Role of IL-27 in Epstein-Barr virus infection revealed by IL-27RA deficiency.

Epstein-Barr virus (EBV) infection can engender severe B cell lymphoproliferative diseases1,2. The primary infection is often asymptomatic or causes infectious mononucleosis (IM), a self-limiting lymphoproliferative disorder3. Selective vulnerability to EBV has been reported in association with inherited mutations impairing T cell immunity to EBV4. Here we report biallelic loss-of-function variants in IL27RA that underlie an acute and severe primary EBV infection with a nevertheless favourable outcome requiring a minimal treatment. One mutant allele (rs201107107) was enriched in the Finnish population (minor allele frequency = 0.0068) and carried a high risk of severe infectious mononucleosis when homozygous. IL27RA encodes the IL-27 receptor alpha subunit5,6. In the absence of IL-27RA, phosphorylation of STAT1 and STAT3 by IL-27 is abolished in T cells. In in vitro studies, IL-27 exerts a synergistic effect on T-cell-receptor-dependent T cell proliferation7 that is deficient in cells from the patients, leading to impaired expansion of potent anti-EBV effector cytotoxic CD8+ T cells. IL-27 is produced by EBV-infected B lymphocytes and an IL-27RA-IL-27 autocrine loop is required for the maintenance of EBV-transformed B cells. This potentially explains the eventual favourable outcome of the EBV-induced viral disease in patients with IL-27RA deficiency. Furthermore, we identified neutralizing anti-IL-27 autoantibodies in most individuals who developed sporadic infectious mononucleosis and chronic EBV infection. These results demonstrate the critical role of IL-27RA-IL-27 in immunity to EBV, but also the hijacking of this defence by EBV to promote the expansion of infected transformed B cells.

Antinuclear antibody-associated autoimmune cytopenia in childhood is a risk factor for systemic lupus erythematosus.

ABSTRACT: Autoimmune cytopenia (AIC) in children may be associated with positive antinuclear antibodies (ANA) and may progress to systemic lupus erythematosus (SLE). We evaluated the risk of progression to SLE of childhood-onset ANA-associated AIC. In the French national prospective OBS'CEREVANCE cohort, the long-term outcome of children with ANA-associated AIC (ANA titer ≥1/160) and a subgroup of children who developed SLE were described. ANA were positive in 355 of 1803 (20%) children with AIC. With a median follow-up of 5.8 (range, 0.1-29.6) years, 79 of 355 (22%) patients developed SLE at a median age of 14.5 (1.1-21.4) years; 20% of chronic immune thrombocytopenic purpura, 19% of autoimmune hemolytic anemia, and 45% of Evans syndrome. None of the patients with ANA-negative test developed SLE. Severe manifestations of SLE were observed in 21 patients, and 2 patients died. In multivariate analysis including patients with positive ANA within the first 3 months after AIC diagnosis, age >10 years at AIC diagnosis (relative risk [RR], 3.67; 95% confidence interval [CI], 1.18-11.4; P = .024) and ANA titer >1/160 (RR, 5.28; 95% CI, 1.20-23.17; P = .027) were associated with the occurrence of SLE after AIC diagnosis. ANA-associated AIC is a risk factor for progression to SLE, especially in children with an initial ANA titer >1/160 and an age >10 years at AIC diagnosis. ANA screening should be recommended in children with AIC, and patients with ANA should be monitored long-term for SLE, with special attention to the transition period. This trial was registered at www.ClinicalTrials.gov as #NCT05937828.

Determinants of long-term outcomes of splenectomy in pediatric autoimmune cytopenias.

Splenectomy is effective in ∼70% to 80% of pediatric chronic immune thrombocytopenia (cITP) cases, and few data exist about it in autoimmune hemolytic anemia (AIHA) and Evans syndrome (ES). Because of the irreversibility of the procedure and the lack of predictions regarding long-term outcomes, the decision to undertake splenectomy is difficult in children. We report here factors associated with splenectomy outcomes from the OBS'CEREVANCE cohort, which prospectively includes French children with autoimmune cytopenia (AIC) since 2004. The primary outcome was failure-free survival (FFS), defined as the time from splenectomy to the initiation of a second-line treatment (other than steroids and intravenous immunoglobulins) or death. We included 161 patients (cITP, n = 120; AIHA, n = 19; ES, n = 22) with a median (minimum-maximum) follow-up of 6.8 years (1.0-33.3) after splenectomy. AIC subtype was not associated with FFS. We found that immunopathological manifestations (IMs) were strongly associated with unfavorable outcomes. Diagnosis of an IM before splenectomy was associated with a lower FFS (hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.21-0.72, P = .003, adjusted for AIC subtype). Diagnosis of an IM at any timepoint during follow-up was associated with an even lower FFS (HR, 0.22; 95% CI, 0.12-0.39; P = 2.8 × 10-7, adjusted for AIC subtype) as well as with higher risk of recurrent or severe bacterial infections and thrombosis. In conclusion, our results support the search for associated IMs when considering a splenectomy to refine the risk-benefit ratio. After the procedure, monitoring IMs helps to identify patients with higher risk of unfavorable outcomes.

Pediatric refractory chronic immune thrombocytopenia: Identification, patients' characteristics, and outcome.

Refractory chronic immune thrombocytopenia (r-cITP) is one of the most challenging situations in chronic immune thrombocytopenia (cITP). Pediatric r-cITP is inconsistently defined in literature, contributing to the scarcity of data. Moreover, no evidence is available to guide the choice of treatment. We compared seven definitions of r-cITP including five pediatric definitions in 886 patients with cITP (median [min-max] follow-up 5.3 [1.0-29.3] years). The pediatric definitions identified overlapping groups of various sizes (4%-20%) but with similar characteristics (higher proportion of immunopathological manifestations [IM] and systemic lupus erythematosus [SLE]), suggesting that they adequately captured the population of interest. Based on the 79 patients with r-cITP (median follow-up 3.1 [0-18.2] years) according to the CEREVANCE definition (≥3 second-line treatments), we showed that r-cITP occurred at a rate of 1.15% new patients per year and did not plateau over time. In multivariate analysis, older age was associated with r-cITP. One patient (1%) experienced two grade five bleeding events after meeting r-cITP criteria and while not receiving second-line treatment. The cumulative incidence of continuous complete remission (CCR) at 2 years after r-cITP diagnosis was 9%. In this analysis, splenectomy was associated with a higher cumulative incidence of CCR (hazard ratio: 5.43, 95% confidence interval: 1.48-19.84, p = 7.8 × 10-4). In sum, children with cITP may be diagnosed with r-cITP at any time point of the follow-up and are at increased risk of IM and SLE. Second-line treatments seem to be effective for preventing grade 5 bleeding. Splenectomy may be considered to achieve CCR.

Late-onset enteric virus infection associated with hepatitis (EVAH) in transplanted SCID patients.

BACKGROUND: Allogenic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT) are potentially curative treatments for severe combined immunodeficiency (SCID). Late-onset posttreatment manifestations (such as persistent hepatitis) are not uncommon. OBJECTIVE: We sought to characterize the prevalence and pathophysiology of persistent hepatitis in transplanted SCID patients (SCIDH+) and to evaluate risk factors and treatments. METHODS: We used various techniques (including pathology assessments, metagenomics, single-cell transcriptomics, and cytometry by time of flight) to perform an in-depth study of different tissues from patients in the SCIDH+ group and corresponding asymptomatic similarly transplanted SCID patients without hepatitis (SCIDH-). RESULTS: Eleven patients developed persistent hepatitis (median of 6 years after HSCT or GT). This condition was associated with the chronic detection of enteric viruses (human Aichi virus, norovirus, and sapovirus) in liver and/or stools, which were not found in stools from the SCIDH- group (n = 12). Multiomics analysis identified an expansion of effector memory CD8+ T cells with high type I and II interferon signatures. Hepatitis was associated with absence of myeloablation during conditioning, split chimerism, and defective B-cell function, representing 25% of the 44 patients with SCID having these characteristics. Partially myeloablative retransplantation or GT of patients with this condition (which we have named as "enteric virus infection associated with hepatitis") led to the reconstitution of T- and B-cell immunity and remission of hepatitis in 5 patients, concomitantly with viral clearance. CONCLUSIONS: Enteric virus infection associated with hepatitis is related to chronic enteric viral infection and immune dysregulation and is an important risk for transplanted SCID patients with defective B-cell function.

Impact of age at diagnosis, sex, and immunopathological manifestations in 886 patients with pediatric chronic immune thrombocytopenia.

Pediatric chronic immune thrombocytopenia (cITP) is a heterogeneous condition in terms of bleeding severity, second-line treatment use, association with clinical and/or biological immunopathological manifestations (IMs), and progression to systemic lupus erythematosus (SLE). No risk factors for these outcomes are known. Specifically, whether age at ITP diagnosis, sex, or IMs impact cITP outcomes is unknown. We report the outcomes of patients with pediatric cITP from the French nationwide prospective cohort OBS'CEREVANCE. We used multivariate analyses to investigate the effect of age at ITP diagnosis, sex, and IMs on cITP outcomes. We included 886 patients with a median (min-max) follow-up duration of 5.3 (1.0-29.3) years. We identified an age cutoff that dichotomized the risk of the outcomes and defined two risk groups: patients with ITP diagnosed <10 years (children) and ≥ 10 years (adolescents). Adolescents had a two to four-fold higher risk of grade ≥3 bleeding, second-line treatment use, clinical and biological IMs, and SLE diagnosis. Moreover, female sex and biological IMs were independently associated with higher risks of biological IMs and SLE diagnosis, second-line treatment use, and SLE diagnosis, respectively. The combination of these three risk factors defined outcome-specific risk groups. Finally, we showed that patients clustered in mild and severe phenotypes, more frequent in children and adolescents, respectively. In conclusion, we identified that age at ITP diagnosis, sex, and biological IMs impacted the long-term outcomes of pediatric cITP. We defined risk groups for each outcome, which will help clinical management and further studies.

Long term follow-up of pediatric-onset Evans syndrome: broad immunopathological manifestations and high treatment burden.

Pediatric-onset Evans syndrome (pES) is defined by both immune thrombocytopenic purpura (ITP) and autoimmune hemolytic anemia (AIHA) before the age of 18 years. There have been no comprehensive long-term studies of this rare disease, which can be associated to various immunopathological manifestations (IM). We report outcomes of the 151 patients with pES and more than 5 years of follow-up from the nationwide French prospective OBS'CEREVANCE cohort. Median age at final follow-up was 18.5 years (range, 6.8-50.0 years) and the median follow-up period was 11.3 years (range, 5.1-38.0 years). At 10 years, ITP and AIHA were in sustained complete remission in 54.5% and 78.4% of patients, respectively. The frequency and number of clinical and biological IM increased with age: at the age of 20 years, 74% had at least one clinical IM (cIM). A wide range of cIM occurred, mainly lymphoproliferation, dermatological, gastrointestinal/hepatic and pneumological IM. The number of cIM was associated with a subsequent increase in the number of second-line treatments received (other than steroids and immunoglobulins; hazard ratio 1.4, 95% Confidence Interval: 1.15-1.60, P=0.0002, Cox proportional hazards method). Survival at 15 years after diagnosis was 84%. Death occurred at a median age of 18 years (range, 1.7-31.5 years), and the most frequent cause was infection. The number of second-line treatments and severe/recurrent infections were independently associated with mortality. In conclusion, long-term outcomes of pES showed remission of cytopenias but frequent IM linked to high second-line treatment burden. Mortality was associated to drugs and/or underlying immunodeficiencies, and adolescents-young adults are a high-risk subgroup.

Therapeutic approach and outcome of children with Philadelphia chromosome-positive acute lymphoblastic leukemia at first relapse in the era of tyrosine kinase inhibitors: An SFCE retrospective study.

BACKGROUND: Since the introduction of tyrosine kinase inhibitors (TKIs), the profile of pediatric relapse of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) has changed. However, the management of pediatric Ph+ ALL relapses is not currently standardized. PROCEDURE: We retrospectively analyzed the therapeutic strategies and outcomes of pediatric Ph+ ALL patients in first relapse who were initially treated with a TKI-containing regimen in one of the French pediatric hematology centers from 2004 to 2019. RESULTS: Twenty-seven children experienced a Ph+ ALL relapse: 24 (89%) had an overt relapse and three a molecular relapse. Eight involved the central nervous system. A second complete remission (CR2) was obtained for 26 patients (96%). Induction consisted of nonintensive chemotherapy for 13 patients (48%) and intensive chemotherapy for 14 (52%). Thirteen patients (48%) received consolidation. Allogenic hematopoietic stem cell transplantation (alloHSCT) was performed for 21 patients (78%). The TKI was changed for 23 patients (88%), mainly with dasatinib (n = 15). T315I was the most common mutation at relapse (4/7). The 4-year event-free survival and survival rates were 60.9% and 76.1%, respectively. Survival was positively associated with alloHSCT in CR2. CONCLUSION: We show that pediatric first-relapse Ph+ ALL reinduces well with a second course of TKI exposure, despite the use of different therapeutic approaches. The main prognostic factor for survival was alloHSCT in CR2. Because of the small size of the cohort, we could not draw any conclusions about the respective impact of TKIs, but the predominance of the T315I mutation should encourage careful consideration of the TKI choice.

Prospective Evaluation of the First Option, Second-Line Therapy in Childhood Chronic Immune Thrombocytopenia: Splenectomy or Immunomodulation.

OBJECTIVE: To describe 4 subgroups of pediatric patients treated with splenectomy, hydroxychloroquine, azathioprine, or rituximab as the first-option, second-line treatment for chronic immune thrombocytopenia. STUDY DESIGN: Selection of patients with chronic immune thrombocytopenia from the French national prospective cohort of pediatric autoimmune cytopenia OBS'CEREVANCE and VIGICAIRE study, treated by splenectomy, hydroxychloroquine, azathioprine, or rituximab as a first second-line treatment. RESULTS: For 137 patients, treated between 1989 and 2016, the median follow-up after diagnosis and after treatment initiation was 8.5 (2.8-26.4) years and 4.7 (1.1-25.1) years, respectively. Median age at diagnosis and at initiation of treatment were 9 (0.7; 16) and 12 (2; 18.1) years, respectively without significant difference between subgroups. For the whole cohort, 24-month event-free survival was 62% (95% CI 55; 71). It was 85% (95% CI 77; 95) for the 56 patients treated with splenectomy, 60% (95% CI 44; 84) for the 23 patients treated with rituximab, 46% (95% CI 30; 71) for the 24 patients treated with azathioprine, and 37% (95% CI 24; 59) for the 34 patients treated with hydroxychloroquine (log-rank P < .0001). For the splenectomy subgroup, being older than 10 years at splenectomy tended to improve event-free survival (P = .05). Female teenagers with antinuclear antibody positivity benefited from hydroxychloroquine therapy. CONCLUSIONS: This national study, limiting pitfalls in the analysis of the effects of second-line therapies, showed that splenectomy remains the treatment associated with the better response at 24 months.

Invasive Fungal Infections in Immunocompromised Children: Novel Insight Following a National Study.

OBJECTIVE: To obtain a national overview of the epidemiology and management of invasive fungal infections (IFIs) in France for severely immunocompromised children who were treated for acute leukemia or had undergone allogeneic hematopoietic stem cell transplantation (a-HSCT). STUDY DESIGN: We performed a national multicenter retrospective study to collect epidemiologic data for proven and probable IFIs in children with acute leukemia under first- line or relapse treatment or who had undergone a-HSCT. We also conducted a prospective practice survey to provide a national overview of IFI management in pediatric hematology units. RESULTS: From January 2014 to December 2017, 144 cases of IFI were diagnosed (5.3%) in 2721 patients, including 61 cases of candidiasis, 60 cases of aspergillosis, and 23 cases of infection with "emergent" fungi, including 10 cases of mucormycosis and 6 cases of fusariosis. The IFI rate was higher in patients with acute myelogenous leukemia (12.9%) (OR, 3.24; 95% CI, 2.15-4.81; P < .0001) compared with the rest of the cohort. Patients undergoing a-HSCT had an IFI rate of only 4.3%. In these patients, the use of primary antifungal prophylaxis (principally fluconazole) was associated with a lower IFI rate (OR, 0.28; 95% CI, 0.14-0.60; P = 4.90 ×10-4) compared with a-HSCT recipients who did not receive antifungal prophylaxis. The main cause of IFI in children receiving prophylaxis was emergent pathogens (41%), such as mucormycosis and fusariosis, which were resistant to the prophylactic agents. CONCLUSIONS: The emerging fungi and new antifungal resistance profiles uncovered in this study should be considered in IFI management in immunocompromised children.

Pediatric Evans syndrome is associated with a high frequency of potentially damaging variants in immune genes.

Evans syndrome (ES) is a rare severe autoimmune disorder characterized by the combination of autoimmune hemolytic anemia and immune thrombocytopenia. In most cases, the underlying cause is unknown. We sought to identify genetic defects in pediatric ES (pES), based on a hypothesis of strong genetic determinism. In a national, prospective cohort of 203 patients with early-onset ES (median [range] age at last follow-up: 16.3 years ([1.2-41.0 years]) initiated in 2004, 80 nonselected consecutive individuals underwent genetic testing. The clinical data were analyzed as a function of the genetic findings. Fifty-two patients (65%) received a genetic diagnosis (the M+ group): 49 carried germline mutations and 3 carried somatic variants. Thirty-two (40%) had pathogenic mutations in 1 of 9 genes known to be involved in primary immunodeficiencies (TNFRSF6, CTLA4, STAT3, PIK3CD, CBL, ADAR1, LRBA, RAG1, and KRAS), whereas 20 patients (25%) carried probable pathogenic variants in 16 genes that had not previously been reported in the context of autoimmune disease. Lastly, no genetic abnormalities were found in the remaining 28 patients (35%, the M- group). The M+ group displayed more severe disease than the M- group, with a greater frequency of additional immunopathologic manifestations and a greater median number of lines of treatment. Six patients (all from the M+ group) died during the study. In conclusion, pES was potentially genetically determined in at least 65% of cases. Systematic, wide-ranging genetic screening should be offered in pES; the genetic findings have prognostic significance and may guide the choice of a targeted treatment.

Second-line treatment trends and long-term outcomes of 392 children with chronic immune thrombocytopenic purpura: the French experience over the past 25 years.

Childhood chronic immune thrombocytopenic purpura (cITP) is a rare disease. In severe cases, there is no evidence for the optimal therapeutic strategy. Our aim was to describe the real-life management of non-selected children with cITP at diagnosis. Since 2004, patients less than 18 years old with cITP have been enrolled in the national prospective cohort, OBS'CEREVANCE. From 1990 to 2014, in 29 centres, 392 children were diagnosed with cITP. With a median follow-up of six years (2·0-25), 45% did not need second-line therapy, and 55% (n = 217) received one or more second lines, mainly splenectomy (n = 108), hydroxychloroquine (n = 61), rituximab (n = 61) or azathioprine (n = 40). The overall five-year further second-line treatment-free survival was 56% [95% CI 49·5-64.1]. The use of splenectomy significantly decreased over time. Hydroxychloroquine was administered to children with positive antinuclear antibodies, more frequently older and girls, and reached 55% efficacy. None of the patients died. Ten years after the initial diagnosis, 55% of the 56 followed children had achieved complete remission. Children with cITP do not need second-line treatments in 45% of cases. Basing the treatment decision on the pathophysiological pathways is challenging, as illustrated by ITP patients with positive antinuclear antibodies treated with hydroxychloroquine.

G6PD deficiency and absence of α-thalassemia increase the risk for cerebral vasculopathy in children with sickle cell anemia.

The aim of this study was to test the association between hematological/genetic factors and cerebral vasculopathy in children with sickle cell anemia (SCA). A group with cerebral vasculopathy (VASC) was composed of children who had stroke (n = 6), silent infarct (n = 11), or an abnormal transcranial Doppler (n = 5). Eighty-four patients had neither positive history of stroke or silent infarct, nor abnormal transcranial Doppler (NORM group). An intermediate group (COND; n = 15) was composed of SCA children with a conditional transcranial Doppler. Biological analyses were performed on samples obtained at steady state and before the beginning of any chronic treatment. The comparisons of the three groups demonstrated a protective effect of α-thalassemia against cerebral vasculopathy through its effects on hemoglobin and reticulocyte levels. Moreover, we observed higher frequency of G6PD deficiency in the VASC group compared with the other groups. Our study confirms the key role of α-thalassemia and G6PD status in the pathophysiology of cerebral vasculopathy in SCA children.

Human type I IFN deficiency does not impair B cell response to SARS-CoV-2 mRNA vaccination.

Inborn and acquired deficits of type I interferon (IFN) immunity predispose to life-threatening COVID-19 pneumonia. We longitudinally profiled the B cell response to mRNA vaccination in SARS-CoV-2 naive patients with inherited TLR7, IRF7, or IFNAR1 deficiency, as well as young patients with autoantibodies neutralizing type I IFNs due to autoimmune polyendocrine syndrome type-1 (APS-1) and older individuals with age-associated autoantibodies to type I IFNs. The receptor-binding domain spike protein (RBD)-specific memory B cell response in all patients was quantitatively and qualitatively similar to healthy donors. Sustained germinal center responses led to accumulation of somatic hypermutations in immunoglobulin heavy chain genes. The amplitude and duration of, and viral neutralization by, RBD-specific IgG serological response were also largely unaffected by TLR7, IRF7, or IFNAR1 deficiencies up to 7 mo after vaccination in all patients. These results suggest that induction of type I IFN is not required for efficient generation of a humoral response against SARS-CoV-2 by mRNA vaccines.

Discontinuation of Imatinib in Children with Chronic Myeloid Leukemia: A Study from the International Registry of Childhood CML.

Within the International Registry of Childhood Chronic Myeloid Leukemia (CML), we identified 18 patients less than 18 years old at diagnosis of CML who were in the chronic phase and exhibiting a sustained deep molecular response (DMR) to imatinib defined as BCR-ABL1/ABL1 < 0.01% (MR4) for at least two years followed by discontinuation of imatinib. Before discontinuation, the median duration of imatinib was 73.2 months (range, 32-109) and the median duration of MR4 was 46.2 months (range, 23.9-98.6). Seven patients experienced loss of major molecular response (MMR) 4.1 months (range, 1.9-6.4) after stopping and so restarted imatinib. The median molecular follow-up after discontinuation was 51 months (range, 6-100) for the nine patients without molecular relapse. The molecular free remission rate was 61% (95% CI, 38-83%), 56% (95% CI, 33-79%) and 56% (95% CI, 33-79%) at 6, 12 and 36 months, respectively. Six of the seven children who experienced molecular relapse after discontinuation regained DMR (median, 4.7 months; range, 2.5-18) after restarting imatinib. No withdrawal syndrome was observed. In univariate analysis, age, sex, Sokal and ELTS scores, imatinib treatment and DMR durations before discontinuation had no influence on treatment free remission. These data suggest that imatinib can be safely discontinued in children with sustained MR4 for at least two years.

Preexisting autoantibodies to type I IFNs underlie critical COVID-19 pneumonia in patients with APS-1.

Patients with biallelic loss-of-function variants of AIRE suffer from autoimmune polyendocrine syndrome type-1 (APS-1) and produce a broad range of autoantibodies (auto-Abs), including circulating auto-Abs neutralizing most type I interferons (IFNs). These auto-Abs were recently reported to account for at least 10% of cases of life-threatening COVID-19 pneumonia in the general population. We report 22 APS-1 patients from 21 kindreds in seven countries, aged between 8 and 48 yr and infected with SARS-CoV-2 since February 2020. The 21 patients tested had auto-Abs neutralizing IFN-α subtypes and/or IFN-ω; one had anti-IFN-ß and another anti-IFN-ε, but none had anti-IFN-κ. Strikingly, 19 patients (86%) were hospitalized for COVID-19 pneumonia, including 15 (68%) admitted to an intensive care unit, 11 (50%) who required mechanical ventilation, and four (18%) who died. Ambulatory disease in three patients (14%) was possibly accounted for by prior or early specific interventions. Preexisting auto-Abs neutralizing type I IFNs in APS-1 patients confer a very high risk of life-threatening COVID-19 pneumonia at any age.