Low Percentage of Perforin-Expressing NK Cells during Severe SARS-CoV-2 Infection: Consumption Rather than Primary Deficiency.

Genetic defects in the ability to deliver effective perforin have been reported in patients with hemophagocytic lymphohistiocytosis. We tested the hypothesis that a primary perforin deficiency might also be causal in severe SARS-CoV-2 infection. We recruited 54 volunteers confirmed as being SARS-CoV-2-infected by RT-PCR and admitted to intensive care units or non-intensive care units and age- and sex-matched healthy controls. Compared with healthy controls, the percentage of perforin-expressing CD3-CD56+ NK cells quantified by flow cytometry was low in COVID-19 patients (69.9 ± 17.7 versus 78.6 ± 14.6%, p = 0.026). There was no correlation between the proportions of perforin-positive NK cells and T8 lymphocytes. Moreover, the frequency of NK cells producing perforin was neither linked to disease severity nor predictive of death. Although IL-6 is known to downregulate perforin production in NK cells, we did not find any link between perforin expression and IL-6 plasma level. However, we unveiled a negative correlation between the degranulation marker CD107a and perforin expression in NK cells (r = -0.488, p = 10-4). PRF1 gene expression and the frequency of NK cells harboring perforin were normal in patients 1 y after acute SARS-CoV-2 infection. A primary perforin defect does not seem to be a driver of COVID-19 because NK perforin expression is 1) linked neither to T8 perforin expression nor to disease severity, 2) inversely correlated with NK degranulation, and 3) normalized at distance from acute infection. Thus, the cause of low frequency of perforin-positive NK cells appears, rather, to be consumption.

Post-polio syndrome is not a dysimmune condition.

BACKGROUND: Poliomyelitis is a global disabling disease affecting 12-20 million of people. Post poliomyelitis syndrome (PPS) may affect up to 80% of polio survivors: increased muscle weakness, pain, fatigue, functional decline. It relies on aging of an impaired neuro-muscular system with ongoing denervation processes. A late involvement of humoral or cellular pro-inflammatory phenomena is also suspected. AIM: To assess the dysimmune hypothesis of PPS by comparing lymphocyte subpopulations and humoral immune factors between PPS patients and controls. DESIGN: Cross-sectional study. SETTING: Montpellier University Hospital. POPULATION: Forty-seven PPS and 27 healthy controls. METHODS: PPS patients and controls were compared on their lymphocyte subpopulations and humoral immune factors (IL-1ß, IL-6, IL-8, IL-17, IL-21, IL-22, IL-23, IFN-γ, TNF-α, GM-CSF, RANTES, MCP1, MIP-3a, IL-10, TGF-ß, IL4, IL13). Patients were further compared according to their dominant clinical symptoms. Sample size guaranteed a power >90% for all comparisons. RESULTS: PPS patients and controls were comparable in gender, age and corpulence. Most patients had lower limb motor sequelae (N.=45, 95.7%), a minority had upper limb motor impairment (N.=16, 34.0%). Forty-five were able to walk (94%), 35/45 with technical aids. The median of the two-minute walking test was 110 meters (interquartile range 55; 132). Eighteen (38%) required help in their daily life. Their quality of life was low (SF36). All described an increased muscular weakness, 40 (85%) a general fatigue, and 39 (83%) muscular or joint pain. Blood count, serum electrolytes, T and B lymphocyte subpopulations and cytokines were comparable between patients and controls, except for creatine phospho kinase that was significantly higher in PPS patients. None of these variables differed between the 20/47 patients whose late main symptoms were pain or fatigue, and other patients. CONCLUSIONS: Our results suggest that PPS is not a dysimmune disease. CLINICAL REHABILITATION IMPACT: Our results do not sustain immunotherapy for PPS. Our work suggest that PPS may be mostly linked to physiological age-related phenomena in a disabled neuromuscular condition. Thus, our results emphasize the role of prevention and elimination of aggravating factors to avoid late functional worsening, and the importance of rehabilitation programs that should be adapted to patients' specific conditions.

Clinico-biological refinement of BCL11B-related disorder and identification of an episignature: A series of 20 unreported individuals.

PURPOSE: BCL11B-related disorder (BCL11B-RD) arises from rare genetic variants within the BCL11B gene, resulting in a distinctive clinical spectrum encompassing syndromic neurodevelopmental disorder, with or without intellectual disability, associated with facial features and impaired immune function. This study presents an in-depth clinico-biological analysis of 20 newly reported individuals with BCL11B-RD, coupled with a characterization of genome-wide DNA methylation patterns of this genetic condition. METHODS: Through an international collaboration, clinical and molecular data from 20 individuals were systematically gathered, and a comparative analysis was conducted between this series and existing literature. We further scrutinized peripheral blood DNA methylation profile of individuals with BCL11B-RD, contrasting them with healthy controls and other neurodevelopmental disorders marked by established episignature. RESULTS: Our findings unveil rarely documented clinical manifestations, notably including Rubinstein-Taybi-like facial features, craniosynostosis, and autoimmune disorders, all manifesting within the realm of BCL11B-RD. We refine the intricacies of T cell compartment alterations of BCL11B-RD, revealing decreased levels naive CD4+ T cells and recent thymic emigrants while concurrently observing an elevated proportion of effector-memory expressing CD45RA CD8+ T cells (TEMRA). Finally, a distinct DNA methylation episignature exclusive to BCL11B-RD is unveiled. CONCLUSION: This study serves to enrich our comprehension of the clinico-biological landscape of BCL11B-RD, potentially furnishing a more precise framework for diagnosis and follow-up of individuals carrying pathogenic BCL11B variant. Moreover, the identification of a unique DNA methylation episignature offers a valuable diagnosis tool for BCL11B-RD, thereby facilitating routine clinical practice by empowering physicians to reevaluate variants of uncertain significance within the BCL11B gene.

Comparative Evaluation of Four Commercially Available Immunoassays for Therapeutic Drug Monitoring of Infliximab and Adalimumab.

Therapeutic drug monitoring (TDM) of anti-TNF-α is an important tool in clinical practice for inflammatory diseases. In this study, we have evaluated the performance of several assays for drug and antidrug antibodies (ADA) measurement in the serum. 50 sera from patients treated with infliximab (IFX) and 49 sera from patients treated with adalimumab (ADAL) were monitored with four immunoassays. We have compared Promonitor, i-Track10®, and ez-track1 assays to our gold standard Lisa Tracker® ELISA using Cohen's kappa, Passing-Bablok, and Bland-Altman analysis. The qualitative analysis evaluated by Cohen's kappa values found for IFX measurements an "almost perfect" concordance for Promonitor, "moderate" for i-Track10® and "substantial" for ez-Track1. For ADAL, kappa values were "moderate" for all tested methods. For anti-IFX, kappa values were "almost perfect" for Promonitor, "fair" for i-Track10®, and "substantial" for ez-Track1. For anti-ADAL, kappa values were "almost perfect" for all three assays. For quantitative analysis of drug measurements, Pearson's r values were all above 0.9 and Lin's concordance coefficients of all immunoassays were around 0.80. Performances of the four evaluated immunoassays were acceptable for TDM based on our laboratory experience. Nevertheless, concordance between the four methods for IFX measurement was not perfect and we recommend the use of the same assay for the follow-up of a given patient. The performances of the four immunoassays evaluated were similar and are acceptable for TDM based on our laboratory experience.

T4 apoptosis in the acute phase of SARS-CoV-2 infection predicts long COVID.

Background: As about 10% of patients with COVID-19 present sequelae, it is important to better understand the physiopathology of so-called long COVID. Method: To this aim, we recruited 29 patients hospitalized for SARS-CoV-2 infection and, by Luminex®, quantified 19 soluble factors in their plasma and in the supernatant of their peripheral blood mononuclear cells, including inflammatory and anti-inflammatory cytokines and chemokines, Th1/Th2/Th17 cytokines, and endothelium activation markers. We also measured their T4, T8 and NK differentiation, activation, exhaustion and senescence, T cell apoptosis, and monocyte subpopulations by flow cytometry. We compared these markers between participants who developed long COVID or not one year later. Results: None of these markers was predictive for sequelae, except programmed T4 cell death. T4 lymphocytes from participants who later presented long COVID were more apoptotic in culture than those of sequelae-free participants at Month 12 (36.9 ± 14.7 vs. 24.2 ± 9.0%, p = 0.016). Conclusions: Our observation raises the hypothesis that T4 cell death during the acute phase of SARS-CoV-2 infection might pave the way for long COVID. Mechanistically, T4 lymphopenia might favor phenomena that could cause sequelae, including SARS-CoV-2 persistence, reactivation of other viruses, autoimmunity and immune dysregulation. In this scenario, inhibiting T cell apoptosis, for instance, by caspase inhibitors, could prevent long COVID.

Low perforin expression in CD8+ T lymphocytes during the acute phase of severe SARS-CoV-2 infection predicts long COVID.

T cell cytotoxicity plays a major role in antiviral immunity. Anti-SARS-CoV-2 immunity may determine acute disease severity, but also the potential persistence of symptoms (long COVID). We therefore measured the expression of perforin, a cytotoxic mediator, in T cells of patients recently hospitalized for SARS-CoV-2 infection. We recruited 54 volunteers confirmed as being SARS-CoV-2-infected by RT-PCR and admitted to Intensive Care Units (ICUs) or non-ICU, and 29 age- and sex-matched healthy controls (HCs). Amounts of intracellular perforin and granzyme-B, as well as cell surface expression of the degranulation marker CD107A were determined by flow cytometry. The levels of 15 cytokines in plasma were measured by Luminex. The frequency of perforin-positive T4 cells and T8 cells was higher in patients than in HCs (9.9 ± 10.1% versus 4.6 ± 6.4%, p = 0.006 and 46.7 ± 20.6% vs 33.3 ± 18.8%, p = 0.004, respectively). Perforin expression was neither correlated with clinical and biological markers of disease severity nor predictive of death. By contrast, the percentage of perforin-positive T8 cells in the acute phase of the disease predicted the onset of long COVID one year later. A low T8 cytotoxicity in the first days of SARS-CoV-2 infection might favor virus replication and persistence, autoimmunity, and/or reactivation of other viruses such as Epstein-Barr virus or cytomegalovirus, paving the way for long COVID. Under this hypothesis, boosting T cell cytotoxicity during the acute phase of the infection could prevent delayed sequelae.

Angiotensin II induces reactive oxygen species, DNA damage, and T-cell apoptosis in severe COVID-19.

BACKGROUND: Lymphopenia is predictive of survival in patients with coronavirus disease 2019 (COVID-19). OBJECTIVE: The aim of this study was to understand the cause of the lymphocyte count drop in severe forms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: Monocytic production of reactive oxygen species (ROSs) and T-cell apoptosis were measured by flow cytometry, DNA damage in PBMCs was measured by immunofluorescence, and angiotensin II (AngII) was measured by ELISA in patients infected with SARS-CoV-2 at admission to an intensive care unit (ICU) (n = 29) or not admitted to an ICU (n = 29) and in age- and sex-matched healthy controls. RESULTS: We showed that the monocytes of certain patients with COVID-19 spontaneously released ROSs able to induce DNA damage and apoptosis in neighboring cells. Of note, high ROS production was predictive of death in ICU patients. Accordingly, in most patients, we observed the presence of DNA damage in up to 50% of their PBMCs and T-cell apoptosis. Moreover, the intensity of this DNA damage was linked to lymphopenia. SARS-CoV-2 is known to induce the internalization of its receptor, angiotensin-converting enzyme 2, which is a protease capable of catabolizing AngII. Accordingly, in certain patients with COVID-19 we observed high plasma levels of AngII. When looking for the stimulus responsible for their monocytic ROS production, we revealed that AngII triggers ROS production by monocytes via angiotensin receptor I. ROSs released by AngII-activated monocytes induced DNA damage and apoptosis in neighboring lymphocytes. CONCLUSION: We conclude that T-cell apoptosis provoked via DNA damage due to the release of monocytic ROSs could play a major role in COVID-19 pathogenesis.

Clinical and Product Features Associated with Outcome of DLBCL Patients to CD19-Targeted CAR T-Cell Therapy.

CD19-directed CAR T-cells have been remarkably successful in treating patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) and transformed follicular lymphoma (t-FL). In this cohort study, we treated 60 patients with axicabtagene ciloleucel or tisagenlecleucel. Complete and partial metabolic responses (CMR/PMR) were obtained in 40% and 23% of patients, respectively. After 6.9 months of median follow-up, median progression-free survival (mPFS) and overall survival (mOS) were estimated at 3.1 and 12.3 months, respectively. Statistical analyses revealed that CMR, PFS, and OS were all significantly associated with age-adjusted international prognostic index (aaIPI, p < 0.05). T-cell subset phenotypes in the apheresis product tended to correlate with PFS. Within the final product, increased percentages of both CD4 and CD8 CAR+ effector memory cells (p = 0.02 and 0.01) were significantly associated with CMR. Furthermore, higher CMR/PMR rates were observed in patients with a higher maximal in vivo expansion of CAR T-cells (p = 0.05) and lower expression of the LAG3 and Tim3 markers of exhaustion phenotype (p = 0.01 and p = 0.04). Thus, we find that aaIPI at the time of infusion, phenotype of the CAR T product, in vivo CAR T-cell expansion, and low levels of LAG3/Tim3 are associated with the efficacy of CAR T-cell therapy in DLBCL patients.

Inherited GATA2 Deficiency Is Dominant by Haploinsufficiency and Displays Incomplete Clinical Penetrance.

PURPOSE: Germline heterozygous mutations of GATA2 underlie a variety of hematological and clinical phenotypes. The genetic, immunological, and clinical features of GATA2-deficient patients with mycobacterial diseases in the familial context remain largely unknown. METHODS: We enrolled 15 GATA2 index cases referred for mycobacterial disease. We describe their genetic and clinical features including their relatives. RESULTS: We identified 12 heterozygous GATA2 mutations, two of which had not been reported. Eight of these mutations were loss-of-function, and four were hypomorphic. None was dominant-negative in vitro, and the GATA2 locus was found to be subject to purifying selection, strongly suggesting a mechanism of haploinsufficiency. Three relatives of index cases had mycobacterial disease and were also heterozygous, resulting in 18 patients in total. Mycobacterial infection was the first clinical manifestation in 11 patients, at a mean age of 22.5 years (range: 12 to 42 years). Most patients also suffered from other infections, monocytopenia, or myelodysplasia. Strikingly, the clinical penetrance was incomplete (32.9% by age 40 years), as 16 heterozygous relatives aged between 6 and 78 years, including 4 older than 60 years, were completely asymptomatic. CONCLUSION: Clinical penetrance for mycobacterial disease was found to be similar to other GATA2 deficiency-related manifestations. These observations suggest that other mechanisms contribute to the phenotypic expression of GATA2 deficiency. A diagnosis of autosomal dominant GATA2 deficiency should be considered in patients with mycobacterial infections and/or other GATA2 deficiency-related phenotypes at any age in life. Moreover, all direct relatives should be genotyped at the GATA2 locus.

Two neurologic facets of CTLA4-related haploinsufficiency.

OBJECTIVE: To describe the clinical and radiologic neurologic characteristics of patients with cytotoxic T-lymphocyte antigen-4 (CTLA4) haploinsufficiency. METHODS: Three patients from 2 families had neurologic manifestations in the context of CTLA4 haploinsufficiency. Their clinical and MRI findings are presented. RESULTS: A 16-year-old boy with a previous diagnosis of combined immunodeficiency presented with severe recurrent episodes of headaches, motor deficit, and seizures associated with waxing and waning gadolinium-enhancing FLAIR cortical/juxtacortical hyperintensities. His sister, who also had combined immunodeficiency, had a brain MRI when she was aged 13 years due to recent headaches and transient right hemianopsia. It revealed a gadolinium-enhancing left occipital white matter hyperintensity. Another 49-year-old woman had progressive visual loss and cerebellar ataxia in the context of recurrent pulmonary infections. All 3 patients were found to have inherited CTLA4 haploinsufficiency. Patient 1's general condition and neurologic manifestations were completely controlled with abatacept (CTLA4-Ig). CONCLUSIONS: These cases suggest that in addition to the variable clinical penetrance and wide spectrum of CTLA4 haploinsufficiency, its neurologic spectrum is broad, ranging from recurrent tumefactive lesions to progressive deficits including cerebellar ataxia and optic atrophy with leukoencephalopathy. These phenotypes must be recognized, and should lead to a complete immunologic workup, because potentially effective targeted immunotherapy exists.

Risk factors of clinical dysimmune manifestations in a cohort of 86 children with 22q11.2 deletion syndrome: A retrospective study in France.

In this study, we describe the biological immune profiles and clinical dysimmune manifestations (infections, autoimmune diseases, and allergies) of patients with 22q11.2 deletion syndrome with the aim of determining risk factors for clinical events. This retrospective study concerned all the patients with 22q11 deletion syndrome attending the Montpellier University Hospital from January 1, 1992, to December 31, 2014 who had at least one immune investigation before the age of 18. We analyzed the clinical features, biological tests and the course of infections, autoimmunity, and allergy of 86 children. Among these 86 children, 48 (59%) had a low T lymphocyte level. Twenty-nine patients (34%) had a severe infection. The only risk factor for severe infection was the low level of CD4+ T-cells (OR: 3.3; 95% confidence interval (CI) [1.020-11.108]). Eleven patients (13%) developed an autoimmune disease; the only risk factor was an antecedent of severe infection (OR: 4.1; 95% CI [1.099-15.573]). Twenty-three patients (27%) had allergic episodes. A low level of CD8+ T-cells (OR: 3.2; 95% CI [1.07-9.409]) was significantly associated with allergy manifestations. Patients with 22q11 deletion syndrome have a high rate of dysimmune manifestations. We found statistic correlations among CD4+ T-cell count, infectious manifestations, and autoimmunity.

MicroRNAs: Key Regulators to Understand Osteoclast Differentiation?

MicroRNAs (miRNAs) are small non-coding single-stranded RNAs that represent important posttranscriptional regulators of protein-encoding genes. In particular, miRNAs play key roles in regulating cellular processes such as proliferation, migration, and cell differentiation. Recently, miRNAs emerged as critical regulators of osteoclasts (OCs) biology and have been involved in OCs pathogenic role in several disorders. OCs are multinucleated cells generated from myeloid precursors in the bone marrow, specialized in bone resorption. While there is a growing number of information on the cytokines and signaling pathways that are critical to control the differentiation of osteoclast precursors (OCPs) into mature OCs, the connection between OC differentiation steps and miRNAs is less well-understood. The present review will first summarize our current understanding of the miRNA-regulated pathways in the sequential steps required for OC formation, from the motility and migration of OCPs to the cell-cell fusion and the final formation of the actin ring and ruffled border in the functionally resorbing multinucleated OCs. Then, considering the difficulty of working on primary OCs and on the generation of robust data we will give an update on the most recent advances in the detection technologies for miRNAs quantification and how these are of particular interest for the understanding of OC biology and their use as potential biomarkers.

Respiratory Complications Lead to the Diagnosis of Chronic Granulomatous Disease in Two Adult Patients.

Chronic granulomatous disease (CGD) is a primary immunodeficiency associated to multiple life-threatening bacterial and fungal infections, beginning in childhood. There are rare cases of diagnosis in adulthood. We describe here two cases of late diagnosis in adults: a 45-year-old woman and 59-year-old-man. CGD diagnosis should be considered in adult patients with unexplained infectious diseases with tissue granuloma.

5' and 3' untranslated regions contribute to the differential expression of specific HLA-A alleles.

In hematopoietic stem cell transplantation (HSCT), when no HLA full-matched donor is available, alternative donors could include one HLA-mismatched donor. Recently, the low expressed HLA-C alleles have been identified as permissive mismatches for the best donor choice. Concerning HLA-A, the degree of variability of expression is poorly understood. Here, we evaluated HLA-A expression in healthy individuals carrying HLA-A*02 allele in different genotypes using flow cytometry and allele-specific quantitative RT-PCR. While an interindividual variability of HLA-A*02 cell surface expression, not due to the allele associated, was observed, no difference of the mRNA expression level was shown, suggesting the involvement of the posttranscriptional regulation. The results of qRT-PCR analyses exhibit a differential expression of HLA-A alleles with HLA-A*02 as the strongest expressed allele independently of the second allele. The associated non-HLA-A*02 alleles were differentially expressed, particularly the HLA-A*31 and HLA-A*33 alleles (strong expression) and the HLA-A*29 (low expression). The presence of specific polymorphisms in the 5' and 3' untranslated regions of the HLA-A*31 and HLA-A*33 alleles could contribute to this high level of expression. As previously described for HLA-C, low-expressed HLA-A alleles, such as HLA-A*29, could be considered as a permissive mismatch, although this needs to be confirmed by clinical studies.