01.</p