Early and prolonged intravenous immunoglobulin replacement therapy in childhood agammaglobulinemia: a retrospective survey of 31 patients

Immunoglobulin A deficiency on serological coeliac screening: an opportunity for early diagnosis of hypogammaglobulinaemia

We present a serendipitous case of clinically significant pan-hypogammaglobulinaemia, diagnosed after routine serological testing for possible coeliac disease led first to identification of IgA deficiency (discovered as a low background in IgA-based routine serological screening), and subsequently to confirmed pan-hypogammaglobulinaemia (antibody immunodeficiency). Hypogammaglobulinaemia is a relatively rare diagnosis (estimated at 1 in 36,000), in which delayed diagnosis and treatment are associated with chronic organ damage including bronchiectasis. Routine serological testing for coeliac disease using the IgA anti-tissue transglutaminase (IgA TTG) test is in widespread use and provides an opportunity for early diagnosis of hypogammaglobulinaemia. Routine serological screening for coeliac disease may uncover IgA deficiency, and we suggest that all IgA-deficient cases identified should also be checked for antibody deficiency by quantifying the other immunoglobulins (IgG, IgM).

Dosing and therapy utilization: a discussion of updates on PI treatment guidelines

Treatment decisions made in clinical practice, based on current guidelines, often conflict with decisions by third-party payors that restrict the ability of patients with primary immunodeficiency disease (PI) to adhere to appropriate treatment. This is seen by many physicians as potentially placing the health of patients at risk. Key treatment decisions challenged by third-party payors and discussed here include dosing, product safety, and routes of administration. Data on safety issues emphasize that IgG products are not generic drugs and each of the products currently licensed by the Food and Drug Administration (FDA) must be regarded as an individual therapy, given the products' different manufacturing processes and stabilizing ingredients. The issue of switching patients to a different product needs careful consideration as evidence shows that infusion-related adverse events in many patients are frequently related to this activity. Decisions regarding the route of therapy should also be individualized to the patient, weighing such factors as side effects, adherence with therapy, and lifestyle.

Higher doses of subcutaneous IgG reduce resource utilization in patients with primary immunodeficiency

The recommended dose of IgG in primary immunodeficiency (PID) has been increasing since its first use. This study aimed to determine if higher subcutaneous IgG doses resulted in improved patient outcomes by comparing results from two parallel clinical studies with similar design. One patient cohort received subcutaneous IgG doses that were 1.5 times higher than their previous intravenous doses (mean 213 mg/kg/week), whereas the other cohort received doses identical to previous subcutaneous or intravenous doses (mean 120 mg/kg/week). While neither cohort had any serious infections, the cohort maintained on higher mean IgG dose had significantly lower rates of non-serious infections (2.76 vs. 5.18 episodes/year, P < 0.0001), hospitalization (0.20 vs. 3.48 days/year, P < 0.0001), antibiotic use (48.50 vs. 72.75 days/year, P < 0.001), and missed work/school activity (2.10 vs. 8.00 days/year, P < 0.001). The higher-dose cohort had lower health care utilization and improved indices of well being compared to the cohort treated with traditional IgG doses.

Common variable immunodeficiency complicated with hemolytic uremic syndrome

Common variable immunodeficiency is a primary immunodeficiency disease characterized by reduced serum immunoglobulins and heterogeneous clinical features. Recurrent pyogenic infections of upper and lower respiratory tracts are the main clinical manifestations of common variable immunodeficiency. Hemolytic uremic syndrome is a multisystemic disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, and organ ischemia due to platelet aggregation in the arterial microvasculature. This is one of the rare cases of patients diagnosed with common variable immunodeficiency, which was complicated by hemolytic uremic syndrome.

Exogenous immunoglobulin downregulates T-cell receptor signaling and cytokine production

Intravenous immune globulin (IVIG), a polyvalent solution of pooled human immunoglobulin, is a potent immunomodulating agent. It is currently approved to treat autoimmune diseases, including idiopathic thrombocytopenia purpura, autoimmune hemolytic anemia, and Kawasaki disease. The basis of IVIG's immunomodulatory properties is not entirely understood. Proposed mechanisms include Fc receptor blockade, interference with cytokine network, and provision of anti-idiotypic antibodies. IVIG has also been shown to affect T-lymphocyte function, although a direct effect has been difficult to reconcile given the lack of immunoglobulin or Fc-receptors on T cells. Experiments were thus carried out to determine whether IVIG was acting on a specific T-cell subset and at the level of the T-cell receptor (TCR), and whether cytokine expression patterns were modulated. T lymphocytes obtained from adult peripheral blood and umbilical cord blood were cultured over a 1-wk time course in the presence of pharmacological IVIG concentrations (Gamunex(®) , 0-2.0 mg/ml). Cells were exposed to various stimulation conditions, and TCR signaling competence was assessed by quantifying activation-induced upregulation of CD25 and CD69, as well as production of specific T-cell cytokines. IVIG was found to significantly decrease T-lymphocyte proliferation, in a dose and time-dependent manner, in both cord and adult blood. IVIG markedly reduced phytohemagglutinin and anti-CD3-induced upregulation of CD25 and CD69 in both CD4 and CD8 T-cell subsets, although phorbol ester-induced responses were intact, suggesting a defect in the CD3/TCR signaling pathway. IVIG also inhibited anti-CD3-induced cytokine production of IL-10, IL-2, and IFN-γ in a dose-dependent manner. These data suggest that IVIG may have direct T-cell immunomodulatory properties by dampening TCR responses. Further studies are needed to more precisely define the molecular targets of IVIG.

Protective effect of IgM against colonization of the respiratory tract by nontypeable Haemophilus influenzae in patients with hypogammaglobulinemia

BACKGROUND

Primary immunoglobulin deficiencies lead to recurrent bacterial infections of the respiratory tract and bronchiectasis, even with adequate immunoglobulin replacement therapy. It is not known whether patients able to secrete IgM (eg, those with hyper-IgM [HIgM] syndrome) are as susceptible to these infections as patients who lack IgM production (eg, those with panhypogammaglobulinemia [PHG]).

OBJECTIVE

This study is aimed at identifying specific microbiological and clinical (infections) characteristics that distinguish immunoglobulin-substituted patients with PHG from patients with HIgM syndrome.

METHODS

A cohort of patients with HIgM syndrome (n = 25) and a cohort of patients with PHG (n = 86) were monitored prospectively for 2 years while receiving similar polyvalent immunoglobulin replacement therapies. Regular bacterial analyses of nasal swabs and sputum were performed, and clinical events were recorded. In parallel, serum and saliva IgM antibody concentrations were measured.

RESULTS

When compared with patients with PHG, patients with HIgM syndrome were found to have a significantly lower risk of nontypeable Haemophilus influenzae carriage in particular (relative risk, 0.39; 95% CI, 0.21-0.63). Moreover, patients with HIgM syndrome (including those unable to generate somatic hypermutations of immunoglobulin genes) displayed anti-nontypeable H influenzae IgM antibodies in their serum and saliva. Also, patients with HIgM syndrome had a lower incidence of acute respiratory tract infections.

CONCLUSIONS

IgM antibodies appear to be microbiologically and clinically protective and might thus attenuate the infectious consequences of a lack of production of other immunoglobulin isotypes in patients with HIgM syndrome. Polyvalent IgG replacement therapy might not fully compensate for IgM deficiency. It might thus be worth adapting long-term antimicrobial prophylactic regimens according to the underlying B-cell immunodeficiency phenotype.

Modern management of primary B-cell immunodeficiencies

B-cell defects constitute the majority of primary immunodeficiencies. Although a heterogeneous group of diseases, all are characterized by the reduction in or absence of immunoglobulins and/or specific antimicrobial antibodies. Substitution of immunoglobulin G (IgG) is therefore the mainstay of treatment. While from the late 1970s, the intravenous route of administration was the most common, in the past decades, subcutaneous immunoglobulin replacement therapy has become more popular among patients and physicians. Independently of the optimal route of administration, dosage and IgG trough level remain subjects of debate. Higher IgG trough levels seem to improve the protection against recurrent infections and thus better prevent complications such as bronchiectasis. Some patients, however, achieve protection with IgG trough levels on the lower IgG limit of healthy persons. Therefore, an individual protective IgG trough level needs to be defined for each patient. Use of additional prophylactic antibiotics and immunosuppressive drugs differs amongst specialized immunodeficiency centres and clearly requires future investigation in multi-centre trials. Haematopoietic stem cell transplantation (HSCT) is to date indicated as curative treatment in certain patients with B-cell defects associated with cell deficiencies, for example in two class-switch recombination defects and in selected severe forms of common variable immunodeficiency.

Nationwide survey of patients with primary immunodeficiency diseases in Japan

To determine the prevalence and clinical characteristics of patients with in Japan, we conducted a nationwide survey of primary immunodeficiency disease (PID) patients for the first time in 30 years. Questionnaires were sent to 1,224 pediatric departments and 1,670 internal medicine departments of Japanese hospitals. A total of 1,240 patients were registered. The estimated number of patients with PID was 2,900 with a prevalence of 2.3 per 100,000 people and homogenous regional distribution in Japan. The male-to-female ratio was 2.3:1 with a median age of 12.8 years. Adolescents or adults constituted 42.8% of the patients. A number of 25 (2.7%) and 78 (8.5%) patients developed malignant disorders and immune-related diseases, respectively, as complications of primary immunodeficiency disease. Close monitoring and appropriate management for these complications in addition to prevention of infectious diseases is important for improving the quality of life of PID patients.

Efficacy and safety of hizentra®, a new 20% immunoglobulin preparation for subcutaneous administration, in pediatric patients with primary immunodeficiency

Subcutaneous IgG treatment for primary immunodeficiencies (PI) is particularly well suited for children because it does not require venous access and is mostly free of systemic adverse events (AEs). In a prospective, open-label, multicenter, single-arm, Phase III study, 18 children and five adolescents with PI were switched from previous intravenous (IVIG) or subcutaneous (SCIG) IgG treatment to receive dose-equivalent, weekly subcutaneous infusions of Hizentra^® for 40 weeks. Mean IgG trough levels were maintained in patients previously on SCIG, or increased in those previously on IVIG, regardless of age. No serious bacterial infections were reported during the efficacy period of the study. The rates of non-serious infections were 4.77 (children) and 5.18 (adolescents) infections per patient per year. Related AEs were observed in seven children (38.9%) and two adolescents (40%). Three serious AEs and two AEs leading to discontinuation (all unrelated) were reported in children. Hizentra^® is an effective and well-tolerated treatment for pediatric patients.

TEC family kinases in health and disease--loss-of-function of BTK and ITK and the gain-of-function fusions ITK-SYK and BTK-SYK

The TEC family is ancient and constitutes the second largest family of cytoplasmic tyrosine kinases. In 1993, loss-of-function mutations in the BTK gene were reported as the cause of X-linked agammaglobulinemia. Of all the existing 90 tyrosine kinases in humans, Bruton's tyrosine kinase (BTK) is the kinase for which most mutations have been identified. These experiments of nature collectively provide a form of mutation scanning with direct implications for the several hundred endogenous signaling proteins carrying domains also found in BTK. In 2009, an inactivating mutation in the ITK gene was shown to cause susceptibility to lethal Epstein-Barr virus infection. Both kinases represent interesting targets for inhibition: in the case of BTK, as an immunosuppressant, whereas there is evidence that the inhibition of inducible T-cell kinase (ITK) could influence the infectivity of HIV and also have anti-inflammatory activity. Since 2006, several patients carrying a fusion protein, originating from a translocation joining genes encoding the kinases ITK and spleen tyrosine kinase (SYK), have been shown to develop T-cell lymphoma. We review these disease processes and also describe the role of the N-terminal pleckstrin homology-Tec homology (PH-TH) domain doublet of BTK and ITK in the downstream intracellular signaling of such fusion proteins.

Effectiveness of immunoglobulin replacement therapy on clinical outcome in patients with primary antibody deficiencies: results from a multicenter prospective cohort study

A 5-years multicenter prospective study on 201 patients with common variable immunodeficiencies and 101 patients with X-linked agammaglobulinemia over a cumulative follow-up period of 1,365 patient-years was conducted to identify prognostic markers and risk factors for associated clinical co-morbidities, the effects of long-term immunoglobulin treatment and the IgG trough level to be maintained over time required to minimise infection risk. Overall, 21% of the patients with common variable immunodeficiencies and 24% of patients with X-linked agammaglobulinemia remained infection free during the study. A reduction of pneumonia episodes has been observed after initiation of Ig replacement. During the observation time, pneumonia incidence remained low and constant over time. Patients with pneumonia did not have significant lower IgG trough levels than patients without pneumonia, with the exception of patients whose IgG trough levels were persistently <400 mg/dL. In X-linked agammaglobulinemia, the only co-morbidity risk factor identified for pneumonia by the final multivariable model was the presence of bronchiectasis. In common variable immunodeficiencies, our data allowed us to identify a clinical phenotype characterised by a high pneumonia risk: patients with low IgG and IgA levels at diagnosis; patients who had IgA level <7 mg/dL and who had bronchiectasis. The effect of therapy with immunoglobulins at replacement dosage for non-infectious co-morbidities (autoimmunity, lymphocytic hyperplasia and enteropathy) remains to be established. A unique general protective trough IgG level in antibody deficiency patients will remain undefined because of the major role played by the progression of lung disease in X-linked agammaglobulinemia and in a subset of patients with common variable immunodeficiencies.

Pharmacokinetics and safety of subcutaneous immune globulin (human), 10% caprylate/chromatography purified in patients with primary immunodeficiency disease

Subcutaneous administration of intravenous immunoglobulin G (IgG) preparations provides an additional level of patient convenience and more options for patients with poor venous access or a history of intravenous IgG reactions. An open-label, pharmacokinetic trial (n = 32) determined the non-inferiority of the subcutaneous versus intravenous route of 10% caprylate/chromatography purified human immune globulin intravenous (IGIV-C; Gamunex®) administration by comparing the steady-state area under the concentration-versus-time curve (AUC) of total plasma IgG in patients with primary immunodeficiency disease. Patients on stable IGIV-C received two intravenous infusions (administered 3 or 4 weeks apart). Seven to 10 days after the second intravenous infusion, all patients switched to a weekly infusion of subcutaneous IGIV-C, with the dose equal to 137% of the previous weekly equivalent intravenous dose, for up to 24 weeks. Samples for pharmacokinetic analysis were collected during steady state for intravenous and subcutaneous IGIV-C treatments. The AUC(0-) τ geometric least-squares mean ratio was 0·89 (90% confidence interval, 0·86-0·92) and met the criteria for non-inferiority. The overall mean steady-state trough concentration of plasma total IgG with subcutaneous IGIV-C was 11·4 mg/ml, 18·8% higher than intravenous IGIV-C (9·6 mg/ml). Subcutaneous IGIV-C was safe and well tolerated. Subcutaneous IGIV-C infusion-site reactions were generally mild/moderate and the incidence decreased over time. No serious bacterial infections were reported. Weekly subcutaneous IGIV-C infusion using 137% of the weekly equivalent intravenous immunoglobulin dose provides an AUC comparable to intravenous administration, thus allowing patients to maintain the same IgG preparation/formulation if switching between intravenous and subcutaneous infusions.

Impact of delayed diagnosis in children with primary antibody deficiencies

BACKGROUND

Primary antibody deficiencies (PADs) are heterogeneous group of disorders, characterized by hypogammaglobulinemia and increased susceptibility to recurrent infections. To evaluate the diagnostic delay in Iranian PADs in association with their infections, we scored such manifestations to find an association between such delay and the scoring system.

METHODS

Forty-eight patients with PADs, who were referred to our center during a 25-year period, were enrolled in this study. Each episode of infection, before making the PADs diagnosis, got a score of 5 or 10 based on the severity of infections.

RESULTS

The diagnosis was made with median delay of 34.5 months, when the patients had mean score of 94.48 ± 52.89. There was a significant direct association between this scoring system and delay diagnosis. The score of 50 was considered as the cutoff point in our patient group. In this score, the suspicions to PADs in more than 90% of patients true positively lead to diagnosis of PADs.

CONCLUSION

Although diagnosis delay significantly decreased over time, PADs still continue to be diagnosed late. Based on the results of this study, the assessment of immune system should be performed in the patients with 50 total score or about 25 score per year.

Adoptive transfer of syngeneic T cells transduced with a chimeric antigen receptor that recognizes murine CD19 can eradicate lymphoma and normal B cells

Adoptive T-cell therapy with anti-CD19 chimeric antigen receptor (CAR)-expressing T cells is a new approach for treating advanced B-cell malignancies. To evaluate anti-CD19-CAR-transduced T cells in a murine model of adoptive T-cell therapy, we developed a CAR that specifically recognized murine CD19. We used T cells that were retrovirally transduced with this CAR to treat mice bearing a syngeneic lymphoma that naturally expressed the self-antigen murine CD19. One infusion of anti-CD19-CAR-transduced T cells completely eliminated normal B cells from mice for at least 143 days. Anti-CD19-CAR-transduced T cells eradicated intraperitoneally injected lymphoma cells and large subcutaneous lymphoma masses. The antilymphoma efficacy of anti-CD19-CAR-transduced T cells was critically dependent on irradiation of mice before anti-CD19-CAR-transduced T-cell infusion. Anti-CD19-CAR-transduced T cells had superior antilymphoma efficacy compared with the anti-CD19 monoclonal antibody from which the anti-CD19 CAR was derived. Our results demonstrated impressive antilymphoma activity and profound destruction of normal B cells caused by anti-CD19-CAR-transduced T cells in a clinically relevant murine model.

Impact of trough IgG on pneumonia incidence in primary immunodeficiency: A meta-analysis of clinical studies

Primary immunodeficiency disease (PIDD) associated with hypogammaglobulinemia is typically treated with immunoglobulin replacement therapy. When administered as intravenous immunoglobulin (IVIG), an IgG trough occurs prior to the next replacement dose. While frequently measured, IgG trough levels required to minimize infection risk are not established. To address this question, all available studies evaluating trough IgG and pneumonia incidence in PIDD patients with hypogammaglobulinemia receiving IVIG were quantitatively combined by meta-analysis. Seventeen studies with 676 total patients and 2,127 patient-years of follow-up were included. Pneumonia incidence declined by 27% with each 100mg/dL increment in trough IgG (incidence rate ratio, 0.726; 95% confidence interval, 0.658-0.801). Pneumonia incidence with maintenance of 500 mg/dL IgG trough levels (0.113 cases per patient-year) was 5-fold that with 1000 mg/dL (0.023 cases per patient-year). This meta-analysis provides evidence that pneumonia risk can be progressively reduced by higher trough IgG levels up to at least 1000 mg/dL.

Behavior abnormality following intravenous immunoglobulin treatment in patients with primary antibody deficiencies

OBJECTIVE

Treatment with intravenous immunoglobulin (IVIG) is considered a safe therapy for patients with primary antibody deficiencies (PADs), whilst adverse effects have been frequently reported. Meantime behavioral disorders reactions have not been reported yet. In this study, we describe for the first time a group of patients with PADs, who were under IVIG therapy and experienced some behavioral disorders.

METHODS

Five patients, including two hyper IgM syndromes, one X-linked agammaglobulinemia, one common variable immunodeficiency, and one hypo IgM disease, were surveyed. Analysis of Conner's Parents Rating Scales-Revised Short (CPRS-R:S) and child behavior checklist (CBCL) was performed for the patients, suspected to hyperactivity.

RESULTS

Analysis of CPRS-R:S showed an evidence of mild hyperactivity before IVIG administration in four patients, whereas another patient had evidence of severe hyperactivity. After IVIG administration, hyperactivity scores of three patients were changed from mild hyperactive behavior to markedly hyperactive behavior or attention deficit hyperactivity disorder range of hyperactivity. In the CBCL scores, there were abnormal externalization scores for three patients; while two remaining patients had abnormal internalization scores.

CONCLUSIONS

Although predisposition to behavioral disorders can be due to a genetic background, further investigations are necessary to test the hypotheses about responsibility of either IVIG or underling disease in progression of behavioral abnormalities.

Evidence for the use of intravenous immunoglobulins--a review of the literature

Intravenous immunoglobulins (IVIg) were first introduced in the middle of the twentieth century for the treatment of primary immunodeficiencies. In 1981, Paul Imbach noticed an improvement of immune-mediated thrombocytopenia, in patients receiving IVIg for immunodeficiencies. This opened a new era for the treatment of autoimmune conditions with IVIg. Since then, IVIg has become an important treatment option in a wide spectrum of diseases, including autoimmune and acute inflammatory conditions, most of them off-label (not included in the US Food and Drug Administration recommendation). A panel of immunologists and internists with experience in IVIg therapy reviewed the medical literature for published data concerning treatment with IVIg. The quality of evidence was assessed, and a summary of the available relevant literature in each disease was given. To our knowledge, this is the first all-inclusive comprehensive review, developed to assist the clinician when considering the use of IVIg in autoimmune diseases, immune deficiencies, and other conditions.

Echocardiographic abnormalities and their correlation with bronchiectasis score in primary antibody deficiencies

BACKGROUND

Primary antibody deficiencies are characterized by defective antibody production and recurrent infections. Patients usually present with recurrent respiratory tract infections with consequent chronic pulmonary damage and bronchiectasis, which could potentially influence cardiac function. Our aim was to assess noninvasively the cardiac complications due to pulmonary disease in patients with primary antibody deficiency.

METHODS

A cross-sectional series of patients with primary antibody deficiency syndromes from our referral immunology center were recruited. Individuals undergoing high-resolution computed tomography (HRCT) and transthoracic echocardiography were reviewed.

RESULTS

Thirty primary immunodeficient patients aged 5-55 years of age (21 males and 9 females) were enrolled in this study. Half of the patients (50%) were found to have bronchiectasis in HRCT imaging. In echocardiographic examination, 20 patients (67%) had at least one abnormality; among which pulmonary hypertension was the most common (33%). Patients with bronchiectasis had higher pulmonary artery pressures and HRCT bronchiectasis score was strongly correlated with pulmonary artery pressure (regression R = 0.59, P value = 0.001).

CONCLUSION

Echocardiographic evaluation of right ventricular function and noninvasive estimation of pulmonary artery pressure could have an important diagnostic role in the follow-up and therapeutic management of patients with primary immune deficiency.

Common variable immunodeficiency: computed tomography evaluation of bronchopulmonary changes including nodular lesions in 40 patients. Correlation with clinical and immunological data

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by recurrent respiratory tract infections, mainly sustained by encapsulated bacteria, that may cause irreversible changes in the lungs.

METHODS

Forty patients with CVID were evaluated by computed tomography of the lung; 20 of these underwent computed tomographic follow-up in a 5-year period, during which immunoglobulin replacement therapy was regularly performed.

RESULTS

Pulmonary changes were present in 65% of patients; bronchiectases were present in 65.38%. The incidence of pulmonary nodules was very high (38.46%) and correlated with splenomegaly (70%) and autoimmune phenomena (80%).

CONCLUSIONS

Our study underscores the essential role of imaging, in particular computed tomography, in the identification and monitoring of pulmonary lesions in a large cohort of CVID patients, contributing at the same time to select patients more at risk to develop nodular lesions and potentially to use more appropriate therapeutic strategies.

Efficacy and safety of a new 20% immunoglobulin preparation for subcutaneous administration, IgPro20, in patients with primary immunodeficiency

Subcutaneous human IgG (SCIG) therapy in primary immunodeficiency (PID) offers sustained IgG levels throughout the dosing cycle and fewer adverse events (AEs) compared to intravenous immunoglobulin (IVIG). A phase I study showed good local tolerability of IgPro20, a new 20% liquid SCIG stabilized with L-proline. A prospective, open-label, multicenter, single-arm, phase III study evaluated the efficacy and safety of IgPro20 in patients with PID over 15 months. Forty-nine patients (5–72 years) previously treated with IVIG received weekly subcutaneous infusions of IgPro20. The mean serum IgG level was 12.5 g/L. No serious bacterial infections were reported. There were 96 nonserious infections (rate 2.76/patient per year). The rate of days missed from work/school was 2.06/patient per year, and the rate of hospitalization was 0.2/patient per year. Ninety-nine percent of AEs were mild or moderate. No serious, IgPro20-related AEs were reported. IgPro20 effectively protected patients with PID against infections and maintained serum IgG levels without causing unexpected AEs.

Evaluation of immunoglobulin levels and infection rate in patients with common variable immunodeficiency after immunoglobulin replacement therapy

BACKGROUND/PURPOSE

Common variable immunodeficiency (CVID) is characterized by decreased serum levels of IgG and increased susceptibility to recurrent infections. The aim of this study was to evaluate the IgG subclass levels of CVID patients.

METHODS

Twenty-four CVID patients who had been under regular intravenous immunoglobulin replacement therapy for 96.13 +/- 54.83 months were enrolled in this study. Serum IgG and IgG subclass levels, and clinical outcomes for these patients were evaluated after this period of treatment.

RESULTS

Mean serum IgG levels were significantly increased from 272.91 +/- 185.58 mg/dL at the time of diagnosis to 455.29 +/- 200.23 mg/dL after treatment, while there was no significant difference in the serum levels of IgM and IgA. Decreased serum levels of IgG1 were detected in 75% of the patients studied. Decreased serum levels of IgG2, IgG3 and IgG4 were also detected in 6, 11, and 11 patients, respectively. All patients experienced recurrent infectious diseases either before, or after, diagnosis.

CONCLUSION

Although serum IgG levels in the patients significantly increased after regular intravenous immunoglobulin replacement therapy, serum IgM and IgA levels remained diminished over time. Furthermore, a number of cases had low levels of IgG subclasses, in spite of normal total IgG levels, which could explain why some patients had continued infections, even after immunoglobulin replacement therapy.

Comparison of pulmonary diseases in common variable immunodeficiency and X-linked agammaglobulinaemia

Patients with CVID are at greater risk of developing lung complications than patients with XLA because of delayed diagnosis and possible immune dysregulation. Early diagnosis and appropriate treatment reduces the incidence of pulmonary infections in both groups of patients. However, CVID patients are prone to progressive lung disease despite optimal immunoglobulin therapy.

BACKGROUND AND OBJECTIVE

Pulmonary disease is the most common complication in patients with common variable immunodeficiency (CVID) or X-linked agammaglobulinaemia (XLA). Pulmonary disease may progress despite immunoglobulin replacement therapy. In this study pulmonary complications were compared in patients with CVID or XLA.

METHODS

Pulmonary complications were evaluated in 115 patients (76 with CVID and 39 with XLA) by reviewing hospital records of chest infections, pulmonary function tests and high-resolution CT scans.

RESULTS

Thirty-two patients with XLA (82%) presented with 59 episodes of pneumonia before diagnosis, whereas 15 patients (38.4%) experienced pneumonia after immunoglobulin replacement therapy (1.67 vs 0.45 episodes per patient per year). Among the CVID patients, 196 episodes of pneumonia were documented in 59 patients (77.6%) before diagnosis, while 36 patients (47.3%) experienced pneumonia after therapy (1.11 vs 0.58 episodes of pneumonia per patient per year). Forty-seven (41%) patients (38 with CVID and 9 with XLA) developed chronic lung disease. The CVID patients developed more complications, including bronchiectasis and lymphoid interstitial pneumonitis, than the XLA patients.

CONCLUSIONS

Patients with CVID had a greater likelihood of developing lung disease, possibly due to delayed diagnosis and immune dysregulation, as compared with XLA patients. Early diagnosis of patients with primary antibody deficiencies and adequate i.v. immunoglobulin replacement therapy substantially reduces the number of pulmonary infections. However, CVID patients are prone to progression of lung disease despite optimal immunoglobulin therapy because of the nature of the disease. This important issue should be addressed in further studies.

Use of intravenous immunoglobulin and adjunctive therapies in the treatment of primary immunodeficiencies: A working group report of and study by the Primary Immunodeficiency Committee of the American Academy of Allergy Asthma and Immunology

There are an expanding number of primary immunodeficiency diseases (PIDDs), each associated with unique diagnostic and therapeutic complexities. Limited data, however, exist supporting specific therapeutic interventions. Thus, a survey of PIDD management was administered to allergists/immunologists in the United States to identify current perspectives and practices. Among 405 respondents, the majority of key management practices identified were consistent with existing data and guidelines, including the provision of immunoglobulin therapy, immunoglobulin dosing and selective avoidance of live viral vaccines. Practices for which there are little specific data or evidence-based guidance were also examined, including evaluation of IgG trough levels for patients receiving immunoglobulin, use of prophylactic antibiotics and recommendations for complementary/alternative medicine. Here, variability applied to PIDD patients was identified. Differences between practitioners clinically focused upon PIDD and general allergists/immunologists were also identified. Thus, a need for expanded clinical research in PIDD to optimize management and potentially improve outcomes was defined.

Pathogenesis, diagnosis, and management of primary antibody deficiencies and infections

Primary antibody deficiencies are the most common primary immunodeficiency diseases. They are a heterogeneous group of disorders with various degrees of dysfunctional antibody production resulting from a disruption of B-cell differentiation at different stages. While there has been tremendous recent progress in the understanding of some of these disorders, the etiology remains unknown for the majority of patients. As there is a large spectrum of underlying defects, the age at presentation varies widely, and the clinical manifestations range from an almost complete absence of B cells and serum immunoglobulins to selectively impaired antibody responses to specific antigens with normal total serum immunoglobulin concentrations. However, all of these disorders share an increased susceptibility to infections, affecting predominantly the respiratory tract. A delay of appropriate treatment for some diseases can result in serious complications related to infections, while timely diagnosis and adequate therapy can significantly decrease morbidity and increase life expectancy and quality of life.

Lung disease, antibodies and other unresolved issues in immune globulin therapy for antibody deficiency

Defects of antibody production are the most common of the primary immune defects of man. While these defects have been described in clinical terms for more than five decades, in most cases, the pathogenesis is still poorly understood. The most common clinically important of these is common variable immune deficiency. However there is no strict definition of this defect and the criteria for initiating immune globulin therapy are not standardized, leading to wide variation in treatment practices. In addition there has been no clear means to adequate assess progression of lung disease or elucidate the causes of progressive pulmonary inflammation found in some subjects. Moreover, there are still questions such as what are the best predictors of chronic lung disease and how can we prevent this disorder. Other complications such as autoimmunity, granulomatous disease, gastrointestinal inflation, are similarly poorly understood although treatment with various biological agents has been used with some success. A few bio-markers for assessing clinical and immunologic status have been proposed, and some have proved to be useful, but additional methods to gauge the benefits of therapy, predict outcomes, and harmonize treatment practices are needed. Aside from Ig replacement, additional means of prevention of lung disease may need consideration to reduce lung damage apart from prophylactic antibiotics. These might include using macrolides as anti-inflammatory agents, inhaled corticosteroids, bronchodilators, mucolytics or mechanical or rehabilitative respiratory methods.

Identification of target antigens of self-reactive IgG in intravenous immunoglobulin preparations

Intravenous immunoglobulin (IVIg) contains a wide range of self-reactive immunoglobulins (Ig) G. Acidic pH is known to increase the reactivity of purified IgG with self-antigens. We describe here the target antigens of IgG autoantibodies in IVIg and analyze the influence of acidic pH on IgG reactivities. We used 2-DE and immunoblotting with protein extracts of human umbilical vein endothelial cells (HUVEC) and HEp-2 cells. Two IVIg preparations obtained by ethanol fractionation [one with an acidic pH step (acidic-IVIg) and one with beta-propiolactone (propiolactone-IVIg)] and a pool of sera from 12 healthy individuals were tested. Serum IgG of 3 healthy individuals and IgG purified from the same sera with elution at pH 2.8 were also tested individually. Finally, propiolactone-IVIg was acidified at pH 2.8. IgG obtained with a step at low pH recognized many more target spots than IgG obtained without acidic pH. Our findings demonstrate that an acidic pH step artificially enlarges the repertoire of self-reactive IgG. Thus, protein spots recognized by IgG in propiolactone-IVIg represent the core set of self-antigens targeted by IVIg. Overall, 96 proteins were identified by MS. Fourteen were recognized in both extracts including glycolysis proteins such as alpha-enolase, RNA processing and cytoskeletal proteins such as lamin-A/C.

Bronchiectasis secondary to primary immunodeficiency in children: longitudinal changes in structure and function

BACKGROUND

Primary immunodeficiency is a common cause of bronchiectasis in children. The term bronchiectasis suggests an irreversible process; however, disease progression following treatment is controversial. The aim of this study was to evaluate the progression of bronchiectasis in children with primary immunodeficiency after institution of treatment.

METHODS

A retrospective review of case notes of children with primary immunodeficiency was undertaken to identify patients with confirmed bronchiectasis. Children who had two high-resolution computed tomography scans of the chest (HRCT chest) with an interval of at least 2 years were identified. The HRCT-chest scans at diagnosis and follow up were scored using a Bhalla score. Spirometry results (FEV1, FVC, and FEV1:FVC ratios) were related to HRCT-chest scores, where available. Statistical analysis was by Wilcoxon signed rank test and Spearman's rank order correlation.

RESULTS

Eighteen subjects were studied. The diagnosis of primary immunodeficiency was established at median (range) age 3.4 (1-13) years, and bronchiectasis at 9.3 (3.1-13.8) years. There was no significant difference between baseline and follow-up median (range) HRCT-chest scores (6 [1-13] and 7.5 [0-15], P = 0.21) respectively. The follow-up FEV1 and FVC percent predicted median (range) were significantly higher than baseline (86% [49-124%] vs. 75% [36-93%], P < 0.005, and 86% [47-112%] vs. 78% [31-96%], P < 0.05), respectively; there was no significant difference between baseline and follow-up FEV(1):FVC ratios. There was no significant correlation between HRCT-chest score changes and FEV1 or FVC changes.

CONCLUSIONS

Bronchiectasis secondary to primary immunodeficiency in childhood is not always a progressive condition, suggesting a potential to slow or prevent disease progression with appropriate treatment.

Common variable immunodeficiency: etiological and treatment issues

One of the great advances in clinical medicine was the recognition of the pleomorphism of the immune response and the multiple afferent and efferent limbs of antigen processing and responsiveness. A significant contribution to this understanding was derived from studies of human immunodeficiency states, including both inherited and acquired syndromes. Amongst these syndromes, one of the most common, and least understood, is common variable immune deficiency (CVID). CVID is a syndrome that leads to a reduction in serum immunoglobulins and complications including recurrent infections. Management includes immunoglobulin replacement therapy; however, patients with CVID are at risk for complications of exogenous immunoglobulin administration as well as CVID-associated diseases such as autoimmune processes and malignancies. To assess the current state of knowledge in the field, we performed a literature review of a total of 753 publications covering the period of 1968 until 2008. From this list, 189 publications were selected for discussion. In this review, we demonstrate that while the molecular basis of CVID in many cases remains incompletely understood, significant strides have been made and it is now clear that there is involvement of several pathways of immune activation, with contributions from both T and B cells. Furthermore, despite the current gaps in our knowledge of the molecular pathogenesis of the syndrome, there have been dramatic advances in management that have led to improved survival and significantly reduced morbidity in affected patients.

Update in understanding common variable immunodeficiency disorders (CVIDs) and the management of patients with these conditions

The common variable immunodeficiency disorders are a mixed group of heterogeneous conditions linked by lack of immunoglobulin production and primary antibody failure. This variability results in difficulty in making coherent sense of either immunopathogenesis or the role of various genetic abnormalities reported in the literature. The recent attempt to collate the varied complications in these conditions and to define particular clinical phenotypes has improved our understanding of these diseases. Once refined and confirmed by other studies, these definitions will facilitate improved accuracy of prognosis and better management of clinical complication. They may also provide a method of analysing outcomes as related to new immunopathological and genetic findings.

History of immunoglobulin replacement

The provision of antibodies to prevent and treat infection began with the application of "curative serum" in the first years of the last century. After the process of large-scale plasma fractionation was developed in the 1940s, the general use of immunoglobulin expanded. Intravenous immunoglobulin products became available in the 1970s, and their only use for the provision of antibodies governed the opinion of experts over the next decade. Modulation of inflammation and immunosuppression were introduced in treatment of inflammatory and autoimmune diseases and became accepted indications. The history of adverse events of treatment and their management are outlined in this article. Consensus indications and evidence-based off-label uses are discussed.

Clinical immunology review series: An approach to the management of pulmonary disease in primary antibody deficiency

The sinopulmonary tract is the major site of infection in patients with primary antibody deficiency syndromes, and structural lung damage arising from repeated sepsis is a major determinant of morbidity and mortality. Patients with common variable immunodeficiency may, in addition, develop inflammatory lung disease, often associated with multi-system granulomatous disease. This review discusses the presentation and management of lung disease in patients with primary antibody deficiency.

Primary antibody deficiency syndromes

The primary antibody deficiency syndromes are a group of rare disorders characterized by an inability to produce clinically effective immunoglobulin responses. Some of these disorders result from genetic mutations in genes involved in B cell development, whereas others appear to be complex polygenic disorders. They most commonly present with recurrent infections due to encapsulated bacteria, although in the most common antibody deficiency, Common Variable Immunodeficiency, systemic and organ-specific autoimmunity can be a presenting feature. Diagnostic delay in this group of disorders remains a problem, and the laboratory has a vital role in the detection of abnormalities in immunoglobulin concentration and function. It is critical to distinguish this group of disorders from secondary causes of hypogammaglobulinaemia, in particular lymphoid malignancy, and appropriate laboratory investigations are of critical importance. Treatment of primary antibody deficiencies involves immunoglobulin replacement therapy, either via the intravenous or subcutaneous route. Patients remain at risk of a wide variety of complications, not all linked to diagnostic delay and inadequate therapy. In common variable immunodeficiency (CVID) in particular, patients remain at significantly increased risk of lymphoid malignancy, and regular clinical and laboratory monitoring is required. This review aims to give an overview of these conditions for the general reader, covering pathogenesis, clinical presentation, laboratory investigation, therapy and clinical management.

Immunoglobulin replacement therapy in children

The benefit of immunoglobulin (IG) replacement in primary antibody deficiencies is unquestionable. Many of these congenital disorders present early in life and this therapy is often first implemented in the young. This article focuses on the indications of IG replacement in children, with an emphasis on the specific diagnostic problems encountered in this population. Also presented is an overview of the practical aspects of IG administration in the pediatric setting, including the recognition and management of adverse reactions. Finally, the advent of subcutaneous IG, a therapeutic IG modality with the potential to have a great impact on the quality of life of children with antibody deficiencies and their families, is discussed.

Adults with X-linked agammaglobulinemia: impact of disease on daily lives, quality of life, educational and socioeconomic status, knowledge of inheritance, and reproductive attitudes

Since many children with X-linked agammaglobulinemia (XLA) can now be expected to reach adulthood, knowledge of the status of adults with XLA would be of importance to the patients, their families, and the physicians caring for these patients. We performed the current study in adults with XLA to examine the impact of XLA on their daily lives and quality of life, their educational and socioeconomic status, their knowledge of the inheritance of their disorder, and their reproductive attitudes. Physicians who had entered adult patients with XLA in a national registry were asked to pass on a survey instrument to their patients. The patients then filled out the survey instrument and returned it directly to the investigators. Adults with XLA were hospitalized more frequently and missed more work and/or school than did the general United States population. However, their quality of life was comparable to that of the general United States population. They achieved a higher level of education and had a higher income than did the general United States population. Their knowledge of the inheritance of their disease was excellent. Sixty percent of them would not exercise any reproductive planning options as a result of their disease. The results of the current study suggest that although the disease impacts the daily lives of adults with XLA, they still become productive members of society and excel in many areas.

Common variable immunodeficiency: a new look at an old disease

Primary immunodeficiencies comprise many diseases caused by genetic defects primarily affecting the immune system. About 150 such diseases have been identified with more than 120 associated genetic defects. Although primary immunodeficiencies are quite rare in incidence, the prevalence can range from one in 500 to one in 500 000 in the general population, depending on the diagnostic skills and medical resources available in different countries. Common variable immunodeficiency (CVID) is the primary immunodeficiency most commonly encountered in clinical practice, and appropriate diagnosis and management of patients will have a significant effect on morbidity and mortality as well as financial aspects of health care. Advances in diagnostic laboratory methods, including B-cell subset analysis and genetic testing, coupled with new insights into the molecular basis of immune dysfunction in some patients with CVID, have enabled advances in the clinical classification of this heterogeneous disease.