Clinical, immunological, and molecular analysis in a large cohort of patients with X-linked agammaglobulinemia: an Italian multicenter study

A Novel BTK Gene Mutation in a Child With Atypical X-Linked Agammaglobulinemia and Recurrent Hemophagocytosis: A Case Report

X-linked agammaglobulinemia (XLA), caused by a mutation in the Bruton's tyrosine kinase (BTK) gene, is rarely reported in patients with recurrent hemophagocytic lymphohistiocytosis (HLH). This mutation leads to significantly reduced numbers of circulatory B cells and serum immunoglobulins in patients. Therefore, they exhibit repetitive bacterial infections since infancy, and immunoglobulin (Ig) replacement therapy is the primary treatment. HLH is a life-threatening condition with manifestations of non-remitting fever, hepatosplenomegaly, cytopenias, coagulopathy, lipid disorder, and multiple organ failure. It is caused by the immune dysregulation between cytotoxic T cells, NK cells, and histiocytes. The treatment is based on HLH-2004 protocol including immunotherapy, chemotherapy, supportive therapy, and stem cell transplantation. However, as we know more about the classification and pathophysiology of HLH, the treatment is modified. T-cell-directed immunotherapy is effective in patients with primary HLH, and strong immunosuppression is contraindicated in patients with severe ongoing infections or some primary immunodeficiency diseases (PIDs). Here, we report the case of a 7-year-old boy who presented with ecthyma gangrenosum and several episodes of pyogenic infections during childhood. At the age of 5 years, he exhibited cyclic HLH every 2–3 months. The remission of HLH episodes finally achieved after he received monthly Ig replacement therapy (400 mg/kg) at the 4th HLH. However, transient elevation of IgM was incidentally discovered after 6 cycles of monthly Ig replacement therapy. IgM-secreting multiple myeloma, Waldenström's macroglobulinemia, and lymphoma were excluded. The IgM levels then declined and returned to the normal range within a year. The patient and his parents received whole-genome sequencing analysis. It revealed a novel hemizygous c.1632-1G>A mutation in the BTK gene and XLA was diagnosed. XLA exhibits a spectrum of clinical and immunological presentations in patients. The identification of the mutation in the BTK gene contribute to an accurate diagnosis. Ig replacement therapy is the primary treatment for HLH in patients with XLA.

Appropriate lung management in patients with primary antibody deficiencies

Introduction: Human primary immunodeficiency diseases (PIDs) include a broad spectrum of more than 350 disorders, involving different branches of the immune system and classified as 'rare diseases.' Predominantly antibody deficiencies (PADs) represent more than half of the PIDs diagnosed in Europe and are often diagnosed in the adulthood. Areas covered: Although PAD could first present with autoimmune or neoplastic features, respiratory infections are frequent and respiratory disease represents a relevant cause of morbidity and mortality. Pulmonary complications may be classified as infection-related (acute and chronic), immune-mediated, and neoplastic. Expert opinion: At present, no consensus guidelines are available on how to monitor and manage lung complications in PAD patients. In this review, we will discuss the available diagnostic, prognostic and therapeutic instruments and we will suggest an appropriate and evidence-based approach to lung diseases in primary antibody deficiencies. We will also highlight the possible role of promising new tools and strategies in the management of pulmonary complications. However, future studies are needed to reduce of diagnostic delay of PAD and to better understand lung diseases mechanisms, with the final aim to ameliorate therapeutic options that will have a strong impact on Quality of Life and long-term prognosis of PAD patients.

Plasma therapy leads to an increase in functional IgA and IgM concentration in the blood and saliva of a patient with X-linked agammaglobulinemia

BACKGROUND

Patients with X-linked agammaglobulinemia (XLA) are protected against invasive bacterial infections due to IgG replacement therapy, but are still at higher risk for mucosal infections of the gut and respiratory tract. This might be explained by to the lack of IgA and IgM, as these antibodies are especially important for protection against invading bacterial pathogens on the mucosal surface.

METHODS

In an attempt to eliminate a chronic norovirus infection in a patient with X-linked agammaglobulinemia, fresh frozen plasma (FFP) was given two times a week for 3 weeks. At each visit, pre- and post-FFP infusion serum and saliva was collected to determine IgG-, IgA- and IgM-concentrations and serum half-life was calculated. Functionality of the immunoglobulins pre- and post-FFP infusion in both serum and saliva was tested by measuring complement activation, agglutination and killing of non-typeable Haemophilus influenzae (NTHi).

RESULTS

Administration of FFP failed to eradicate the chronic norovirus infection. Serum IgA and IgM half-life was 4.2 ± 0.3 and 3.8 ± 0.3 days, respectively. The presence of serum IgM was associated with increased complement binding and complement-mediated killing of NTHi. IgA in saliva was detectable post-FFP and was associated with increased agglutination of NTHi. IgM in saliva was not detectable.

CONCLUSIONS

We conclude that FFP treatment, although ineffective in clearing a chronic norovirus infection in this single patient, might be beneficial to prevent or eliminate bacterial infections in XLA patients by increasing IgM dependent complement-mediated killing in serum and IgA dependent bacterial agglutination on the mucosal surface.

Life-Threatening Infections Due to Live-Attenuated Vaccines: Early Manifestations of Inborn Errors of Immunity

Live-attenuated vaccines (LAVs) can protect humans against 12 viral and three bacterial diseases. By definition, any clinical infection caused by a LAV that is sufficiently severe to require medical intervention attests to an inherited or acquired immunodeficiency that must be diagnosed or identified. Self-healing infections can also result from milder forms of immunodeficiency. We review here the inherited forms of immunodeficiency underlying severe infections of LAVs. Inborn errors of immunity (IEIs) underlying bacille Calmette-Guérin (BCG), oral poliovirus (OPV), vaccine measles virus (vMeV), and oral rotavirus vaccine (ORV) disease have been described from 1951, 1963, 1966, and 2009 onward, respectively. For each of these four LAVs, the underlying IEIs show immunological homogeneity despite genetic heterogeneity. Specifically, BCG disease is due to inborn errors of IFN-γ immunity, OPV disease to inborn errors of B cell immunity, vMeV disease to inborn errors of IFN-α/β and IFN-λ immunity, and ORV disease to adaptive immunity. Severe reactions to the other 11 LAVs have been described yet remain "idiopathic," in the absence of known underlying inherited or acquired immunodeficiencies, and are warranted to be the focus of research efforts. The study of IEIs underlying life-threatening LAV infections is clinically important for the affected patients and their families, as well as immunologically, for the study of the molecular and cellular basis of host defense against both attenuated and parental pathogens.

Primary and Secondary Immunodeficiency Diseases in Oncohaematology: Warning Signs, Diagnosis, and Management

Background: Immunodeficiencies (ID), in particular primary immunodeficiencies (PID), are often associated with haematological manifestations, such as peripheral cytopenias or lymphoproliferative syndromes. Early diagnosis and management have significant prognostic implications. Secondary immunodeficiencies (SID) may also be induced by oncohaematological diseases and their treatments. Haematologists and oncologists must therefore be aware of the association between blood disorders and cancer and ID, and be prepared to offer their patients appropriate treatment without delay. Our aim was to define the warning signs of primary and secondary IDs in paediatric and adult patients with oncohaematological manifestations. Methods: A multidisciplinary group of six experts (2 haematologists, 2 immunologists, and 2 paediatricians specializing in ID) conducted a literature review and prepared a document based on agreements reached an in-person meeting. An external group of 44 IDs specialists from all over Spain assessed the document and were consulted regarding their level of agreement. Results: This document identifies the haematological and extra-haematological diseases that should prompt a suspicion of PIDs in adults and children, in both primary care and haematology and oncology departments. Cytopenia and certain lymphoproliferative disorders are key diagnostic pointers. The diagnosis must be based on a detailed clinical history, physical exploration, complete blood count and standard laboratory tests. The immunological and haematological tests included in the diagnostic process will depend on the care level. Patients who are candidates for immunoglobulin replacement therapy must be carefully selected, and treatment should be offered as soon as possible to avoid the development of complications. Finally, this document recommends procedures for monitoring these patients. Conclusions: This document combines scientific evidence with the opinion of a broad panel of experts, and emphasizes the importance of an early diagnosis and treatment to avoid complications. The resulting document is a useful tool for primary care physicians and specialists who see both adult and paediatric patients with oncohaematological diseases.

X-linked agammaglobulinemia (XLA):Phenotype, diagnosis, and therapeutic challenges around the world

BACKGROUND

X-linked agammaglobulinemia is an inherited immunodeficiency recognized since 1952. In spite of seven decades of experience, there is still a limited understanding of regional differences in presentation and complications. This study was designed by the Primary Immunodeficiencies Committee of the World Allergy Organization to better understand regional needs, challenges and unique patient features.

METHODS

A survey instrument was designed by the Primary Immunodeficiencies Committee of the World Allergy Organization to collect both structured and semi-structured data on X-linked agammaglobulinemia. The survey was sent to 54 centers around the world chosen on the basis of World Allergy Organization participation and/or registration in the European Society for Immunodeficiencies. There were 40 centers that responded, comprising 32 countries.

RESULTS

This study reports on 783 patients from 40 centers around the world. Problems with diagnosis are highlighted by the reported delays in diagnosis>24 months in 34% of patients and the lack of genetic studies in 39% of centers Two infections exhibited regional variation. Vaccine-associated paralytic poliomyelitis was seen only in countries with live polio vaccination and two centers reported mycobacteria. High rates of morbidity were reported. Acute and chronic lung diseases accounted for 41% of the deaths. Unusual complications such as inflammatory bowel disease and large granular lymphocyte disease, among others were specifically enumerated, and while individually uncommon, they were collectively seen in 20.3% of patients. These data suggest that a broad range of both inflammatory, infectious, and autoimmune conditions can occur in patients. The breadth of complications and lack of data on management subsequently appeared as a significant challenge reported by centers. Survival above 20 years of age was lowest in Africa (22%) and reached above 70% in Australia, Europe and the Americas. Centers were asked to report their challenges and responses (n = 116) emphasized the difficulties in access to immunoglobulin products (16%) and reflected the ongoing need for education of both patients and referring physicians.

CONCLUSIONS

This is the largest study of patients with X-linked agammaglobulinemia and emphasizes the continued morbidity and mortality of XLA despite progress in diagnosis and treatment. It presents a world view of the successes and challenges for patients and physicians alike. A pivotal finding is the need for education of physicians regarding typical symptoms suggesting a possible diagnosis of X-linked agammaglobulinemia and sharing of best practices for the less common complications.

Double-blind, placebo-controlled, randomized trial on low-dose azithromycin prophylaxis in patients with primary antibody deficiencies

BACKGROUND

Lacking protective antibodies, patients with primary antibody deficiencies (PADs) experience frequent respiratory tract infections, leading to chronic pulmonary damage. Macrolide prophylaxis has proved effective in patients with chronic respiratory diseases.

OBJECTIVE

We aimed to test the efficacy and safety of orally administered low-dose azithromycin prophylaxis in patients with PADs.

METHODS

We designed a 3-year, double-blind, placebo-controlled, randomized clinical trial to test whether oral azithromycin (250 mg administered once daily 3 times a week for 2 years) would reduce respiratory exacerbations in patients with PADs and chronic infection-related pulmonary diseases. The primary end point was the number of annual respiratory exacerbations. Secondary end points included time to first exacerbation, additional antibiotic courses, number of hospitalizations, and safety.

RESULTS

Eighty-nine patients received azithromycin (n = 44) or placebo (n = 45). The number of exacerbations was 3.6 (95% CI, 2.5-4.7) per patient-year in the azithromycin arm and 5.2 (95% CI, 4.1-6.4) per patient-year in the placebo arm (P = .02). In the azithromycin group the hazard risk for having an acute exacerbation was 0.5 (95% CI, 0.3-0.9; P = .03), and the hazard risk for hospitalization was 0.5 (95% CI, 0.2-1.1; P = .04). The rate of additional antibiotic treatment per patient-year was 2.3 (95% CI, 2.1-3.4) in the intervention group and 3.6 (95% CI, 2.9-4.3) in the placebo group (P = .004). Haemophilus influenzae and Streptococcus pneumoniae were the prevalent isolates, and they were not susceptible to macrolides in 25% of patients of both arms. Azithromycin's safety profile was comparable with that of placebo.

CONCLUSION

The study reached the main outcome centered on the reduction of exacerbation episodes per patient-year, with a consequent reduction in additional courses of antibiotics and risk of hospitalization.

Differing Performance of the Warning Signs for Immunodeficiency in the Diagnosis of Pediatric Versus Adult Patients in a Two-Center Tertiary Referral Population

PURPOSE

Primary immunodeficiency (PID) represents disorders with a spectrum of clinical presentations. The medical community seeks clinical features to prompt evaluation for immunodeficiency given improved prognosis with early identification. We hoped to identify clinical characteristics that would improve the diagnostic accuracy of the widely disseminated Jeffrey Modell Foundation warning signs for immunodeficiency.

METHODS

We performed a retrospective chart review in a two-center North American cohort of patients with PID. Charts of 137 pediatric and 400 adult patients with PID were evaluated for the presence of these warning signs and compared to controls with normal preliminary biochemical immune evaluation.

RESULTS

Fewer than 45% of adults with PID presented with ≥ 2 warning signs, while diagnostic utility was improved in the pediatric population where the warning signs were found to be 64% sensitive. The warning signs found in a significantly increased proportion compared to controls differed for pediatric PID patients (recurrent pneumonia (OR 2.9, p < 0.001), failure to thrive (OR 2.1, p < 0.001), need for IV antibiotics (OR 2.1, p < 0.001), serious bacterial infection (OR 4.8, p < 0.001), recurrent otitis media (OR 1.5, p = 0.027)), versus adult PID patients (recurrent otitis media (OR 2.9, p < 0.001), recurrent sinusitis (OR 2.1, p < 0.001), diarrhea with weight loss (OR 2.2, p < 0.001), recurrent viral infection (OR 3.3 p < 0.001)). In evaluation for additional criteria to promote identification of immunodeficiency, linear regression models showed slightly improved diagnostic accuracy of the warning signs with the addition of autoimmunity in our pediatric PID cohort (8.7% v 2.8%, p < 0.001, ROC 0.58). Adult PID patients demonstrated atopy more frequently than controls (48.0% vs 40.3%, p = 0.011), while atopy was found to have a negative association with the presence of PID in the pediatric age group (OR 0.3, p < 0.01). No improvement in diagnostic accuracy of the warning signs was found with the addition of allergic disease, autoimmunity, or malignant and benign proliferative disease in the adult cohort.

CONCLUSIONS

We demonstrate poor diagnostic performance of warning signs for immunodeficiency in patients with PID in a retrospective chart review. Divergent warning signs of statistically significant diagnostic utility were found in pediatric versus adult patients. We suggest education of physicians on differing presentations of possible immunodeficiency between age groups, and expansion of the warning signs to include non-infectious comorbidities such as autoimmunity in pediatric patients.

Clinical and genetic profiles of patients with X-linked agammaglobulinemia from southeast Turkey: Novel mutations in BTK gene

BACKGROUND

X-linked agammaglobulinemia (XLA) is characterized by absent or severely reduced B cells, low or undetectable immunoglobulin levels, and clinically by extracellular bacterial infections which mainly compromise the respiratory tract. We aimed to analyze the clinical, immunological and genetic characteristics of 22 male children with XLA.

METHODS

Twenty-two children with XLA from 12 unrelated families were enrolled in this study. Clinical and demographic features of patients, serum immunoglobulin levels, percentage of B cells and BTK gene mutations were reviewed retrospectively.

RESULTS

We identified 12 different mutations in 22 patients from 12 unrelated families. The most frequent type of mutation was premature stop codon (33.3%). Ten mutations had been reported previously including three missense mutations (c.1774T>C, c.1684C>T, c.83G>T), three premature stop codons (c.1558C>T, c.1573C>T, c.753G>A), two splice-site (c.683-1G>A, c.1567-12_1567-9delTTTG) and two small nucleotide deletions (c.902-904_delAAG, c.179_181delAGA). Two novel mutations of the BTK gene were also presented and included one splice-site mutation (c.391+1G>C) and one premature stop codon mutation (c.1243_1243delG). Six out of 12 mutations of the BTK gene were located in the SH1 domain, two in the PH domain, two in the SH3 domain and two in the SH2 domain. Three patients had a history of severe infection before diagnosis. We did not identify any correlation between severity of clinical symptoms and the genotype.

CONCLUSIONS

Our results show that mutations in southeast Turkey could be different from those in the rest of the world and molecular genetic tests are an important tool for early confirmed diagnosis of XLA.

Pulmonary Manifestations of Predominantly Antibody Deficiencies

Predominantly antibody deficiencies (PADs) are the most frequent forms of primary immunodeficiency diseases (PIDs). Commonly accompanied with complications involving several body systems, immunoglobulin substitution therapy along with prophylactic antibiotics remained the cornerstone of treatment for PADs and related complications. Patients with respiratory complications should be prescribed an appropriate therapy as soon as possible and have to be adhering to more and longer medical therapies. Recent studies identified a gap for screening protocols to monitor respiratory manifestations in patients with PADs. In the present chapter, the pulmonary manifestations of different PADs for each have been discussed. The chapter is mainly focused on X-linked agammaglobulinemia, common variable immunodeficiency, activated PI3K-δ syndrome, LRBA deficiency, CD19 complex deficiencies, CD20 deficiency, other monogenic defects associated with hypogammaglobulinemia, immunoglobulin class switch recombination deficiencies affecting B-cells, transient hypogammaglobulinemia of infancy, and selective IgA deficiency.

Imaging of Bronchial Pathology in Antibody Deficiency: Data from the European Chest CT Group

Studies of chest computed tomography (CT) in patients with primary antibody deficiency syndromes (ADS) suggest a broad range of bronchial pathology. However, there are as yet no multicentre studies to assess the variety of bronchial pathology in this patient group. One of the underlying reasons is the lack of a consensus methodology, a prerequisite to jointly document chest CT findings. We aimed to establish an international platform for the evaluation of bronchial pathology as assessed by chest CT and to describe the range of bronchial pathologies in patients with antibody deficiency. Ffteen immunodeficiency centres from 9 countries evaluated chest CT scans of patients with ADS using a predefined list of potential findings including an extent score for bronchiectasis. Data of 282 patients with ADS were collected. Patients with common variable immunodeficiency disorders (CVID) comprised the largest subgroup (232 patients, 82.3%). Eighty percent of CVID patients had radiological evidence of bronchial pathology including bronchiectasis in 61%, bronchial wall thickening in 44% and mucus plugging in 29%. Bronchiectasis was detected in 44% of CVID patients aged less than 20 years. Cough was a better predictor for bronchiectasis than spirometry values. Delay of diagnosis as well as duration of disease correlated positively with presence of bronchiectasis. The use of consensus diagnostic criteria and a pre-defined list of bronchial pathologies allows for comparison of chest CT data in multicentre studies. Our data suggest a high prevalence of bronchial pathology in CVID due to late diagnosis or duration of disease.

Primary immunodeficiency diseases in lung disease: warning signs, diagnosis and management

Background

Pulmonary complications are common in primary immunodeficiency diseases (PID) and contribute to morbidity and mortality in these patients. However, their varied presentation and a general lack of awareness of PID in this setting make early diagnosis and treatment difficult. The aim of this study was to define the warning signs of PID in patients with respiratory manifestations, the necessary diagnostic tests, and the therapeutic management of both children and adults.

Methods

A review of the literature was performed, and 43 PID interdisciplinary specialists were consulted.

Results

This document identifies the pulmonary and extrapulmonary manifestations that should prompt a suspicion of PID, the immunological and respiratory tests that should be included in the diagnostic process according to the level of care, recommendations regarding the use of immunoglobulin replacement therapy according to the specific immunodeficiency, and the minimum recommended immunological and pulmonary monitoring in these patients.

Conclusions

This document is the first to combine scientific evidence with the opinion of a broad panel of experts specializing in the treatment of patients with immunodeficiencies. It aims to provide a useful tool for all practitioners who are regularly involved in the management of these patients.

The broad spectrum of lung diseases in primary antibody deficiencies

Human primary immunodeficiency diseases (PIDs) represent a heterogeneous group of more than 350 disorders. They are rare diseases, but their global incidence is more relevant than generally thought. The underlying defect may involve different branches of the innate and/or adaptive immune response. Thus, the clinical picture may range from severe phenotypes characterised by a broad spectrum of infections to milder infectious phenotypes due to more selective (and frequent) immune defects. Moreover, infections may not be the main clinical features in some PIDs that might present with autoimmunity, auto-inflammation and/or cancer. Primary antibody deficiencies (PADs) represent a small percentage of the known PIDs but they are the most frequently diagnosed, particularly in adulthood. Common variable immunodeficiency (CVID) is the most prevalent symptomatic PAD.

PAD patients share a significant susceptibility to respiratory diseases that represent a relevant cause of morbidity and mortality. Pulmonary complications include acute and chronic infection-related diseases, such as pneumonia and bronchiectasis. They also include immune-mediated interstitial lung diseases, such as granulomatous-lymphocytic interstitial lung disease (GLILD) and cancer. Herein we will discuss the main pulmonary manifestations of PADs, the associated functional and imaging findings, and the relevant role of pulmonologists and chest radiologists in diagnosis and surveillance.

The spectrum of lung complications in primary antibody deficiency ranges from asthma or COPD to extremely rare and specific ILDs. Early diagnosis of the underlying immune defect might significantly improve patients' lung disease, QoL and long-term prognosis.http://ow.ly/5cP230kZvOB

Limited Innovations After More Than 65 Years of Immunoglobulin Replacement Therapy: Potential of IgA- and IgM-Enriched Formulations to Prevent Bacterial Respiratory Tract Infections

Patients with primary immunoglobulin deficiency have lower immunoglobulin levels or decreased immunoglobulin function, which makes these patients more susceptible to bacterial infection. Most prevalent are the selective IgA deficiencies (~1:3,000), followed by common variable immune deficiency (~1:25,000). Agammaglobulinemia is less common (~1:400,000) and is characterized by very low or no immunoglobulin production resulting in a more severe disease phenotype. Therapy for patients with agammaglobulinemia mainly relies on prophylactic antibiotics and the use of IgG replacement therapy, which successfully reduces the frequency of invasive bacterial infections. Currently used immunoglobulin preparations contain only IgG. As a result, concurrent IgA and IgM deficiency persist in a large proportion of agammaglobulinemia patients. Especially patients with IgM deficiency remain at risk for recurrent infections at mucosal surfaces, which includes the respiratory tract. IgA and IgM have multiple functions in the protection against bacterial infections at the mucosal surface. Because of their multimeric structure, both IgA and IgM are able to agglutinate bacteria efficiently. Agglutination allows for entrapment of bacteria in mucus that increases clearance from the respiratory tract. IgA is also important for blocking bacterial adhesion by interfering with bacterial adhesion receptors. IgM in its place is very well capable of activating complement, therefore, it is thought to be important in complement-mediated protection at the mucosal surface. The purpose of this Mini Review is to highlight the latest advances regarding IgA- and IgM-enriched immunoglobulin replacement therapy. We describe the different IgA- and IgM-enriched IgG formulations, their possible modes of action and potential to protect against respiratory tract infections in patients with primary immunoglobulin deficiencies.

The Lung in Primary Immunodeficiencies: New Concepts in Infection and Inflammation

Immunoglobulin replacement therapy (IGRT) has contributed critically to the management of primary antibody deficiencies (PAD) and the decrease in pneumonia rate. However, despite adequate IGRT and improved prognosis, patients with PAD continue to experience recurrent respiratory tract infections, leading to bronchiectasis and continuing decline in lung function with a severe impact on their quality of life. Moreover, non-infectious inflammatory and interstitial lung complications, such as granulomatous-lymphocytic interstitial lung disease, contribute substantially to the overall morbidity of PAD. These conditions develop much more often than appreciated and represent a major therapeutic challenge. Therefore, a regular assessment of the structural and functional condition of the lung and the upper airways with appropriate treatment is required to minimize the deterioration of lung function. This work summarizes the knowledge on lung complications in PAD and discusses the currently available diagnostic tools and treatment options.

ABBV-105, a selective and irreversible inhibitor of Bruton's tyrosine kinase, is efficacious in multiple preclinical models of inflammation

OBJECTIVES

Bruton's tyrosine kinase (BTK) is a non-receptor tyrosine kinase required for intracellular signaling downstream of multiple immunoreceptors. We evaluated ABBV-105, a covalent BTK inhibitor, using in vitro and in vivo assays to determine potency, selectivity, and efficacy to validate the therapeutic potential of ABBV-105 in inflammatory disease.

METHODS

ABBV-105 potency and selectivity were evaluated in enzymatic and cellular assays. The impact of ABBV-105 on B cell function in vivo was assessed using mechanistic models of antibody production. Efficacy of ABBV-105 in chronic inflammatory disease was evaluated in animal models of arthritis and lupus. Measurement of BTK occupancy was employed as a target engagement biomarker.

RESULTS

ABBV-105 irreversibly inhibits BTK, demonstrating superior kinome selectivity and is potent in B cell receptor, Fc receptor, and TLR-9-dependent cellular assays. Oral administration resulted in rapid clearance in plasma, but maintenance of BTK splenic occupancy. ABBV-105 inhibited antibody responses to thymus-independent and thymus-dependent antigens, paw swelling and bone destruction in rat collagen induced arthritis, and reduced disease in an IFNα-accelerated lupus nephritis model. BTK occupancy in disease models correlated with in vivo efficacy.

CONCLUSION

ABBV-105, a selective BTK inhibitor, demonstrates compelling efficacy in pre-clinical mechanistic models of antibody production and in models of rheumatoid arthritis and lupus.

A loop region of BAFF controls B cell survival and regulates recognition by different inhibitors

The B cell survival factor (TNFSF13B/BAFF) is often elevated in autoimmune diseases and is targeted in the clinic for the treatment of systemic lupus erythematosus. BAFF contains a loop region designated the flap, which is dispensable for receptor binding. Here we show that the flap of BAFF has two functions. In addition to facilitating the formation of a highly active BAFF 60-mer as shown previously, it also converts binding of BAFF to TNFRSF13C (BAFFR) into a signaling event via oligomerization of individual BAFF-BAFFR complexes. Binding and activation of BAFFR can therefore be targeted independently to inhibit or activate the function of BAFF. Moreover, structural analyses suggest that the flap of BAFF 60-mer temporarily prevents binding of an anti-BAFF antibody (belimumab) but not of a decoy receptor (atacicept). The observed differences in profiles of BAFF inhibition may confer distinct biological and clinical efficacies to these therapeutically relevant inhibitors.

BAFF is an important cytokine for B cell survival, and is a therapeutic target for autoimmune disorders. Here the authors show that a 'flap' region of BAFF converts BAFFR binding events into survival signals and, with structural data, that this ‘flap’ differentially modulates binding of drugs such as belimumab or atacicept.

Clinical and genetic features of the patients with X-Linked agammaglobulinemia from Turkey: Single-centre experience

X-linked agammaglobulinemia is a primary immunodeficiency disorder resulting from BTK gene mutations. There are many studies in the literature suggesting contradictory ideas about phenotype-genotype correlation. The aim of this study was to identify the mutations and clinical findings of patients with XLA in Turkey, to determine long-term complications related to the disease and to analyse the phenotype-genotype correlation. Thirty-two patients with XLA diagnosed between 1985 and 2016 in Pediatric Immunology Department of Hacettepe University Ihsan Dogramaci Children's Hospital were investigated. A clinical survey including clinical features of the patients was completed, and thirty-two patients from 26 different families were included in the study. Getting early diagnosis and regular assessment with imaging techniques seem to be the most important issues for improving the health status of the patients with XLA. Early molecular analysis gives chance for definitive diagnosis and genetic counselling, but not for predicting the clinical severity and prognosis.

Recent thymic emigrants, T regulatory cells, and BAFF level in children with X-linked agammaglobulinaemia in association with chronic respiratory disease

BACKGROUND

X-linked agammaglobulinaemia (XLA) is a genetic disorder affecting B cell maturation, which is characterised by a low number of B cells, agammaglobulinaemia and increased susceptibility to a variety of bacterial infections. This study was performed to assess T cell subpopulations in a group of children with XLA in association with chronic respiratory disease (CRD).

METHODS

Numbers of T cell subpopulations (CD3+, CD4+, CD8+, CD3+DR+, naïve, memory, recent thymic emigrants (RTE), regulatory T cells, follicular T helpers) were measured by eight-colour flow cytometry in 22 XLA patients and 50 controls. BAFF level was measured by ELISA.

RESULTS

XLA patients with CRD had a significantly lower percentage of RTE numbers and Tregs, while significantly higher absolute counts of lymphocytes, CD3+, CD8+, CD3+DR+ and CD4+CD45RO+ T cells were detected as compared with healthy controls. In patients with XLA without CRD, the number of follicular T helper cells was altered significantly (percentage and absolute), as compared with healthy controls. Additionally, they had significantly higher counts (percentage and absolute) of CD4+CD45RA+ cells and lower percentage of CD4+CD45RO+ cells in comparison with healthy controls.

CONCLUSIONS

Our study affords new information concerning CRD and T cell subsets that differentiate or are maintained in the absence of B cells in children with XLA. T cell's homeostasis depends on the presence of chronic respiratory disease that may be caused by the delay in diagnosis.

Disseminated Pseudomonas aeruginosa sepsis as presenting diagnosis of X-linked agammaglobulinaemia in a previously well 16-month-old child

We report a previously healthy 16-month-old child who presented to us with membranous pharyngitis and ecthyma gangrenosum. In this patient, Pseudomonas aeruginosa was isolated from throat swab, cerebrospinal fluid, skin swab, urine, blood and synovial fluid in a single admission. In further workup, this child was diagnosed as a case of X-linked agammaglobulinaemia. The child was treated successfully with antipseudomonal antibiotics for 6 weeks and intravenous immunoglobulin.

Chronic lung disease in common variable immune deficiency (CVID): A pathophysiological role for microbial and non-B cell immune factors

One of the most common and most severe forms of primary antibody deficiency encountered in the clinical setting is a heterogeneous group of syndromes termed common variable immune deficiency (CVID). This disorder is characterized by reduced immunoglobulin production and increased susceptibility to infection, particularly of the respiratory tract. Infection and subsequent immunological/inflammatory processes may contribute to the development of pulmonary complications such as bronchiectasis and interstitial lung disease. Immunoglobulin replacement and/or antibiotic therapy, to prevent infection, are routinely prescribed treatments. However, chronic lung disease, the major cause of morbidity and mortality in this patient cohort, may still progress. This clinical progression suggests that pathogens recalcitrant to currently prescribed treatments and other immunological defects may be contributing to the development of pulmonary disease. This review describes the potential role of microbiological and non-B cell immunological factors, including T-cells, neutrophils, complement, toll like receptors, and antimicrobial peptides, in the pathogenicity of chronic lung disease in patients with CVID.

A Multicentre Study on the Efficacy, Safety and Pharmacokinetics of IqYmune®, a Highly Purified 10% Liquid Intravenous Immunoglobulin, in Patients with Primary Immune Deficiency

This multicentre, open-label, prospective, single-arm study was designed to evaluate the efficacy, pharmacokinetics, and safety of IqYmune®, a highly purified 10% polyvalent immunoglobulin preparation for intravenous administration in patients with primary immunodeficiency. IqYmune® was administered to 62 patients (aged 2–61 years) with X-linked agammaglobulinemia or common variable immune deficiency at a dose from 0.22 to 0.97 g/kg every 3 to 4 weeks for 12 months with an infusion rate up to 8 mL/kg/h. A pharmacokinetic study was performed at steady state between the 8th and the 9th infusion. A single case of serious bacterial infection was observed, leading to an annualized rate of serious bacterial infections/patient (primary endpoint) of 0.017 (98% CI: 0.000, 0.115). Overall, 228 infections were reported, most frequently bronchitis, chronic sinusitis, nasopharyngitis and upper respiratory tract infection. The mean annualized rate of infections was 3.79/patient. A lower risk of infections was associated with an IgG trough level > 8 g/L (p = 0.01). The mean annualized durations of absence from work or school and of hospitalization due to infections were 1.01 and 0.89 days/patient, respectively. The mean serum IgG trough level before the 6th infusion was 7.73 g/L after a mean dose of IqYmune® of 0.57 g/kg. The pharmacokinetic profile of IqYmune® was consistent with that of other intravenous immunoglobulins. Overall, 15.5% of infusions were associated with an adverse event occurring within 72 h post infusion. Headache was the most common adverse event. In conclusion, IqYmune® was shown to be effective and well tolerated in patients with primary immunodeficiency.

Inhibition of B Cell Receptor Signaling by Ibrutinib in Primary CNS Lymphoma

Primary CNS lymphoma (PCNSL) harbors mutations that reinforce B cell receptor (BCR) signaling. Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, targets BCR signaling and is particularly active in lymphomas with mutations altering the BCR subunit CD79B and MYD88. We performed a proof-of-concept phase Ib study of ibrutinib monotherapy followed by ibrutinib plus chemotherapy (DA-TEDDi-R). In 18 PCNSL patients, 94% showed tumor reductions with ibrutinib alone, including patients having PCNSL with CD79B and/or MYD88 mutations, and 86% of evaluable patients achieved complete remission with DA-TEDDi-R. Increased aspergillosis was observed with ibrutinib monotherapy and DA-TEDDi-R. Aspergillosis was linked to BTK-dependent fungal immunity in a murine model. PCNSL is highly dependent on BCR signaling, and ibrutinib appears to enhance the efficacy of chemotherapy.

Expression of X-linked Toll-like receptor 4 signaling genes in female vs. male neonates

BACKGROUND

Male neonates display poorer disease prognosis and outcomes compared with females. Immune genes which exhibit higher expression in umbilical cord blood (UCB) of females may contribute to the female immune advantage during infection and inflammation. The aim of this study was to quantify expression of Toll-like receptor (TLR) 4 signaling genes encoded on the X-chromosome in UCB from term female vs. male neonates.

METHODS

UCB samples were collected from term neonates (n = 26) born by elective Caesarean section and whole blood was collected from adults (n = 20). Leukocyte RNA was isolated and used in quantitative PCR reactions for IκB kinase γ (IKKγ), Bruton's tyrosine kinase (BTK), and IL-1 receptor associated kinase (IRAK)1. IRAK1 protein was analyzed by Western blot and confocal microscopy.

RESULTS

In neonates there was no significant difference in the relative expression of IKKγ or BTK mRNA between genders. IRAK1 gene and protein expression was significantly higher in female vs. male UCB, with increased cytosolic IRAK1 expression also evident in female UCB mononuclear cells. Adults had higher expression of all three genes compared with neonates.

CONCLUSION

Increased expression of IRAK1 could be responsible, in part, for sex-specific responses to infection and subsequent immune advantage in female neonates.

The lack of BTK does not impair monocytes and polymorphonuclear cells functions in X-linked agammaglobulinemia under treatment with intravenous immunoglobulin replacement

The lack of BTK in X-linked agammaglobulinemia (XLA) patients does not affect monocytes and polymorphonuclear cells (PMN) phenotype and functions. In this study, we show that XLA patients had an increased frequency of the intermediate monocytes subset and that BTK-deficient monocytes and PMN had a normal expression of receptors involved in the activation and cellular responses. We demonstrate that BTK is not required for migration, phagocytosis and the production of reactive oxygen species (ROS) following engagement of FC gamma receptors (FcγR). XLA monocytes and PMN showed an efficient calcium (Ca2+)-independent activation of oxidative burst, suggesting that oxidative burst is less dependent by Ca2+ mobilization. The phagocytosis was functional and it remained unaltered also after Ca2+ chelation, confirming the independence of phagocytosis on Ca2+ mobilization. Intravenous immunoglobulin (IVIg) infusion exerted an anti-inflammatory effect by reducing the frequency of pro-inflammatory monocytes. In monocytes, the IVIg reduce the oxidative burst and phagocytosis even if these functions remained efficient.

Gastrointestinal disorders next to respiratory infections as leading symptoms of X-linked agammaglobulinemia in children - 34-year experience of a single center

INTRODUCTION

Respiratory tract infections constitute the most frequent manifestation of X-linked agammaglobulinemia (XLA). There are not many papers elucidating gastrointestinal (GI) disorders, including inflammatory bowel disease (IBD), in such patients. The aim of the study was to evaluate the occurrence of gastrointestinal disorders and IBD compared to respiratory tract infections in XLA individuals.

MATERIAL AND METHODS

Of 1563 patients with primary immunodeficiencies diagnosed in the Department of Immunology, the Children's Memorial Health Institute (CMHI), 66 boys had a provisional diagnosis of agammaglobulinemia. Forty-four subjects fulfilled definitive ESID (European Society for Immunodeficiencies) diagnostic criteria of XLA. A retrospective analysis of medical history of XLA patients was undertaken.

RESULTS

Recurrent respiratory tract infections, particularly bronchitis (73%) and pneumonia (59%), were the most common symptoms of XLA. The GI disorders constituted the next main manifestation (63.6%), followed by upper respiratory tract infections. Twenty-six of 28 XLA patients with GI disorders complained of diarrhea, which was resolved generally after immunoglobulin therapy introduction. Single but prolonged episodes of Campylobacter jejuni diarrhea were reported in two individuals. Inflammatory bowel disease of mild to moderate activity was diagnosed in 1 patient, and local enteritis of mild activity in another one.

CONCLUSIONS

Gastrointestinal disorders were one of the main manifestations of XLA, reported almost as often as lower respiratory tract infections. The most common GI symptom was diarrhea, which usually resolved after immunoglobulin therapy was started. Infections caused by Giardia lamblia were reported occasionally. Inflammatory bowel disease was diagnosed quite exceptionally, which presumably may be connected with normal T cell immunity.

Bruton's Tyrosine Kinase Small Molecule Inhibitors Induce a Distinct Pancreatic Toxicity in Rats

Bruton's tyrosine kinase (BTK) is a member of the Tec family of cytoplasmic tyrosine kinases involved in B-cell and myeloid cell signaling. Small molecule inhibitors of BTK are being investigated for treatment of several hematologic cancers and autoimmune diseases. GDC-0853 ((S)-2-(3'-(hydroxymethyl)-1-methyl-5-((5-(2-methyl-4-(oxetan-3-yl)piperazin-1-yl)pyridin-2-yl)amino)-6-oxo-1,6-dihydro-[3,4'-bipyridin]-2'-yl)-7,7-dimethyl-3,4,7,8-tetrahydro-2H-cyclopenta[4,5]pyrrolo[1,2-a]pyrazin-1(6H)-one) is a selective and reversible oral small-molecule BTK inhibitor in development for the treatment of rheumatoid arthritis and systemic lupus erythematosus. In Sprague-Dawley (SD) rats, administration of GDC-0853 and other structurally diverse BTK inhibitors for 7 days or longer caused pancreatic lesions consisting of multifocal islet-centered hemorrhage, inflammation, fibrosis, and pigment-laden macrophages with adjacent lobular exocrine acinar cell atrophy, degeneration, and inflammation. Similar findings were not observed in mice or dogs at much higher exposures. Hemorrhage in the peri-islet vasculature emerged between four and seven daily doses of GDC-0853 and was histologically similar to spontaneously occurring changes in aging SD rats. This suggests that GDC-0853 could exacerbate a background finding in younger animals. Glucose homeostasis was dysregulated following a glucose challenge; however, this occurred only after 28 days of administration and was not directly associated with onset or severity of pancreatic lesions. There were no changes in other common serum biomarkers assessing endocrine and exocrine pancreatic function. Additionally, these lesions were not readily detectable via Doppler ultrasound, computed tomography, or magnetic resonance imaging. Our results indicate that pancreatic lesions in rats are likely a class effect of BTK inhibitors, which may exacerbate an islet-centered pathology that is unlikely to be relevant to humans.

Bruton's agammaglobulinemia in an adult male due to a novel mutation: a case report

X-linked agammaglobulinemia (XLA) is caused by mutation in the gene coding for Bruton's tyrosine kinase (BTK), which impairs peripheral B cell maturation and hypogammaglobulinemia. In this report, we present a case of XLA in a 22-year-old adult male. Genetic testing revealed a novel mutation located at the conserved region (c.383T>C). The patient had a history of recurrent respiratory tract infection which eventually progressed to chronic type II respiratory failure. Several pathogenic bacteria were isolated on culture of respiratory secretions obtained on bronchoscopy. The patient improved on treatment with antibiotics.

X-linked agammaglobulinemia: Twenty years of single-center experience from North West India

BACKGROUND

X-linked agammaglobulinemia (XLA) is an X-linked genetic defect in maturation of B lymphocytes that results in the absence of B lymphocytes in the peripheral blood and profound hypogammaglobulinemia. It is caused by a mutation in the BTK gene located on the X chromosome. There are no large series describing XLA from the developing world.

OBJECTIVE

To analyze the clinical features, immunologic and genetic characteristics, and outcomes of 36 patients with XLA diagnosed and managed for a period of 2 decades.

METHODS

Diagnosis of XLA was made on the basis of presence of BTK gene mutation or marked reduction of B lymphocytes in peripheral blood with a family history of an affected male relative. The diagnosis was confirmed by genetic mutation studies in 28 patients with 25 unique mutations in the BTK gene.

RESULTS

There was a significant delay in diagnosis in most of the patients. The mean (SD) delay in the diagnosis was 4.2 (3.5) years. Point mutations were the most common mutations detected, accounting for 68% of all mutations. Deletions and insertions were also seen in a few cases. Four of the mutations are novel mutations that have not been previously reported. Seven of the 36 patients (19%) were dead at the time of analysis in the present cohort. The mean survival was 137 months (95% confidence interval, 13-163 months).

CONCLUSION

The present study is perhaps the largest series of patients with XLA from any developing country so far.

Primary hypogammaglobulinemia: The impact of early diagnosis in lung complications

Summary Objective: To describe clinical features, tomographic findings and pulmonary function in pediatric patients with primary hypogammaglobulinemia (PH). Method: A retrospective cohort study of children with PH who received intravenous immunoglobulin (IVIG) and prophylactic antibiotics between 2005 and 2010. Epidemiological and clinical features, computed tomography (CT) findings, and spirometric data were compared, assuming a 5% significance level. Results: We evaluated 30 patients with PH. After the start of IVIG replacement, there was a decline in the frequency of pneumonia (p<0.001). The 11 patients with bronchiectasis in their first CT scan were older at diagnosis (p=0.001) and had greater diagnostic delay (p=0.001) compared to patients without bronchiectasis. At the end of the study, 18 patients had bronchiectasis and 27 also had other lung disorders, alone or in combination. The Bhalla score was applied to the last CT scan of 16 patients, with a median score of 11 (range 7-21), with a positive correlation between the score and the number of pneumonias after the start of treatment (r=0.561; p=0.024). The score was also correlated with forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) values in 13/16 patients, with negative correlation to FEV1 previously to bronchodilator (r=-0.778; p=0.002) and after bronchodilator (r =-0.837; p<0.001) and FVC (r=-0.773; p=0.002). Conclusion: Pulmonary complications were common in this cohort, despite the decrease in the frequency of pneumonia with treatment. Early investigation of patients with recurrent infections for primary immunodeficiencies can reduce the frequency of these complications. The monitoring of changes in spirometry may indicate the need to carry out radiological investigation.

Overview of Infections in the Immunocompromised Host

Understanding the components of the immune system that contribute to host defense against infection is key to recognizing infections that are more likely to occur in an immunocompromised patient. In this review, we discuss the integrated system of physical barriers and of innate and adaptive immunity that contributes to host defense. Specific defects in the components of this system that predispose to particular infections are presented. This is followed by a review of primary immunodeficiency diseases and secondary immunodeficiencies, the latter of which develop because of a specific illness or condition or are treatment-related. The effects of treatment for neoplasia, autoimmune diseases, solid organ and stem cell transplants on host defenses are reviewed and associated with susceptibility to particular infections. In conclusion, an approach to laboratory screening for a suspected immunodeficiency is presented. Knowledge of which host defects predispose to specific infections allows clinicians to prevent, diagnose, and manage infections in their immunocompromised patients most effectively.

Clinical characteristics and genetic profiles of 174 patients with X-linked agammaglobulinemia: Report from Shanghai, China (2000-2015)

X-linked agammaglobulinemia (XLA) is a humoral primary immunodeficiency. XLA patients typically present with very low numbers of peripheral B cells and a profound deficiency of all immunoglobulin isotypes. Most XLA patients carry mutations in Bruton tyrosine kinase (BTK) gene.The genetic background and clinical features of 174 Chinese patients with XLA were investigated. The relationship between specific BTK gene mutations and severity of clinical manifestations was also examined. Mutations were graded from mild to severe based on structural and functional prediction through bioinformatics analysis.One hundred twenty-seven mutations were identified in 142 patients from 124 families, including 45 novel mutations and 82 recurrent mutations that were distributed over the entire BTK gene sequence. Variation in phenotypes was observed, and there was a tendency of association between genotype and age of disease onset.This report constitutes the largest group of patients with BTK mutations in China. A genotype-phenotype correlation was observed in this study. Early diagnosis of congenital agammaglobulinemia should be based on clinical symptoms, family history, and molecular analysis of the BTK gene.

Long-term follow-up of ninety eight Iranian patients with primary immune deficiency in a single tertiary centre

PURPOSE

The aim was to describe the clinical manifestations, complications and long-term outcome of a cohort of Iranian patients with primary immune deficiency (PID).

METHOD

We retrospectively studied the demographic, clinical and immunological characteristics of the PID patients in a single tertiary centre, from January 1989 to July 2014. The patients were classified according to the International Union of Immunological Societies Expert Committee on PID.

RESULTS

98 patients were diagnosed with and followed-up for 15 disorders. The mean age at onset and diagnosis and the diagnostic delay were 8±10, 14.2±13.1 and 6.1±7 years, respectively. Parental consanguinity rate was 57%. Predominantly Antibody Deficiency was the most common diagnosis (n=63), followed by congenital defects of phagocytes (n=16), combined immunodeficiencies (n=12), well defined syndromes (n=4) and defects in innate immunity (n=3). Recurrent sinopulmonary infection was the most common presentation. Active infections were treated appropriately, in addition to prophylactic therapy with IVIG and antimicrobials. Not all the patients were compliant with prophylactic regimens due to cost and unavailability. One SCID patient underwent successful bone marrow transplantation. The total mortality rate was 19% during the follow-up period (7.8±7.6 years). The mean age of living patients at the time of study was 23±11.7 years.

CONCLUSIONS

Physicians awareness of PID has been rising dramatically in Iran, ensuring an increasing number of patients being diagnosed and treated. More effective treatment services, including health insurance coverage and drug availability are needed to improve the outcome of PID patients.

Primary immunodeficiency and recalcitrant chronic sinusitis: a systematic review

BACKGROUND

A subset of patients with chronic rhinosinusitis (CRS) has disease refractory to standard therapies. Primary immunodeficiency should be considered in this group. Past literature has demonstrated an association between immunodeficiency and chronic sinusitis.

METHODS

A systematic literature search was performed using OVID, MEDLINE, EMBASE, and Cochrane databases to identify English language papers containing original human data on subjects with primary immunodeficiency and chronic sinusitis. A total of 39 studies met inclusion criteria. Data was collected pertaining to immune dysfunction in patients with chronic sinusitis, the clinical workup for these patients, and the effectiveness of medical and surgical treatments. The studies were assessed to determine their level of evidence.

RESULTS

The majority of studies were supported by Level 4 evidence. Up to 50% of patients with recalcitrant CRS were found to have immune dysfunction. The most frequent primary immunodeficiencies studied were common variable immunodeficiency (CVID) and X-linked agammaglobulinemia (XLA). Common collected data included measurement of serum immunoglobulins and functional antibody responses. Treatments reviewed include immunoglobulin replacement, long-term antibiotics and endoscopic sinus surgery.

CONCLUSION

Patients with recalcitrant CRS should be evaluated for primary immunodeficiency. This should include as assessment of quantitative serum immunoglobulin levels as well as functional antibody responses. Medical therapy, particularly immunoglobulin replacement therapy, appears to be most effective when administered at high doses early in the disease course. The addition of surgery is less clearly supported, but may also provide benefit if performed early.

Respiratory Health and Related Quality of Life in Patients with Congenital Agammaglobulinemia in the Northern Region of the UK

Introduction

Patients with congenital agammaglobulinemia, characterized by a defect in B lymphocyte differentiation causing B alymphocytosis, require life-long IgG replacement. There is scant literature regarding the effectiveness of IgG treatment at preventing mucosal (particularly sinopulmonary tract) infection and whether current management adequately restores “normal” health and quality of life (QoL). We aimed to document infective episodes pre- and post-commencing IgG replacement, determine any change in lung function and structure and assess respiratory status and QoL in a cohort of patients treated in Newcastle.

Methods

Clinical data were extracted from medical records of 15 patients identified from the immunology database, focusing on infective episodes, serial chest CT and spirometry results. Thirteen patients completed a selection of standardized and validated questionnaires assessing physical health, respiratory health and QoL.

Results

Pediatric patients on IgG therapy suffered fewer infections per patient year (0.74) than adults (2.13). 6/14 patients showed deteriorating respiratory status despite adequate therapy. Health questionnaires revealed a significant burden of respiratory disease on a patient’s life.

Conclusion

Clinical data showed patients with congenital agammaglobulinemia receiving immunoglobulin therapy retained a higher than average infection rate, most of which affected mucosal barriers. Most patients self-reported worse respiratory symptoms, a lower respiratory-related QoL and a lower general health QoL relative to a healthy population. Most participants had progressive structural lung damage and decreased lung function. These results suggest that current management is not entirely effective at preventing deterioration of respiratory health or restoring QoL.

PROTECTIVE LEVELS OF VARICELLA-ZOSTER ANTIBODY DID NOT EFFECTIVELY PREVENT CHICKENPOX IN AN X-LINKED AGAMMAGLOBULINEMIA PATIENT

We describe the case of an eight-year-old boy with X-linked agammaglobulinemia who developed mild varicella despite regular intravenous immunoglobulin (IVIG) therapy. He maintained protective antibody levels against varicella and the previous batches of IVIG that he received had adequate varicella-specific IgG levels. The case illustrates that IVIG may not prevent VZV infection.

X-linked Agammaglobulinemia

X-linked agammaglobulinemia (XLA) is one of the commonest primary immune deficiencies encountered in pediatric clinical practice. In adults, common variable immunodeficiency (CVID) is the most common primary immunodeficiency disease (PID). It is an X-linked disorder characterized by increased susceptibility to encapsulated bacteria, severe hypergammaglobulinemia and absent circulating B cells in the peripheral blood. Replacement immunoglobulin therapy is the main cornerstone of treatment. Aggressive management of intercurrent infections and prophylactic antimicrobials are needed. This review attempts to highlight varied clinical manifestations and management of XLA, especially in the context of developing country.

Clinical and mutational features of X-linked agammaglobulinemia in Mexico

X-linked agammaglobulinemia (XLA) is caused by BTK mutations, patients typically show <2% of peripheral B cells and reduced levels of all immunoglobulins; they suffer from recurrent infections of bacterial origin; however, viral infections, autoimmune-like diseases, and an increased risk of developing gastric cancer are also reported. In this work, we report the BTK mutations and clinical features of 12 patients diagnosed with XLA. Furthermore, a clinical revision is also presented for an additional cohort of previously reported patients with XLA. Four novel mutations were identified, one of these located in the previously reported mutation refractory SH3 domain. Clinical data support previous reports accounting for frequent respiratory, gastrointestinal tract infections and other symptoms such as the occurrence of reactive arthritis in 19.2% of the patients. An equal proportion of patients developed septic arthritis; missense mutations and mutations in SH1, SH2 and PH domains predominated in patients who developed arthritis.

Allogeneic stem cell transplantation for X-linked agammaglobulinemia using reduced intensity conditioning as a model of the reconstitution of humoral immunity

BACKGROUND

We herein report the first case of X-linked agammaglobulinemia (XLA) that underwent allogeneic stem cell transplantation using reduced intensity conditioning (RIC). We chronologically observed the reconstitution of humoral immunity in this case.

CASE PRESENTATION

The patient was a 28-year-old Japanese male with XLA who previously had life-threatening infectious episodes and was referred for the possible indication of allogeneic stem cell transplantation. After a thorough discussion within specialists from different backgrounds, we decided to perform allogeneic peripheral stem cell transplantation from his HLA-identical elder brother. Due to the non-malignant nature of XLA, we selected RIC consisting of fludarabine, cyclophosphamide, anti-thymocyte globulin, and 3 Gy of total body irradiation. Neutrophil engraftment was achieved on day 11 with complete donor chimerism. No major complications, except for stage 1 skin graft-versus-host disease, were observed. The patient was discharged on day 75 and has been followed as an outpatient without any infectious episodes for more than 500 days.

CONCLUSIONS

Regarding immune reconstitution, CD19(+) cells, IgA, and IgM, which were undetectable before allogeneic stem cell transplantation (allo-SCT), started to increase in number 10 days after allo-SCT and continued to increase for more than 1 year. Anti-B antibodies appeared as early as day 10. Total IgG levels decreased after the discontinuation of IgG replacement and spontaneously recovered after day 350. However, most anti-viral IgG titers, except EB virus-virus capsid antigen IgG, disappeared after the discontinuation of IgG replacement. A seasonal vaccination to influenza was performed on day 148, with neither anti-influenza type A nor type B being positive after the vaccination. The transient transfer of allergic immunity to orchard grass was observed. Similar Bruton's tyrosine kinase (BTK) expression levels in monocytes and B-cells were observed between the patient and healthy control. B-cells in the peripheral blood (PB) of the patient on day 279 showed sufficient proliferation after a CD40L and IL-21 or CD40L and CpG stimulation. Effective immunoglobulin production and class switching were also observed after a CD40L and IL-21 or CpG stimulation. Signal joint kappa-deleting recombination excision circles (sjKRECs) became positive 16 days post-SCT, increased to 6300 copies/μg DNA at 42 days, and were maintained at a high level thereafter. The recovery of T-cell receptor excision circles (TRECs) was slow, but became detectable 1 year post-hematopoietic stem cell transplantation (HSCT).

Prospective neonatal screening for severe T- and B-lymphocyte deficiencies in Seville

BACKGROUND

Early diagnosis of primary immunodeficiency such as severe combined immunodeficiency (SCID) and X-linked agammaglobulinemia (XLA) improves outcome of affected children. T-cell-receptor-excision circles (TRECs) and kappa-deleting-recombination-excision circles (KRECs) determination from dried blood spots (DBS) identify neonates with severe T- and/or B-lymphopenia. No prospective data exist of the impact of gestational age (GA) and birth weight (BW) on TRECs and KRECs values.

METHODS

TRECs and KRECs determination using triplex RT-PCR (TRECS-KRECS-β-actin-Assay) from prospectively collected DBS between 02/2014 and 02/2015 in three hospitals in Seville, Spain. Cut-off levels were TRECs < 6/punch, KRECs < 4/punch and -β-actin>700/punch. Internal (SCID, XLA, ataxia telangiectasia) and external controls (NBS quality assurance program, CDC) were included.

RESULTS

A total of 5160 DBS were tested. Re-punch was needed in 77 samples (1.5%) due to insufficient β-actin (<700 copies/punch). Pre-term neonates (GA<37 weeks) and neonates with a BW<2500 g showed significantly lower TRECs and KRECs levels (p < 0.001). Due to repeat positive results five neonates were re-called (<0.1%): Fatal chromosomopathy (n = 1; TRECs 1/KRECs 4); extreme pre-maturity (n = 2; TRECs 0/KRECs 0 and TRECs 1/KRECs 20 copies/punch); neonates born to mothers receiving azathioprine during pregnancy (n = 2; TRECs 92/KRECs 1 and TRECs 154/KRECs 3 copies/punch). All internal and external controls were correctly identified.

CONCLUSIONS

TRECS-KRECS-β-actin-Assay correctly identifies T- and B-cell lymphopenias. Pre-maturity and low BW is associated with lower TREC and KREC levels. Extreme pre-maturity and maternal immune suppressive therapy may be a cause for false positive results of TRECs and KRECs values, respectively. To reduce the rate of insufficient samples, DBS extraction and storage need to be improved.

Prevalence of BTK mutations in male Algerian patterns with agammaglobulinemia and severe B cell lymphopenia

X linked agammaglobulinemia (XLA) is the first described primary immunodeficiency and the most common form of agammaglobulinemia. It is characterized by susceptibility to recurrent infections, profound decrease of all immunoglobulin isotypes and very low level of B lymphocytes in peripheral blood. The disorder is caused by mutations in the Bruton's Tyrosine Kinase (BTK). Nine male patients suspected to have XLA from nine unrelated families were enrolled in this study. We performed sequencing of the BTK gene in all nine patients, and in the patients' relatives when possible. The XLA diagnosis was confirmed for six patients with six different mutations; we identified a novel mutation (c.1522G>A) and five known mutations. One third of nine unrelated patients do not have mutations in BTK and thus likely suffer from autosomal recessive agammaglobulinemia in the setting of consanguinity. Our results support that the autosomal recessive agammaglobulinemia can be more common in Algeria.

Successful hematopoietic cell transplantation in a patient with X-linked agammaglobulinemia and acute myeloid leukemia

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency characterized by marked reduction in all classes of serum immunoglobulins and the near absence of mature CD19(+) B-cells. Although malignancy has been observed in patients with XLA, we present the first reported case of acute myeloid leukemia (AML) in a patient with XLA. We also demonstrate the complete correction of the XLA phenotype following allogeneic hematopoietic cell transplantation for treatment of the patient's leukemia.

A Novel Targeted Screening Tool for Hypogammaglobulinemia: Measurement of Serum Immunoglobulin (IgG, IgM, IgA) Levels from Dried Blood Spots (Ig-DBS Assay)

PURPOSE

To develop an assay to quantify serum immunoglobulin (IgG, IgM, IgA) levels using dried blood spots (DBS) obtained on collection cards to be used as a tool for targeted screening for hypogammaglobulinemia.

METHODS

DBS samples, along with simultaneous serum samples, were collected from 107 healthy individuals (11 months to 57 years of age). After eluting proteins from DBS, IgG, IgM, and IgA were quantified by an enzyme-linked immunosorbent assay (ELISA). The Ig-DBS assay was validated through calibration curve performance, intra- and inter-assay precision, accuracy, specificity, selectivity, and linearity. The ELISA measurements were compared with serum Ig levels obtained using a standard nephelometry assay on serum samples collected simultaneously with the DBS samples and the results of the two assays were correlated. The stability of IgG, IgM, and IgA in the DBS was tested at room temperature, 36° to 38 °C, 2 to 8 °C, and -25 to -40 °C, from 4 to 14 days.

RESULTS

The Ig-DBS assay demonstrated precision, accuracy, specificity, selectivity, and linearity. Using the identified correlation coefficients of 0.834 for IgG, 0.789 for IgM, and 0.918 for IgA, the standard nephelometry-based normal reference ranges for all 3 serum Ig isotypes could be used with the Ig-DBS assay in individuals ≥16 years of age. The DBS samples were stable for 14 days at room temperature in a closed polyethylene bag.

CONCLUSIONS

The Ig-DBS assay is both sensitive and accurate for quantification of serum immunoglobulins. Samples are sufficiently stable at ambient temperature to allow for convenient shipping and analysis at a centralized laboratory. This assay therefore presents a new option for screening patients ≥16 years of age for hypogammaglobulinemia in any setting.