Current screening approaches for antibody deficiency. Curr Opin Allergy Clin Immunol. 2015;15:547-555. [PMID: 26513714 DOI: 10.1097/aci.0000000000000222]

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.

Current Issues in the Management of IgG Subclass Deficiencies in Adults With Chronic Respiratory Diseases

Primary immunodeficiency diseases (PIDs) are uncommon in adults; however, immunoglobulin G subclass deficiency (IGGSCD) is often found in a subset of adult patients with chronic respiratory diseases. As quantitative laboratory tests are used to diagnose IGGSCD, the clinical significance of IGGSCD remains controversial. However, respiratory infection is a common presenting feature of IGGSCD, and respiratory complications are responsible for subsequent morbidities, such as severe asthma, bronchiectasis, chronic obstructive airway diseases, and mortality. This review summarizes the current epidemiological data for PIDs, focusing on IGGSCD in the adult population. In addition, the investigation, treatment, and management strategies are detailed, including distinct issues faced by patients with chronic airway disease and their physicians in the proper diagnosis and treatment of IGGSCD.

Development of a primary care screening algorithm for the early detection of patients at risk of primary antibody deficiency

BACKGROUND

Primary antibody deficiencies (PAD) are characterized by a heterogeneous clinical presentation and low prevalence, contributing to a median diagnostic delay of 3-10 years. This increases the risk of morbidity and mortality from undiagnosed PAD, which may be prevented with adequate therapy. To reduce the diagnostic delay of PAD, we developed a screening algorithm using primary care electronic health record (EHR) data to identify patients at risk of PAD. This screening algorithm can be used as an aid to notify general practitioners when further laboratory evaluation of immunoglobulins should be considered, thereby facilitating a timely diagnosis of PAD.

METHODS

Candidate components for the algorithm were based on a broad range of presenting signs and symptoms of PAD that are available in primary care EHRs. The decision on inclusion and weight of the components in the algorithm was based on the prevalence of these components among PAD patients and control groups, as well as clinical rationale.

RESULTS

We analyzed the primary care EHRs of 30 PAD patients, 26 primary care immunodeficiency patients and 58,223 control patients. The median diagnostic delay of PAD patients was 9.5 years. Several candidate components showed a clear difference in prevalence between PAD patients and controls, most notably the mean number of antibiotic prescriptions in the 4 years prior to diagnosis (5.14 vs. 0.48). The final algorithm included antibiotic prescriptions, diagnostic codes for respiratory tract and other infections, gastro-intestinal complaints, auto-immune symptoms, malignancies and lymphoproliferative symptoms, as well as laboratory values and visits to the general practitioner.

CONCLUSIONS

In this study, we developed a screening algorithm based on a broad range of presenting signs and symptoms of PAD, which is suitable to implement in primary care. It has the potential to considerably reduce diagnostic delay in PAD, and will be validated in a prospective study. Trial registration The consecutive prospective study is registered at clinicaltrials.gov under NCT05310604.

Calculated Globulin as a potential screening tool for paraproteinemia to aid in the early diagnosis of Multiple Myeloma

BACKGROUND

Multiple Myeloma (MM) is a haematological malignancy with increasing global incidence. Diagnosis of MM should be initiated at the primary care level to achieve the best patient outcome. However, this can be delayed due to nonspecific presenting symptoms, such as back pain and fatigue.

OBJECTIVES

The aim of this study was to investigate if commonly requested blood tests could indicate MM in primary care and potentially lead to earlier diagnosis.

DESIGN AND METHODS

This retrospective observational study involved an audit of clinical and laboratory data from 109 MM patients, including patients with Active MM (N=53), Smouldering MM (N=33), and Free light chain MM (N=23).

RESULTS

Of the 16 potential biomarkers investigated, the most promising indicator for early detection of active MM and Smouldering MM was an increased Calculated Globulin (CG). The median CG for patients with active MM (50g/L) was 78.6% higher than the healthy control group (28g/L). Smouldering MM patients had a median CG value (38g/L), which was 35.7% higher than the control group. Of interest, the median CG result was only 16.7% higher in the control group than in the free light chain MM group, suggesting CG would not be as effective at detecting this subtype.

CONCLUSIONS

CG is derived from Total Protein and Albumin data, which are commonly measured in routine liver function profiles, thus there is no additional test or cost requirement. Based on these data, CG has potential as a clinical biomarker to support early detection of MM at the primary care level and allow for appropriate targeted investigations.

Pediatric Prediction Model for Low Immunoglobulin G Level Based on Serum Globulin and Illness Status

Hypogammaglobulinemia is a condition that requires prompt diagnosis and treatment. Unfortunately, serum immunoglobulin (Ig) measurements are not widely accessible in numerous developing countries. Serum globulin is potentially the best candidate for screening of low IgG level (IgGLo) due to its high availability, low cost, and rapid turnover time. However, multiple factors may influence the probability of prediction. Our study aimed to establish a simple prediction model using serum globulin to predict the likelihood of IgGLo in children. For retrospective data of patients who were suspected of having IgGLo, both serum IgG and globulin were simultaneously collected and measured. Potential factors interfering with serum globulin and IgG levels were investigated for their impact using bivariate binary logistic regression. A multivariate binary logistic regression was used to generate a formula and score to predict IgGLo. We obtained 953 samples from 143 pediatric patients. A strong positive correlation between serum globulin and IgG levels was observed (r=0.83, p < 0.001). A screening test model using serum globulin and illness status was constructed to predict IgGLo. The formula for predicting IgGLo was generated as follows; Predicted score = (2 x globulin (g/dl)) – illness condition score (well=0, sick=1). When the score was <4, the patient has the probability of having IgGLo with a sensitivity of 0.78 (0.71, 0.84), a specificity of 0.71 (0.68, 0.74), PPV of 0.34 (0.29, 0.40) and NPV of 0.94 (0.92, 0.96). This formula will be useful as rapid and inexpensive screening tool for early IgGLo detection, particularly in countries/locations where serum IgG measurement is inaccessible.

Serum Protein Electrophoresis May Be Used as a Screening Tool for Antibody Deficiency in Children and Adolescents

Background

Patients with antibody deficiency may experience exceptionally long diagnostic delays, increasing the risk of life-threatening infections, end-organ damage, mortality, and health costs.

Objective

This study aimed to analyze serum protein electrophoresis and verify the correlation between calculated globulin (CG, total protein minus albumin levels) or electrophoretically determined serum gamma globulin fraction (Gamma) with IgG levels in children and adolescents under 18 years old (yo).

Methods

We analyzed serum protein electrophoresis (GC or Gamma) and IgG levels from 1215 children and adolescents under 18 yo, classified into 5 age groups. We verified the correlation between CG or Gamma with serum IgG levels.

Results

Serum IgG levels varied according to age groups (from 4.3 ± 2.3 g/l in children under 6 months old to 11.4 ± 3.2 g/l in adolescents in the 10-<18 yo group). CG sensitivity and specificity to detect IgG below the reference range for all patients were 93.1% and 81.8%, respectively, and varied according to age group. Gamma sensitivity and specificity for all patients were 100% and 87.8%, respectively, and varied according to age group as well. We found serum IgG levels below the age reference level in 29 patients (2.4% of the cases) using CG or Gamma levels.

Conclusion

Both CG and Gamma levels may be of utility as a screening tool for earlier diagnosis of antibody deficiency in children and adolescents under 18 yo.

Evaluation of the frequency and diagnostic delay of primary immunodeficiency disorders among suspected patients based on the 10 warning sign criteria: A cross-sectional study in Iran

INTRODUCTION

The prevalence of undiagnosed primary immunodeficiency diseases is remarkably high and contributes to increasing the rate of morbidity and mortality among this group of patients.

OBJECTIVE

To examine the 10 warning sign scoring system in patients suspected of primary immune deficiency and also estimate the diagnostic delay in patients with proven disease.

METHODS

This descriptive cross-sectional study was carried out during the years 2015-2016 in Ali Asghar (AS) Clinic and Hospital. Two hundred patients with suspected primary immune deficiency disease were eligible for inclusion in the study. Multivariable logistic regression analysis was used to determine the relation between findings.

RESULTS

In this study, the majority of suspected cases of immunodeficiency were males (57%) with a mean age of 3.33±2.89 years. Twenty-one (10.5%) patients were diagnosed with immunodeficiency disease. The mean diagnostic delay among primary immune deficient patients was 2.05±1.7 years. There was a significant relationship between having parental consanguinity (OR=2.68, 95% CI: 1.07-6.70), allergies (OR=5.03, 95% CI: 1.13-22.31), vaccine adverse effects (OR=9.31, 95% CI: 1.24-69.96) and primary immune deficiency diagnosis. No association was observed between age (OR=0.98, 95% CI: 0.84-1.14), gender (OR=0.99, 95% CI: 0.39-2.47), immune deficiency scoring (OR=0.68, 95% CI: 0.31-1.45) and primary immune deficiency diagnosis.

CONCLUSION

Ten warning sign scoring system is of less value to consider a patient suspected of having primary immune deficiency. There is a meaningful delay in diagnosis of primary immune deficiencies especially in antibody deficiency defects which seeks further upgrading of knowledge in physicians.

Global immunoglobulin supply: steaming towards the iceberg?

PURPOSE OF REVIEW

This review describes how plasma is sourced for fractionation into plasma-derived medicinal products (PDMPs), such as immunoglobulin (Ig) together with differences between plasma from whole blood (recovered plasma) and from plasmapheresis (source plasma) in terms of global plasma supply. Specific areas of growth in immunoglobulin use are identified alongside novel therapies, which may reduce demand for some immunoglobulin indications.

RECENT FINDINGS

There has been a 6--8% annual growth in immunoglobulin use. Secondary immunodeficiency alongside improved recognition and diagnosis primary immunodeficiency disorders are drivers whereas the novel neonatal Fc receptor inhibitors (FcRni) may reduce demand for some immunomodulatory indications.

SUMMARY

There is a significant geographical imbalance in global supply of plasma with 65% collected in the United States. This results in a dependency of other countries on United States supply and argues for both more plasma supply and greater regionally balanced plasma collection. In addition, progress towards a transparent, regulated and well tolerated framework for the coexistence of unpaid and compensated plasma donations is needed as unpaid donation will not be sufficient. These discussions should be informed by the needs of patients for this life-saving therapy, the care of donors and the safety of plasma and PDMPs.

From infections to autoimmunity: Diagnostic challenges in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most common clinically significant primary antibody deficiency diagnosed in adults. The early symptoms are not specific. They include common infections, mainly of the respiratory tract, caused by typical microorganisms, so cases can be missed in primary care. In the majority of patients increased susceptibility to infections coexists with signs or symptoms of autoimmunity, inflammation or polyclonal lymphoproliferation, which can divert diagnosis from immune deficiency. The overall incidence of malignancy is increased in CVID and certain cancers are significantly more common. Lymphomas and gastric carcinoma are the most frequently reported malignancies in CVID, so a high index of suspicion is recommended. Diagnostic delay in CVID is seen worldwide. The main goal of this paper is to increase the awareness about CVID among health care professionals. We aim to present features which can be helpful in CVID diagnosis in order to shorten the “latency” of proper management of CVID patients. We review clinical symptoms, complications and laboratory abnormalities of CVID. Immunoglobulin replacement therapy is regarded as the cornerstone of pharmacological intervention. New modes of Ig application, mainly subcutaneously and via the hyaluronidase-facilitated subcutaneous route, help to adjust therapy to patients’ needs and preferences. Still there remain unmet needs. It remains to be seen whether CVID complications can be avoided by earlier diagnosis, treatment and thorough monitoring in the context of increased risk of malignancy. Development of patient tailored protocols depending on the clinical phenotype and risk factors might be more appropriate. The most important consideration is to diagnose suspected cases and stratify patients in a precise and timely way. Work is needed to define features predictive of unfavorable prognosis.

Clozapine-associated secondary antibody deficiency

PURPOSE OF REVIEW

Clozapine has recently been described as a novel cause of secondary antibody deficiency (SAD), associated with long-term therapy. Here we critically review the evidence linking clozapine use to an increased infection risk, describe immunological alterations, and discuss potential mechanisms.

RECENT FINDINGS

Individuals with schizophrenia are at two to five times more likely to develop pneumonia than the general population, in particular, when receiving clozapine. Delayed-onset distinguishes clozapine-associated hypogammaglobulinaemia from agranulocytosis or neutropenia that occur at lesser frequency. Biomarker searches in treatment-resistant schizophrenia highlight an immune signature associated with long-term clozapine use. This includes reduction in class-switched memory B cells, echoing common variable immunodeficiency. Recent identification of a role for dopamine in T follicular helper-B cell interactions may inform future clinical studies.

SUMMARY

The detrimental impact of the increased infection risk associated with clozapine necessitates a re-evaluation of the current monitoring strategies as well as further studies to better understand the underlying mechanisms of SAD in this setting. On the basis of available evidence, we suggest simple modifications to clozapine monitoring including integration of routine vaccination, smoking cessation, and assessment of humoral immunity. Further studies are required to understand the role of clozapine in neuroinflammation as well as other potentially autoantibody-mediated diseases.

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.

Screening for Humoral Immunodeficiency in Patients with Community-Acquired Pneumonia

BACKGROUND

Immunodeficiency is an underrecognized risk factor for infections, such as community-acquired pneumonia (CAP).

OBJECTIVE

We evaluated patients admitted with CAP for humoral immunodeficiency.

DESIGN

Prospective Cohort Study.

SETTING

Inpatients.

PATIENTS, INTERVENTION, AND MEASUREMENTS

We enrolled 100 consecutive patients admitted with a diagnosis of CAP from February 2017 to April 2017. Serum IgG, IgM, IgA, and IgE levels were obtained within the first 24 hours of admission. CURB-65 score and length of hospital stay were calculated. The Wilcoxon rank-sum test, Kruskal-Wallis test, and simple linear regression analysis were used in data analysis.

RESULTS

The prevalence of hypogammaglobinemia in patients with CAP was 38% (95% confidence interval: 28.47% to 48.25%). Twenty-seven of 100 patients had IgG hypogammaglobinemia (median: 598 mg/dL, IQ range: 459-654), 23 of 100 had IgM hypogammaglobinemia (median: 38 mg/dL, IQ range: 25-43), and 6 of 100 had IgA hypogammaglobinemia (median: 36 mg/dL, IQ range: 18-50). The median hospital length of stay for patients with IgG hypogammaglobinemia was significantly higher when compared to patients with normal IgG levels (five days, IQ range [3-10] vs three days, IQ range [2-5], P = .0085). Fourteen patients underwent further immune evaluation, resulting in one diagnosis of multiple myeloma, three patients diagnosed with specific antibody deficiency, and one patient diagnosed with selective IgA deficiency.

CONCLUSION

There is a high prevalence of hypogammaglobinemia in patients hospitalized with CAP, with IgG and IgM being the most commonly affected classes. IgG hypogammaglobinemia was associated with an increased length of hospitalization. Screening immunoglobulin levels in CAP patients may also uncover underlying humoral immunodeficiency or immunoproliferative disorders.

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.

Low immunoglobulin E flags two distinct types of immune dysregulation

During the last two decades, hyper-immunoglobulin (Ig)E syndromes have been characterized clinically and molecularly in patients with genetically determined primary immunodeficiencies. However, the detection of low IgE levels, defined here as below detection limit in the routine clinical immunology laboratory, has received little attention. We analysed the association of serum IgA, IgM and IgG levels (including IgG subclasses) with low, normal or high serum IgE levels in patients evaluated in a single-centre out-patient immunodeficiency and allergy clinic. The correlation of serum IgE levels with IgG subclasses depended on the clinical phenotype. In patients with immunodeficiencies, IgE correlated with IgG2 and IgG4 but not with IgG3. In contrast, in patients referred for signs of allergy, IgE correlated with IgG3 but not with IgG2. A low IgE result was associated with low IgG3 and IgG4 in allergy referrals, while immunodeficiency referrals with a low IgE result had significantly lower IgG1, IgG2 and IgG4 levels. Hierarchical clustering of non-IgE immunoglobulin profiles (IgM, IgA, IgG, IgG1-4) validated that non-IgE immunoglobulin levels predict the clinic referral, i.e. phenotype, of low-IgE patients. These results suggesto guide the clinical management of patients with low serum IgE levels.

Immune deficiency in chronic rhinosinusitis: screening and treatment

INTRODUCTION

Chronic rhinosinusitis (CRS) is a prevalent disease with a high annual cost of treatment. Immune deficiencies are more common in individuals with CRS and should be especially considered in those patients who are refractory to medical and surgical therapy. Areas covered: We performed a literature search in PubMed of the terms "immunodeficiency" and "sinusitis" or "rhinosinusitis" from 2006 through March 2016. All abstracts were reviewed to determine if they pertained to human disease; relevant articles were evaluated in their entirety and included in this review. Expert commentary: CRS is a common disease; in those patients with frequent exacerbations or who are refractory to treatment, an immunodeficiency evaluation should be considered. Treatment includes vaccination, antibiotic therapy, immunoglobulin replacement and surgery.