MAIT cell activation in adolescents is impacted by bile acid concentrations and body weight.

Bile acids (BAs) are produced by liver hepatocytes and were recently shown to exert functions additional to their well-known role in lipid digestion. As yet it is not known whether the mucosal-associated invariant T (MAIT) cells, which represent 10-15% of the hepatic T cell population, are affected by BAs. The focus of the present investigation was on the association of BA serum concentration with MAIT cell function and inflammatory parameters as well as on the relationship of these parameters to body weight. Blood samples from 41 normal weight and 41 overweight children of the Lifestyle Immune System Allergy (LISA) study were analyzed with respect to MAIT cell surface and activation markers [CD107a, CD137, CD69, interferon (IFN)-γ, tumor necrosis factor (TNF)-α] after Escherichia coli stimulation, mRNA expression of promyelocytic leukemia zinc finger protein (PLZF) and major histocompatibility complex class I-related gene protein (MR1), the inflammatory markers C-reactive protein (CRP), interleukin (IL)-8 and macrophage inflammatory protein (MIP)-1α as well as the concentrations of 13 conjugated and unconjugated BAs. Higher body weight was associated with reduced MAIT cell activation and expression of natural killer cell marker (NKp80) and chemokine receptor (CXCR3). BA concentrations were positively associated with the inflammatory parameters CRP, IL-8 and MIP-1α, but were negatively associated with the number of activated MAIT cells and the MAIT cell transcription factor PLZF. These relationships were exclusively found with conjugated BAs. BA-mediated inhibition of MAIT cell activation was confirmed in vitro. Thus, conjugated BAs have the capacity to modulate the balance between pro- and anti-inflammatory immune responses.

Stressful life events in childhood and allergic sensitization.

Stressful life events evidently have an impact on development of allergic diseases, but the mechanism linking stress to pathological changes of immune system function is still not fully understood. The aim of our study was to investigate the relationship between stressful life events, neuropeptide and cytokine concentrations in children as well as the association between early stressful life events and atopic eczema (AE). Within the LISA plus (Life style - Immune system - Allergy) study, blood samples from children of 6 years of age were analyzed for concentration of the neuropeptides vasoactive intestinal peptide (VIP), somatostatin (SOM), substance P (SP) and the Th1/Th2 cytokines IFN-γ and IL-4. Life events such as severe disease or death of a family member, unemployment or divorce of the parents were assessed with a questionnaire filled in by the parents. Furthermore, lifetime prevalence of AE and incidence after the assessment period of life events were compared. Our data suggest that separation/ divorce of parents increase childrens risk of developing AE later in life. Children with separated/divorced parents showed high VIP levels and high concentrations of the Th2 cytokine IL-4 in their blood. Severe diseases and death of a family member were neither associated with neuropeptide levels nor with cytokine concentrations. Unemployment of the parents was associated with decreased IFN-γ concentrations in childrens blood but not with neuropeptide levels. Thus, the neuropeptide VIP might be a mediator between stressful life events and immune regulation contributing to the Th2-shifted immune response in children with separated/divorced parents.

Maternal cytokine status may prime the metabolic profile and increase risk of obesity in children.

BACKGROUND: The maternal inflammation status during pregnancy has been associated with metabolic imprinting and obesity development in the child. However, the influence of the maternal Th2 cytokines, interleukin-4 (IL4), IL5 and IL13, has not been studied so far. METHODS: We investigated the relationship between maternal innate (IL6, IL8, IL10 and tumor necrosis factor-α (TNFa)) and adaptive (interferon-γ, IL4, IL5 and IL13) blood cytokine levels at 34 weeks of gestation and children's overweight development until the age of 3 years in 407 children of the German longitudinal LINA (Lifestyle and Environmental Factors and their Influence on Newborns Allergy risk) cohort. Children's body weight and height were measured during the annual clinical visits or acquired from questionnaires. Body mass index (BMI) Z-scores were calculated according to the WHO reference data to adjust for child's age and gender. Cytokine secretion was stimulated with phytohemagglutinin or lipopolysaccharide and measured by cytometric bead assay. Furthermore, we assessed metabolic parameter in blood of 318 children at age 1 using the AbsoluteIDQ p180 Kit (Biocrates LIFE Science AG). RESULTS: Applying logistic regression models, we found that an increase of maternal IL4 and IL13 was associated with a decreased risk for overweight development in 1- and 2-year-old children. This effect was consistent up to the age of 3 years for IL13 and mainly concerns children without maternal history of atopy. Children's acylcarnitine concentrations at 1 year were positively correlated with maternal IL13 levels and inversely associated with the BMI Z-score at age 1. CONCLUSIONS: We were able to show for the first time that the maternal Th2 status may be linked inversely to early childhood overweight development accompanied by an altered metabolic profile of the fetus. However, our data do not support a direct mediating role of acylcarnitines on maternal IL13-induced weight development.

GINIplus and LISAplus - Design and selected results of two German birth cohorts about natural course of atopic diseases and their determinants.

The increasing prevalence of asthma, hay fever, and allergic sensitization in Western Germany after east-west division in 1949 and their rapid increase in East German children after re-unification in 1990 are strong indications for the role of life-style and/or environmental factors in the development of atopic diseases. Obviously, the perinatal period is crucial for priming the immune system. Therefore, explorations of determinants of atopic diseases need pregnancy or birth cohorts as the most appropriate epidemiological study designs. This review presents the design and selected results of the two German birth cohorts GINIplus and LISAplus. GINIplus and LISAplus recruited 5.991 and 3.097 healthy, term newborns, respectively, from Munich, Wesel, Leipzig, and Bad Honnef. Approximately 55% could be followed for the first 10 years. We analyzed the natural course of atopic diseases and the role of life-style, environmental, and genetic factors for disease onset, intermediate phenotypes, and genes involved in detoxification and oxidative stress. The results of these two large birth cohorts contributed substantially to the understanding of atopic diseases and their determinants.

Efficacy, safety, tolerability and pharmacokinetics of a novel human immune globulin subcutaneous, 20%: a Phase 2/3 study in Europe in patients with primary immunodeficiencies.

A highly concentrated (20%) immunoglobulin (Ig)G preparation for subcutaneous administration (IGSC 20%), would offer a new option for antibody replacement therapy in patients with primary immunodeficiency diseases (PIDD). The efficacy, safety, tolerability and pharmacokinetics of IGSC 20% were evaluated in a prospective trial in Europe in 49 patients with PIDD aged 2-67 years. Over a median of 358 days, patients received 2349 IGSC 20% infusions at monthly doses equivalent to those administered for previous intravenous or subcutaneous IgG treatment. The rate of validated acute bacterial infections (VASBIs) was significantly lower than 1 per year (0·022/patient-year, P < 0·0001); the rate of all infections was 4·38/patient-year. Median trough IgG concentrations were ≥ 8 g/l. There was no serious adverse event (AE) deemed related to IGSC 20% treatment; related non-serious AEs occurred at a rate of 0·101 event/infusion. The incidence of local related AEs was 0·069 event/infusion (0·036 event/infusion, when excluding a 13-year-old patient who reported 79 of 162 total related local AEs). The incidence of related systemic AEs was 0·032 event/infusion. Most related AEs were mild, none were severe. For 64·6% of patients and in 94·8% of IGSC 20% infusions, no local related AE occurred. The median infusion duration was 0·95 (range = 0·3-4·1) h using mainly one to two administration sites [median = 2 sites (range = 1-5)]. Almost all infusions (99·8%) were administered without interruption/stopping or rate reduction. These results demonstrate that IGSC 20% provides an effective and well-tolerated therapy for patients previously on intravenous or subcutaneous treatment, without the need for dose adjustment.

Biomonitoring of prenatal analgesic intake and correlation with infantile anti-aeroallergens IgE.

An association between prenatal acetaminophen or ibuprofen intake and an increased risk of asthma and increased IgE level in children is discussed in various epidemiological studies. Although the molecular mechanistic link is still unknown, the question whether or not acetaminophen and/or ibuprofen are safe pain medications during pregnancy arose. In this study, we associate maternal acetaminophen and ibuprofen intake during pregnancy and breastfeeding to infantile asthma phenotypes and elevated IgE level. Therefore, we analysed questionnaires from a local mother-child cohort and monitored drug intake by LC-MS biomonitoring in urine. No association was found between drug intake and any analysed health outcome using questionnaire data. For the information obtained from biomonitoring, no association was found for ibuprofen and acetaminophen intakes during breastfeeding. However, an association between prenatal acetaminophen intake and increased infantile IgEs related to aeroallergens was statistically detected, but not for asthma phenotypes.

Current treatment options with immunoglobulin G for the individualization of care in patients with primary immunodeficiency disease.

Primary antibody deficiencies require lifelong replacement therapy with immunoglobulin (Ig)G to reduce the incidence and severity of infections. Both subcutaneous and intravenous routes of administering IgG can be effective and well tolerated. Treatment regimens can be individualized to provide optimal medical and quality-of-life outcomes in infants, children, adults and elderly people. Frequency, dose, route of administration, home or infusion-centre administration, and the use of self- or health-professional-administered infusion can be tailored to suit individual patient needs and circumstances. Patient education is needed to understand the disease and the importance of continuous therapy. Both the subcutaneous and intravenous routes have advantages and disadvantages, which should be considered in selecting each patient's treatment regimen. The subcutaneous route is attractive to many patients because of a reduced incidence of systemic adverse events, flexibility in scheduling and its comparative ease of administration, at home or in a clinic. Self-infusion regimens, however, require independence and self-reliance, good compliance on the part of the patient/parent and the confidence of the physician and the nurse. Intravenous administration in a clinic setting may be more appropriate in patients with reduced manual dexterity, reluctance to self-administer or a lack of self-reliance, and intravenous administration at home for those with good venous access who prefer less frequent treatments. Both therapy approaches have been demonstrated to provide protection from infections and improve health-related quality of life. Data supporting current options in IgG replacement are presented, and considerations in choosing between the two routes of therapy are discussed.

7th International Immunoglobulin Conference: Immunoglobulin in clinical practice.

Immunoglobulin (Ig) replacement therapy has been the mainstay of primary immunodeficiencies (PID) treatment for more than 30 years and has substantially changed the lives of patients. This review focuses on aspects of Ig use in clinical practice in addition to discussing prioritizing future Ig use. Despite Ig therapy, PID patients continue to be predisposed to recurrent, subclinical respiratory tract infections, which may lead to chronic lung disease. Research has shown that one of the underlying reasons for this deterioration in lung function is the differential distribution and concentration of Ig isotypes in the airway lumen. Further to this, the relationship between Ig dose and infection outcome is explored, expanding on end-of-cycle loss of efficacy (wear-off) particularly with intravenous immunoglobulin (IVIg), how this can confound the determination of optimal IgG dose and how our aim of treatment should be to improve clinical outcome. This review goes on to discuss the safety of Ig replacement therapy, which is generally well tolerated by most patients, compares the rates of systemic adverse reactions between IVIg and SCIg and highlights the advantages of SCIg administration in this respect, including the use of pre-infused subcutaneous recombinant human hyaluronidase to aid subcutaneous infusion volumes. The growing demand for Ig replacement therapy is challenging physicians; here we show the development of prioritization algorithms to assist in identifying those who will benefit most from this clinically valuable therapy.

7th International Immunoglobulin Conference: Immunoglobulin in clinical practice.

Intravenous and subcutaneous immunoglobulins (IVIg and SCIg, respectively) are increasingly used in clinical practice, not only as replacement therapy but also for immunomodulation. Physicians have learned that primary immunodeficiency (PID) patients are susceptible to recurrent respiratory tract infections even when appropriately treated with immunoglobulin (Ig) therapy. Further investigation will establish whether a combined therapeutic approach including Ig dose optimization will prevent progressive lung disease in PID. The wear-off effects observed with IVIg can be minimized by adjusting the dosing regimen. It is also possible to avoid the cyclic wear-off following transition to SCIg administration. Consideration of benefit versus risk with Ig therapy includes evaluating the potential occurrence of thromboembolic and haemolytic events, which may be more frequent when Ig is administered in high doses and in the presence of pre-existing risk factors. The ability to select an administration method from IVIg, SCIg or hyaluronidase-facilitated SCIg infusions provides patient choice and alternatives if one or other administration route is not suitable for a patient. The evolution in indications, applications, and understanding of Ig therapy described here has reinforced the need for robust methods to prioritize Ig use.

[Immunization in children and adolescents with rheumatic and musculoskeletal diseases]. / Sinnvolle Impfprävention bei Kindern und Jugendlichen mit rheumatischen und muskuloskelettalen Erkrankungen.

BACKGROUND: Children and adolescents with inflammatory rheumatic diseases have a disease and treatment-related increased risk of infections. This risk includes vaccine-preventable diseases; therefore, vaccinations represent an important preventive measure against infection in these patients. However, approximately one in three patients with a juvenile rheumatic disease is nowadays still inadequately vaccinated, mostly due to uncertainty regarding the efficacy and safety of vaccination in these patients. OBJECTIVES: This paper summarizes the available evidence regarding the efficacy and safety of vaccinations in children and adolescents with rheumatic diseases and gives recommendations for the clinical practice. RESULTS AND PERSPECTIVES: Almost 2000 children and adolescents with rheumatic diseases were examined in the more than 30 previously published vaccination studies, comprising nearly all standard vaccinations in the immunization schedule. The immunogenicity was usually sufficient and there was no evidence of a relevant aggravation of the underlying disease. Recommendations for the clinical practice are given also considering data beyond pediatric rheumatology; however, a final benefit-risk assessment is not yet possible.

The case for mandatory newborn screening for severe combined immunodeficiency (SCID).

Severe combined immunodeficiency (SCID) is the most severe form of inherited primary immunodeficiency and is a paediatric emergency. Delay in recognising and detecting SCID can have fatal consequences and also reduces the chances of a successful haematopoietic stem cell transplant (HSCT). Screening for SCID at birth would prevent children from dying before HSCT can be attempted and would increase the success of HSCT. There is strong evidence to show that SCID fulfills the internationally-established criteria for a condition to be screened for at birth. There is also a test (the T-cell receptor excision circle (TREC) assay) that is now being successfully used in an increasing number of US states to screen for SCID in routine newborn Guthrie samples. Concerted lobbying efforts have highlighted the need for newborn screening (NBS) for SCID, and its implementation is being discussed in Europe both at EU and individual country level, but as yet there is no global mandate to screen for this rare and frequently lethal condition. This paper summarizes the current evidence for, and the success of SCID NBS, together with a review of the practical aspects of SCID testing and the arguments in favour of adding SCID to the conditions screened for at birth.

The German national registry for primary immunodeficiencies (PID).

In 2009, a federally funded clinical and research consortium (PID-NET, http://www.pid-net.org) established the first national registry for primary immunodeficiencies (PID) in Germany. The registry contains clinical and genetic information on PID patients and is set up within the framework of the existing European Database for Primary Immunodeficiencies, run by the European Society for Primary Immunodeficiencies. Following the example of other national registries, a central data entry clerk has been employed to support data entry at the participating centres. Regulations for ethics approvals have presented a major challenge for participation of individual centres and have led to a delay in data entry in some cases. Data on 630 patients, entered into the European registry between 2004 and 2009, were incorporated into the national registry. From April 2009 to March 2012, the number of contributing centres increased from seven to 21 and 738 additional patients were reported, leading to a total number of 1368 patients, of whom 1232 were alive. The age distribution of living patients differs significantly by gender, with twice as many males than females among children, but 15% more women than men in the age group 30 years and older. The diagnostic delay between onset of symptoms and diagnosis has decreased for some PID over the past 20 years, but remains particularly high at a median of 4 years in common variable immunodeficiency (CVID), the most prevalent PID.

Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study.

BACKGROUND: Vitamin D levels are known to be associated with atopic disease development; however, existing data are controversial. The aim of this study was to investigate whether corresponding maternal and cord blood vitamin D levels are associated with atopic outcomes in early infancy. METHODS: Within the LINA cohort study (Lifestyle and environmental factors and their Influence on Newborns Allergy risk), 25(OH)D was measured in blood samples of 378 mother-child pairs during pregnancy and at birth. Information about children's atopic manifestations during the first 2 years of life was obtained from questionnaires filled out by the parents during pregnancy and annually thereafter. Cord blood regulatory T cells (Treg) were detected by methylation-specific PCR using a Treg-specific demethylated region in the FOXP3 gene. RESULTS: The median maternal 25(OH)D(3) level was 22.19 ng/ml (IQR 14.40-31.19 ng/ml); the median cord blood 25(OH)D(3) 10.95 ng/ml (6.99-17.39 ng/ml). A high correlation was seen between maternal and cord blood 25(OH)D(3) levels, both showing a seasonal distribution. Maternal and cord blood 25(OH)D(3) was positively associated with children's risk for food allergy within the first 2 years. Further, higher maternal 25(OH)D(3) resulted in a higher risk for sensitization against food allergens at the age of two. Cord blood 25(OH)D(3) levels were negatively correlated with regulatory T cell numbers. CONCLUSION: Our study demonstrates that high vitamin D levels in pregnancy and at birth may contribute to a higher risk for food allergy and therefore argues against vitamin D supplement to protect against allergy.

[Interdisciplinary AWMF guideline for the treatment of primary antibody deficiencies]. / Interdisziplinäre AWMF-Leitlinie zur Therapie primärer Antikörpermangelerkrankungen.

BACKGROUND: Currently, management of antibody deficient patients differs significantly among caregivers. Evidence and consensus based (S3) guidelines for the treatment of primary antibody deficiencies were developed to improve the management of these patients. METHODS: Based on a thorough analysis of current evidence (systematic literature search in PubMed; deadline November 2011) 14 recommendations were finalized during a consensus meeting in Frankfurt in November 2011 using structured consensus methods (nominal group technique). Experts were nominated by their scientific societies/patient initiatives (Tab. 1). RESULTS: The guidelines focus on indication, practical issues and monitoring of immunoglobulin replacement therapy as well as on different routes of administration. Furthermore recommendations regarding supportive measures such as antiinfective therapy, vaccinations and physiotherapy are given. Combining literature evidence and experience of caregivers within this evidence and consensus based guidelines offers the chance to improve the quality of care for anti-body deficient patients.

The LINA cohort: indoor chemical exposure, circulating eosinophil/basophil (Eo/B) progenitors and early life skin manifestations.

BACKGROUND: Hematopoietic progenitor cells, especially those committed to the Eo/B lineage, are known to contribute to allergic inflammation. OBJECTIVE: The aim of the present study was to investigate whether environmental factors are associated with changes in numbers of circulating Eo/B progenitors at 1 year of age. METHODS: Peripheral blood from 60 1-year-old children enrolled in the LINA (Lifestyle and environmental factors and their Influence on Newborns Allergy risk) birth cohort was assessed for Eo/B progenitor cells (Eo/B CFU) using standardized and validated methylcellulose assays. Frozen peripheral blood mononuclear cells (PBMC) were cultured in the presence of IL-3, IL-5 or GM-CSF, and Eo/B CFUs enumerated. Clinical outcomes and exposure to environmental tobacco smoke (ETS) were documented by standardized questionnaires, and indoor volatile organic compound (VOC) concentrations were assessed by passive sampling. RESULTS: Children with skin manifestations (atopic dermatitis or cradle cap) within the first year of life had higher numbers of circulating IL-3-, IL-5- or GM-CSF-stimulated Eo/B CFUs (P < 0.05) at 1 year. In children with cradle cap, a positive correlation was found between Eo/B CFUs and exposure to ETS-related VOCs during pregnancy or at 1 year of age (P < 0.05). CONCLUSIONS AND CLINICAL RELEVANCE: This is the first demonstration that environmental exposures are positively associated with levels of circulating Eo/B progenitors. The recruitment and differentiation of Eo/B progenitors in response to environmental triggers may play a role in the development of skin manifestations during the first year of life.

Evaluation of correlation between dose and clinical outcomes in subcutaneous immunoglobulin replacement therapy.

The importance of serum immunoglobulin (Ig)G concentration in IgG replacement therapy for primary immunodeficiency diseases is established in certain settings. Generally, IgG is infused via the intravenous (IVIG) or subcutaneous (SCIG) route. For IVIG infusion, published data demonstrate that higher IgG doses and trough levels provide patients with improved protection from infection. The same conclusions are not yet accepted for SCIG; data from two recent Phase III studies and a recent post-hoc analysis, however, suggest the same correlation between higher SCIG dose and serum IgG concentration and decreased incidence of infection seen with IVIG. Other measures of clinical efficacy have not been considered similarly. Thus, combined analyses of these and other published SCIG studies were performed; a full comparison of the 13 studies was, however, limited by non-standardized definitions and reporting. Despite these limitations, our analyses indicate that certain clinical outcomes improve at higher SCIG doses and associated higher serum IgG concentrations, and suggest that there might be opportunity to improve patient outcomes via SCIG dose adjustment.

[Immunoglobulins in PID, SID and neurological autoimmune disease]. / Anwendung von Immunglobulinen bei primären und sekundären Immundefekten und neurologischen Autoimmunerkrankungen.

Human immunoglobulins (IG, mostly IgG) are used as replacement therapy in patients with inherited primary immunodeficiencies, and in patients with secondary immuno-deficiencies often observed in multiple myeloma or chronic lymphocytic leukemia. Ig are also approved as immunomodulatory therapy in neurological autoimmune diseases (NAID) such as Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). 16 different Ig preparations for intravenous and subcutaneous use are at the moment available in Germany. The SIGNS study (Assessment of immunoglobulins in a long-term non-interventional study) investigates the clinical use of these drugs under clinical practice conditions. In this non-interventional prospective open-label cohort study, 550 patients with new or maintenance Ig therapy are observed with respect to drug utilization, effectiveness, (i. e. number of infections in PID and SID, functionality in NAID), tolerability, quality of life and costs in approximately 50 sites throughout Germany (neurologists, pediatricians, oncologists, other) for at least two years. This largest study of its kind is expected to contribute to optimization of Ig therapy in the postmarketing setting.

Cord blood Tregs with stable FOXP3 expression are influenced by prenatal environment and associated with atopic dermatitis at the age of one year.

BACKGROUND: Regulatory T cells (Tregs) with stable FOXP3 expression are characterized by a specific demethylated region in the FOXP3 gene (Treg-specific demethylated region, TSDR). The aim of this study was to analyse the influence of prenatal factors on cord blood Treg numbers, as detected by changes in the TSDR demethylation, and the subsequent risk for allergic diseases. METHODS: Analyses were performed within the LINA study in blood samples from pregnant women (34th gestational week) and in cord blood (n = 346 mother-child pairs). Treg numbers were detected via DNA demethylation in the FOXP3 TSDR. At age 1, total and specific IgE was measured in children's blood. In addition, maternal cytokine production (Th1/Th2/Th17) was analysed. Exposure and disease outcomes were assessed by questionnaires. RESULTS: Boys had lower Treg numbers compared with girls (P < 0.001). Parental atopy history, particularly maternal hay fever and paternal asthma were related to lower Treg numbers in cord blood (adj. MR = 0.81, 95% CI = 0.68-0.97; adj. MR = 0.60, 95% CI = 0.45-0.81). Maternal cytokines (IL-13, IL-17E and IFN-γ) and maternal smoking/exposure to tobacco smoke during pregnancy were also associated with decreased cord blood Treg numbers (adj. MR = 0.89, 95% CI = 0.97-1.00). Children with lower Treg numbers at birth had a higher risk to develop atopic dermatitis (adj. OR = 1.55, 95% CI = 1.00-2.41) and sensitization to food allergens (adj. OR = 1.55, 95% CI = 1.06-2.25) during the first year of life. CONCLUSIONS: These results indicate that both genetic and environmental factors presumably influence the development of foetal Tregs. Low cord blood Treg numbers may predict early atopic dermatitis.

[Interdisciplinary AWMF guideline for the diagnostics of primary immunodeficiency]. / Interdisziplinäre AWMF-Leitlinie zur Diagnostik von primären Immundefekten (S2k).

BACKGROUND: Primary immunodeficiencies are potentially life-threatening diseases. Over the last years, the clinical phenotype and the molecular basis of an increasing number of immunological defects have been characterized. However, in daily practice primary immunodeficiencies are still often diagnosed too late. Considering that an early diagnosis may reduce morbidity and mortality of affected patients, an interdisciplinary guideline for the diagnosis of primary immunodeficiencies was developed on behalf of the Arbeitsgemeinschaft Pädiatrische Immunologie (API) and the Deutsche Gesellschaft für Immunologie (DGfI). METHODS: The guideline is based on expert opinion and on knowledge from other guidelines and recommendations from Germany and other countries, supplemented by data from studies that support the postulated key messages (level of evidence III). With the contribution of 20 representatives, belonging to 14 different medical societies and associations, a consensus-based guideline with a representative group of developers and a structured consensus process was created (S2k). Under the moderation of a representative of the Association of the Scientific Medical Societies in Germany (AWMF) the nominal group process took place in April 2011. RESULTS: The postulated key messages were discussed and voted on following a structured consensus procedure. In particular, modified warning signs for primary immunodeficiencies were formulated and immunological emergency situations were defined.