A False-Negative Newborn Screen for Tyrosinemia Type 1-Need for Re-Evaluation of Newborn Screening with Succinylacetone.

Undiagnosed and untreated tyrosinemia type 1 (TT1) individuals carry a significant risk for developing liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Elevated succinylacetone (SA) is pathognomonic for TT1 and therefore often used as marker for TT1 newborn screening (NBS). While SA was long considered to be elevated in every TT1 patient, here we present a recent false-negative SA TT1 screen. A nine-year-old boy presented with HCC in a cirrhotic liver. Additional tests for the underlying cause unexpectedly revealed TT1. Nine years prior, the patient was screened for TT1 via SA NBS with a negative result: SA 1.08 µmol/L, NBS cut-off 1.20 µmol/L. To our knowledge, this report is the first to describe a false-negative result from the TT1 NBS using SA. False-negative TT1 NBS results may be caused by milder TT1 variants with lower SA excretion. Such patients are more likely to be missed in NBS programs and can be asymptomatic for years. Based on our case, we advise TT1 to be considered in patients with otherwise unexplained liver pathology, including fibrosis, cirrhosis and HCC, despite a previous negative TT1 NBS status. Moreover, because the NBS SA concentration of this patient fell below the Dutch cut-off value (1.20 µmol/L at that time), as well as below the range of cut-off values used in other countries (1.29-10 µmol/L), it is likely that false-negative screening results for TT1 may also be occurring internationally. This underscores the need to re-evaluate TT1 SA NBS programs.

Severe Immune-Related Enteritis after In Utero Exposure to Pembrolizumab.

Immune checkpoint blockade has become standard treatment for many types of cancer. Such therapy is indicated most often in patients with advanced or metastatic disease but has been increasingly used as adjuvant therapy in those with early-stage disease. Adverse events include immune-related organ inflammation resembling autoimmune diseases. We describe a case of severe immune-related gastroenterocolitis in a 4-month-old infant who presented with intractable diarrhea and failure to thrive after in utero exposure to pembrolizumab. Known causes of the symptoms were ruled out, and the diagnosis of pembrolizumab-induced immune-related gastroenterocolitis was supported by the results of histopathological assays, immunophenotyping, and analysis of the level of antibodies against programmed cell death protein 1 (PD-1). The infant's condition was successfully treated with prednisolone and infliximab.

Non-invasive diagnostics of pathogenic bacteria using a breath sampler in children with cystic fibrosis.

Cystic fibrosis (CF) is a common autosomal recessive disease causing thick, viscous secretions leading to pulmonary infections with pathogenic bacteria. As part of routine patient care, colonization and infection with these bacteria is monitored with cough swab or sputum cultures and sometimes bronchoalveolar lavage. In this cross-sectional proof-of-concept study in a cohort of CF patients we collected swabs or sputa and exhaled breath samples with the modular breath sampler (MBS), a newly developed two-way non-rebreathing sampling device. Pathogen specific polymerase chain reactions (PCRs) were performed on the MBS samples and compared with the results obtained with conventional diagnostics (i.e. culturing of swabs and sputa). A control group of stable asthma patients was used as negative control for the MBS measurements. The pathogens detected using MBS and conventional culturing differed:S. aureuswas found more often in swab or sputum samples whereasPseudomonas aeruginosaandS. pneumoniaewere found more often in MBS samples. We hypothesize that this is due to sampling of different compartments, MBS samples are derived from the lower respiratory tract while cultures from cough swabs and sputa are dominated by pathogens residing in the upper respiratory tract. Another important difference is the readout, i.e. culture versus PCR. The majority of CF patients in whomP. aeruginosawas found did not have recent positive cultures suggesting higher sensitivity of MBS-based than conventional diagnostics. The majority of parents/patients found the MBS easy to use and less of a burden than respiratory sampling.

Clinical characteristics and an evaluation of predictors for a favourable outcome of Mycobacterium abscessus otomastoiditis: a systematic review and meta-analysis of individual participant data.

BACKGROUND: Otomastoiditis caused by Mycobacterium abscessus is rare, but its incidence has increased over the past decades and its optimal treatment remains unknown. This study aims to summarise the clinical and therapeutic features and find characteristics of patients with M. abscessus otomastoiditis associated with favourable treatment outcomes. METHODS: We searched MEDLINE, Embase and Web of Science to identify studies including patients with M. abscessus otomastoiditis. A 1-stage individual patient data (IPD) meta-analysis was conducted. A 2-level mixed-effects linear regression model was provided for antimycobacterial treatment duration. RESULTS: Twenty-three studies reported a total of 85 patients. Children possess a unique clinical profile including a history of ear infections, tympanostomy tube placement and antibiotic treatment. Antimycobacterial treatment was administered for 26 (interquartile range [IQR]: 15-35) weeks. Macrolides were prescribed in 98.8% of the cases. Surgery was performed in 80.5% of the cases, of which, 47.1% required revision surgery. Otalgia was a significant predictor (ß = 9.3; P = .049) of antimycobacterial treatment duration. CONCLUSIONS: Mastoid surgery (regularly requiring revision) and a multidrug regimen for a minimum of 6 months, including a minimum of 3 active agents, are most often needed to attain cure. The presence of otalgia significantly extends the treatment duration of M. abscessus otomastoiditis.

Simple Measurement of IgA Predicts Immunity and Mortality in Ataxia-Telangiectasia.

Patients with ataxia-telangiectasia (A-T) suffer from progressive cerebellar ataxia, immunodeficiency, respiratory failure, and cancer susceptibility. From a clinical point of view, A-T patients with IgA deficiency show more symptoms and may have a poorer prognosis. In this study, we analyzed mortality and immunity data of 659 A-T patients with regard to IgA deficiency collected from the European Society for Immunodeficiencies (ESID) registry and from 66 patients with classical A-T who attended at the Frankfurt Goethe-University between 2012 and 2018. We studied peripheral B- and T-cell subsets and T-cell repertoire of the Frankfurt cohort and survival rates of all A-T patients in the ESID registry. Patients with A-T have significant alterations in their lymphocyte phenotypes. All subsets (CD3, CD4, CD8, CD19, CD4/CD45RA, and CD8/CD45RA) were significantly diminished compared to standard values. Patients with IgA deficiency (n = 35) had significantly lower lymphocyte counts compared to A-T patients without IgA deficiency (n = 31) due to a further decrease of naïve CD4 T-cells, central memory CD4 cells, and regulatory T-cells. Although both patient groups showed affected TCR-ß repertoires compared to controls, no differences could be detected between patients with and without IgA deficiency. Overall survival of patients with IgA deficiency was significantly diminished. For the first time, our data show that patients with IgA deficiency have significantly lower lymphocyte counts and subsets, which are accompanied with reduced survival, compared to A-T patients without IgA deficiency. IgA, a simple surrogate marker, is indicating the poorest prognosis for classical A-T patients. Both non-interventional clinical trials were registered at clinicaltrials.gov 2012 (Susceptibility to infections in ataxia-telangiectasia; NCT02345135) and 2017 (Susceptibility to Infections, tumor risk and liver disease in patients with ataxia-telangiectasia; NCT03357978).

MKL1 deficiency results in a severe neutrophil motility defect due to impaired actin polymerization.

Megakaryoblastic leukemia 1 (MKL1) promotes the regulation of essential cell processes, including actin cytoskeletal dynamics, by coactivating serum response factor. Recently, the first human with MKL1 deficiency, leading to a novel primary immunodeficiency, was identified. We report a second family with 2 siblings with a homozygous frameshift mutation in MKL1. The index case died as an infant from progressive and severe pneumonia caused by Pseudomonas aeruginosa and poor wound healing. The younger sibling was preemptively transplanted shortly after birth. The immunodeficiency was marked by a pronounced actin polymerization defect and a strongly reduced motility and chemotactic response by MKL1-deficient neutrophils. In addition to the lack of MKL1, subsequent proteomic and transcriptomic analyses of patient neutrophils revealed actin and several actin-related proteins to be downregulated, confirming a role for MKL1 as a transcriptional coregulator. Degranulation was enhanced upon suboptimal neutrophil activation, whereas production of reactive oxygen species was normal. Neutrophil adhesion was intact but without proper spreading. The latter could explain the observed failure in firm adherence and transendothelial migration under flow conditions. No apparent defect in phagocytosis or bacterial killing was found. Also, monocyte-derived macrophages showed intact phagocytosis, and lymphocyte counts and proliferative capacity were normal. Nonhematopoietic primary fibroblasts demonstrated defective differentiation into myofibroblasts but normal migration and F-actin content, most likely as a result of compensatory mechanisms of MKL2, which is not expressed in neutrophils. Our findings extend current insight into the severe immune dysfunction in MKL1 deficiency, with cytoskeletal dysfunction and defective extravasation of neutrophils as the most prominent features.

Successful Systemic and Topical Treatment of Mycobacterium abscessus Otomastoiditis.

Mycobacterium abscessus is an extensively drug-resistant opportunistic pathogen that can cause chronic otomastoiditis. There are no evidence-based treatment regimens for this severe infection. We treated four children with M. abscessus otomastoiditis with a structured regimen of topical imipenem and tigecycline, intravenous imipenem and tigecycline, and oral clofazimine and azithromycin and adjunctive surgery. This structured approach led to cure, with 1 year of follow-up after treatment. Adverse events were frequent, mostly caused by tigecycline.

Morphological and immunohistochemical differences between gonadal maturation delay and early germ cell neoplasia in patients with undervirilization syndromes.

CONTEXT: Maturation delay of germ cells and their progression into carcinoma in situ (CIS) frequently occurs in intersex patients. A developmentally delayed germ cell resembles a CIS cell and displays prolonged expression of immunohistochemical markers used for the diagnosis of CIS. This questions their applicability in young children. OBJECTIVE: The objective of the study was the elaboration of tools to distinguish germ cells with maturation delay and CIS. DESIGN: The design was a qualitative and quantitative analysis of the expression of diagnostic markers for CIS in gonads of young patients with undervirilization syndromes. SETTING: The study was conducted in the pathology department of a university center, specializing in germ cell tumor pathogenesis. PATIENTS: Fifty-eight formalin-fixed, paraffin-embedded testicular tissue samples of 30 undervirilized patients (1 month to 23 yr of age) were analyzed. INTERVENTIONS: INTERVENTIONS included hematoxylin-eosin staining, immunohistochemistry for octamer binding transcription factor (OCT)3/4, gene encoding the stem cell factor receptor that has tyrosine kinase activity c-KIT, placental/germ alkaline phosphatase (PLAP), testis-specific protein Y encoded (TSPY), and VASA, double staining for OCT3/4 and VASA, with ploidy determination by fluorescent in situ hybridization. MAIN OUTCOME MEASURE: Maturation delay and CIS are characterized by the staining patterns of the immunohistochemical markers. RESULTS: CIS was diagnosed in three of 30 patients (10%) and four of 58 gonads (6.9%). Patient age, distribution of OCT3/4-positive cells throughout the gonad, and their position within the seminiferous tubule differ between maturation delay and CIS. Abnormal OCT3/4 and testis-specific protein Y encoded expression appear to be of pathogenetic relevance in the development of these lesions. CONCLUSION: The dimorphic expression of OCT3/4 allows distinction between maturation delay and CIS. Studies in larger patient series are essential before a biopsy to evaluate the neoplastic risk can eventually be proposed as an alternative for gonadectomy.