Secondary antibody deficiencies

Access and use of immunoglobulins in supportive cancer care: A thematic analysis of a systematic review data set

Background

Secondary immunodeficiency (SID) disorders are known to occur in patients with haematological malignancies (HM) due to immunosuppressive treatments. Recurring infections causing subsequent morbidity and mortality commonly occur in this patient cohort. Immunoglobulin replacement therapy (IgRT) benefits patients with primary antibody deficiencies. However, evidence supporting their therapeutic role is not as explicit in SID-associated antibody deficiencies, which raises the questions regarding its use in SID and the knock-on effects of this use on its access and availability more generally.

Objectives

This study aimed to learn about the use of immunoglobulins in SID, identify themes concerning its use and access and suggest methods for improving access.

Design

This study included a thematic analysis of a published data set of 43 articles concerning immunoglobulin use and access in SID.

Data Sources and Methods

The data set used to perform the thematic analysis is based on research articles identified from Excerpta Medica Database (EMBASE) and PubMed databases, published as part of a systematic review and part 1 of this two-part publication series.

Results

A thematic synthesis was conducted to identify recurrent themes. The three primary themes included (1) the context for IgRT prescription, which included patient characteristics and cost burden of IgRT administration, and its use in different countries; (2) factors contributing to inappropriate IgRT use, including health care professionals' awareness of IgRT, disparity between guidelines and actual clinical practice, and the effect of shortages on prescription and chemotherapy-induced hypogammaglobulinemia (HGG); and (3) measures identified to improve IgRT use and access, which included multidisciplinary involvement, improved diagnostic tools and safer withdrawal and stewardship protocols.

Conclusions

IgRT use is increasing in HM as a supportive therapy but without comprehensive clinical guidelines and appropriate prescribing recommendations, medication wastage may occur with consequences for immunoglobulin access.

Evaluation and treatment of rhinosinusitis with primary antibody deficiency in adults: Evidence-based review with recommendations

BACKGROUND

There is clear evidence that the prevalence of primary antibody deficiency (PAD) is higher in patients with recurrent and chronic rhinosinusitis (CRS) than in the general population. The purpose of this multi-institutional and multidisciplinary evidence-based review with recommendations (EBRR) is to thoroughly review the literature on rhinosinusitis with PAD, summarize the existing evidence, and provide recommendations on the evaluation and management of rhinosinusitis in patients with PAD.

METHODS

The PubMed, EMBASE, and Cochrane databases were systematically reviewed from inception through August 2022. Studies on the evaluation and management of rhinosinusitis in PAD patients were included. An iterative review process was utilized in accordance with EBRR guidelines. Levels of evidence and recommendations on the evaluation and management principles for PAD were generated.

RESULTS

A total of 42 studies were included in this evidence-based review. These studies were evaluated on incidence of PAD in rhinosinusitis patients, incidence of rhinosinusitis in PAD patients, and on the different treatment modalities used and their outcome. The aggregate quality of evidence was varied across reviewed domains.

CONCLUSION

Based on the currently available evidence, PAD can occur in up to 50% of patients with recalcitrant CRS. Despite the presence of multiple studies addressing rhinosinusitis and PAD, the level of evidence supporting different treatment options continues to be lacking. Optimal management requires a multidisciplinary approach through collaboration with clinical immunology. There is need for higher-level studies that compare different treatments in patients with PAD and rhinosinusitis.

Clinical outcomes of immunoglobulin treatment for patients with secondary antibody deficiency: Data from the Ontario immunoglobulin treatment case registry

BACKGROUND

Despite the increasing number of cases of secondary antibody deficiency (SAD) and immunoglobulin (Ig) utilization, there is a paucity of data in the literature on clinical and patient-reported outcomes in this population.

OBJECTIVE

To describe immunoglobulin utilization patterns, clinical and patient-reported outcomes in patients with SAD on immunoglobulin replacement therapy (IgRT).

METHODS

A cross-sectional study of patients with secondary antibody deficiency enrolled in the Ontario Immunoglobulin Treatment (ONIT) Case Registry from June 2020 to September 2022 was completed. Demographics, comorbidities, indications for immunoglobulin treatment, clinical infections at baseline and post IgRT, and patient-reported outcomes were collected and analyzed.

RESULTS

There were 140 patients (58 males; 82 females; median age 68) with SAD during the study period; 131 were on subcutaneous Ig (SCIG) and 9 were on intravenous Ig (IVIG). The most common indication was chronic lymphocytic leukemia (CLL) (N = 52). IgRT reduced the average annual number of infections by 82.6%, emergency room (ER) visits by 84.6%, and hospitalizations by 83.3%. Overall, 84.6% of patients reported their health as better compared to before IgRT. Among those patients who switched from IVIG to SCIG (N = 35), 33.3% reported their health as the same, and 62.9% reported their health as better.

CONCLUSIONS

This study demonstrates that IgRT significantly improved clinical outcomes and patient-reported general health state in patients with SAD. This study also further supports the use of SCIG in patients with SAD.

Supportive Care in Older Lymphoma Patients to Reduce Toxicity and Preserve Quality of Life

The treatment paradigm in older patients with malignant hemopathies is the choice between an effective conservative treatment that preserves quality of life and an intensive, potentially curative treatment with more toxicities. For each patient, it is important to determine the risk/benefit ratio. The patient should be involved in the discussion, sufficiently informed and able to express himself and his expectations in terms of quality of life. However, this informed consent is conditioned by the ability of the patient to understand the risks and benefits of the treatment. Decline in quality of life is an important parameter for older patients with cancer and many prospective trials have now confirmed the impact of different side effects of treatment, such as recurrent hospitalization, loss of autonomy in daily activities, loss of contact with grandchildren and loss of cognitive functions. Interventions oriented to vulnerabilities detected in the older patients (by comprehensive geriatric assessment) and an optimal approach, including preventive measures to reduce treatment-related toxicity and mortality, are directly correlated to improvement in quality of life.

Screening for Antibody Deficiencies in Adults by Serum Electrophoresis and Calculated Globin

PURPOSE

This study aimed to investigate the correlation between calculated globulin (CG, total protein level minus albumin level) and the gamma globulin fraction (Gamma), obtained from serum protein electrophoresis with serum IgG levels in adults (≥ 18 years).

METHODS

Using linear regression models, analyses of CG and Gamma levels correlation with IgG levels in adults were performed. Receiver-operator curves were created to determine cutoff values and the respective sensitivity and specificity measures.

RESULTS

A total of 886 samples were analyzed. CG and Gamma were positively and statistically correlated with IgG levels (r2 = 0.4628 for CG, and = 0.7941 for Gamma, p < 0.0001 for both analyses). For the detection of hypogammaglobulinemia, i.e., IgG level below the reference value (6 g/L), a CG cutoff value of 24 g/L showed a sensitivity of 86.2% (95% CI 69.4-94.5) and a specificity of 92% (90.0-93.6). A Gamma cutoff value of 7.15 g/L yielded a sensitivity of 100% (88.3-100) and a specificity of 96.8 (95.3-97.8).

CONCLUSION

Both CG and Gamma levels determined by protein electrophoresis analysis may be used to screen for antibody deficiencies in adults, enabling earlier diagnosis of antibody deficiencies in a routine clinical setting.

Recommendations for Management of Secondary Antibody Deficiency in Multiple Myeloma

Secondary antibody deficiency (SAD) is a subtype of secondary immunodeficiency characterized by low serum antibody concentrations (hypogammaglobulinemia) or poor antibody function. SAD is common in patients with multiple myeloma (MM) due to underlying disease pathophysiology and treatment-related immune system effects. Patients with SAD are more susceptible to infections and infection-related morbidity and mortality. With therapeutic advancements improving MM disease control and survival, it is increasingly important to recognize and treat the often-overlooked concurrent immunodeficiency present in patients with MM. The aims of this review are to define SAD and its consequences in MM, increase SAD awareness, and provide recommendations for SAD management. Based on expert panel discussions at a standalone meeting and supportive literature, several recommendations were made. Firstly, all patients with MM should be suspected to have SAD regardless of serum antibody concentrations. Patients should be evaluated for immunodeficiency at MM diagnosis and stratified into management categories based on their individualized risk of SAD and infection. Infection-prevention strategy education, early infection reporting, and anti-infective prophylaxis are key. We recommend prophylactic antibiotics or immunoglobulin replacement therapy (IgRT) should be considered in patients with severe hypogammaglobulinemia associated with a recurrent or persistent infection. To ensure an individualized and efficient treatment approach is utilized, patient's immunoglobin G concentration and infection burden should be closely monitored throughout treatment. Patient choice regarding route and IgRT treatment is also key in reducing treatment burden. Together, these recommendations and proposed management algorithms can be used to aid physician decision-making to improve patient outcomes.

Management of humoral secondary immunodeficiency in hematological malignancies and following hematopoietic stem cell transplantation: Regional perspectives

Secondary immunodeficiency (SID) can occur as a result of multiple factors, including hematological malignancies, hematopoietic stem cell transplantation (HSCT), immunosuppressive treatment, biologics, and anti-inflammatory drugs. SID includes disorders resulting from impairment of both cellular and humoral immunity. This review focuses on the current risk factors, implications, and challenges in managing SID patients with impaired humoral immunity, which includes quantitative (hypogammaglobulinemia) and/or functional antibody and B-cell deficiencies specifically related to hematological malignancies and post-HSCT. Increased physician awareness is needed surrounding the disease presentation and early risk factors, as SID may be caused by several etiologies. Careful clinical assessment is then required to optimize management, which encompasses close monitoring of clinical parameters, vaccination, antibiotic prophylaxis, and immunoglobulin replacement therapy (IGRT). Novel methods of IGRT administration are associated with enhanced pharmacokinetics, IgG trough level stability, no need for venous access, as well as fewer systemic adverse events and better administration flexibility compared with traditional methods. Published international guidelines supported by observations from clinical data are broadly followed; however, best practices within each country have nuances that underline the need to tailor treatment plans to the individual patient.

Hypogammaglobulinemia in neonates: illustrative cases and review of the literature

This article presents a review of causes of hypogammaglobulinemia in neonates utilizing illustrative cases to demonstrate commonly seen conditions. Overall, the causes of low immunoglobulin level can be divided into three main categories: decreased maternal transfer or production (due to physiological nadir, transient hypogammaglobulinemia of infancy, medication effects, or immunodeficiency), increased loss of immunoglobulins (from the gastrointestinal (GI) system, lymphatics, kidneys, skin disease, or blood loss) or destruction/suppression (from medication effects). Treatment of hypogammaglobulinemia is generally tailored to the underlying cause and condition of the patient. This can be through supportive care, prophylactic measures, or with immunoglobulin G (IgG) replacement at the recommendation of an immunologist.

Clinical use of polyvalent intravenous immunoglobulins during intensive polychemotherapy in children with acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is seen in almost 30% of cases of cancer among children. Drop in absolute neutrophil count (ANC) and immunosuppression during chemotherapy are causing the significant increase in the risk of other complications, which can lead to prolonged hospitalization, higher costs of therapy and increased mortality.

METHODS

The analysis concerned 78 patients treated for ALL at the Department of Pediatric Oncology, Hematology and Transplantology. The indications for the use of immunoglobulins, the regimen of administration, the dose and adverse reactions were analyzed.

RESULTS

Intravenous immunoglobulins (IVIGs) were used in 66 (85%) of 78 patients. The standard risk group (SR) was represented by 10 (15%) patients, intermediate (IR) - 29 (44%), and high (HR) - 27 (41%). The most common were 1 and 2-day administrations - 60% and 28%, respectively, of transfusions. The spread of the IVIG doses used ranged from 43 mg to 882 mg/kg body weight. In the SR and IR groups, preparations were transfused at the reinduction stage, while in the HR-consolidation. Among the indications for IVIG, the most common was hypogammaglobulinemia-117 (42%), neutropenia-69 (25%) and infection-62 (22%). During the implementation of 279 patterns of immunoglobulin preparations, 8 (3%) post-transfusion reactions were registered.

CONCLUSIONS

The vast majority of ALL patients required immunoglobulin substitution during polychemotherapy. The supply of preparations is safe, however, there are no unambiguous guidelines regarding their dosage.

Calculated Globulin Is Clinically Useful as a Screening Test for Antibody Deficiency in Turkish Adult Patients

INTRODUCTION

Heterogeneous clinical features of antibody deficiency (AD) may cause diagnostic delays. Calculated globulin (CG) (total protein minus albumin) has been proposed as a screening test to prevent morbidity due to diagnostic delays in AD. Our aim was to validate CG as a screening test for AD in Turkish adult patients by comparing its role with gamma globulin analysis in protein electrophoresis.

METHODS

Fifty serum samples were randomly collected for each level of CG from 15 to 25 g/L and tested for serum IgG, IgA, IgM levels and protein electrophoresis. Cut-off values predicting low IgG levels were calculated for electrophoretically determined gamma globulin and CG. Additionally, the data of 47 patients followed up in our clinic with a diagnosis of primary antibody deficiency (PAD) were retrospectively analyzed.

RESULTS

A total of 550 adult patients were included in the study. The CG value predicting patients with IgG <6 g/L as a screening test was determined as <20 g/L with 83.8% sensitivity and 74.9% specificity. The gamma globulin value which predicted patients with the same IgG value of 89.0% sensitivity and 89.4% specificity was determined as <7 g/L. In the retrospective analysis, 37 of 47 patients (78.7%) with PAD had a CG value of <20 g/L at the time of the diagnosis and all 13 patients (100%) whose gamma globulin values were measured at the time of the diagnosis had a gamma globulin value of <7 g/L.

CONCLUSION

The determined CG cut-off value of <20 g/L can be used as a screening test in Turkish adult patients.

Access and use of immunoglobulins in secondary supportive cancer care: A systematic literature review

Background

Immunoglobulin replacement therapy (IgRT) benefits patients with primary immuno deficiency (PID) originating from the innate or polygenic defects in the immune system. However, evidence supporting their therapeutic role is not as explicit in secondary immuno deficiency (SID) resulting from the treatment of haematological malignancies.

Objectives

This study aimed to (1) create a dataset of relevant research papers, which explore the use of IgRT in SID for analysis, (2) assess the risk of bias within this dataset and (3) study the characteristics of these papers.

Design

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. In addition to the risk of bias, the study characteristics explored in this article included study design, study geographical location and year of publication.

Data Sources and Methods

To identify studies relevant to the research question, EMBASE and PubMed databases were searched. The Population, Intervention, Comparison and Outcome (PICO) framework was used to assess study quality. Risk of bias and quality of studies were assessed in accordance with the study design. As one model was not appropriate to assess bias in all articles, several tools were used.

Results

A total of 43 studies were identified from the literature search as relevant to the research objective. The most common study design was a retrospective case-control cohort study (n = 16/43), and randomised trials were among the least commonly used approaches (n = 1). Research in this area is occurring around the globe including the United States (n = 7), Italy (n = 7), China, India, Japan and throughout Europe. The annual number of papers in this area has varied from 2012 (n = 1) to 2021 (n = 7). The studies in this article demonstrated a varied risk of bias, with 9 of the 20 cohort studies scoring less than 5 out of 9 stars.

Conclusions

Randomised controlled trials are less frequently used to assess access and use of immunoglobulins. More commonly, a retrospective case-control cohort study was used which correlates with the higher risk of bias seen in the studies in this article. Most of the research concerning immunoglobulin use and access occurs in higher-income countries.

Management of secondary immunodeficiency in hematological malignancies in the era of modern oncology

Secondary immunodeficiency (SID) in patients with B-cell hematological malignancies is a common condition that presents with recurrent infection. SID is due to both the inherent immune defects due to the malignancy, as well as secondary to cancer therapies, many of which have B-cell depleting properties. The early diagnosis of SID and the optimization of intervention strategies are key to delivering the most effective cancer treatments and reducing infection-related morbidity and mortality. This review discusses current practice, recommendations, and challenges for SID diagnosis, based on the evaluation of clinical history and laboratory assessments, and the effectiveness of specific vaccines and immunoglobulin replacement therapy in reducing the frequency and recurrence of infections in patients with SID, and the healthcare system-associated costs.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Infections in secondary immunodeficiency patients treated with Privigen® or Hizentra®: a retrospective US administrative claims study in patients with hematological malignancies

B cell-derived lymphoproliferative disorders are associated with secondary immunodeficiency (SID); some patients require immunoglobulin replacement therapy (IgRT) to mitigate infections. Using IQVIA's PharMetrics^® Plus database, patients with SID who received IgPro10/IgPro20 in the 12 months post-diagnosis (IgRT users) were matched to patients with SID not receiving IgRT (non-IgRT users). The risk of severe infection was compared using within-patient change from baseline to follow-up as well as between cohorts. Overall, 277 IgRT users were matched to 1019 non-IgRT users. Before IgRT, more IgRT users experienced any bacterial infection (88.4% vs. 72.9%; p<.0001) or ≥1 severe bacterial infection (SBI) (42.2% vs. 31.8%; p=.0011) vs. non-IgRT users. During follow-up, risk of SBI among IgRT users (21.7%) reached parity with non-IgRT users (21.2%). IgRT was associated with a reduction in SBIs to levels comparable with the lower 'baseline infection risk' of non-IgRT users. These criteria help define SID patients who may benefit from IgRT.

Multiple modes of action mediate the therapeutic effect of IVIg in experimental epidermolysis bullosa acquisita

Substitution of IgG in antibody deficiency or application of high-dose intravenous IgG (IVIg) in patients with autoimmunity are well-established treatments. Data on the mode of action of IVIg are, however, controversial and may differ for distinct diseases. In this study, we investigated the impact and molecular mechanism of high-dose IgG treatment in murine autoantibody-induced skin inflammation, namely, epidermolysis bullosa acquisita (EBA). EBA is caused by antibodies directed against type VII collagen (COL7) and is mediated by complement activation, release of reactive oxygen species, and proteases by myeloid cells. In murine experimental EBA the disease can be induced by injection of anti-COL7 IgG. Here, we substantiate that treatment with high-dose IgG improves clinical disease manifestation. Mechanistically, high-dose IgG reduced the amount of anti-COL7 in skin and sera, which is indicative for an FcRn-dependent mode-of-action. Furthermore, in a non-receptor-mediated fashion, high-dose IgG showed antioxidative properties by scavenging extracellular reactive oxygen species. High-dose IgG also impaired complement activation and served as substrate for proteases, both key events during EBA pathogenesis. Collectively, the non-receptor-mediated anti-inflammatory properties of high-dose IgG may explain the therapeutic benefit of IVIg treatment in skin autoimmunity.

Polyvalent Immunoglobulin as a Potential Treatment Option for Patients with Recurrent COPD Exacerbations

Chronic obstructive pulmonary disease (COPD) is characterized by chronic airway inflammation and episodes of worsening respiratory symptoms and pulmonary function, termed acute exacerbations of COPD (AECOPD). AECOPD episodes are associated with heightened airway inflammation and are often triggered by infection. A subset of COPD patients develops frequent exacerbations despite maximal existing standard medical therapy. It is therefore clear that a targeted and more effective prevention strategy is needed. Immunoglobulins are glycoprotein molecules that are secreted by B lymphocytes and plasma cells and play a critical role in the adaptive immune response against many pathogens. Altered serum immunoglobulin levels have been observed in patients with immunodeficiencies and inflammatory diseases. Serum immunoglobulin has also been identified as potential biomarkers of AECOPD frequency. Since plasma-derived polyvalent immunoglobulin treatment is effective in preventing recurrent infections in immunodeficient patients and in suppressing inflammation in many inflammatory diseases, it may be conceivable that immunoglobulin treatment may be effective in preventing recurrent AECOPD. In this article, we provide a review of the current knowledge on immunoglobulin treatment in patients with COPD and discuss plausible mechanisms as to how immunoglobulin treatment may work to reduce AECOPD frequency.

T Cell Immunity and the Quest for Protective Vaccines against Staphylococcus aureus Infection

Staphylococcus aureus is a wide-spread human pathogen, and one of the top causative agents of nosocomial infections. The prevalence of antibiotic-resistant S. aureus strains, which are associated with higher mortality and morbidity rates than antibiotic-susceptible strains, is increasing around the world. Vaccination would be an effective preventive measure against S. aureus infection, but to date, every vaccine developed has failed in clinical trials, despite inducing robust antibody responses. These results suggest that induction of humoral immunity does not suffice to confer protection against the infection. Evidence from studies in murine models and in patients with immune defects support a role of T cell-mediated immunity in protective responses against S. aureus. Here, we review the current understanding of the mechanisms underlying adaptive immunity to S. aureus infections and discuss these findings in light of the recent S. aureus vaccine trial failures. We make the case for the need to develop anti-S. aureus vaccines that can specifically elicit robust and durable protective memory T cell subsets.

A systematic literature review of the effects of immunoglobulin replacement therapy on the burden of secondary immunodeficiency diseases associated with hematological malignancies and stem cell transplants

INTRODUCTION

Secondary immunodeficiency diseases (SID) caused by hematological malignancies (HMs), stem cell transplant (SCT), and associated therapies are mainly characterized by the presence of hypogammaglobulinemia or antibody production deficits.

AREAS COVERED

The authors summarized the scientific literature on disease burden of SIDs in patients who had HMs or SCT. Systematic searches were conducted to identify English-language articles from 1994-2020, reporting on clinical, humanistic, and economic burdens of SID due to HMs or SCT. Definitions of SID and serum immunoglobulin G thresholds varied across 24 eligible studies. In most (n = 16) studies, patients received immunoglobulin replacement therapy (IGRT). Several studies found IGRT was associated with significant reductions in rates of infection and antimicrobial use. However, 1 study found no statistically significant difference in antibiotic use with IGRT. Only 3 studies reported on quality of life, and no economic studies were identified.

EXPERT OPINION

Overall, the findings show several beneficial effects of IGRT on clinical outcomes and quality of life; however, disparate definitions, infrequent reporting of statistical significance, and scarcity of clinical trial data after the 1990s present areas for further investigation. This paucity indicates an unmet need of current evidence to assess the benefits of IGRT in SID.

Secondary immunodeficiencies with predominant antibody deficiency: multidisciplinary perspectives of Polish experts

At present, secondary immune deficiencies have become a clinical problem, recognized in different specialties. The aim of this paper was to increase awareness and support the need for screening at-risk populations. Secondary immune deficiencies result in variety of conditions, but not all of them require immunoglobulin replacement therapy, as specific antibody response might be preserved. Moreover, the management of secondary immune deficiencies vary between countries and different medical disciplines. This literature review presents the most common causes and clinical presentation of secondary immunodeficiencies with predominant impaired antibody production. We present diagnostic guidelines for patients at-risk, with an emphasis on the role of prophylactic vaccination as a treatment and diagnostic tool. This review considers the specificity and disparities of the Polish healthcare system and ultimately, suggests that management teams should include a clinical immunologist experienced in the treatment of humoral immunodeficiencies.

Development of a vaccine against Staphylococcus aureus invasive infections: Evidence based on human immunity, genetics and bacterial evasion mechanisms

Invasive Staphylococcus aureus infections are a leading cause of morbidity and mortality in both hospital and community settings, especially with the widespread emergence of virulent and multi-drug resistant methicillin-resistant S. aureus strains. There is an urgent and unmet clinical need for non-antibiotic immune-based approaches to treat these infections as the increasing antibiotic resistance is creating a serious threat to public health. However, all vaccination attempts aimed at preventing S. aureus invasive infections have failed in human trials, especially all vaccines aimed at generating high titers of opsonic antibodies against S. aureus surface antigens to facilitate antibody-mediated bacterial clearance. In this review, we summarize the data from humans regarding the immune responses that protect against invasive S. aureus infections as well as host genetic factors and bacterial evasion mechanisms, which are important to consider for the future development of effective and successful vaccines and immunotherapies against invasive S. aureus infections in humans. The evidence presented form the basis for a hypothesis that staphylococcal toxins (including superantigens and pore-forming toxins) are important virulence factors, and targeting the neutralization of these toxins are more likely to provide a therapeutic benefit in contrast to prior vaccine attempts to generate antibodies to facilitate opsonophagocytosis.

Prevalence of Hypogammaglobulinemia in Adult Invasive Pneumococcal Disease

Background

Patients with humoral immune deficiency are susceptible to invasive pneumococcal disease (IPD). This study estimates the prevalence of underlying hypogammaglobulinemia in admitted IPD cases and examines whether IPD cases had received preventative treatment.

Methods

All adult IPD cases (Streptococcus pneumoniae in blood or cerebrospinal fluid) admitted to The Ottawa Hospital (TOH) from January 2013 to December 2015 were identified through the Eastern Ontario Regional Laboratory. Documented clinical demographics, S. pneumoniae serotype, serum immunoglobulins measured previously or in convalescence, and vaccination status of the cases were collected retrospectively for descriptive analyses.

Results

There were 134 IPD in 133 patients (47.4% male; mean age 63, standard deviation [SD] = 15.6 years) during a 3-year observation period. All-cause mortality rate was 22.6% over a mean follow-up time of 362, SD = 345 days. Fifty-seven patients (42.9%) had serum immunoglobulin levels measured. Eighteen were either found to have hypogammaglobulinemia in convalescence (8/18) or previously known to have hypogammaglobulinemia (10/18). None of the known hypogammaglobulinemic patients had received antibiotic prophylaxis and/or immunoglobulin replacement therapy within 4 months prior to IPD. The high and low estimates of prevalence of hypogammaglobulinemia were 31.6% (of all measured) and 13.5% (of all cases). Among 18 patients with hematological malignancies in our cohort, 13 had hypogammaglobulinemia. Many isolates were vaccine serotypes; however, only 8 had documented previous pneumococcal vaccination.

Conclusions

IPD has high mortality, and hypogammaglobulinemia was present in at least 13.5% of IPD cases. Secondary hypogammaglobulinemia is especially common in cases with hematological malignancy and IPD.

Determination of antibodies in everyday rheumatological practice

Antibody determination is routinely used in everyday rheumatological practice. Its result repeatedly determines the diagnosis or exclusion of a particular disease. Antibodies are immunoglobulins, i.e. some of the most important proteins in the immune system, and have specific properties that we should know. In addition, there are a number of factors that can affect their concentration, including drugs commonly used in the treatment of rheumatic diseases. There are definite indications, when the total concentrations of individual classes of immunoglobulins should be initially determined and it should be evaluated whether the patient produces them at all or their production is impaired. In some cases, we should evaluate the levels of specific antibodies along with the total protein concentration and the γ-globulin fraction, in which the antibodies are contained. The article presents information on the most common mistakes made when performing these tests.

The Expanding Field of Secondary Antibody Deficiency: Causes, Diagnosis, and Management

Antibody deficiency or hypogammaglobulinemia can have primary or secondary etiologies. Primary antibody deficiency (PAD) is the result of intrinsic genetic defects, whereas secondary antibody deficiency may arise as a consequence of underlying conditions or medication use. On a global level, malnutrition, HIV, and malaria are major causes of secondary immunodeficiency. In this review we consider secondary antibody deficiency, for which common causes include hematological malignancies, such as chronic lymphocytic leukemia or multiple myeloma, and their treatment, protein-losing states, and side effects of a number of immunosuppressive agents and procedures involved in solid organ transplantation. Secondary antibody deficiency is not only much more common than PAD, but is also being increasingly recognized with the wider and more prolonged use of a growing list of agents targeting B cells. SAD may thus present to a broad range of specialties and is associated with an increased risk of infection. Early diagnosis and intervention is key to avoiding morbidity and mortality. Optimizing treatment requires careful clinical and laboratory assessment and may involve close monitoring of risk parameters, vaccination, antibiotic strategies, and in some patients, immunoglobulin replacement therapy (IgRT). This review discusses the rapidly evolving list of underlying causes of secondary antibody deficiency, specifically focusing on therapies targeting B cells, alongside recent advances in screening, biomarkers of risk for the development of secondary antibody deficiency, diagnosis, monitoring, and management.

Lifelong immunoglobulin replacement is not always necessary: A case description of a patient with recurrent infections and hypogammaglobulinemia

Humoral immunodeficiency with accompanying infections is an indication for human immunoglobulin replacement therapy. Whether treatment will be lifelong or necessary only temporarily depends on the nature of deficiency: primary (persistent) or secondary (persistent or transient). It is not always easy to distinguish between primary and secondary immunodeficiency, especially in adults. The article presents a case of a 39-year-old patient with anamnesis and medical tests results that suggested primary humoral immunodeficiency. The deficiency was diagnosed for the first time at the age of 38, when the patient was pregnant. The patient was qualified for immunoglobulin G replacement therapy. Clinical improvement was achieved. After the end of pregnancy, systematic improvement in immunological parameters was observed, suggesting the resolution of immunodeficiency. A decision was made to discontinue immunoglobulin replacement. Due to the ability to respond to vaccine, confirmed during diagnosis, preventive vaccines were recommended. There was no recurrence of serious infections. The clinical course finally enabled a diagnosis of secondary immunodeficiency. The presented case shows the importance of an active approach to the diagnostic and therapeutic process, constant assessment of clinical course, monitoring of IgG concentrations, and the awareness that in the situation when we do not have a genetic confirmation of the disease, the diagnosis may change.

A Prospective Observational Study of Hypogammaglobulinemia in the First Year After Lung Transplantation

Background

Immunosuppressive therapies have led to improved survival for lung transplant (LT) recipients but these therapies can lead to hypogammaglobulinemia (HGG) and potentially an increased risk of infection. Large prospective studies have not been performed to evaluate the impact of HGG on outcomes for LT recipients.

Methods

This is a single-center prospective observational study of LT recipients. Pretransplant and posttransplant IgG levels were measured and related to infection, rejection, antibiotic use, and immunosuppression use.

Results

One hundred thirty-three LT recipients were prospectively evaluated. Pretransplant IgG values were higher than IgG values at the time of transplant or any time thereafter (all P < 0.0001). Severe HGG (IgG < 400 mg/dL) was highest at the time of transplant (32.4%) while at 3, 6, 9, and 12 months posttransplant the prevalence of severe HGG was 7.4%, 7.5%, 8.9%, and 6.3%, respectively. Severe HGG was associated with 2 or more pneumonias (P = 0.0006) and increased number of antibiotic courses (P = 0.003) compared with the subjects without severe HGG. Pretransplant IgG level and less than 30% of pretransplant protective pneumococcal antibody levels were identified as pretransplant risk factors for severe HGG. In multivariate analysis, chronic obstructive pulmonary disease as the underlying disease and the use of basiliximab as the induction agent in conjunction with higher prednisone and mycophenolate dosing were most predictive of severe HGG (P = 0.005), whereas the combination of age, severe HGG and number of acute steroid courses were most predictive of total days of pneumonia (P = 0.0001).

Conclusions

Our large prospective study identifies risk factors for severe HGG after LT and demonstrates that LT recipients with severe HGG are at increased risk for recurrent pneumonias and more antibiotic courses.

Measurement and interpretation of Salmonella typhi Vi IgG antibodies for the assessment of adaptive immunity

Response to polysaccharide vaccination can be an invaluable tool for assessing functionality of the adaptive immune system. Measurement of antibodies raised in response to Pneumovax®23 is the current gold standard test, but there are significant challenges and constraints in both the measurement and interpretation of the response. An alternative polysaccharide vaccine approach (Salmonella typhi Vi capsule (ViCPS)) has been suggested. In the present article, we review current evidence for the measurement of ViCPS antibodies in the diagnosis of primary and secondary antibody deficiencies. In particular, we review emerging data suggesting their interpretation in combination with the response to Pneumovax®23 and comment upon the utility of these vaccines to assess humoral immune responses while receiving immunoglobulin replacement therapy (IGRT).

Age-specific pediatric reference ranges for immunoglobulins and complement proteins on the Optilite™ automated turbidimetric analyzer

BACKGROUND

Measurement of immunoglobulins and complement proteins are frontline tests used in the assessment of immune system integrity, and reference values can vary with age. Their measurement provides an insight into the function of the innate and adaptive immune systems.

METHODS

We generated pediatric reference ranges for IgG, IgA, IgM, IgD, the IgG and IgA subclasses, and C3 and C4 using the Optilite™ turbidimetric analyzer.

RESULTS

The concentrations of IgG, IgA, and IgD showed an increase with age, as expected, while IgM remained stable between the age groups. For the IgG subclasses, no significant differences were observed in IgG1 or IgG3, while IgG2 and IgG4 concentrations increased steadily with age. The concentration of IgG2 plateaued at 15-18 years, while IgG4 plateaued at 10-14 years. The trend of concentrations across all groups was IgG1 > IgG2 > IgG3 > IgG4. For both IgA1 and IgA2, concentrations increased significantly with age, plateauing at 15-18 years. The median IgA1 concentration was greater than IgA2 across all groups. There was a good correlation between the total IgG or IgA concentration and summation of their subclasses (R²  = 0.89, P < .0001, slope y = 0.98x + 14.51 mg/dL and R²  = 0.91, P < .0001, slope y = 1.35x-3.28 mg/dL, respectively). The concentration of C3 and C4 remained stable across the groups, with no significant differences observed.

CONCLUSION

We have generated age-specific reference ranges in healthy children for C3, C4, IgG, IgA, IgM, IgD and the IgG and IgA subclasses using the Optilite^™ turbidimetric analyzer. These ranges will help identify individuals with abnormal concentrations, thus will aid in the diagnosis of both primary and secondary immunological disorders.

Prescribing Immunoglobulin Replacement Therapy for Patients with Non-classical and Secondary Antibody Deficiency: an Analysis of the Practice of Clinical Immunologists in the UK and Republic of Ireland

Background

Immunologists are increasingly being asked to assess patients with non-classical and secondary antibody deficiency to determine their potential need for immunoglobulin replacement therapy (IGRT). Immunoglobulin is a limited, expensive resource and no clear guidance exists for this broad patient group. The purpose of this survey is to establish what factors influence the decision to commence IGRT in adult patients, when diagnostic criteria for primary antibody deficiency are not fulfilled.

Methods

Under the auspices of the United Kingdom Primary Immunodeficiency Network (UKPIN), a study group was established which circulated an online questionnaire to the consultant body across the UK and Ireland. Results provided a snapshot of the current clinical practice of 71% of consultant immunologists, from 30 centers.

Results

In order of importance, factors which influence the decision to commence IGRT include number of hospital admissions with infection, serum IgG level, bronchiectasis, radiologically proven pneumonia, number of positive sputum cultures, number of antibiotic courses, and results of immunization studies. The commonest test vaccine used was Pneumovax 23 with measurement of serotype-specific responses at 4 weeks, with a threshold of 0.35 μg/ml in 2/3 of serotypes measured. Eighty-six percent of patients are treated with a trial of prophylactic antibiotics prior to consideration of IGRT. Efficacy of IGRT trial is assessed at between 6 and 12 months.

Conclusions

There was consistency in clinical practice using a combination of clinical history, evidence of infections, and vaccination testing for diagnosis. However, there was some variation in the implementation of this practice, particularly in vaccine choice and assessment of response to vaccination.

Cancer Therapy-associated Lymphoproliferative Disorders: An Under-recognized Type of Immunodeficiency-associated Lymphoproliferative Disorder

We describe the clinicopathologic features of 17 patients who had a hematologic malignancy of various types, were treated, and subsequently developed a lymphoproliferative disorder (LPD). There were 10 men and 7 women with a median age of 59 years (range, 36 to 83 y). The primary hematologic neoplasms included: 5 chronic lymphocytic leukemia/small lymphocytic lymphoma, 3 plasma cell myeloma, 2 acute monoblastic leukemia, and 1 case each of mixed-phenotype acute leukemia, chronic myeloid leukemia, splenic marginal zone lymphoma, follicular lymphoma, mantle cell lymphoma, T-cell prolymphocytic leukemia, and peripheral T-cell lymphoma. All patients were treated with chemotherapy with or without therapeutic antibodies; 3 also underwent autologous stem cell transplantation. The mean interval from initiation of therapy for initial hematologic malignancy to onset of LPD was 66 months (range, 3 to 299 mo). Ten (59%) LPDs were extranodal and 7 (41%) involved nodal tissues. The histologic diagnoses included: 8 diffuse large B-cell lymphoma, 4 classical Hodgkin lymphoma, 3 polymorphic LPD, 1 lymphomatoid granulomatosis, and 1 Epstein-Barr virus (EBV) mucocutaneous ulcer. Fourteen cases were EBV. Following the onset of LPD, chemotherapy was administered to 10 (59%) patients. With a median follow-up of 100 months (range, 5 to 328 mo), 8 (47%) patients are alive and 9 (53%) died. One (6%) patient with lymphomatoid granulomatosis underwent spontaneous remission. On the basis of the clinicopathologic features and high prevalence of EBV infection in this cohort, we believe that these LPDs show similarities with other types of immunodeficiency-associated LPDs. We suggest that cancer therapy-associated LPD be included in future classification systems for immunodeficiency-associated LPDs.

II Brazilian Consensus on the use of human immunoglobulin in patients with primary immunodeficiencies

In the last few years, new primary immunodeficiencies and genetic defects have been described. Recently, immunoglobulin products with improved compositions and for subcutaneous use have become available in Brazil. In order to guide physicians on the use of human immunoglobulin to treat primary immunodeficiencies, based on a narrative literature review and their professional experience, the members of the Primary Immunodeficiency Group of the Brazilian Society of Allergy and Immunology prepared an updated document of the 1^st Brazilian Consensus, published in 2010. The document presents new knowledge about the indications and efficacy of immunoglobulin therapy in primary immunodeficiencies, relevant production-related aspects, mode of use (routes of administration, pharmacokinetics, doses and intervals), adverse events (major, prevention, treatment and reporting), patient monitoring, presentations available and how to have access to this therapeutic resource in Brazil.

Considerations for dosing immunoglobulin in obese patients

Obesity is a very common condition; however, the effect of excess body weight on the appropriate dose of immunoglobulin has not been defined empirically. The proposed pharmacokinetic differences between lean and obese patients and the opportunity to reduce costs has led to the proposition that obese patients should receive proportionally lower doses of immunoglobulin once a certain threshold is reached. Here the theoretical factors which could affect dosing in obese patients are considered alongside the available empirical evidence. The available evidence indicates that obesity may affect the pharmacokinetics of immunoglobulin; however, the effect is likely to be too small to have a clinically important effect on dosing. Wide interpatient individuality and highly variable clinical need mean that obesity should not play a major factor in dosing considerations. However, patients who are obese are more likely to have multiple cardiovascular risk factors and their weight indicates a large dose. This puts these patients at a higher risk of adverse reactions, and therefore caution is advised.

When to initiate immunoglobulin replacement therapy (IGRT) in antibody deficiency: a practical approach

Primary antibody deficiencies (PAD) constitute the majority of all primary immunodeficiency diseases (PID) and immunoglobulin replacement forms the mainstay of therapy for many patients in this category. Secondary antibody deficiencies (SAD) represent a larger and expanding number of patients resulting from the use of a wide range of immunosuppressive therapies, in particular those targeting B cells, and may also result from renal or gastrointestinal immunoglobulin losses. While there are clear similarities between primary and secondary antibody deficiencies, there are also significant differences. This review describes a practical approach to the clinical, laboratory and radiological assessment of patients with antibody deficiency, focusing on the factors that determine whether or not immunoglobulin replacement should be used. The decision to treat is more straightforward when defined diagnostic criteria for some of the major PADs, such as common variable immunodeficiency disorders (CVID) or X-linked agammaglobulinaemia (XLA), are fulfilled or, indeed, when there is a very low level of immunoglobulin production in association with an increased frequency of severe or recurrent infections in SAD. However, the presentation of many patients is less clear-cut and represents a considerable challenge in terms of the decision whether or not to treat and the best way in which to assess the outcome of therapy. This decision is important, not least to improve individual quality of life and reduce the morbidity and mortality associated with recurrent infections but also to avoid inappropriate exposure to blood products and to ensure that immunoglobulin, a costly and limited resource, is used to maximal benefit.