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Little is known about antibody responses to natural Omicron infection and the risk factors for poor responders in patients with hematological malignancies (HM). We conducted a multicenter, prospective cohort study during the latest Omicron wave in Chongqing, China, aiming to compare the antibody responses, as assessed by IgG levels of anti‐receptor binding domain of spike protein (anti‐S‐RBD), to Omicron infection in the HM cohort (HMC) with healthy control cohort (HCC), and solid cancer cohort (SCC). In addition, we intend to explore the risk factors for poor responders in the HMC. Among the 466 HM patients in this cohort, the seroconversion rate was 92.7%, no statistically difference compared with HCC (98.2%, p = 0.0513) or SCC (100%, p = 0.1363). The median anti‐S‐RBD IgG titer was 29.9 ng/mL, significantly lower than that of HCC (46.9 ng/mL, p < 0.0001) or SCC (46.2 ng/mL, p < 0.0001). Risk factors associated with nonseroconversion included no COVID‐19 vaccination history (odds ratio [OR] = 4.58, 95% confidence interval [CI]: 1.75–12.00, p = 0.002), clinical course of COVID‐19 ≤ 7 days (OR = 2.86, 95% CI: 1.31–6.25, p = 0.008) and severe B‐cell reduction (0–10/μL) (OR = 3.22, 95% CI: 1.32–7.88, p = 0.010). Risk factors associated with low anti‐S‐RBD IgG titer were clinical course of COVID‐19 ≤ 7 days (OR = 2.58, 95% CI: 1.59–4.18, p < 0.001) and severe B‐cell reduction (0–10/μL) (OR = 2.87, 95% CI: 1.57–5.24, p < 0.001). This study reveals a poor antibody responses to Omicron (BA.5.2.48) infection in HM patients and identified risk factors for poor responders. Highlights that HM patients, especially those with these risk factors, may be susceptible to SARS‐CoV‐2 reinfection, and the postinfection vaccination strategies for these patients should be tailored. Clinical trial: ChiCTR2300071830. [ABSTRACT FROM AUTHOR]

Iron is necessary for various critical biological processes, but iron overload is also dangerous since labile iron is redox-active and toxic. We found that low serum iron and decidual local iron deposition existed simultaneously in recurrent pregnancy loss (RPL) patients. Mice fed with a low-iron diet (LID) also showed iron deposition in the decidua and adverse pregnancy outcomes. Decreased ferroportin (cellular iron exporter) expression that inhibited the iron export from decidual stromal cells (DSCs) might be the reason for local iron deposition in DSCs from low-serum-iron RPL patients and LID-fed mice. Iron supplementation reduced iron deposition in the decidua of spontaneous abortion models and improved pregnancy outcomes. Local iron overload caused ferroptosis of DSCs by downregulating glutathione (GSH) and glutathione peroxidase 4 levels. Both GSH and cystine (for the synthesis of GSH) supplementation reduced iron-induced lipid reactive oxygen species (ROS) and cell death in DSCs. Ferroptosis inhibitor, cysteine, and GSH supplementation all effectively attenuated DSC ferroptosis and reversed embryo loss in the spontaneous abortion model and LPS-induced abortion model, making ferroptosis mitigation a potential therapeutic target for RPL patients. Further study that improves our understanding of low-serum-iron-induced DSC ferroptosis is needed to inform further clinical evaluations of the safety and efficacy of iron supplementation in women during pregnancy. [ABSTRACT FROM AUTHOR]

T-cell immunoglobulin mucin-3 (Tim-3) is an important checkpoint that induces maternal–fetal tolerance in pregnancy. Macrophages (Mφs) play essential roles in maintaining maternal–fetal tolerance, remodeling spiral arteries, and regulating trophoblast biological behaviors. In the present study, the formation of the labyrinth zone showed striking defects in pregnant mice treated with Tim-3 neutralizing antibodies. The adoptive transfer of Tim-3+Mφs, rather than Tim-3−Mφs, reversed the murine placental dysplasia resulting from Mφ depletion. With the higher production of angiogenic growth factors (AGFs, including PDGF-AA, TGF-α, and VEGF), Tim-3+dMφs were more beneficial in promoting the invasion and tube formation ability of trophoblasts. The blockade of AGFs in Tim-3+Mφs led to the narrowing of the labyrinthine layer of the placenta, compromising maternal–fetal tolerance, and increasing the risk of fetal loss. Meanwhile, the AGFs-treated Tim-3−Mφs could resolve the placental dysplasia and fetal loss resulting from Mφ depletion. These findings emphasized the vital roles of Tim-3 in coordinating Mφs-extravillous trophoblasts interaction via AGFs to promote pregnancy maintenance and in extending the role of checkpoint signaling in placental development. The results obtained in our study also firmly demonstrated that careful consideration of reproductive safety should be taken when selecting immune checkpoint and AGF blockade therapies in real-world clinical care. [ABSTRACT FROM AUTHOR]

Lower extremity arteriosclerosis obliterans (LEASO) is a vascular disease that may result in adult limb loss worldwide. CD4+T cell-mediated immunity plays a significant role in LEASO. The T cell immunoglobulin and mucin domain 3 (Tim-3) and inhibitory receptor programmed cell death-1 (PD-1) are well-known immune checkpoints that play crucial roles in regulating CD4+T cell activation or tolerance. In this study, blood mononuclear cells were isolated from the blood samples of healthy controls and patients who were diagnosed with LEASO for the first time [stage III or IV according to the Fontaine classification system and had not received drugs (except for heparin) or surgery treatment]. We concluded the higher proportion of Tim-3+PD-1+CD4+T cells in human higher stage LEASO, and oxidized low-density lipoprotein increased Tim-3 and PD-1 co-expression by activating CD4+T cells in a dose- dependent manner. Tim-3+PD-1+CD4+T cells displayed a more active status and produced more anti-atherogenic cytokines compared to Tim-3-PD-1-CD4+T cells. Apart from the increased frequency, the altered function of Tim-3+PD-1+CD4+T cells was also observed in LEASO compared to those from healthy controls. These in vitro results indicated that Tim-3 and PD-1 might be promising early warning targets of higher stage LEASO. In addition, the blockade of Tim-3 and PD-1 signaling pathways aggravated the pro-atherogenic Th1 responses in LEASO, further suggesting that the cardiovascular safety must be a criterion considered in using immune checkpoint inhibitors to reverse T cell exhaustion during tumors and chronic viral infections. [ABSTRACT FROM AUTHOR]