No abstract

Antibody-mediated rejection is responsible for 30%-50% of renal graft failures. Differentiation of B cells into antibody-producing plasmablasts depends on the collaboration of follicular helper T cells (Tfh). We analyzed circulating Tfh (cTfh) in kidney recipients and studied cTfh relationship with anti-HLA antibody production and graft outcome. cTfh were longitudinally analyzed in a prospective cohort of patients (n = 206), pre- and posttransplantation. Clinical data, HLA sensitization, and cTfh function were recorded. Both pretransplant and 6-month posttransplant cTfh were able to derive IgG-producing plasmablasts. Pretransplant cTfh was decreased in patients, especially in those who received dialysis. However, these cells were increased in patients with previous allograft or transfusions and in HLA-sensitized recipients. After transplantation cTfh expanded, significantly more in patients who developed de novo anti-HLA antibodies than in patients who remained unsensitized. Augmented pretransplant cTfh positively correlated with higher intensity of pretransplant anti-HLA class I and with de novo anti-HLA class I and anti-HLA class II antibodies. Consistently, pretransplantation cTfh were higher in patients who experienced acute rejection (HR = 1.14 [1.04-1.25]). Thus, we show a role for Tfh in anti-HLA sensitization and rejection. Multicenter studies with additional patient cohorts are needed to validate these results. Immunosuppressive drugs targeting Tfh could be useful to improve outcomes.

The Th1/Th2 balance plays a crucial role in the progression of different pathologies and is a determining factor in the evolution of infectious diseases. This work has aimed to evaluate the early, or on diagnosis, T-cell compartment response, T-helper subsets and anti-SARS-CoV-2 antibody specificity in COVID-19 patients and to classify them according to evolution based on infection severity. A unicenter, randomized group of 146 COVID-19 patients was divided into four groups in accordance with the most critical events during the course of disease. The immunophenotype and T-helper subsets were analyzed by flow cytometry. Asymptomatic SARS-CoV-2 infected individuals showed a potent and robust Th1 immunity, with a lower Th17 and less activated T-cells at the time of sample acquisition compared not only with symptomatic patients, but also with healthy controls. Conversely, severe COVID-19 patients presented with Th17-skewed immunity, fewer Th1 responses and more activated T-cells. The multivariate analysis of the immunological and inflammatory parameters, together with the comorbidities, showed that the Th1 response was an independent protective factor for the prevention of hospitalization (OR 0.17, 95% CI 0.03–0.81), with an AUC of 0.844. Likewise, the Th1 response was found to be an independent protective factor for severe forms of the disease (OR 0.09, 95% CI: 0.01–0.63, p = 0.015, AUC: 0.873). In conclusion, a predominant Th1 immune response in the acute phase of the SARS-CoV-2 infection could be used as a tool to identify patients who might have a good disease evolution.

Life-threatening ‘breakthrough’ cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS-CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals (age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto-Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-α2 and IFN-ω, while two neutralized IFN-ω only. No patient neutralized IFN-β. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population.

Primary infection and/or reactivation of cytomegalovirus (CMV) in kidney transplant recipients (KTR) favor rejection and mortality. T follicular helper cells (TFH) could contribute to protection against CMV. Circulatory TFH (cTFH) were studied pretransplant and early posttransplant in 90 CMV seropositive KTR not receiving antithymocyte globulin or antiviral prophylaxis, followed‐up for 1 year. Patients who presented CMV infection had significantly lower cTFH and activated cTFH pretransplant and early posttransplant. Pretransplant activated cTFH were also lower within patients who developed CMV disease. Pre‐ and 14 days posttransplant activated cTFH were an independent protective factor for CMV infection (HR 0.41, p = .01; and 0.52, p = .02, respectively). KTR with low cTFH 7 days posttransplant (<11.9%) had lower CMV infection‐free survival than patients with high cTFH (28.2% vs. 67.6%, p = .002). cTFH were associated with CMV‐specific neutralizing antibodies (Nabs). In addition, IL‐21 increased interferon‐γ secretion by CMV‐specific CD8+ T cells in healthy controls. Thus, we show an association between cTFH and lower incidence of CMV infection, probably through their cooperation in CMV‐specific Nab production and IL‐21‐mediated enhancement of CD8+ T cell activity. Moreover, monitoring cTFH pre‐ and early posttransplant could improve CMV risk stratification and help select KTR catalogued at low/intermediate risk who could benefit from prophylaxis.

No abstract

BackgroundCOVID-19 is associated with higher morbidity and mortality burdens in immunocompromised individuals, including patients with systemic lupus erythematosus (SLE; 1). These patients might benefit from treatment with anti-SARS-CoV-2-specific antiviral agents and monoclonal antibodies, but clinical evidence is to date limited.Objectivesto comparatively assess the course of COVID-19 in patients with SLE treated or untreated with COVID-19-specific agents.MethodsPatients with SLE and COVID-19 treated with antivirals and/or monoclonal antibodies from February 2020 to December 2022 were identified within a three-centre cohort of tertiary referral centres and age-, sex- SLE extension- and SLE duration-matched 1:2 with patients with a history of untreated COVID-19. Data on COVID-19 presentation, course (including time to viral clearance) and sequelae, along with SLE treatment at COVID-19 onset and SLE course after COVID-19 were collected. COVID-19 severity at presentation was quantitated through a 0-4 analogue scale [2]. Data are expressed as median (interquartile range, IQR) unless otherwise specified.ResultsOver three years, 39% of patients with SLE had at least one COVID-19 event. Eighteen subjects (16 women) were treated with antivirals (n=12) or monoclonal antibodies (n=6) and were matched with 36 controls. There was no difference in the frequency of organ involvement between the two groups. Treated patients were receiving significantly higher prednisone daily doses at COVID-19 onset (6.25 (0-10) vs 0 (0-2.5) mg; p=0.005) and had a higher prevalence of previous high-dose steroid treatments (83% vs 47%; p=0.019) compared to controls. SLE disease activity index (3 (0-5) vs 1 (0-4)) and SLE International Collaborating Clinics Damage Index scores (1 (0-3) vs 0 (0-1)) were also numerically higher in treated patients at COVID-19 onset. Patients in the treated group had more severe COVID-19 at presentation but showed no significant differences with control subjects in terms of COVID-19 resolution, prevalence of sequelae and viral clearance (Table 1). There was also no difference in flare occurrence between the two groups (Log-rank=0.02, p=0.889). Two patients reported mild adverse events with monoclonal antibodies (muscle cramps and chest pain, both self-resolving).ConclusionThese data support the safe use of COVID-19 specific treatments in patients with SLE. Patients treated with antivirals and monoclonal antibodies had a favourable COVID-19 course, despite a more severe presentation and a higher risk of deterioration due to SLE and corticosteroid treatment burden, suggesting the potential efficacy of COVID-specific treatments in preventing severe COVID-19 in patients with SLE.References[1]Strangfeld A et al, Ann Rheum Dis, 2021[2]World Health Organization. Clinical management of COVID-19; Interim guidance 27 May 2020.Table 1.COVID-19 presentation and courseTreated (n=18)Untreated (n=36)Number of vaccine doses3 (2-3)3 (2-3)Time from last vaccine administration (days)118 (53-184)134 (30-210)COVID-19 featuresWHO class at presentation1 (1-1)**0 (0-1)Symptoms at presentation: n(%)Dyspnoea3 (17)3 (8)Fever10 (56)22 (61)Upper Respiratory Symptoms16 (89)29 (81)GI symptoms1 (6)2 (6)Pneumonia3 (17)3 (8)COVID-19 courseTime to symptom resolution (days)5 (4-8)7 (3-8)Time to viral clearance (days)10 (7-14)9 (7-14)Any complication: n(%)1 (6)6 (17)Hospitalisations: n(%)1 (6)0 (0)Long COVID: n(%)3 (17)6 (17)Deaths: n(%)0 (0)1 (3)AcknowledgementsWe thank Dr. Giordano Vitali and his staff for assisting and treating patients with SLE and COVID-19 from IRCCS San Raffaele Hospital in the local mild COVID-19 clinic.Disclosure of InterestsGiuseppe Alvise Ramirez Consultant of: Astrazeneca, Maria Gerosa: None declared, Daniel Arroyo-Sánchez: None declared, Chiara Asperti: None declared, Lorenza Maria Argolini: None declared, Gabriele Gallina: None declared, Chiara Bellocchi: None declared, Martina Cornalba: None declared, Isabella Scotti: None declared, Ilaria Suardi: None declared, Lorenzo Beretta: None declared, Luca Moroni Consultant of: Astrazeneca, Enrica Bozzolo: None declared, Roberto Caporali Speakers bureau: AbbVie, Amgen, BMS, Celltrion, Fresenius, Galapagos, Janssen, Lilly, Novartis, Pfizer, and UCB, Consultant of: AbbVie, Fresenius, Galapagos, Lilly, Novartis, Pfizer, and UCB, Lorenzo Dagna Consultant of: Abbvie, Amgen, Astra-Zeneca, Biogen, Boehringer-Ingelheim, Bristol-Myers Squibb, Celltrion, Eli Lilly and Company, Galapagos, GlaxoSmithKline, Janssen, Kiniksa Pharmaceuticals, Novartis, Pfizer, Roche, Sanofi-Genzyme, Swedish Orphan Biovitrium (SOBI), and Takeda, Grant/research support from: Abbvie, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Kiniksa, Merk Sharp & Dohme, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, Sanofi-Genzyme, and SOBI.

No abstract