The Robustness of Cellular Immunity Determines the Fate of SARS-CoV-2 Infection

Two years after the appearance of the SARS-CoV-2 virus, the causal agent of the current global pandemic, it is time to analyze the evolution of the immune protection that infection and vaccination provide. Cellular immunity plays an important role in limiting disease severity and the resolution of infection. The early appearance, breadth and magnitude of SARS-CoV-2 specific T cell response has been correlated with disease severity and it has been thought that T cell responses may be sufficient to clear infection with minimal disease in COVID-19 patients with X-linked or autosomal recessive agammaglobulinemia. However, our knowledge of the phenotypic and functional diversity of CD8+ cytotoxic lymphocytes, CD4+ T helper cells, mucosal-associated invariant T (MAIT) cells and CD4+ T follicular helper (Tfh), which play a critical role in infection control as well as long-term protection, is still evolving. It has been described how CD8+ cytotoxic lymphocytes interrupt viral replication by secreting antiviral cytokines (IFN-γ and TNF-α) and directly killing infected cells, negatively correlating with stages of disease progression. In addition, CD4+ T helper cells have been reported to be key pieces, leading, coordinating and ultimately regulating antiviral immunity. For instance, in some more severe COVID-19 cases a dysregulated CD4+ T cell signature may contribute to the greater production of pro-inflammatory cytokines responsible for pathogenic inflammation. Here we discuss how cellular immunity is the axis around which the rest of the immune system components revolve, since it orchestrates and leads antiviral response by regulating the inflammatory cascade and, as a consequence, the innate immune system, as well as promoting a correct humoral response through CD4+ Tfh cells. This review also analyses the critical role of cellular immunity in modulating the development of high-affinity neutralizing antibodies and germinal center B cell differentiation in memory and long-lived antibody secreting cells. Finally, since there is currently a high percentage of vaccinated population and, in some cases, vaccine booster doses are even being administered in certain countries, we have also summarized newer approaches to long-lasting protective immunity and the cross-protection of cellular immune response against SARS-CoV-2

Growth differentiation factor 15 (Gdf-15) : A novel biomarker associated with poorer respiratory function in covid-19

It is essential to find new biomarkers for severity stratification of patients with coronavirus disease (COVID-19). Growth differentiation factor 15 (GDF-15) is upregulated in pathological conditions that involve inflammation and/or oxidative stress. We determined circulating levels of GDF-15 and correlated them with clinical and laboratory parameters reflecting severity in 84 patients with COVID-19, finding that GDF-15 levels were higher in both patients than in 20 healthy controls and were higher in patients with poorer respiratory function. GDF-15 levels also correlated with interleukin-6, C-reactive protein, ferritin and D-dimer levels and with neutrophilia and lymphopenia. Of all the analysed biomarkers, GDF-15 showed the best area under the receiver operating characteristics curve in identifying patients with poor respiratory function. In conclusion, our data support GDF-15 as a biomarker associated with pulmonary impairment in COVID-19 and so can potentially be useful in stratifying COVID-19 cases by severity

Comparison of a human acellular dermal matrix and a polypropylene mesh for pelvic floor reconstruction : a randomized trial study in a rabbit model

Non-absorbable polypropylene (PP) meshes have been widely used in surgical reconstruction of the pelvic floor disorders. However, they are associated with serious complications. Human acellular dermal matrices (hADM) have demonstrated safety and efficacy in reconstructive medicine, but their suitability and efficacy at vaginal level is not known. This study compares the biological performance of PP mesh and a newly developed hADM. 20 rabbits were randomized to receive the hADM graft or the PP mesh. Grafts were surgically implanted in the abdominal wall and vagina. After 180 days, grafts were explanted and evaluated. The vaginal mesh extrusion rate was higher in the PP group (33% vs. 0%, p = 0.015). Full integration of the vaginal grafts was more frequent in the hADM group, where 35% of the grafts were difficult to recognize. In the PP group, the vaginal mesh was identified in 100% of the animals (p = 0.014). In PP group, the infiltrates had a focal distribution and were mostly located in the internal part of the epithelium, while in the hADM group, the infiltrates had a diffuse distribution. Additionally, the hADM group also presented more B-lymphocytes and less T-lymphocytes. Biomechanical analysis showed that hADM had lower resistance to stress. Moreover, PP mesh stiffness and elasticity were higher. Then, hADM is associated with fewer clinical complications, as well as better tissue integration. However, it shows greater incorporation into the surrounding native tissue, especially in the vaginal location, undergoing a reduction in its biomechanical properties 6 months after implantation

Antibodies against the flotillin-1/2 complex in patients with multiple sclerosis

Lleixa and Caballero-avila et al. report that antibodies targeting the flotillin-1/2 complex are present in a subgroup of patients with multiple sclerosis. Further studies are needed to understand the clinical and pathological relevance of anti-flotillin-1/2 autoantibodies in multiple sclerosis. Multiple sclerosis is a tissue-specific autoimmune disease of the central nervous system in which the antigen(s) remains elusive. Antibodies targeting the flotillin-1/2 complex have been described in 1-2% of the patients in a recent study. Other candidate antigens as anoctamin-2 or neurofascin-155 have been previously described in multiple sclerosis patients, although their clinical relevance remains uncertain. Our study aims to analyse the frequency and clinical relevance of antibodies against neurofascin-155, anoctamin-2 and flotillin-1/2 complex in multiple sclerosis. Serum (n = 252) and CSF (n = 50) samples from 282 multiple sclerosis patients were included in the study. The control group was composed of 260 serum samples (71 healthy donors and 189 with other neuroinflammatory disorders). Anti-flotillin-1/2, anti-anoctamin-2 and anti-neurofascin-155 antibodies were tested by cell-based assays using transfected cells. We identified six multiple sclerosis patients with antibodies against the flotillin-1/2 complex (2.1%) and one multiple sclerosis patient with antibodies against anoctamin-2 (0.35%). All multiple sclerosis patients were negative for anti-neurofascin-155 antibodies. Three of the anti-flotillin-1/2 positive patients showed anti-flotillin-1/2 positivity in other serum samples extracted at different moments of their disease. Immunoglobulin G subclasses of anti-flotillin-1/2 antibodies were predominantly one and three. We confirm that antibodies targeting the flotillin-1/2 complex are present in a subgroup of patients with multiple sclerosis. Further studies are needed to understand the clinical and pathological relevance of anti-flotillin-1/2 autoantibodies in multiple sclerosis

Reversions of QuantiFERON-TB Gold Plus in tuberculosis contact investigation: A prospective multicentre cohort study

Background: Interferon-y Release Assays (IGRA) reversions have been reported in different clinical scenarios for the diagnosis of tuberculosis (TB) infection. This study aimed to determine the rate of QuantiFERON-TB Gold Plus (QFT-Plus) reversions during contact investigation as a potential strategy to reduce the number of preventive treatments. Methods: Prospective, multicentre cohort study of immunocompetent adult contacts of patients with pulmonary TB tested with QFT-Plus. Contacts with an initial positive QFT-Plus (QFT-i) underwent a second test within 4 weeks (QFT-1), and if negative, underwent a repeat test 4 weeks later (QFT-2). Based on the QFT-2 result, we classified cases as sustained reversion if they remained negative and as temporary reversion if they turned positive. Results: We included 415 contacts, of whom 96 (23.1%) had an initial positive test (QFT-i). Following this, 10 had negative QFT-1 results and 4 (4.2%) of these persisted with a negative result in the QFT-2 (sustained reversions). All four sustained reversions occurred in contacts with IFN-γ concentrations between ≥0.35 and ≤0.99 IU•mL-1 in one or both QFT-i tubes. Conclusion: In this study, TB contact investigations rarely reveal QFT-Plus reversion. These results do not support retesting cases with an initial positive result to reduce the number of preventive treatments

Identification of recent tuberculosis exposure using QuantiFERON-TB Gold Plus, a multicenter study.

We investigated whether the difference of antigen tube 2 (TB2) minus antigen tube 1 (TB1) (TB22TB1) of the QuantiFERON-TB gold plus test, which has been postulated as a surrogate for the CD81 T-cell response, could be useful in identifying recent tuberculosis (TB) exposure. We looked at the interferon gamma (IFN-g) responses and differences in TB2 and TB1 tubes for 686 adults with QFT-plus positive test results. These results were compared among groups with high (368 TB contacts), low (229 patients with immune-mediated inflammatory diseases [IMID]), and indeterminate (89 asylum seekers or people from abroad [ASPFA]) risks of recent TB exposure. A TB22TB1 value .0.6 IU ml21 was deemed to indicate a true difference between tubes. In the whole cohort, 13.6%, 10.9%, and 11.2% of cases had a TB2.TB1 result in the contact, IMID, and ASPFA groups, respectively (P = 0.591). The adjusted odds ratios (aORs) for an association between a TB22TB1 result of .0.6 IU ml21 and risk of recent exposure versus contacts were 0.71 (95% confidence interval [CI], 0.31 to 1.61) for the IMID group and 0.86 (95% CI, 0.49 to 1.52) for the ASPFA group. In TB contact subgroups, 11.4%, 5.4%, and 17.7% with close, frequent, and sporadic contact had a TB2.TB1 result (P = 0.362). The aORs versus the close subgroup were 1.29 (95% CI, 0.63 to 2.62) for the frequent subgroup and 1.55 (95% CI, 0.67 to 3.60) for the sporadic subgroup. A TB22TB1 difference of .0.6 IU ml21 was not associated with increased risk of recent TB exposure, which puts into question the clinical potential as a proxy marker for recently acquired TB infection

Potenciació de la citotoxicitat cel·lular induïda pel rituximab en cèl·lules B de LLC

Consultable des del TDXTítol obtingut de la portada digitalitzadaL'evolució clínica de la leucèmia limfocitària crònica (LLC) és amb freqüència indolent, però és una malaltia que roman incurable. Els pacients simptomàtics tenen una supervivència entre 1-7 anys, fins i tot utilitzant les millors opcions terapèutiques. Encara que han estat avaluades tot una sèrie de combinacions terapèutiques en pacients amb recaiguda o refractaris als tractaments, cap alternativa ha demostrat ser superior. Per tant, és evident la necessitat de trobar alternatives terapèutiques per aquests pacients. Diferents estudis en fase II han mostrat que l'associació del rituximab a la quimioteràpia ha millorat el percentatge de resposta i el període lliure de malaltia. No obstant, tots els pacients a la llarga experimenten una progressió de la malaltia. Un dels principals mecanismes d'acció del rituximab és la citotoxicitat cel·lular depenent d'anticossos. Les principals cèl·lules efectores implicades en aquest mecanisme d'acció són les cèl·lules portadores de receptors Fc, i dintre d'aquest grup les que juguen un paper primordial són les cèl·lules NK. La hipòtesi general va ser l'anàlisi de molècules potenciadores de la capacitat citotòxica de les cèl·lules NK i de l'ADCC, per poder ser utilitzades associades al rituximab com a adjuvants en el tractament de les leucèmies limfàtiques cròniques. Entre aquestes molècules es va estudiar el CpG ODN A per mimetitzar l'activitat estimuladora del DNA bacterià, a través del TLR9 i provocar una forta activació i síntesi d'IFN per cèl·lules NK. L'altre molècula va ser l'IL-15 per estar estretament relacionada en la supervivència, proliferació i activació de les cèl·lules NK. Es va observar que la IL-15 i el CpG ODN A eren 2 molècules estimuladores que potenciaven significativament la capacitat citotòxica de PBMCs, en presència o absència de rituximab, quan s'enfrontaven tant a una línia cel·lular de limfoma B humà com a cèl·lules leucèmiques de LLC-B. La principal població efectora responsable d'aquesta potenciació citotòxica van ser les cèl·lules NK. No obstant el mecanisme d'acció responsable va ser diferent. Mentre que la IL-15 incrementava la capacitat citotòxica de la cèl·lula NK tant directament com indirectament, el CpG ODN A ho feia només indirectament requerint de senyals addicionals presents a les PBMCs. Quan les PBMCs es van enfrontar a cèl·lules de limfoma B de la línia cel·lular Raji va resultar que els dos estímuls es comportaven igual. Però quan van ser cèl·lules leucèmiques de LLC-B, la IL-15 es va comportar com un estímul significativament més potent que el CpG ODN A incrementant la citotoxicitat natural i l'ADCC. La IL-15 en aquest sentit va actuar incrementant l'expressió de receptors relacionats amb cèl·lules NK en desgranulació (CD16, CD69 i NKG2D) i del receptor LFA-1 implicat en la senyalització de la citotoxicitat (adhesió cel·lular). Així com produint un augment significatiu d'IFN-. En presència de TGF-, citocina immunosupressora que disminueix de manera significativa la citotoxicitat natural i l'ADCC de PBMCs enfrontades a cèl·lules leucèmiques de LLC, la IL-15 va poder contrarestar aquest efecte supressor. De la mateixa manera en presència d'IL-15, la disminució que provoca el TGF- en la producció d'IFN-, va ser menor i més variable no sent significativa.The clinical course of chronic lymphocytic leukemia is often insidious, but it is a disease that remains not treatable. Even using the best therapeutic options, symptomatic patients have a survival between 1-7 years. Several series of therapeutic combinations have been evaluated for patients with relapses and refractory to treatment, but none has been demonstrated to be superior. Therefore, it is notable the need to find therapeutic alternatives for these patients. Different studies in phase II have shown that the addition of rituximab to chemotherapy has improved the percentage of response and the disease free period. However, all patients suffer progression of the disease at long term. One of the main mechanisms of action of rituximab is the antibody mediated cytotoxicity. The most important effector cells involved in this mechanism of action are Fc receptors cells, specifically NK cells. The general hypothesis is the analysis of molecules enhancing the cytotoxic capacity of NK cells and ADCC, for them to be used in addition to rituximab as adjuvant in the treatment of chronic lymphocytic leukemia. Amongst these molecules, CpG ODN A was studied because its capacity to mimetise the stimulating activity of bacterial DNA through TLR9 and to induce a strong activation and synthesis of IFN by NK cells. The other molecule was IL-15, due to its involvement in survival, proliferation and activation of NK cells. It was observed that IL-15 and CpG ODN A were two stimulating molecules than significantly enhanced the cytotoxic capacity of PBMCs, in the presence or absence of rituximab, when they were confronted to cells from B lymphoma Raji line and to leukemic cells from CLL-B. The major effector population responsible for this cytotoxic enhancement are the NK cells. However, the mechanism of action is different. Whereas IL-15 increased the cytotoxic capacity of the NK cell directly as much as indirectly, CpG ODN A did it only indirectly, requiring of additional signals present in PBMCs. When PBMCs were confronted to Raji cells from B cell lymphoma, the two stimuli had a similar behavior. However, when PBMCs were confronted to leukemic cells from CLL-B, Il-15 was a stronger stimulus than CpG ODN A, enhancing the natural cytotoxicity and ADCC. In this way, IL-15 worked increasing the expression of receptors related to degranulating NK cells (CD16, CD69 and NKG2D) and of LFA-1 receptor, implied in the cytotoxicity signaling (cellular adhesion), and increasing significantly IFN production. In the presence of TGF-, immunosupressor cytokine that decrease significantly the natural cytotoxicity and ADCC of PBMCs confronted to leukemic cells from CLL, IL-15 is able to counteract this suppressive effect. In the same way, the reduction caused in IFN- production is going to be smaller and more variable in the presence of IL-15, although not significantly

Comparison of a human acellular dermal matrix and a polypropylene mesh for pelvic floor reconstruction: a randomized trial study in a rabbit model

Non-absorbable polypropylene (PP) meshes have been widely used in surgical reconstruction of the pelvic floor disorders. However, they are associated with serious complications. Human acellular dermal matrices (hADM) have demonstrated safety and efficacy in reconstructive medicine, but their suitability and efficacy at vaginal level is not known. This study compares the biological performance of PP mesh and a newly developed hADM. 20 rabbits were randomized to receive the hADM graft or the PP mesh. Grafts were surgically implanted in the abdominal wall and vagina. After 180 days, grafts were explanted and evaluated. The vaginal mesh extrusion rate was higher in the PP group (33% vs. 0%, p = 0.015). Full integration of the vaginal grafts was more frequent in the hADM group, where 35% of the grafts were difficult to recognize. In the PP group, the vaginal mesh was identified in 100% of the animals (p = 0.014). In PP group, the infiltrates had a focal distribution and were mostly located in the internal part of the epithelium, while in the hADM group, the infiltrates had a diffuse distribution. Additionally, the hADM group also presented more B-lymphocytes and less T-lymphocytes. Biomechanical analysis showed that hADM had lower resistance to stress. Moreover, PP mesh stiffness and elasticity were higher. Then, hADM is associated with fewer clinical complications, as well as better tissue integration. However, it shows greater incorporation into the surrounding native tissue, especially in the vaginal location, undergoing a reduction in its biomechanical properties 6 months after implantation

Rabbit as an animal model for the study of biological grafts in pelvic floor dysfunctions

The aims of this study were to evaluate the feasibility of the New Zealand White (NZW) rabbit for studying implanted biomaterials in pelvic reconstructive surgery; and to compare the occurrence of graft-related complications of a commercial polypropylene (PP) mesh and new developed human dermal matrix implanted at vaginal and abdominal level. 20 white female NZW rabbits were randomized into two groups, experimental group (human acellular dermal matrices-hADM-graft) and control group (commercial PP graft). In each animal, grafts were surgically implanted subcutaneously in the abdominal wall and in the vaginal submucosa layer for 180 days. The graft segments were then removed and the surgical and clinical results were analyzed. The main surgical challenges during graft implantation were: (a) an adequate vaginal exposure while maintaining the integrity of the vaginal mucosa layer; (b) to keep aseptic conditions; (c) to locate and dissect the breast vein abdominal surgery; and (d) to withdraw blood samples from the ear artery. The most abnormal findings during the explant surgery were found in the PP group (33% of vaginal mesh extrusion) in comparison with the hADM group (0% of vaginal graft extrusion), p = 0.015. Interestingly, macroscopic observation showed that the integration of the vaginal grafts was more common in the hADM group (40%) than in the PP group, in which the vaginal mesh was identified in 100% of the animals (p = 0.014). The NZW rabbit is a good model for assessing materials to be used as grafts for pelvic reconstructive surgery and vaginal surgery. Animals are easily managed during the procedures, including surgical intervention and vaginal mucosa approach. Additionally, hADM is associated with fewer clinical complications, as well as better macroscopic tissue integration, compared to PP mesh