Genomic Spectrum and Phenotypic Heterogeneity of Human IL-21 Receptor Deficiency.

Biallelic inactivating mutations in IL21R causes a combined immunodeficiency that is often complicated by cryptosporidium infections. While eight IL-21R-deficient patients have been reported previously, the natural course, immune characteristics of disease, and response to hematopoietic stem cell transplantation (HSCT) remain to be comprehensively examined. In our study, we have collected clinical histories of 13 patients with IL-21R deficiency from eight families across seven centers worldwide, including five novel patients identified by exome or NGS panel sequencing. Eight unique mutations in IL21R were identified in these patients, including two novel mutations. Median age at disease onset was 2.5 years (0.5-7 years). The main clinical manifestations were recurrent bacterial (84.6%), fungal (46.2%), and viral (38.5%) infections; cryptosporidiosis-associated cholangitis (46.2%); and asthma (23.1%). Inflammatory skin diseases (15.3%) and recurrent anaphylaxis (7.9%) constitute novel phenotypes of this combined immunodeficiency. Most patients exhibited hypogammaglobulinemia and reduced proportions of memory B cells, circulating T follicular helper cells, MAIT cells and terminally differentiated NK cells. However, IgE levels were elevated in 50% of IL-21R-deficient patients. Overall survival following HSCT (6 patients, mean follow-up 1.8 year) was 33.3%, with pre-existing organ damage constituting a negative prognostic factor. Mortality of non-transplanted patients (n = 7) was 57.1%. Our detailed analysis of the largest cohort of IL-21R-deficient patients to date provides in-depth clinical, immunological and immunophenotypic features of these patients, thereby establishing critical non-redundant functions of IL-21/IL-21R signaling in lymphocyte differentiation, humoral immunity and host defense against infection, and mechanisms of disease pathogenesis due to IL-21R deficiency. Outcome following HSCT depends on prior chronic infections and organ damage, which should thus be considered as early as possible following molecular diagnosis.

Impact of interruption of CFTR modulator therapies.

Novel drug therapy targeting the defective cystic fibrosis transmembrane conductance regulator protein has the potential to significantly enhance the quality of life for numerous patients with cystic fibrosis. However, in some countries social insurance does not pay for modulators because these drugs are extremely expensive. This study sought to understand the impact on the health of children whose modulator treatments were interrupted because of legal procedures and delivery processes. Our study identified that the significant increase in percent-predicted forced expiratory volume levels (FEV1) and BMI z-score values associated with modulator therapies decreased sharply with their discontinuation. Significant worsening in FEV1, BMI z-scores, and BW z-scores were detected in the first follow-up visit after therapy discontinuation within 1 month. Eight patients had a reduction of FEV1 of more than 10%. The findings suggest that modulatory treatment continuation is important, and it is crucial that treatment is not interrupted.

Evaluation of otorhinolaryngologic, audiologic, and genetic findings in children with cystic fibrosis: A tertiary care experience.

OBJECTIVES: To evaluate otorhinolaryngologic findings and the relationship between aminoglycoside (AG) exposure and hearing loss in paediatric patients with cystic fibrosis (cwCF). We also aimed to investigate the genetic predisposition to AG ototoxicity by screening for m.1555A>G mutations. METHODS: CwCF who underwent otorhinolaryngologic and audiologic examinations were retrospectively included. Clinical characteristics, ear-nose-throat related symptoms, and a history of ototoxic drug exposure were recorded. m.1555A>G mutations were retrospectively screened among patients with audiologic evaluations. RESULTS: Two hundred thirty-four cwCF were included in this study with a median age of 10.7 (range, 6.8-14.2) years. Nasal obstruction (14.1%) was the most common symptom. Fifty-two (22.2%) patients had chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP). There was a positive correlation between CRSwNP and the symptom of nasal obstruction (r:.234, p < .001), snoring (r:.179, p = .006), and sleeping with mouth open (r:.138, p = .034). One hundred forty-nine (63.6%) patients had audiologic evaluations; 14 (9.4%) had hearing impairment. No statistical significance existed between ototoxicity and IV AG exposure (p = .90). Six (42.8%) of 14 patients did not receive ototoxic drugs. One hundred nineteen (50.8%) patients were screened for m.1555A>G mutations, and none were detected. CONCLUSIONS: Almost a quarter of the study population had CRSwNP. Neither the relationship between AGs exposure and hearing loss nor the genetic predisposition to AG ototoxicity could be shown in cwCF.

The outcomes of renin-angiotensin-aldosterone system inhibition and immunosuppressive therapy in children with X-linked Alport syndrome.

BACKGROUND: Alport syndrome (AS) is characterized by progressive kidney disease. There is increasing evidence that renin-angiotensin-aldosterone system (RAAS) inhibition delays chronic kidney disease (CKD) while the effectiveness of immunosuppressive (IS) therapy in AS is still uncertain. In this study, we aimed to analyze the outcomes of pediatric patients with X-linked AS (XLAS) who received RAAS inhibitors and IS therapy. METHODS: Seventy-four children with XLAS were included in this multicenter study. Demographic features, clinical and laboratory data, treatments, histopathological examinations, and genetic analyses were analyzed retrospectively. RESULTS: Among 74 children, 52 (70.2%) received RAAS inhibitors, 11 (14.9%) received RAAS inhibitors and IS, and 11 (14.9%) were followed up without treatment. During follow-up, glomerular filtration rate (GFR) decreased < 60 ml/min/1.73 m2 in 7 (9.5%) of 74 patients (M/F=6/1). In male patients with XLAS, kidney survival was not different between RAAS and RAAS+IS groups (p=0.42). The rate of progression to CKD was significantly higher in patients with nephrotic range proteinuria and nephrotic syndrome (NS), respectively (p=0.006, p=0.05). The median age at the onset of RAAS inhibitors was significantly higher in male patients who progressed to CKD (13.9 vs 8.1 years, p=0.003). CONCLUSIONS: RAAS inhibitors have beneficial effects on proteinuria and early initiation of therapy may delay the progression to CKD in children with XLAS. There was no significant difference between the RAAS and RAAS+IS groups in kidney survival. AS patients presenting with NS or nephrotic range proteinuria should be followed up more carefully considering the risk of early progression to CKD.