(1) Background: The serum ferritin cut-off to define absolute iron deficiency is not well-established. The aim of the present study was to determine a clinically relevant ferritin threshold by using early serum biomarkers of iron deficiency such as hepcidin and the soluble transferrin receptor; (2) Methods: Two hundred and twenty-eight asymptomatic subjects attending a hospital as outpatients between 1st April 2020 and 27th February 2022 were selected. Iron metabolism parameters as part of the blood analysis were requested by their doctor and included in the study. Then, they were classified into groups according to their ferritin levels and iron-related biomarkers in serum were determined, quantified, and compared between ferritin score groups and anemic subjects. (3) Results: Serum ferritin levels below 50 ng/mL establish the point from which the serum biomarker, the soluble transferrin receptor to hepcidin ratio (sTfR/Hep ratio), begins to correlate significantly with ferritin levels. (4) Conclusion: Ferritin levels ≤ 50 ng/mL are indicative of early iron deficiency; hence, this should be considered as a clinically relevant cut-off for iron deficiency.

Introduction: Severe COVID-19 can result in a significant and irreversible impact on long-term recovery and subsequent immune protection. Understanding the complex immune reactions may be useful for establishing clinically relevant monitoring. Methods: Hospitalized adults with SARS-CoV-2 between March/October 2020 (n = 64) were selected. Cryopreserved peripheral blood mononuclear cells (PBMCs) and plasma samples were obtained at hospitalization (baseline) and 6 months after recovery. Immunological components’ phenotyping and SARS-CoV-2-specific T-cell response were studied in PBMCs by flow cytometry. Up to 25 plasma pro/anti-inflammatory cytokines/chemokines were assessed by LEGENDplex immunoassays. The SARS-CoV-2 group was compared to matched healthy donors. Results: Biochemical altered parameters during infection were normalized at a follow-up time point in the SARS-CoV-2 group. Most of the cytokine/chemokine levels were increased at baseline in the SARS-CoV-2 group. This group showed increased Natural Killer cells (NK) activation and decreased CD16^high NK subset, which normalized six months later. They also presented a higher intermediate and patrolling monocyte proportion at baseline. T cells showed an increased terminally differentiated (TemRA) and effector memory (EM) subsets distribution in the SARS-CoV-2 group at baseline and continued to increase six months later. Interestingly, T-cell activation (CD38) in this group decreased at the follow-up time point, contrary to exhaustion markers (TIM3/PD1). In addition, we observed the highest SARS-CoV-2-specific T-cell magnitude response in TemRA CD4 T-cell and EM CD8 T-cell subsets at the six-months time point. Conclusions: The immunological activation in the SARS-CoV-2 group during hospitalization is reversed at the follow-up time point. However, the marked exhaustion pattern remains over time. This dysregulation could constitute a risk factor for reinfection and the development of other pathologies. Additionally, high SARS-CoV-2-specific T-cells response levels appear to be associated with infection severity.

Torque teno virus (TTV) viral load (VL), a component of the human virome, increases during immune suppression or dysregulation. This study aimed to explore TTV VL in youths living with vertically acquired HIV (YWVH) and its potential as an immunovirological marker. We performed an observational, retrospective study involving YWVH under antiretroviral treatment (ART) from the Spanish Cohort of HIV-infected children, adolescents, and vertically HIV-infected patients transferred to Adult Units (CoRISpe-FARO), compared to HIV-negative healthy donors (HD). Plasma TTV VL was assessed by qPCR. T-cell phenotype was analysed on cryopreserved peripheral blood mononuclear cells by flow cytometry. Correlations with baseline CD4 and CD8 and long-term virological evolution were examined. A total of 57 YWVH were compared with 23 HD. YWVH had a median CD4 T-cells of 736 cells/mm³ [IQR: 574–906], a median of 17 years [IQR: 14–20.5] since ART initiation, and 65 months [IQR: 39–116] under HIV-RNA virological control. TTV VL was higher among YWVH and in males compared with females (p < 0.05). Among YWVH, TTV VL correlated with CD4 and CD8 counts and the CD4/CD8 ratio (p = 0.002; r = − 0.39, p = 0.037; r = 0.277, p = 0.005; r = − 0.37 respectively). TTV VL correlated with activation expression markers (HLA-DR+/CD38+) on CD4 (p = 0.007, r = 0.39) and the soluble proinflammatory cytokine IL-6 (p = 0.006, r = 0.38).

Plasmacytoid dendritic cells (pDCs) sense viral and bacterial products through Toll-like receptor (TLR)-7 and -9 and translate this sensing into Interferon-α (IFN-α) production and T-cell activation. The understanding of the mechanisms involved in pDCs stimulation may contribute to HIV-cure immunotherapeutic strategies. The objective of the present study was to characterize the immunomodulatory effects of TLR agonist stimulations in several HIV-1 disease progression phenotypes and in non HIV-1 infected donors. pDCs, CD4 and CD8 T-cells were isolated from 450 ml of whole blood from non HIV-1 infected donors, immune responders (IR), immune non responders (INR), viremic (VIR) and elite controller (EC) participants. pDCs were stimulated overnight with AT-2, CpG-A, CpG-C and GS-9620 or no stimuli. After that, pDCs were co-cultured with autologous CD4 or CD8 T-cells and with/without HIV-1 (Gag peptide pool) or SEB (Staphylococcal Enterotoxin B). Cytokine array, gene expression and deep immunophenotyping were assayed. pDCs showed an increase of activation markers levels, interferon related genes, HIV-1 restriction factors and cytokines levels after TLR stimulation in the different HIV-disease progression phenotypes. This pDC activation was prominent with CpG-C and GS-9620 and induced an increase of HIV-specific T-cell response even in VIR and INR comparable with EC. This HIV-1 specific T-cell response was associated with the upregulation of HIV-1 restriction factors and IFN-α production by pDC. These results shed light on the mechanisms associated with TLR-specific pDCs stimulation associated with the induction of a T-cell mediated antiviral response which is essential for HIV-1 eradication strategies. This work was supported by 10.13039/100005564 Gilead fellowship program, the 10.13039/501100004587 Instituto de Salud Carlos III ( 10.13039/501100008530 Fondo Europeo de Desarrollo Regional , 10.13039/501100002924 FEDER , “a way to make Europe”) and the Red Temática de Investigación Cooperativa en SIDA and by the 10.13039/501100003339 Spanish National Research Council ( 10.13039/501100003339 CSIC ).

Obesity and iron deficiency (ID) are widespread health issues, with subclinical inflammation in obesity potentially contributing to ID through unclear mechanisms. The aim of the present work was to elucidate how obesity-associated inflammation disturb iron metabolism and to investigate the effect of intravenous (IV) iron supplementation on absolute iron deficient pre-obese (BMI 25.0–29.9 kg/m²) and obese (BMI > 30 kg/m²) individuals compared to healthy weight (HW) group (BMI 18.5–24.9 kg/m²). Iron-related, hematological and inflammatory biomarkers along with erythropoietin (EPO) were studied based on body mass index (BMI) in a Spanish cohort of non-anemic participants (n = 721; 67% women; median age of 48 years [IQR: 39–57]) and in a subgroup of subjects (n = 110) with absolute ID (ferritin < 50 ng/mL) after completing an IV iron therapy. Obese group exhibited higher levels of ferritin, hemoglobin (Hb), soluble transferrin receptor (sTfR) and hepcidin compared to HW group. Elevated BMI was independently associated with increased sTfR levels. While no statistical differences were found in EPO among groups, obese showed increased levels that inversely correlated with Hb only in pre-obese and obese groups. IV iron therapy on obese participants had significant improvements on iron-related parameters and Hb levels. Notable obesity-associated disturbances in iron metabolism are described and indicate a mixed ID among both, women and men. These findings highlight the importance of tailored interventions to correctly address ID in obese population.