Activated phosphoinositide 3-kinase (PI3K) δ Syndrome (APDS), caused by autosomal dominant mutations in PIK3CD (APDS1) or PIK3R1 (APDS2), is a heterogeneous primary immunodeficiency. While initial cohort-descriptions summarized the spectrum of clinical and immunological manifestations, questions about long-term disease evolution and response to therapy remain. The prospective European Society for Immunodeficiencies (ESID)-APDS registry aims to characterize the disease course, identify outcome predictors, and evaluate treatment responses. So far, 77 patients have been recruited (51 APDS1, 26 APDS2). Analysis of disease evolution in the first 68 patients pinpoints the early occurrence of recurrent respiratory infections followed by chronic lymphoproliferation, gastrointestinal manifestations, and cytopenias. Although most manifestations occur by age 15, adult-onset and asymptomatic courses were documented. Bronchiectasis was observed in 24/40 APDS1 patients who received a CT-scan compared with 4/15 APDS2 patients. By age 20, half of the patients had received at least one immunosuppressant, but 2–3 lines of immunosuppressive therapy were not unusual before age 10. Response to rapamycin was rated by physician visual analog scale as good in 10, moderate in 9, and poor in 7. Lymphoproliferation showed the best response (8 complete, 11 partial, 6 no remission), while bowel inflammation (3 complete, 3 partial, 9 no remission) and cytopenia (3 complete, 2 partial, 9 no remission) responded less well. Hence, non-lymphoproliferative manifestations should be a key target for novel therapies. This report from the ESID-APDS registry provides comprehensive baseline documentation for a growing cohort that will be followed prospectively to establish prognostic factors and identify patients for treatment studies.

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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.

SummaryHereditary angioedema (HAE) and acquired angioedema (AAE) are rare lifethreatening 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 clinical phenotypes of specific complement immunodeficiencies vary considerably both in terms of the predominant bacterial pathogen, and the risk and type of auto-inflammatory disease. Appreciation of these phenotypic differences should help both immunologists and other specialists in their diagnosis and management of these rare and complex patients.

Immunoglobulin replacement therapy enhances survival and reduces infection risk in patients with agammaglobulinaemia. We hypothesized that despite regular immunoglobulin therapy, some patients will experience ongoing respiratory infections and develop progressive bronchiectasis with deteriorating lung function. One hundred and thirty-nine (70%) of 199 patients aged 1-80 years from nine cities in the United Kingdom with agammaglobulinaemia currently listed on the UK Primary Immune Deficiency (UKPID) registry were recruited into this retrospective case study and their clinical and laboratory features analysed; 94% were male, 78% of whom had Bruton tyrosine kinase (BTK) gene mutations. All patients were on immunoglobulin replacement therapy and 52% had commenced therapy by the time they were 2 years old. Sixty per cent were also taking prophylactic oral antibiotics; 56% of patients had radiological evidence of bronchiectasis, which developed between the ages of 7 and 45 years. Multivariate analysis showed that three factors were associated significantly with bronchiectasis: reaching 18 years old [relative risk (RR) = 14·2, 95% confidence interval (CI) = 2·7-74·6], history of pneumonia (RR = 3·9, 95% CI = 1·1-13·8) and intravenous immunoglobulin (IVIG) rather than subcutaneous immunoglobulin (SCIG) = (RR = 3·5, 95% CI = 1·2-10·1), while starting immunoglobulin replacement after reaching 2 years of age, gender and recent serum IgG concentration were not associated significantly. Independent of age, patients with bronchiectasis had significantly poorer lung function [predicted forced expiratory volume in 1 s 74% (50-91)] than those without this complication [92% (84-101)] (P < 0·001). We conclude that despite immunoglobulin replacement therapy, many patients with agammaglobulinaemia can develop chronic lung disease and progressive impairment of lung function.

SummaryIdiopathic 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 1 T cell but not natural killer (NK) cell numbers, raising the question as to what extent immune senescence, particularly of CD8 1 T cells, might contribute to the increased risk of cancers as individuals age.

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