Did the UK's public health shielding policy protect the clinically extremely vulnerable during the COVID-19 pandemic in Wales? Results of EVITE Immunity, a linked data retrospective study

INTRODUCTION

The UK shielding policy intended to protect people at the highest risk of harm from COVID-19 infection. We aimed to describe intervention effects in Wales at 1 year.

METHODS

Retrospective comparison of linked demographic and clinical data for cohorts comprising people identified for shielding from 23 March to 21 May 2020; and the rest of the population. Health records were extracted with event dates between 23 March 2020 and 22 March 2021 for the comparator cohort and from the date of inclusion until 1 year later for the shielded cohort.

RESULTS

The shielded cohort included 117,415 people, with 3,086,385 in the comparator cohort. The largest clinical categories in the shielded cohort were severe respiratory condition (35.5%), immunosuppressive therapy (25.9%) and cancer (18.6%). People in the shielded cohort were more likely to be female, aged ≥50 years, living in relatively deprived areas, care home residents and frail. The proportion of people tested for COVID-19 was higher in the shielded cohort (odds ratio [OR] 1.616; 95% confidence interval [CI] 1.597-1.637), with lower positivity rate incident rate ratios 0.716 (95% CI 0.697-0.736). The known infection rate was higher in the shielded cohort (5.9% vs 5.7%). People in the shielded cohort were more likely to die (OR 3.683; 95% CI: 3.583-3.786), have a critical care admission (OR 3.339; 95% CI: 3.111-3.583), hospital emergency admission (OR 2.883; 95% CI: 2.837-2.930), emergency department attendance (OR 1.893; 95% CI: 1.867-1.919) and common mental disorder (OR 1.762; 95% CI: 1.735-1.789).

CONCLUSION

Deaths and healthcare utilisation were higher amongst shielded people than the general population, as would be expected in the sicker population. Differences in testing rates, deprivation and pre-existing health are potential confounders; however, lack of clear impact on infection rates raises questions about the success of shielding and indicates that further research is required to fully evaluate this national policy intervention.

British Society for Immunology and United Kingdom Primary Immunodeficiency Network (UKPIN) consensus guideline for the management of immunoglobulin replacement therapy

Currently, there is no guideline to support the use of immunoglobulin replacement therapy (IgRT) in primary and secondary immunodeficiency disorders in UK. The UK Primary Immunodeficiency Network (UK-PIN) and the British Society of Immunology (BSI) joined forces to address this need. Given the paucity of evidence, a modified Delphi approach was used covering statements for the initiation, monitoring, discontinuation of IgRT as well as home therapy programme. A group of six consultant immunologists and three nurse specialists created the statements, reviewed responses and feedback and agreed on final recommendations. This guideline includes 22 statements for initiation, 22 statements for monitoring, 11 statement for home therapy, and 19 statements for discontinuation of IgRT. Further areas of research are proposed to improve future delivery of care.

The United Kingdom Primary Immune Deficiency (UKPID) registry 2012 to 2017

This is the second report of the United Kingdom Primary Immunodeficiency (UKPID) registry. The registry will be a decade old in 2018 and, as of August 2017, had recruited 4758 patients encompassing 97% of immunology centres within the United Kingdom. This represents a doubling of recruitment into the registry since we reported on 2229 patients included in our first report of 2013. Minimum PID prevalence in the United Kingdom is currently 5·90/100 000 and an average incidence of PID between 1980 and 2000 of 7·6 cases per 100 000 UK live births. Data are presented on the frequency of diseases recorded, disease prevalence, diagnostic delay and treatment modality, including haematopoietic stem cell transplantation (HSCT) and gene therapy. The registry provides valuable information to clinicians, researchers, service commissioners and industry alike on PID within the United Kingdom, which may not otherwise be available without the existence of a well-established registry.

British Society for Immunology/United Kingdom Primary Immunodeficiency Network consensus statement on managing non-infectious complications of common variable immunodeficiency disorders

Common variable immunodeficiency (CVID) represents a heterogeneous group of rare disorders. There is considerable morbidity and mortality as a result of non-infectious complications, and this presents clinicians with management challenges. Clinical guidelines to support the management of CVID are urgently required. The UK Primary Immunodeficiency Network and the British Society for Immunology funded a joint project to address this. A modified Delphi Survey was conducted for the assessment, diagnosis and treatment of the non-infectious blood, respiratory, gut and liver complications of CVID. A steering group of 10 consultant immunologists and one nurse specialist developed and reviewed the survey statements and agreed the final recommendations. In total, 22 recommendations and three areas for research were developed.

Clinical and laboratory features of seventy-eight UK patients with Good's syndrome (thymoma and hypogammaglobulinaemia)

Good’s syndrome (thymoma and hypogammaglobulinaemia) is a rare secondary immunodeficiency disease, previously reported in the published literature as mainly individual cases or small case series. We use the national UK‐Primary Immune Deficiency (UKPID) registry to identify a large cohort of patients in the UK with this PID to review its clinical course, natural history and prognosis. Clinical information, laboratory data, treatment and outcome were collated and analysed. Seventy‐eight patients with a median age of 64 years, 59% of whom were female, were reviewed. Median age of presentation was 54 years. Absolute B cell numbers and serum immunoglobulins were very low in all patients and all received immunoglobulin replacement therapy. All patients had undergone thymectomy and nine (12%) had thymic carcinoma (four locally invasive and five had disseminated disease) requiring adjuvant radiotherapy and/or chemotherapy. CD4 T cells were significantly lower in these patients with malignant thymoma. Seventy‐four (95%) presented with infections, 35 (45%) had bronchiectasis, seven (9%) chronic sinusitis, but only eight (10%) had serious invasive fungal or viral infections. Patients with AB‐type thymomas were more likely to have bronchiectasis. Twenty (26%) suffered from autoimmune diseases (pure red cell aplasia, hypothyroidism, arthritis, myasthenia gravis, systemic lupus erythematosus, Sjögren’s syndrome). There was no association between thymoma type and autoimmunity. Seven (9%) patients had died. Good’s syndrome is associated with significant morbidity relating to infectious and autoimmune complications. Prospective studies are required to understand why some patients with thymoma develop persistent hypogammaglobulinaemia.

Chronic norovirus infection in primary immune deficiency disorders: an international case series

OBJECTIVE

Predictive factors associated with clinical outcomes of chronic norovirus infection (CNI) in primary immunodeficiency diseases (PIDD) are lacking.

METHOD

We sought to characterize CNI using a multi-institutional cohort of patients with PIDD and CNI using the Clinical Immunology Society's CIS-PIDD Listserv e-mail group.

RESULTS

Thirty-four subjects (21 males and 13 females) were reported from centers across North America, Europe, and Asia. All subjects were receiving high doses (median IgG dose: 1200 mg/kg/month) of supplemental immunoglobulin therapy. Fifty-three percent had a complete absence of B cells (median B-cell count 0; range 0-139 cells/μL). Common Variable Immune Deficiency (CVID) subjects manifested a unique phenotype with B-cell lymphopenia, non O+ blood type, and villous atrophy (logistic regression model, P = 0.01). Five subjects died, all of whom had no evidence of villous atrophy.

CONCLUSION

While Norovirus (NoV) is thought to replicate in B cells, in this PIDD cohort of CNI, B-cell lymphopenia was common, indicating that the presence of B lymphocytes is not essential for CNI.

Secondary antibody deficiency: a complication of anti-CD20 therapy for neuroinflammation

B-cell depleting anti-CD20 monoclonal antibody therapies are being increasingly used as long-term maintenance therapy for neuroinflammatory disease compared to many non-neurological diseases where they are used as remission-inducing agents. While hypogammaglobulinaemia is known to occur in over half of patients treated with medium to long-term B-cell-depleting therapy (in our cohort IgG 38, IgM 56 and IgA 18%), the risk of infections it poses seems to be under-recognised. Here, we report five cases of serious infections associated with hypogammaglobulinaemia occurring in patients receiving rituximab for neuromyelitis optica spectrum disorders. Sixty-four per cent of the whole cohort of patients studied had hypogammaglobulinemia. We discuss the implications of these cases to the wider use of anti-CD20 therapy in neuroinflammatory disease.

Measurement of Typhi Vi antibodies can be used to assess adaptive immunity in patients with immunodeficiency

Vaccine‐specific antibody responses are essential in the diagnosis of antibody deficiencies. Responses to Pneumovax II are used to assess the response to polysaccharide antigens, but interpretation may be complicated. Typhim Vi^®, a polysaccharide vaccine for Salmonella typhoid fever, may be an additional option for assessing humoral responses in patients suspected of having an immunodeficiency. Here we report a UK multi‐centre study describing the analytical and clinical performance of a Typhi Vi immunoglobulin (Ig)G enzyme‐linked immunosorbent assay (ELISA) calibrated to an affinity‐purified Typhi Vi IgG preparation. Intra‐ and interassay imprecision was low and the assay was linear, between 7·4 and 574 U/ml (slope = 0·99–1·00; R² > 0·99); 71% of blood donors had undetectable Typhi Vi IgG antibody concentrations. Of those with antibody concentrations  > 7·4 U/ml, the concentration range was 7·7–167 U/ml. In antibody‐deficient patients receiving antibody replacement therapy the median Typhi Vi IgG antibody concentrations were  < 25 U/ml. In vaccinated normal healthy volunteers, the median concentration post‐vaccination was 107 U/ml (range 31–542 U/ml). Eight of eight patients (100%) had post‐vaccination concentration increases of at least threefold and six of eight (75%) of at least 10‐fold. In an antibody‐deficient population (n = 23), only 30% had post‐vaccination concentration increases of at least threefold and 10% of at least 10‐fold. The antibody responses to Pneumovax II and Typhim Vi^® correlated. We conclude that IgG responses to Typhim Vi^® vaccination can be measured using the VaccZyme Salmonella typhi Vi IgG ELISA, and that measurement of these antibodies maybe a useful additional test to accompany Pneumovax II responses for the assessment of antibody deficiencies.

Screening protocols to monitor respiratory status in primary immunodeficiency disease: findings from a European survey and subclinical infection working group

Many patients with primary immunodeficiency (PID) who have antibody deficiency develop progressive lung disease due to underlying subclinical infection and inflammation. To understand how these patients are monitored we conducted a retrospective survey based on patient records of 13 PID centres across Europe, regarding the care of 1061 adult and 178 paediatric patients with PID on immunoglobulin (Ig) G replacement. The most common diagnosis was common variable immunodeficiency in adults (75%) and hypogammaglobulinaemia in children (39%). The frequency of clinic visits varied both within and between centres: every 1-12 months for adult patients and every 3-6 months for paediatric patients. Patients diagnosed with lung diseases were more likely to receive pharmaceutical therapies and received a wider range of therapies than patients without lung disease. Variation existed between centres in the frequency with which some clinical and laboratory monitoring tests are performed, including exercise tests, laboratory testing for IgG subclass levels and specific antibodies, and lung function tests such as spirometry. Some tests were carried out more frequently in adults than in children, probably due to difficulties conducting these tests in younger children. The percentage of patients seen regularly by a chest physician, or who had microbiology tests performed following chest and sinus exacerbations, also varied widely between centres. Our survey revealed a great deal of variation across Europe in how frequently patients with PID visit the clinic and how frequently some monitoring tests are carried out. These results highlight the urgent need for consensus guidelines on how to monitor lung complications in PID patients.

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.

FDG PET-CT imaging of therapeutic response in granulomatous lymphocytic interstitial lung disease (GLILD) in common variable immunodeficiency (CVID)

Common variable immunodeficiency (CVID) is the most common severe adult primary immunodeficiency and is characterized by a failure to produce antibodies leading to recurrent predominantly sinopulmonary infections. Improvements in the prevention and treatment of infection with immunoglobulin replacement and antibiotics have resulted in malignancy, autoimmune, inflammatory and lymphoproliferative disorders emerging as major clinical challenges in the management of patients who have CVID. In a proportion of CVID patients, inflammation manifests as granulomas that frequently involve the lungs, lymph nodes, spleen and liver and may affect almost any organ. Granulomatous lymphocytic interstitial lung disease (GLILD) is associated with a worse outcome. Its underlying pathogenic mechanisms are poorly understood and there is limited evidence to inform how best to monitor, treat or select patients to treat. We describe the use of combined 2-[(18)F]-fluoro-2-deoxy-d-glucose positron emission tomography and computed tomography (FDG PET-CT) scanning for the assessment and monitoring of response to treatment in a patient with GLILD. This enabled a synergistic combination of functional and anatomical imaging in GLILD and demonstrated a widespread and high level of metabolic activity in the lungs and lymph nodes. Following treatment with rituximab and mycophenolate there was almost complete resolution of the previously identified high metabolic activity alongside significant normalization in lymph node size and lung architecture. The results support the view that GLILD represents one facet of a multi-systemic metabolically highly active lymphoproliferative disorder and suggests potential utility of this imaging modality in this subset of patients with CVID.

Efficacy, safety, tolerability and pharmacokinetics of a novel human immune globulin subcutaneous, 20%: a Phase 2/3 study in Europe in patients with primary immunodeficiencies

A highly concentrated (20%) immunoglobulin (Ig)G preparation for subcutaneous administration (IGSC 20%), would offer a new option for antibody replacement therapy in patients with primary immunodeficiency diseases (PIDD). The efficacy, safety, tolerability and pharmacokinetics of IGSC 20% were evaluated in a prospective trial in Europe in 49 patients with PIDD aged 2–67 years. Over a median of 358 days, patients received 2349 IGSC 20% infusions at monthly doses equivalent to those administered for previous intravenous or subcutaneous IgG treatment. The rate of validated acute bacterial infections (VASBIs) was significantly lower than 1 per year (0·022/patient‐year, P < 0·0001); the rate of all infections was 4·38/patient‐year. Median trough IgG concentrations were ≥ 8 g/l. There was no serious adverse event (AE) deemed related to IGSC 20% treatment; related non‐serious AEs occurred at a rate of 0·101 event/infusion. The incidence of local related AEs was 0·069 event/infusion (0·036 event/infusion, when excluding a 13‐year‐old patient who reported 79 of 162 total related local AEs). The incidence of related systemic AEs was 0·032 event/infusion. Most related AEs were mild, none were severe. For 64·6% of patients and in 94·8% of IGSC 20% infusions, no local related AE occurred. The median infusion duration was 0·95 (range = 0·3‐4·1) h using mainly one to two administration sites [median = 2 sites (range = 1–5)]. Almost all infusions (99·8%) were administered without interruption/stopping or rate reduction. These results demonstrate that IGSC 20% provides an effective and well‐tolerated therapy for patients previously on intravenous or subcutaneous treatment, without the need for dose adjustment.

European Guidelines (S1) on the use of high-dose intravenous immunoglobulin in dermatology

BACKGROUND

The treatment of severe dermatological autoimmune diseases and toxic epidermal necrolysis (TEN) with high-dose intravenous immunoglobulin (IVIg) is a well-established procedure in dermatology. As treatment with IVIg is usually considered for rare clinical entities or severe clinical cases, the use of immunoglobulin is not generally based on data from randomized controlled trials that are usually required for the practice of evidence-based medicine. Owing to the rarity of the indications for the use of IVIg, it is also unlikely that such studies will be available in the foreseeable future. Because the high costs of IVIg treatment also limit its first-line use, the first clinical guidelines on its use in dermatological conditions were established in 2008 and renewed in 2011.

MATERIALS AND METHODS

The European guidelines presented here were prepared by a panel of experts nominated by the EDF and the EADV. The guidelines were developed to update the indications for treatment currently considered as effective and to summarize the evidence base for the use of IVIg in dermatological autoimmune diseases and TEN.

RESULTS AND CONCLUSION

The current guidelines represent consensual expert opinions and definitions on the use of IVIg reflecting current published evidence and are intended to serve as a decision-making tool for the use of IVIg in dermatological diseases.

Clinical and laboratory correlates of lung disease and cancer in adults with idiopathic hypogammaglobulinaemia

Idiopathic hypogammaglobulinaemia, including common variable immune deficiency (CVID), has a heterogeneous clinical phenotype. This study used data from the national UK Primary Immune Deficiency (UKPID) registry to examine factors associated with adverse outcomes, particularly lung damage and malignancy. A total of 801 adults labelled with idiopathic hypogammaglobulinaemia and CVID aged 18-96 years from 10 UK cities were recruited using the UKPID registry database. Clinical and laboratory data (leucocyte numbers and serum immunoglobulin concentrations) were collated and analysed using uni- and multivariate statistics. Low serum immunoglobulin (Ig)G pre-immunoglobulin replacement therapy was the key factor associated with lower respiratory tract infections (LRTI) and history of LRTI was the main factor associated with bronchiectasis. History of overt LRTI was also associated with a significantly shorter delay in diagnosis and commencing immunoglobulin replacement therapy [5 (range 1-13 years) versus 9 (range 2-24) years]. Patients with bronchiectasis started immunoglobulin replacement therapy significantly later than those without this complication [7 (range 2-22) years versus 5 (range 1-13) years]. Patients with a history of LRTI had higher serum IgG concentrations on therapy and were twice as likely to be on prophylactic antibiotics. Ensuring prompt commencement of immunoglobulin therapy in patients with idiopathic hypogammaglobulinaemia is likely to help prevent LRTI and subsequent bronchiectasis. Cancer was the only factor associated with mortality. Overt cancer, both haematological and non-haematological, was associated with significantly lower absolute CD8(+) T cell but not natural killer (NK) cell numbers, raising the question as to what extent immune senescence, particularly of CD8(+) T cells, might contribute to the increased risk of cancers as individuals age.

Evaluation of a novel automated allergy microarray platform compared with three other allergy test methods

Microarray platforms, enabling simultaneous measurement of many allergens with a small serum sample, are potentially powerful tools in allergy diagnostics. We report here the first study comparing a fully automated microarray system, the Microtest allergy system, with a manual microarray platform, Immuno-Solid phase Allergen Chip (ISAC), and two well-established singleplex allergy tests, skin prick test (SPT) and ImmunoCAP, all tested on the same patients. One hundred and three adult allergic patients attending the allergy clinic were included into the study. All patients were tested with four allergy test methods (SPT, ImmunoCAP, Microtest and ISAC 112) and a total of 3485 pairwise test results were analysed and compared. The four methods showed comparable results with a positive/negative agreement of 81-88% for any pair of test methods compared, which is in line with data in the literature. The most prevalent allergens (cat, dog, mite, timothy, birch and peanut) and their individual allergen components revealed an agreement between methods with correlation coefficients between 0·73 and 0·95. All four methods revealed deviating individual patient results for a minority of patients. These results indicate that microarray platforms are efficient and useful tools to characterize the specific immunoglobulin (Ig)E profile of allergic patients using a small volume of serum sample. The results produced by the Microtest system were in agreement with diagnostic tests in current use. Further data collection and evaluation are needed for other populations, geographical regions and allergens.

[Recurrent meningitis and inherited complement deficiency]

Complement deficiency represents 5% of primary immunodeficiencies worldwide. A total of seven patients with deficiencies of the classical complement pathway were reported in the Czech Republic by the end of 2015. Typical manifestations of complement deficiency are recurrent meningitis, other bacterial infections, autoimmunity and kidney disease.Two case reports are presented of patients with molecularly confirmed C7 (compound heterozygote, c.663_644del in exon 6 and c.2350+2T:>C in intron 16) and C8 (homozygous c.1282C>T in exon 9) deficiency. The first patient had four attacks of meningococcal meningitis and an episode of pneumonia of unknown aetiology in childhood. The second had six attacks of meningitis. He also suffered from recurrent infections (otitis media, tonsillitis, chronic mucopurulent rhinitis and subsequent pansinusitis complicated by nasal polyposis) since childhood. No autoimmune disease was documented in either patient. They both received meningococcal and pneumococcal vaccines. Antibiotic prophylaxis was used only in the second patient, leading to a decline in the number of ENT infections.Complement deficiency should be suspected in patients with recurrent meningococcal infections, especially if combined with other infections caused by encapsulated bacteria or autoimmunity diseases. Prophylaxis with conjugate polysaccharide vaccines is recommended and antibiotic prophylaxis should be considered in individual cases.

Facilitated subcutaneous immunoglobulin (fSCIg) therapy--practical considerations

There is an increasing range of therapeutic options for primary antibody-deficient patients who require replacement immunoglobulin. These include intravenous immunoglobulin (IVIg), subcutaneous immunoglobulin (SCIg), rapid push SCIg and most recently recombinant human hyaluronidase-facilitated SCIg (fSCIg). Advantages of fSCIg include fewer needle punctures, longer infusion intervals and an improved adverse effect profile relative to IVIg. Limited real-life experience exists concerning the practical aspects of switching or starting patients on fSCIg. We describe the first 14 patients who have been treated with fSCIg at the Immunodeficiency Centre for Wales (ICW), representing more than 6 patient-years of experience. The regimen was well tolerated, with high levels of satisfaction and no increase in training requirement, including for a treatment-naive patient. Two patients discontinued fSCIg due to pain and swelling at the infusion site, and one paused therapy following post-infusion migraines. Ultrasound imaging of paired conventional and facilitated SCIg demonstrated clear differences in subcutaneous space distribution associated with a 10-fold increase in rate and volume delivery with fSCIg. Patient profiles for those choosing fSCIg fell into two main categories: those experiencing clinical problems with their current treatment and those seeking greater convenience and flexibility. When introducing fSCIg, consideration of the type and programming of infusion pump, needle gauge and length, infusion site, up-dosing schedule, home training and patient information are important, as these may differ from conventional SCIg. This paper provides guidance on practical aspects of the administration, training and outcomes to help inform decision-making for this new treatment modality.

C1 inhibitor deficiency: 2014 United Kingdom consensus document

C1 inhibitor deficiency is a rare disorder manifesting with recurrent attacks of disabling and potentially life-threatening angioedema. Here we present an updated 2014 United Kingdom consensus document for the management of C1 inhibitor-deficient patients, representing a joint venture between the United Kingdom Primary Immunodeficiency Network and Hereditary Angioedema UK. To develop the consensus, we assembled a multi-disciplinary steering group of clinicians, nurses and a patient representative. This steering group first met in 2012, developing a total of 48 recommendations across 11 themes. The statements were distributed to relevant clinicians and a representative group of patients to be scored for agreement on a Likert scale. All 48 statements achieved a high degree of consensus, indicating strong alignment of opinion. The recommendations have evolved significantly since the 2005 document, with particularly notable developments including an improved evidence base to guide dosing and indications for acute treatment, greater emphasis on home therapy for acute attacks and a strong focus on service organization.

Current treatment options with immunoglobulin G for the individualization of care in patients with primary immunodeficiency disease

Primary antibody deficiencies require lifelong replacement therapy with immunoglobulin (Ig)G to reduce the incidence and severity of infections. Both subcutaneous and intravenous routes of administering IgG can be effective and well tolerated. Treatment regimens can be individualized to provide optimal medical and quality-of-life outcomes in infants, children, adults and elderly people. Frequency, dose, route of administration, home or infusion-centre administration, and the use of self- or health-professional-administered infusion can be tailored to suit individual patient needs and circumstances. Patient education is needed to understand the disease and the importance of continuous therapy. Both the subcutaneous and intravenous routes have advantages and disadvantages, which should be considered in selecting each patient's treatment regimen. The subcutaneous route is attractive to many patients because of a reduced incidence of systemic adverse events, flexibility in scheduling and its comparative ease of administration, at home or in a clinic. Self-infusion regimens, however, require independence and self-reliance, good compliance on the part of the patient/parent and the confidence of the physician and the nurse. Intravenous administration in a clinic setting may be more appropriate in patients with reduced manual dexterity, reluctance to self-administer or a lack of self-reliance, and intravenous administration at home for those with good venous access who prefer less frequent treatments. Both therapy approaches have been demonstrated to provide protection from infections and improve health-related quality of life. Data supporting current options in IgG replacement are presented, and considerations in choosing between the two routes of therapy are discussed.

The utility of the ISAC allergen array in the investigation of idiopathic anaphylaxis

A diagnosis of idiopathic anaphylaxis following a detailed clinical assessment remains very challenging for patients and clinicians. Risk reduction strategies such as allergen avoidance are not possible. This study investigated whether the (ISAC) allergen array with 103 allergens would add diagnostic value in patients with idiopathic anaphylaxis. We extended the specific immunoglobulin (Ig)E testing in 110 patients with a diagnosis of idiopathic anaphylaxis from five UK specialist centres using ISAC arrays. These were divided into three groups: score I identified no new allergen sensitization beyond those known by previous assessment, score II identified new sensitizations which were not thought likely to explain the anaphylaxis and score III identified new sensitizations felt to have a high likelihood of being responsible for the anaphylaxis. A proportion (50%) of score III patients underwent clinical reassessment to substantiate the link to anaphylaxis in this group. The results show that 20% of the arrays were classified as score III with a high likelihood of identifying the cause of the anaphylaxis. A wide range of major allergens were identified, the most frequent being omega-5-gliadin and shrimp, together accounting for 45% of the previously unrecognized sensitizations. The ISAC array contributed to the diagnosis in 20% of patients with idiopathic anaphylaxis. It may offer additional information where a careful allergy history and follow-on testing have not revealed the cause of the anaphylaxis.

Calculated globulin (CG) as a screening test for antibody deficiency

Calculated globulin (total protein - albumin) is usually tested as part of a liver function test profile in both primary and secondary care and determines the serum globulin concentration, of which immunoglobulins are a major component. The main use hitherto of calculated globulin is to detect paraproteins when the level is high. This study investigated the potential to use low levels of calculated globulin to detect antibody deficiency. Serum samples with calculated globulin cut-off < 18 g/l based on results of a pilot study were collected from nine hospitals in Wales over a 12-month period. Anonymized request information was obtained and the samples tested for immunoglobulin levels, serum electrophoresis and, if appropriate, immunofixation. A method comparison for albumin measurement using bromocresol green and bromocresol purple was undertaken. Eighty-nine per cent (737 of 826) samples had an immunoglobulin (Ig)G level of < 6 g/l using the bromocresol green methodology with a cut-off of < 18 g/l, and 56% (459) had an IgG of < 4 g/l. Patients with both secondary and primary antibody deficiency were discovered and serum electrophoresis and immunofixation showed that 1·2% (10) had previously undetected small paraproteins associated with immune-paresis. Using bromocresol purple, 74% of samples had an IgG of < 6 g/l using a cut-off of < 23 g/l. Screening using calculated globulin with defined cut-off values detects both primary and secondary antibody deficiency and new paraproteins associated with immune-paresis. It is cheap, widely available and under-utilized. Antibody-deficient patients have been discovered using information from calculated globulin values, shortening diagnostic delay and time to treatment with immunoglobulin replacement therapy.

A UK national audit of hereditary and acquired angioedema

Hereditary angioedema (HAE) and acquired angioedema (AAE) are rare life-threatening conditions caused by deficiency of C1 inhibitor (C1INH). Both are characterized by recurrent unpredictable episodes of mucosal swelling involving three main areas: the skin, gastrointestinal tract and larynx. Swelling in the gastrointestinal tract results in abdominal pain and vomiting, while swelling in the larynx may be fatal. There are limited UK data on these patients to help improve practice and understand more clearly the burden of disease. An audit tool was designed, informed by the published UK consensus document and clinical practice, and sent to clinicians involved in the care of HAE patients through a number of national organizations. Data sets on 376 patients were received from 14 centres in England, Scotland and Wales. There were 55 deaths from HAE in 33 families, emphasizing the potentially lethal nature of this disease. These data also show that there is a significant diagnostic delay of on average 10 years for type I HAE, 18 years for type II HAE and 5 years for AAE. For HAE the average annual frequency of swellings per patient affecting the periphery was eight, abdomen 5 and airway 0·5, with wide individual variation. The impact on quality of life was rated as moderate or severe by 37% of adult patients. The audit has helped to define the burden of disease in the UK and has aided planning new treatments for UK patients.

The United Kingdom Primary Immune Deficiency (UKPID) Registry: report of the first 4 years' activity 2008-2012

This report summarizes the establishment of the first national online registry of primary immune deficency in the United Kingdom, the United Kingdom Primary Immunodeficiency (UKPID Registry). This UKPID Registry is based on the European Society for Immune Deficiency (ESID) registry platform, hosted on servers at the Royal Free site of University College, London. It is accessible to users through the website of the United Kingdom Primary Immunodeficiency Network (www.ukpin.org.uk). Twenty-seven centres in the United Kingdom are actively contributing data, with an additional nine centres completing their ethical and governance approvals to participate. This indicates that 36 of 38 (95%) of recognized centres in the United Kingdom have engaged with this project. To date, 2229 patients have been enrolled, with a notable increasing rate of recruitment in the past 12 months. Data are presented on the range of diagnoses recorded, estimated minimum disease prevalence, geographical distribution of patients across the United Kingdom, age at presentation, diagnostic delay, treatment modalities used and evidence of their monitoring and effectiveness.

Evaluation of correlation between dose and clinical outcomes in subcutaneous immunoglobulin replacement therapy

The importance of serum immunoglobulin (Ig)G concentration in IgG replacement therapy for primary immunodeficiency diseases is established in certain settings. Generally, IgG is infused via the intravenous (IVIG) or subcutaneous (SCIG) route. For IVIG infusion, published data demonstrate that higher IgG doses and trough levels provide patients with improved protection from infection. The same conclusions are not yet accepted for SCIG; data from two recent Phase III studies and a recent post-hoc analysis, however, suggest the same correlation between higher SCIG dose and serum IgG concentration and decreased incidence of infection seen with IVIG. Other measures of clinical efficacy have not been considered similarly. Thus, combined analyses of these and other published SCIG studies were performed; a full comparison of the 13 studies was, however, limited by non-standardized definitions and reporting. Despite these limitations, our analyses indicate that certain clinical outcomes improve at higher SCIG doses and associated higher serum IgG concentrations, and suggest that there might be opportunity to improve patient outcomes via SCIG dose adjustment.

Subcutaneous immunoglobulin replacement therapy with Hizentra, the first 20% SCIG preparation: a practical approach

To reduce the risk of infection in adults and children with primary immunodeficiencies, replacement therapy with IgG, which can be administered to patients intravenously or subcutaneously, is required. Although intravenous administration of IgG (IVIG) has been the therapy of choice in the US and widely used in Europe for many years, subcutaneous administration of IgG (SCIG) has recently gained considerable acceptance among patients and doctors. SCIG therapy achieves high and stable serum IgG levels, is well tolerated, and can be self-administered. Hizentra (IgPro20; CSL Behring, Berne, Switzerland) is the first, ready-to-use 20% liquid preparation of human IgG specifically formulated for subcutaneous infusions. The high concentration (20%) might allow shorter infusion times due to smaller infusion volumes, with potential improvement in the convenience of SCIG therapy. Hizentra is well tolerated and has been shown to protect adult and pediatric primary immunodeficiency patients against serious bacterial infections. In addition, it is easy to handle and can be stored at a temperature up to 25°C. In summary, Hizentra is an advance in the field of immunoglobulin replacement therapy, which might offer benefits for home therapy patients.

Clinical applications of intravenous immunoglobulins (IVIg)--beyond immunodeficiencies and neurology

The clinical use of intravenous immunoglobulin (IVIg) has expanded beyond its traditional place in the treatment of patients with primary immunodeficiencies. Due to its multiple anti-inflammatory and immunomodulatory properties, IVIg is used successfully in a wide range of autoimmune and inflammatory conditions. Recognized autoimmune indications include idiopathic thrombocytopenic purpura (ITP), Kawasaki disease, Guillain-Barré syndrome and other autoimmune neuropathies, myasthenia gravis, dermatomyositis and several rare diseases. Several other indications are currently under investigation and require additional studies to establish firmly the benefit of IVIg treatment. Increasing attention is being turned to the use of IVIg in combination with other agents, such as immunosuppressive agents or monoclonal antibodies. For example, recent studies suggest that combination therapy with IVIg and rituximab (an anti-CD20 monoclonal antibody) may be effective for treatment of autoimmune mucocutaneous blistering diseases (AMBDs), with sustained clinical remission. The combination of IVIg and rituximab has also been used in the setting of organ transplantation. Firstly, IVIg +/- rituximab has been administered to highly human leucocyte antigen (HLA)-sensitized patients to reduce anti-HLA antibody levels, thereby allowing transplantation in these patients. Secondly, IVIg in combination with rituximab is effective in the treatment of antibody-mediated rejection following transplantation. Treatment with polyclonal IVIg is a promising adjunctive therapy for severe sepsis and septic shock, but its use remains controversial and further study is needed before it can be recommended routinely. This review covers new developments in these fields and highlights the broad range of potential therapeutic areas in which IVIg may have a clinical impact.

Clinical immunology review series: an approach to the patient with anaphylaxis

Anaphylaxis is a severe, life-threatening, generalized or systemic hypersensitivity reaction. While there is agreement as to this definition of anaphylaxis, the clinical presentation is often variable and it is not uncommon for there to be debate after the event as to whether anaphylaxis had actually occurred. The management of anaphylaxis falls into two distinct phases: (1) emergency treatment and resuscitation of a patient with acute anaphylaxis and (2) the search for a cause for the event and the formulation of a plan to prevent and treat possible further episodes of anaphylaxis. Both aspects are important in preventing death from anaphylaxis and are covered in this review.

Clinical immunology review series: an approach to the use of the immunology laboratory in the diagnosis of clinical allergy

In the last 10 years UK immunology laboratories have seen a dramatic increase in the number and range of allergy tests performed. The reasons for this have been an increase in the incidence of immunoglobulin E (IgE)-mediated allergic disease set against a background of greater public awareness and more referrals for assessment. Laboratory testing forms an integral part of a comprehensive allergy service and physicians treating patients with allergic disease need to have an up-to-date knowledge of the range of tests available, their performance parameters and interpretation as well as the accreditation status of the laboratory to which tests are being sent. The aim of this review is to describe the role of the immunology laboratory in the assessment of patients with IgE-mediated allergic disease and provide an up-to-date summary of the tests currently available, their sensitivity, specificity, interpretation and areas of future development.

Meningococcal meningitis in two patients with primary antibody deficiency treated with replacement intravenous immunoglobulin

The current treatment of primary antibody deficiency (PAD) is the early recognition of the condition and replacement immunoglobulin combined with prompt treatment of infections and complications. The route of administration (intravenous or subcutaneous), dose and frequency of administration of immunoglobulin still vary between centres and countries. Most infections in patients with PAD are reduced but not entirely prevented by replacement immunoglobulin, with sinopulmonary infections accounting for the bulk of the remainder. Although there have been reports of meningitis in patients with PAD before replacement treatment, we describe the first two cases of bacterial meningitis (group B Neisseria meningitidis) on adequate immunoglobulin replacement and discuss the involvement of potential cofactors.

The role of complement testing in dermatology

An up-to-date knowledge of the molecular events involved in the activation and control of the complement cascade is essential to understand the pathogenesis of a number of conditions presenting to dermatologists. This knowledge underpins the pathogenesis of these conditions but allows the clinician to request the most useful tests in terms of diagnosis and monitoring. In this review we aim to discuss complement biology, the diseases in which complement testing is of particular relevance, the types of laboratory tests available, their utility and interpretation. Additionally it is of critical importance for clinicians not only to choose the most appropriate tests but also to choose to send these to an appropriately accredited laboratory.

Systemic treatment with anti-CD40 antibody stimulates Langerhans cell migration from the skin

Epidermal Langerhans cells (LCs) play a pivotal role in the initiation of cutaneous immune responses. The maturation of LCs and their migration from the skin to the T cell areas of draining lymph nodes are essential for the delivery and presentation of antigen to naïve T cells. CD40, which acts as a costimulatory molecule, is present on LCs and the basal layer of keratinocytes in the skin. We show here that systemic treatment of mice with anti-CD40 antibody stimulates the migration of LCs out of the epidermis with a 70% reduction in LC numbers after 7 days, although changes in LC morphology are detectable as early as day 3. LC numbers in the epidermis returned to 90% of normal by day 21. As well as morphological changes, LC showed up-regulated levels of Class II and ICAM-1, with only minimal changes in CD86 expression 3 days following anti-CD40 treatment. Despite increased levels of Class II and ICAM-1, epidermal LC isolated from anti-CD40 treated mice were poor stimulators of a unidirectional allogeneic mixed leucocyte reaction (MLR), as were epidermal LC isolated from control mice. These results indicate that CD40 stimulation is an effective signal for LC migration, distinct from maturation of immunostimulatory function in the epidermis, which is not altered. These observations may have important implications for the mechanism of action of agonistic anti-CD40 antibodies, which have been used as an adjuvant in models of infection and experimental tumours and the primary immunodeficiency Hyper IgM syndrome caused by deficiency of CD40 ligand.