Utility of the antibody response to a conjugated Haemophilus influenzae type B vaccine for diagnosis of primary humoral immunodeficiency

Stability assessment of anti-bacterial antibodies in immunoglobulin G-depleted serum with validated immunoassays

Aim: To investigate the stability of the anti-pneumococcal (PCP) and anti-haemophilus type B (Hib) immunoglobulins (IgGs) in human IgG-depleted serum samples frozen at -20°C. Materials & methods: Modified commercially available immunoassays (ELISAs) were bioanalytically validated. These ELISAs were used to measure levels of the two anti-bacterial IgG in samples kept at -20°C for up to 15 months. Human IgG-depleted serum was spiked with GAMMAGARD Liquid to obtain those samples. Results: Both ELISAs passed the validation test. Anti-PCP IgG and anti-Hib IgG were shown to be stable for at least 15 months at -20°C. Conclusion: These data confirm the stability of anti-bacterial IgG in human IgG-depleted serum and support the common practice of testing frozen samples.

VaccHemInf project: protocol for a prospective cohort study of efficacy, safety and characterisation of immune functional response to vaccinations in haematopoietic stem cell transplant recipients

INTRODUCTION

Immune reconstitution after haematopoietic stem cell transplantation (HSCT) is a complex and dynamic process, varying from a state of nearly complete immunosuppression to an expected full immune recovery. Specific vaccination guidelines recommend reimmunisation after HSCT but data regarding vaccine efficacy in this unique population are scarce. New immune functional assays could enable prediction of vaccine response in the setting of HSCT.

METHODS AND ANALYSIS

A prospective, longitudinal single-centre cohort study of autologous and allogeneic HSCT recipients was designed in order to determine the vaccine response to five vaccine targets (pneumococcus, hepatitis B virus, Haemophilus Influenzae type b, tetanus and diphtheria) and to correlate it to immune function parameters. A workflow was set up to study serological response to vaccines and to describe the functional immune status of 100 HSCT recipients (50 autologous and 50 allogeneic) before and 3, 12 and 24 months after primary immunisation. At each time point, 'basic' immune status recording (serology, immunophenotyping of lymphocyte subsets by flow cytometry) will be assessed. The immune response will furthermore be evaluated before and 3 months after primary vaccination by two ex vivo immune functional assays assessing: (1) tumour necrosis factor alpha, interferon gamma production and host messenger RNA expression on whole-blood stimulation by lipopolysaccharide or Staphylococcus aureus enterotoxin B and (2) T-lymphocyte proliferation in response to a standard mitogen (phytohaemagglutinin) or to selected recall antigens. Reference intervals will be determined from a cohort of 30 healthy volunteers. This translational study will provide data describing vaccine response, immune functionality of HSCT recipients over time and will allow mapping HSCT recipients with regard to their immune function.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the institutional review board (no 69HCL17_0769). Results will be communicated at scientific meetings and submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03659773; Pre-results.

Aetiology and clinical characteristics of patients with bronchiectasis in a Chinese Han population: A prospective study

BACKGROUND AND OBJECTIVE

Bronchiectasis is a chronic respiratory disease with diverse causes that may differ in clinical features and thus treatment options. However, few large-scale studies on the aetiology of bronchiectasis are currently available. This study aims to determine aetiology and clinical features of bronchiectasis in a Chinese Han population.

METHODS

This prospective study enrolled adult patients diagnosed with bronchiectasis as confirmed by high-resolution computed tomography at five general hospitals in Shandong from January 2010 to August 2014. Causes of bronchiectasis were sought by analysis of clinical history and auxiliary examinations (including serum immunoglobulin determination, saccharin test, Aspergillus skin prick test, autoantibody detection and electronic bronchoscopy).

RESULTS

A total of 476 adult patients with bronchiectasis were included, and all patients were of Chinese Han ethnicity. Idiopathic (66.0%) was the most common cause, followed by post-tuberculosis (16.0%). Other uncommon causes included post-infective (3.8%), immunodeficiency (3.8%), allergic bronchopulmonary aspergillosis (4.0%), rheumatic diseases (4.4%) and primary ciliary dyskinesia (0.9%). Patients with post-tuberculosis bronchiectasis had a higher frequency of upper lobe involvement (P < 0.05). Cylindrical bronchiectasis was the most common type of all causes, with varicose bronchiectasis occurring more frequently in post-tuberculosis bronchiectasis and allergic bronchopulmonary aspergillosis (P < 0.05). However, patients with different causes did not differ in lung function and sputum isolation rate of Pseudomonas aeruginosa (P > 0.05).

CONCLUSIONS

In a Chinese Han population in Shandong, idiopathic bronchiectasis is the most common form of bronchiectasis followed by post-tuberculosis bronchiectasis. Patients with different causes differ in distribution and pattern of bronchiectasis on computed tomography.

Serum immunoglobulins in the infected and convalescent phases in community-acquired pneumonia

BACKGROUND

A population-based case-control study was designed to assess changes of serum levels of immunoglobulins and IgG subclasses between infected and convalescent phase in community-acquired pneumonia (CAP).

METHODS

Over a 2-year period, all subjects who were >14 years of age living in the Maresme region (Barcelona, Spain) diagnosed of CAP were registered. Controls were healthy subjects selected from the municipal census. Prognostic factors were assessed and serum levels of total IgG, IgA, IgM, and IgG subclasses were measured at diagnosis and 1 month later (cases).

RESULTS

We studied 171 patients with CAP and 90 controls. All immunoglobulins were significantly lower in cases than in controls. At diagnosis, 42.7% of cases showed low levels of some immunologic parameter, mainly total IgG and IgG2. Low immunoglobulin levels at diagnosis were more frequent in patients requiring in-patient care and in those with pneumonia of other etiology than Streptococcus pneumoniae. In the convalescent phase, 26 (23.6%) patients normalized immunological levels. In 27 (24.5%) cases, some parameter with low levels persisted especially in patients with etiology of CAP other than S. pneumoniae.

CONCLUSIONS

Low serum levels of immunoglobulins particularly total IgG and IgG2 were a common finding in patients with CAP compared to healthy controls. Low immunoglobulin levels may be related to CAP prognosis and persisted in the convalescent phase in one-fourth of cases.

Active vaccination in patients with common variable immunodeficiency (CVID)

Active vaccination of CVID patients with standard vaccines has rarely been studied in depth although some patients have been shown to develop transient vaccine-specific immunity. We addressed the question whether these patients can be identified by functional classification of their B cell subsets in vitro. Twenty-one CVID patients receiving regular IgG substitution were immunized with anti-peptide and anti-polysaccharide vaccines. Humoral vaccination responses were compared to the numbers of circulating memory B cells, CD21(low) B cells and the capacity to produce antibodies in vitro. Our findings allow four conclusions: (1) positive vaccination responses are not contradictory to the diagnosis of CVID; they occurred against polypeptide vaccines in 23% and against polysaccharide antigens in 18% of all vaccinations. (2) Class-switched antibody responses occur preferentially in patients of CVID group II. (3) A normal percentage of IgM memory B cells is necessary but not sufficient for a vaccination response to polysaccharide antigens. (4) Active vaccination in addition to IgG replacement therapy should be performed in patients of CVID type II - especially in case of vaccines for which passive protection cannot be guaranteed.

Antibody Production Deficiency With Normal IgG Levels in Bronchiectasis of Unknown Etiology

BACKGROUND

No defined cause of bronchiectasis is currently found in approximately 50% of cases. Bronchiectasis is a common long-term complication in patients with primary hypogammaglobulinemia.

STUDY OBJECTIVES

To ascertain whether antibody production deficiency with normal total serum IgG levels is associated with bronchiectasis.

DESIGN

Antibody response to a pneumococcal unconjugate vaccine and an Haemophilus influenzae type b conjugate vaccine was prospectively studied in all consecutive adult patients with bronchiectasis of unknown etiology who were assessed in our chest outpatient clinic from January 1994 to October 2001. Serum-specific antibodies were measured by enzyme-linked immunosorbent assay, and the results were compared with those obtained in a healthy adult control group. Antibody production deficiency was defined as a failure to respond to either vaccine.

RESULTS

One hundred seven patients were included in the study (mean age, 46.3 years). Antibody production deficiency was diagnosed in 12 patients (11%). A significantly higher incidence of otitis media, lower serum IgG2 subclass levels, and lower preimmunization antibody levels to Streptococcus pneumoniae and H influenzae type b were observed in patients with antibody production deficiency. The probability of antibody production deficiency in patients with a history of otitis media was 20%, 26% in those with low IgG2 subclass levels, and 58% in those with both a history of otitis media and low IgG2 subclass levels.

CONCLUSIONS

Antibody production deficiency with normal IgG levels may be associated with bronchiectasis, making it advisable to evaluate the antibody response to both the H influenzae and pneumococcal vaccines in patients with bronchiectasis of unknown etiology, particularly in those with a history of otitis media, low IgG2 subclass levels, and low levels of baseline specific antibodies.

Immunoglobulin therapy to control lung damage in patients with common variable immunodeficiency

BACKGROUND

Lung damage progression is the most frequent condition in patients with common variable immunodeficiency (CVID). Appropriate immunoglobulin dose adjustments and follow-up guidelines to evaluate this have not been well established.

OBJECTIVE

To assess the evolution of lung damage once stable residual serum levels of IgG over 600 mg/dl had been achieved.

METHODS

A prospective study was conducted in 24 adult patients consecutively diagnosed with CVID, with no previous intravenous immunoglobulin (IVIG) treatment. IVIG dose, total serum IgG level, bacterial infection rate, pulmonary function tests (PFTs) and high resolution computed tomography (HRCT) of the thorax were monitored over 2 years. Moreover, outcome data were determined by measurement of chronic pulmonary disease (CPD).

RESULTS

IVIG dose variability (205-372 mg/kg/21 days) to obtain the required serum IgG levels was determined. Patients with CPD needed higher doses than those without CPD (p=0.045). A significant reduction in severe and mild infections/patient-year was observed during treatment. Overall, there were no changes in PFTs and HRCT scores in patients without CPD, but both improved in patients with CPD. An increase of over 15% in overall HRCT score was detected in two patients without evidence of impairment in either clinical status or PFT values.

CONCLUSIONS

Residual levels of total IgG over 600 mg/dl may help prevent progression of lung damage in patients with CVID. Levels of IgG, clinical manifestations and PFTs seem sufficient for routine follow-up. HRCT examination of the thorax, at least biennially, may help to identify patients in whom lung injury is progressing even though they may remain symptom-free and with stable PFTs.

Levels of antibodies specific to tetanus toxoid, Haemophilus influenzae type b, and pneumococcal capsular polysaccharide in healthy children and adults

Antibody levels specific for capsular polysaccharides of Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) and for tetanus toxoid were measured in serum samples of 386 age-stratified subjects. The study group consists of healthy adult blood donors and hospitalized children undergoing elective surgery, excluding individuals with a history of infection. In children, anti-tetanus toxoid antibody levels displayed two peaks of 1.20 IU/ml (20.4 mg/liter) and 1.65 IU/ml (28.1 mg/liter) related to the schedule of routine childhood immunization in the first year and at 8 years of age. Eighty percent of the antibodies are of the immunoglobulin G1 (IgG1) isotype. For pneumococcal capsular polysaccharide (PCP), the specific antibody levels represent the acquisition of natural immunity. The initial concentration of 9.2 mg/liter was low in infancy (0.5 to 1 years of age) and remained low until 3 to 4 years of age (14.6 mg/liter). During this period PCP antibodies were almost 100% of the IgG2 subclass. Thereafter, IgG anti-PCP antibody titers increased steadily to adult levels (59.5 mg/liter). The data are intended to provide reference ranges to aid in the interpretation of specific antibody determinations in the clinical setting.

Bronchiectasis

Bronchiectasis is a structural derangement of the bronchial wall that is characterized by airway dilatation and bronchial wall thickening. As a result of this abnormality, chronic inflammation and secondary microbial infections occur, which cause additional damage to the bronchi. Recent insights into the potential pathophysiological mechanisms of bronchiectasis, as well as improvements in computed tomography and the development of new pharmacological agents, might help to improve the clinical management of this chronic infective/inflammatory disorder.