Anne Sophie L'HOnneur

Context: Bispecific antibodies (bsAbs) recently reshaped the treatment landscape of multiple myeloma (MM). Rare cases of progressive multifocal leukoencephalopathy (PML) have been reported in MM patients, and more recently in bsAbs-treated patients. Objectives: We aimed to investigate a potential safety signal for PML in patients with MM treated with bsAbs. Methods: We included all patients with MM treated with bsAbs identified in the French prospective registry of JC polyomavirus infections of the central nervous system and/or from the French pharmacovigilance database (FPVD). We also performed a systematic review. We then assessed whether a disproportionality signal for PML reporting exists, comparing bsAbs and other MM therapies in VigiBase®, the world pharmacovigilance database. Results: In the registry-FPVD cohort, 14 patients were included; all had at least triple-refractory MM, with a median disease duration of 13 years (IQR, 10-14) and were exposed to BCMA-targeting bsAbs (median time to PML diagnosis: 22 months, IQR, 12-24); 10 (71%) were in complete response. Main clinical manifestations included motor deficit, cognitive impairment and visual symptoms (8/14 patients each, 57%). Twelve (86%) had died from PML by month 12. Similar features and outcomes were observed in the systematic review (n=14 cases). PML reporting was significantly higher with bsAbs than with other MM therapies (Reporting Odds Ratio 17.7; 95% CI, 12.1-26.1). Interpretation: PML may represent an emerging complication in patients with MM receiving bsAbs. Vigilant monitoring and rapid assessment of new neurological deficits are critical in this population.

Le polyomavirus humain JC (JCV) est un virus ubiquitaire qui infecte de façon persistante et asymptomatique la majorité de la population, entrainant occasionnellement une excrétion urinaire. Dans le contexte d'immunodépression, le JCV peut infecter les cellules gliales du système nerveux central (SNC), provoquant une maladie démyélinisante fatale, la Leucoencéphalopathie Multifocale Progressive (LEMP). Le génome du JCV est un ADN double brin circulaire de 5 kb composé de 2 régions codantes opposées -précoce et tardive- séparées par une région non codante de contrôle (NCCR). En comparaison à la séquence NCCR urinaire archétypale les séquences obtenues du SNC de patients atteints de LEMP sont constituées de réarrangements dont le rôle n'est pas entièrement connu. Pour étudier l'effet de ces réarrangements en culture cellulaire, la technologie des minicercles d'ADN a été adaptée afin de produire 4 vecteurs bidirectionnels exprimant deux gènes rapporteurs fluorescents sour le contrôle d'une NCCR archétypale (NCCR at) ou réarrangée (NCCR rr) comportant une délétion de 66 pb. Après transfection de cellules humaines gliales U-87MG et rénales HEK293, l'expression des rapporteurs à partir des NCCR at et rr a été mesurée par cytométrie en flux. Dans les cellules HEK293, l'expression des régions codantes précoce et tardive à partir de la NCCR at est similaire tandis que dans les cellules U-87MG, l'expression précoce est 2.1 fois supérieure à l'expression tardive (p <0.001). Par ailleurs, l'expression tardive à partir de la NCCR rr est similaire à l'expression précoce dans les cellules HEK293 et U-87MG. Ces résultats suggèrent que la délétion de 66 pb restaure l'expression tardive dans la lignée de glioblastome. L'utilisation d'un modèle in vitro a permis de mettre en évidence un lien particulier entre la séquence NCCR et l'expression dépendant du type cellulaire. En plus de la variabilité inter compartiment déjà décrite pour un même patient atteint de LEMP, la variabilité intra compartiment a été évaluée au moyen d'une technique de « single molecule real-time (SMRT) sequencing » à partir de 23 liquides céphalorachidiens (LCR), 1 biopsie cérébrale et 19 prélèvements urinaires de patients atteints de LEMP ainsi que 5 prélèvement urinaires de patients non atteints de LEMP. L'ensemble du génome du JCV a été amplifié en 2 fragments chevauchants aux deux extrémités, chacun constitué de la NCCR et de l'une ou l'autre des régions codantes. Les amplicons ont été séquencés par la technique SMRT PacBio. L'analyse phylogénétique montre une répartition des souches cérébrales parmi 6 génotypes différents, révélant l'absence de pathogénicité spécifique de type. Les séquences NCCR cérébrales comportent diverses délétions touchant principalement les sections b, d, et f ainsi que des insertions des sections c et e dupliquées. Chez la majorité des patients atteints de LEMP (18/23), la population virale cérébrale est composée d'au moins 2 formes de NCCR distinctes dont la structure suggère un lien d'apparition chronologique entre ces deux variants. Par ailleurs, des substitutions d'acide aminé au niveau de 7 emplacements déjà décrits dans la protéine VP1 ont été identifiées exclusivement dans les souches cérébrales. Hormis plusieurs mutations en rapport avec des polymorphismes de souches, 2 nouvelles substitutions ont été observées à partir du LCR de deux patients différents situées respectivement dans le domaine hélicase de la séquence AgLT (Tyr407Asn) et dans le domaine N-terminal du gène VP2 (Pro65Ala). Ces mutations pourraient jouer un rôle dans la pathogénicité en modifiant les capacités réplicatives virales, en créant un changement de structure de la particule virale ou en favorisant l'échappement à la réponse immune. Ce travail fournit un argument supplémentaire en faveur de l'implication des réarrangements de la NCCR dans la neuropathogénicité du JCV et apporte un éclairage nouveau sur les populations virales associées à la LEMP.

Background: We aimed to compare the characteristics of human metapneumovirus (hMPV) infection with influenza A and B virus (FLUV) and respiratory syncytial virus (RSV) infections in adults hospitalized with influenza-like illness (ILI). Methods: We conducted a post hoc analysis of adult patients hospitalized with community-acquired ILI who were enrolled in the FLUVAC study at 5 French referral hospitals from 2012 to 2022. Results: At least 1 respiratory virus was detected in 3620 of 6618 patients (55%), including FLUV (1524/3620 [42%]), RSV (248/3620 [7%]), and hMPV (162/3620 [5%]). hMPV+ patients, when compared to FLUV+ patients were more likely to develop at least 1 complication (60% [86/143] vs 50% [716/1435]; P = .02), especially acute heart failure, which occurred twice as often in hMPV+ during the hospital stay (22% [32/143] vs 11% [160/1434]; P < .001). The rates of respiratory (30% [43/143] vs 32% [70/216]; P = .73) or cardiac (22% [32/143] vs 15% [33/216]; P = .09) complications did not differ between hMPV+ and RSV+ patients. The in-hospital all-cause death rate was similar among all 3 populations (4% hMPV+, 4% FLUV+, and 5% RSV+). Conclusions: Hospitalized hMPV infections affect older patients with multiple chronic conditions who face frequent cardiac and pulmonary complications during hospitalization more frequently than with influenza and similar to RSV.

Background: To assess human parechovirus (HPeV) detection by real-time polymerase chain reaction in blood with or without cerebrospinal fluid samples in neonates and infants and compare the clinical and biological characteristics of HPeV patients with those of patients with or without enterovirus (EV) infection. Methods: In all, 92 HPeV-infected patients (40 newborns and 52 infants) presenting with fever without source, sepsis-like disease or suspected meningitis were evaluated in 2 French hospitals from 2007 to 2018. The clinical and biological characteristics of HPeV patients were compared with those of 100 EV-infected patients and of 95 control patients with fever without source or sepsis-like disease. Results: HPeV was detected more frequently in blood [100% (51/51)] than in cerebrospinal fluid specimens [89% (67/75), P = 0.02]. Genotyping identified HPeV3 in 76/85 (89%) positive specimens. HPeV-infected patients were more likely than EV-infected or control patients to have sepsis-like disease and required more frequent vascular filling (39% in newborns and 26% in infants) and empirical antibiotics (91% in newborns and 69% in infants). HPeV patients had lower peripheral white blood cell counts and lower lymphocyte levels (P = 0.002) and longer lengths of hospital stay than EV or control patients (P = 0.03). A white blood cell count 9/L can be helpful in differentiating HPeV patients from control patients. Conclusions: Detection of HPeV should be part of the differential diagnosis of EV infections. The use of small automata to perform real-time polymerase chain reaction assays in emergency units should allow faster diagnosis and, if the result is positive, avoid prolonged length of hospital stay and unnecessary administration of antibiotics in patients without virus-bacteria co-infection.

Human inborn errors of thymic T cell tolerance underlie the production of autoantibodies (auto-Abs) neutralizing type I IFNs, which predispose to severe viral diseases. We analyze 131 female patients with X-linked dominant incontinentia pigmenti (IP), heterozygous for loss-of-function (LOF) NEMO variants, from 99 kindreds in 10 countries. Forty-seven of these patients (36%) have auto-Abs neutralizing IFN-α and/or IFN-ω, a proportion 23 times higher than that for age-matched female controls. This proportion remains stable from the age of 6 years onward. On imaging, female patients with IP have a small, abnormally structured thymus. Auto-Abs against type I IFNs confer a predisposition to life-threatening viral diseases. By contrast, patients with IP lacking auto-Abs against type I IFNs are at no particular risk of viral disease. These results suggest that IP accelerates thymic involution, thereby underlying the production of auto-Abs neutralizing type I IFNs in at least a third of female patients with IP, predisposing them to life-threatening viral diseases.

Severe defects in human IFNγ immunity predispose individuals to both Bacillus Calmette–Guérin disease and tuberculosis, whereas milder defects predispose only to tuberculosis¹. Here we report two adults with recurrent pulmonary tuberculosis who are homozygous for a private loss-of-function TNF variant. Neither has any other clinical phenotype and both mount normal clinical and biological inflammatory responses. Their leukocytes, including monocytes and monocyte-derived macrophages (MDMs) do not produce TNF, even after stimulation with IFNγ. Blood leukocyte subset development is normal in these patients. However, an impairment in the respiratory burst was observed in granulocyte–macrophage colony-stimulating factor (GM-CSF)-matured MDMs and alveolar macrophage-like (AML) cells² from both patients with TNF deficiency, TNF- or TNFR1-deficient induced pluripotent stem (iPS)-cell-derived GM-CSF-matured macrophages, and healthy control MDMs and AML cells differentiated with TNF blockers in vitro, and in lung macrophages treated with TNF blockers ex vivo. The stimulation of TNF-deficient iPS-cell-derived macrophages with TNF rescued the respiratory burst. These findings contrast with those for patients with inherited complete deficiency of the respiratory burst across all phagocytes, who are prone to multiple infections, including both Bacillus Calmette–Guérin disease and tuberculosis³. Human TNF is required for respiratory-burst-dependent immunity to Mycobacterium tuberculosis in macrophages but is surprisingly redundant otherwise, including for inflammation and immunity to weakly virulent mycobacteria and many other infectious agents.

Objective Patients with X linked agammaglobulinemia are susceptible to enterovirus (EV) infections. Similarly, severe EV infections have been described in patients with impaired B-cell response following treatment with anti-CD20 monoclonal antibodies (mAbs), mostly in those treated for haematological malignancies. We aimed to describe severe EV infections in patients receiving anti-CD20 mAbs for immune-mediated inflammatory diseases (IMIDs). Methods Patients were included following a screening of data collected through the routine surveillance of EV infections coordinated by the National Reference Center and a review of the literature. Additionally, neutralising antibodies were assessed in a patient with chronic EV-A71 meningoencephalitis. Results Nine original and 17 previously published cases were retrieved. Meningoencephalitis (n=21/26, 81%) associated with EV-positive cerebrospinal fluid (n=20/22, 91%) was the most common manifestation. The mortality rate was high (27%). EV was the only causal agents in all reported cases. Patients received multiple anti-CD20 mAbs infusions (median 8 (5–10)), resulting in complete B-cell depletion and moderate hypogammaglobulinemia (median 4.9 g/L (4.3–6.7)), and had limited concomitant immunosuppressive treatments. Finally, in a patient with EV-A71 meningoencephalitis, a lack of B-cell response to EV was shown. Conclusion EV infection should be evoked in patients with IMIDs presenting with atypical organ involvement, especially meningoencephalitis. Anti-CD20 mAbs may lead to impaired B-cell response against EV, although an underlying primary immunodeficiency should systematically be discussed.

CD4+ T cells are vital for host defense and immune regulation. However, the fundamental role of CD4 itself remains enigmatic. We report seven patients aged 5–61 years from five families of four ancestries with autosomal recessive CD4 deficiency and a range of infections, including recalcitrant warts and Whipple’s disease. All patients are homozygous for rare deleterious CD4 variants impacting expression of the canonical CD4 isoform. A shorter expressed isoform that interacts with LCK, but not HLA class II, is affected by only one variant. All patients lack CD4+ T cells and have increased numbers of TCRαβ+CD4−CD8− T cells, which phenotypically and transcriptionally resemble conventional Th cells. Finally, patient CD4−CD8− αβ T cells exhibit intact responses to HLA class II–restricted antigens and promote B cell differentiation in vitro. Thus, compensatory development of Th cells enables patients with inherited CD4 deficiency to acquire effective cellular and humoral immunity against an unexpectedly large range of pathogens. Nevertheless, CD4 is indispensable for protective immunity against at least human papillomaviruses and Trophyrema whipplei.

The SARS-CoV-2 variant of concern, α, spread worldwide at the beginning of 2021. It was suggested that this variant was associated with a higher risk of mortality than other variants. We aimed to characterize the genetic diversity of SARS-CoV-2 variants isolated from patients with severe COVID-19 and unravel the relationships between specific viral mutations/mutational patterns and clinical outcomes. This is a prospective multicenter observational cohort study. Patients aged ≥18 years admitted to 11 intensive care units (ICUs) in hospitals in the Greater Paris area for SARS-CoV-2 infection and acute respiratory failure between 1 October 2020 and 30 May 2021 were included. The primary clinical endpoint was day-28 mortality. Full-length SARS-CoV-2 genomes were sequenced by means of next-generation sequencing (Illumina COVIDSeq). In total, 413 patients were included, 183 (44.3%) were infected with pre-existing variants, 197 (47.7%) were infected with variant α, and 33 (8.0%) were infected with other variants. The patients infected with pre-existing variants were significantly older (64.9 ± 11.9 vs. 60.5 ± 11.8 years; p = 0.0005) and had more frequent COPD (11.5% vs. 4.1%; p = 0.009) and higher SOFA scores (4 [3–8] vs. 3 [2–4]; 0.0002). The day-28 mortality was no different between the patients infected with pre-existing, α, or other variants (31.1% vs. 26.2% vs. 30.3%; p = 0.550). There was no association between day-28 mortality and specific variants or the presence of specific mutations. At ICU admission, the patients infected with pre-existing variants had a different clinical presentation from those infected with variant α, but mortality did not differ between these groups. There was no association between specific variants or SARS-CoV-2 genome mutational pattern and day-28 mortality.

Background: From the start of the pandemic, health-care workers (HCW) have paid a heavy toll to the coronavirus disease-19 (COVID-19) outbreak. Objectives: To describe the dynamics and determinants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in HCW. Design: Prospective observational study conducted from February 24th until April 10th, 2020. Setting: Comparison of a 1,500-bed adult and a 600-bed pediatric setting of a tertiary-care university hospital located in central Paris. Participants: All symptomatic HCW screened for SARS-CoV-2 on a nasopharyngeal swab. Measurements: HCW screened positive were prospectively questioned on their profession, symptoms, occupational and non-occupational exposures to SARS-CoV-2. Results: Among 1344 symptomatic HCW tested, 373 were positive (28%) and 336 (90%) corresponding questionnaires were completed. Three hospitalizations and no death were reported. Most HCW (70%) had patient-facing occupational activities (22% in COVID-19 dedicated units). The total number of HCW cases peaked on March 23rd, then decreased slowly, concomitantly with a continuous increase of compliance to preventive measures (including universal medical masking and personal protective equipment (PPE) for direct care to COVID-19 patients). Attack rates were of 3.2% and 2.3% in the adult and pediatric setting, respectively (p=0.0022). In the adult setting, HCW more frequently reported exposure to COVID-19 patients without PPE (25% versus 15%, p=0.046). Report of contacts with children attending out-of-home care facilities dramatically decreased over the study period. Limitations: Lack of COVID-19 negative controls and recall bias. Conclusion: Universal masking, reinforcement of hand hygiene, and PPE with medical masks for patients' care allowed protection of HCW and containment of the outbreak. Residual transmissions were related to persistent exposures with undiagnosed patients or colleagues and not to contacts with children attending out-of-home care facilities.