Hypomorphic RAG deficiency: impact of disease burden on survival and thymic recovery argues for early diagnosis and HSCT.

Patients with hypomorphic mutations in the RAG1 or RAG2 gene present with either Omenn syndrome or atypical combined immunodeficiency with a wide phenotypic range. Hematopoietic stem cell transplantation (HSCT) is potentially curative, but data are scarce. We report on a worldwide cohort of 60 patients with hypomorphic RAG variants who underwent HSCT, 78% of whom experienced infections (29% active at HSCT), 72% had autoimmunity, and 18% had granulomas pretransplant. These complications are frequently associated with organ damage. Eight individuals (13%) were diagnosed by newborn screening or family history. HSCT was performed at a median of 3.4 years (range 0.3-42.9 years) from matched unrelated donors, matched sibling or matched family donors, or mismatched donors in 48%, 22%, and 30% of the patients, respectively. Grafts were T-cell depleted in 15 cases (25%). Overall survival at 1 and 4 years was 77.5% and 67.5% (median follow-up of 39 months). Infection was the main cause of death. In univariable analysis, active infection, organ damage pre-HSCT, T-cell depletion of the graft, and transplant from a mismatched family donor were predictive of worse outcome, whereas organ damage and T-cell depletion remained significant in multivariable analysis (hazard ratio [HR] = 6.01, HR = 8.46, respectively). All patients diagnosed by newborn screening or family history survived. Cumulative incidences of acute and chronic graft-versus-host disease were 35% and 22%, respectively. Cumulative incidences of new-onset autoimmunity was 15%. Immune reconstitution, particularly recovery of naïve CD4+ T cells, was faster and more robust in patients transplanted before 3.5 years of age, and without organ damage. These findings support the indication for early transplantation.

Effect of previous vaccination with pneumococcal conjugate vaccine on pneumococcal polysaccharide vaccine antibody responses.

During the past 10 years, pneumococcal conjugate vaccine (PCV) has become part of the standard childhood vaccination programme. This may impact upon the diagnosis of polysaccharide antibody deficiency by measurement of anti-polysaccharide immunoglobulin (Ig)G after immunization with unconjugated pneumococcal polysaccharide vaccine (PPV). Indeed, contrary to PPV, PCV induces a T-dependent, more pronounced memory response. The antibody response to PPV was studied retrospectively in patients referred for suspected humoral immunodeficiency. The study population was divided into four subgroups based on age (2-5 years versus ≥ 10 years) and time tested (1998-2005 versus 2010-12). Only 2-5-year-old children tested in 2010-12 had been vaccinated with PCV prior to PPV. The PCV primed group showed higher antibody responses for PCV-PPV shared serotypes 4 and 18C than the unprimed groups. To a lesser extent, this was also found for non-PCV serotype 9N, but not for non-PCV serotypes 19A and 8. Furthermore, PCV-priming elicited a higher IgG2 response. In conclusion, previous PCV vaccination affects antibody response to PPV for shared serotypes, but can also influence antibody response to some non-PCV serotypes (9N). With increasing number of serotypes included in PCV, the diagnostic assessment for polysaccharide antibody deficiency requires careful selection of serotypes that are not influenced by prior PCV (e.g. serotype 8). Further research is needed to identify more serotypes that are not influenced.

Value of allohaemagglutinins in the diagnosis of a polysaccharide antibody deficiency.

Polysaccharide antibody deficiency is characterized by a poor or absent antibody response after vaccination with an unconjugated pneumococcal polysaccharide vaccine. Allohaemagglutinins (AHA) are antibodies to A or B polysaccharide antigens on the red blood cells, and are often used as an additional or alternative measure to assess the polysaccharide antibody response. However, few studies have been conducted to establish the clinical significance of AHA. To investigate the value of AHA to diagnose a polysaccharide antibody deficiency, pneumococcal polysaccharide antibody titres and AHA were studied retrospectively in 180 subjects in whom both tests had been performed. Receiver operating characteristic curves for AHA versus the pneumococcal vaccine response as a marker for the anti-polysaccharide immune response revealed an area under the curve between 0·5 and 0·573. Sensitivity and specificity of AHA to detect a polysaccharide antibody deficiency, as diagnosed by vaccination response, were low (calculated for cut-off 1/4-1/32). In subjects with only low pneumococcal antibody response, the prevalence of bronchiectasis was significantly higher than in subjects with only low AHA (45·5 and 1·3%, respectively) or normal pneumococcal antibody response and AHA (2·4%). A logistic regression model showed that low pneumococcal antibody response but not AHA was associated with bronchiectasis (odds ratio 46·2). The results of this study do not support the routine use of AHA to assess the polysaccharide antibody response in patients with suspected immunodeficiency, but more studies are warranted to clarify the subject further.

Terminal Complement Pathway Deficiency in an Adult Patient with Meningococcal Sepsis.

The complement system is an essential part of our innate immune system. Three enzymatic activation pathways are described, all converging into a common terminal pathway which causes lysis of the target cell. Late complement deficiencies (LCDs) are typically diagnosed in children or adolescents with invasive meningococcal disease (IMD). However, IMD can also be a first manifestation in adulthood and should prompt for the evaluation of the LCD. We report the case of a young adult with IMD who was found to have a LCD, caused by a compound heterozygous mutation in C6. His vaccination status was optimized and prophylactic antibiotic treatment was initiated. By means of this case, we would like to raise awareness of underlying LCD in (young) adults presenting with IMD by N. meningitidis. Screening for complement deficiencies after IMD, followed by genetic testing, can be lifesaving and allows for genetic counselling. In addition, we discuss the diagnosis and treatment of LCD.

The role of the IL23/IL17 axis in bronchiolitis obliterans syndrome after lung transplantation.

Bronchiolitis obliterans syndrome (BOS) is the leading cause of death after lung transplantation. Treatment is challenging, as the precise pathophysiology remains unclear. We hypothesize that T(H)17 lineage plays a key role in the pathophysiology of BOS by linking T-cell activation to neutrophil influx and chronic inflammation. In a cross-sectional study, bronchoalveolar lavage (BAL) samples of 132 lung transplant recipients were analyzed. Patients were divided in four groups: stable or suffering from infection (INF), acute rejection (AR) or BOS. The upstream T(H)17 skewing (TGF-beta/IL1beta/IL6/IL23), T(H)17 counteracting (IL2), T(H)17 effector cytokine (IL17) and the principal neutrophil-attracting chemokine (IL8), were quantified at the mRNA or protein level in combination with the cell profiles. The BOS group (n = 36) showed an increase in IL1beta protein (x1.5), IL6 protein (x3), transforming growth factor-beta (TGF-beta) mRNA (x3), IL17 mRNA (x20), IL23 mRNA (x10), IL8 protein (x2), IL8 mRNA (x3) and a decrease in IL2 protein (x0.8). The infection group (n = 11) demonstrated an increase in IL1beta protein (x5), IL6 protein (x20), TGF-beta mRNA (x10), IL17 mRNA (x300), IL23 mRNA (x200) and IL8 protein (x6). The acute rejection group (n = 43) only revealed an increase in IL6 protein (x6) and IL8 protein (x2) and a decrease in IL2 protein (x0.7). Lymphocytes and neutrophils were increased in all groups compared to the stable (n = 42). Our findings demonstrate the IL23/IL17 axis to be involved in the pathophysiology of BOS potentially triggering the IL8-mediated neutrophilia. IL6, IL1beta and IL23 seem to be skewing cytokines and IL2 a counteracting cytokine for T(H)17 alignment. The involvement of TGF-beta could not be confirmed, either as T(H)17 steering or as counteracting cytokine.

A dichotomy in bronchiolitis obliterans syndrome after lung transplantation revealed by azithromycin therapy.

Bronchiolitis obliterans syndrome (BOS) is the most important cause of late mortality following lung transplantation, resulting in major morbidity and a huge burden on healthcare resources. Treatment options are limited, resulting in a mere stabilisation of the lung function decline. Recent introduction of the macrolide antibiotic azithromycin raised new hope after demonstrating lung function improvement in subsets of patients. The present study aimed to provide an overview of the clinical effects on azithromycin in the setting of BOS after lung transplantation, with special emphasis on the anti-inflammatory actions. Moreover, the authors proposed a new frame of thinking centred on a dichotomy in the pathogenesis and clinical phenotype of BOS. Subsets of BOS patients were identified who do or do not respond to azithromycin (regarding forced expiratory volume in one second (FEV(1)), bronchoalveolar lavage (BAL) neutrophilia/interleukin-8). These observations have shed new light on the current belief that BOS represents a homogenous clinical entity in which the neutrophil is the main culprit. Recent clinical observations, supported by research findings, have revealed a dichotomy in the clinical spectrum of BOS with neutrophilic (partially) reversible allograft dysfunction (responding to azithromycin) and fibroproliferative BOS (not responding to azithromycin). This concept is reinforced by unique data obtained in BOS patients, consisting of histology specimens, physical and radiological examination, FEV(1 )and BAL examination. The acceptance of this dichotomy can improve understanding of the heterogeneous pathological condition that constitutes bronchiolitis obliterans syndrome, thus encouraging a more accurate diagnosis and, ultimately, better tailored treatment for each bronchiolitis obliterans syndrome patient.

Type III IFN-lambda mRNA expression in sputum of adult and school-aged asthmatics.

BACKGROUND: The increased susceptibility of asthmatics to rhinovirus infection has recently been related to deficient IFN-lambda 1 (IL-29) and IFN-lambda 2/3 (IL-28) production by bronchial epithelial cells and macrophages. OBJECTIVES: Here, we studied IFN-lambda mRNA expression in the airways of stable asthmatics in comparison with healthy subjects and in relation to asthma symptoms, non-invasive parameters of airway inflammation and lung function parameters. METHODS: Airway cells were obtained by sputum induction, in 14 healthy and 35 asthmatic adults and 12 asthmatic school-aged children. IFN-lambda was studied at the mRNA level by quantitative RT-PCR. RESULTS: Asthmatic adults have increased sputum IL-28 mRNA but similar IL-29 mRNA expression in comparison with healthy subjects. In asthmatics, both sputum IL-28 and IL-29 mRNA expression correlate with the sputum CD3 gamma mRNA expression (reflecting infiltrated T cells). IL-28 (but not IL-29) mRNA levels correlate with the relative and absolute number of eosinophils present in the sputum sample. Sputum IL-29 mRNA (but not IL-28) correlates negatively with asthma symptoms in steroid-naive patients and is significantly higher in steroid-treated than in steroid-naive patients. Finally, both IL-28 and IL-29 mRNA levels are higher in asthmatic children than in asthmatic adults. CONCLUSION: Our results show that asthmatic subjects have substantial type III IFN-lambda mRNA levels in the airways. Our data furthermore suggest that IL-29 could have an immunoprotective role in the lower airways.

Variability of fecal pancreatic elastase measurements in cystic fibrosis patients.

BACKGROUND: the fecal pancreatic elastase-1 (EL-1) test is a new non-invasive test for pancreatic function. The aim of the study was to evaluate the intra-patient variability of the fecal EL-1 test in a cystic fibrosis (CF) population. METHODS: 26 CF patients were recruited. Mean patient (S.D.) age was 13.7 years (5.39). Nineteen patients had classical pancreatic insufficiency (PI) based on a clinical syndrome of malabsorption plus steatorrhea on a 72 h fecal fat balance. They were all treated with enzyme supplements. Four patients had classical pancreatic sufficiency (PS): no symptoms of malabsorption, no steatorrhea on a 72 h fecal fat balance, no enzyme treatment. Two patients had symptoms suggestive of PI but had a normal 72 h fecal fat balance: (doubtful pancreatic status (PD)). The CF patients were asked to collect stool samples on 7 consecutive days. EL-1 content in the samples was measured in duplicate. A cut-off of 200 microgEL-1/g stool was used for diagnosing PI. RESULTS: mean intra-assay variability was 4.06%. All PI patients had EL-1 levels below detection limit. For the PS group maximal intra-patient variability was 35%, one stool sample EL-1 level was below the 200-microg cut-off. In the PD group the maximal intra-patient variability was 37% and EL-1 levels were inconclusive for the diagnosis of PI in both patients. CONCLUSIONS: the EL-1 test can be used for diagnosing severe PI in CF patients with overt clinical symptoms of malabsorption. However, in CF patients where the clinical picture is less clear the EL-1 test may be inconclusive due to significant intra-patient variability.

Ataxia-telangiectasia patients presenting with hyper-IgM syndrome.

Ataxia-telangiectasia (A-T) is characterised by progressive neurological abnormalities, oculocutaneous telangiectasias and immunodeficiency (decreased serum IgG subclass and/or IgA levels and lymphopenia). However, 10% of A-T patients present with decreased serum IgG and IgA with normal or raised IgM levels. As cerebellar ataxia and oculocutaneous telangiectasias are not present at very young age, these patients are often erroneously diagnosed as hyper IgM syndrome (HIGM). Eight patients with A-T, showing serum Ig levels suggestive of HIGM on first presentation, are described. All had decreased numbers of T lymphocytes, unusual in HIGM. The diagnosis A-T was confirmed by raised alpha-fetoprotein levels in all patients. To prevent mistaking A-T patients for HIGM it is proposed to add DNA repair disorders as a possible cause of HIGM.

Aggravation of bronchial eosinophilia in mice by nasal and bronchial exposure to Staphylococcus aureus enterotoxin B.

BACKGROUND: The role of bacterial enterotoxins like Staphylococcus aureus enterotoxin B (SEB) in allergic asthma remains unknown. We used a mouse model of airway allergy to study the effects of nasal or bronchial contact with SEB on bronchial allergic inflammation. METHODS: The features of allergic asthma were induced in ovalbumin (OVA)-sensitized mice (days 1-13) by repeated exposures to nebulized OVA (days 33-37). Nasal or bronchial application of SEB was performed on three occasions (days 33-35-37), and the effects on bronchial inflammation, IgE titres and expression levels of mRNA for T helper type 2 cytokines and other inflammatory mediators were evaluated. RESULTS: Both nasal and bronchial SEB enhanced the allergen-induced bronchial inflammation, as reflected by more eosinophilic inflammation in the airway lumen and in bronchial tissue. Aggravation of experimental asthma correlated with higher expression of mRNA for IL-5, IL-4, IFN-gamma, IL-12 p40, eotaxin-1 and TGF-beta in bronchi. In addition, nasal SEB elevated concentrations of IL-4, IL-5 and IFN-gamma in serum and bronchial SEB increased titres of OVA-specific and total IgE in serum. CONCLUSION: Our data illustrate the potential of both nasal as well as bronchial SEB to aggravate several features of allergic asthma in a mouse model.

The role of interleukin-17 during acute rejection after lung transplantation.

Acute rejection (AR) is an important complication that can occur after lung transplantation and constitutes a risk factor for bronchiolitis obliterans syndrome, which is characterised by a neutrophilic airway inflammation. The specific aim of this study was to investigate the role of interleukin (IL)-17, which promotes chemotaxis of neutrophils by inducing IL-8 production, in AR. Cell differentials, mRNA and protein levels were quantified in bronchoalveolar lavages (BALs) taken from patients at 28 and 90 days after lung transplantation. The patient's rejection status was assessed by transbronchial biopsy. An AR was found in nine out of the 26 patients examined, 28 days after transplantation. The number of BAL neutrophils and lymphocytes were increased in these patients. IL-17 mRNA and protein levels in the BAL were increased in patients with AR. Analysis of BAL obtained at day 90 after transplantation, demonstrated that the increase in IL-17 had disappeared, whereas the increase in neutrophils and lymphocytes persisted. These data showed that interleukin-17 is temporarily upregulated in bronchoalveolar lavage during acute rejection. The number of lymphocytes and neutrophils are increased in bronchoalveolar lavage during acute rejection and may persist up to 2 months after acute rejection. These findings suggest that interleukin-17 is important in the pathophysiology of acute lung rejection.