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Primary Immunodeficiencies (PID) are a group of rare congenital disorders of the immune system. Autoimmune cytopenia (AIC) represents the most common autoimmune manifestation in PID patients. Treatment of AIC in PID patients can be really challenging, since they are often chronic, relapsing and refractory to first line therapies, thus requiring a broad variety of alternative therapeutic options. Moreover, immunosuppression should be fine balanced considering the increased susceptibility to infections in these patients. Specific therapeutic guidelines for AIC in PID patients are lacking. Treatment choice should be guided by the underlying disease. The study of the pathogenic mechanisms involved in the genesis of AIC in PID and our growing ability to define the molecular underpinnings of immune dysregulation has paved the way for the development of novel targeted treatments. Ideally, targeted therapy is directed against an overexpressed or overactive gene product or substitutes a defective protein, restoring the impaired pathway. Actually, the molecular diagnosis or a specific drug is not always available. However, defining the category of PID or the immunological phenotype can help to choose a semi-targeted therapy directed towards the suspected pathogenic mechanism. In this review we overview all the therapeutic interventions available for AIC in PID patients, according to different immunologic targets. In particular, we focus on T and/or B cells targeting therapies. To support decision making in the future, prospective studies to define treatment response and predicting/stratifying biomarkers for patients with AIC and PID are needed.

The complement system plays an essential role in both innate and adaptive immune responses. Any dysregulation in this system can disturb normal host defense and alter inflammatory response leading to both infections and autoimmune diseases. The complement system can be activated through three different pathways. Inherited complement deficiencies have been described for all complement components and their regulators. Despite being rare diseases, complement deficiencies are often severe, with a frequent onset during childhood. We provide an overview of clinical disorders related to these disorders and describe current diagnostic strategies required for their comprehensive characterization and management.

COVID‐19 is a complex new viral disease, in which a strict balance between anti‐viral immune response and the ensuing organ inflammation has a critical role in determining the clinical course. In adults, compelling evidence exists indicating that an uncontrolled inflammatory response ("cytokine storm") is pivotal in determining disease progression and mortality. Children may rarely present with severe disease. Modulating factors related to the host's genetic factors, age‐related susceptibility, and the capability to mount appropriate immune responses might play a role in control virus load at an early stage and regulating the inflammatory reaction. Elucidating these mechanisms seems crucial in developing target therapies according to patient's age, immunologic status, and disease evolution in COVID‐19.

Primary atopic disorders (PADs) are monogenic diseases characterized by allergy or atopy-related symptoms as fundamental features. In patients with PADs, primary immune deficiency and immune dysregulation symptoms are usually coexist. Chronic skin disease, manifesting with erythroderma, severe atopic dermatitis or eczema, and urticaria, is one of the main features observed in PADs, such as hyper-IgE syndromes, Omenn syndrome, Wiskott-Aldrich syndrome, IPEX-linked syndrome, skin barrier disorders, as well as some autoinflammatory diseases. The recognition of PADs in the context of an allergic phenotype is crucial to ensure prompt diagnosis and appropriate treatment. This article provides an overview of the main PADs with skin involvement.

Background and aims Multiple monogenic disorders present as very early onset inflammatory bowel disease (VEO-IBD) or as IBD with severe and atypical features. Establishing a genetic diagnosis may change patients’ management and prognosis. In this study, we describe the diagnostic approach to suspected monogenic IBD in a real clinical setting, discussing genetic and phenotypic findings and therapeutic implications of molecular diagnosis. Methods Information of patients with VEO-IBD and early onset IBD with severe/atypical phenotypes (EO-IBD s/a) managed between 2008–2017 who underwent a genetic workup were collected. Results Ninety-three patients were included, and 12 (13%) reached a genetic diagnosis. Candidate sequencing (CS) was performed in 47 patients (50%), and next generation sequencing (NGS) was performed in 84 patients (90%). Candidate sequencing had a good diagnostic performance only when guided by clinical features specific for known monogenic diseases, whereas NGS helped finding new causative genetic variants and would have anticipated one monogenic diagnosis (XIAP) and consequent bone marrow transplant (BMT). Patients with monogenic IBD more frequently were male (92% vs 54%; P = 0.02), had extraintestinal findings (100% vs 34%; P < 0.001), and had disease onset ≤1 month of life (25% vs 1%; P = 0.006). Genetic diagnosis impacted patient management in 11 patients (92%), 7 of whom underwent BMT. Conclusion A genetic diagnosis can be established in a significant proportion of suspected monogenic IBD and has an impact on patients’ management. Candidate sequencing may be deployed when clinical findings orientate toward a specific diagnosis. Next generation sequencing should be preferred in patients with nonspecific phenotypes.

Primary immunodeficiencies (PIDs) are inherited disorders classically characterized by increased susceptibility to infections. Nevertheless, in the last two decades, genomic analysis (such as NGS) coupled with biochemical and cellular studies led to a more accurate definition for a growing number of novel genetic disorders associated with PIDs. This revealed new aspects of the immune system and its function and regulation within these diseases. In particular, it has been clarified that the clinical features of PIDs are much broader that originally thought and extend beyond an increased susceptibility to infections. More specifically, immune dysregulation is very often described in novel characterized PIDs and can lead to multiple autoimmune diseases, lymphoproliferation and malignancies. If not promptly diagnosed, these could negatively impact patient’s prognosis. The aim of this review is to increase the awareness of recently discovered PIDs, characterized predominantly by immune dysregulation phenotypes. Findings highlighted in this review suggest screening for immunodeficiency in patients with lymphoproliferation or early onset/multiple autoimmune diseases. Prompt diagnosis would potentially allow most successful treatment and clinical outcome for patients with PIDs. (www.actabiomedica.it)

Background: Although autoimmunity and hyperinflammation secondary to recombination activating gene (RAG) deficiency have been associated with delayed diagnosis and even death, our current understanding is limited primarily to small case series. Objective: Understand the frequency, severity, and treatment responsiveness of autoimmunity and hyperinflammation in RAG deficiency. Methods: In reviewing the literature and our own database, we identified 85 patients with RAG deficiency, reported between 2001 and 2016, and compiled the largest case series to date of 63 patients with prominent autoimmune and/or hyperinflammatory pathology. Results: Diagnosis of RAG deficiency was delayed a median of 5 years from the first clinical signs of immune dysregulation. Most patients (55.6%) presented with more than 1 autoimmune or hyperinflammatory complication, with the most common etiologies being cytopenias (84.1%), granulomas (23.8%), and inflammatory skin disorders (19.0%). Infections, including live viral vaccinations, closely preceded the onset of autoimmunity in 28.6% of cases. Autoimmune cytopenias had early onset (median, 1.9, 2.1, and 2.6 years for autoimmune hemolytic anemia, immune thrombocytopenia, and autoimmune neutropenia, respectively) and were refractory to intravenous immunoglobulin, steroids, and rituximab in most cases (64.7%, 73.7%, and 71.4% for autoimmune hemolytic anemia, immune thrombocytopenia, and autoimmune neutropenia, respectively). Evans syndrome specifically was associated with lack of response to first-line therapy. Treatment-refractory autoimmunity/hyperinflammation prompted hematopoietic stem cell transplantation in 20 patients. Conclusions: Autoimmunity/hyperinflammation can be a presenting sign of RAG deficiency and should prompt further evaluation. Multilineage cytopenias are often refractory to immunosuppressive treatment and may require hematopoietic cell transplantation for definitive management. © 2019 The Authors

Objective: To identify predictors of faster time to virological suppression among infants starting combination antiretroviral therapy (cART) early in infancy. Design: Cohort study of infants from Europe and Thailand included in studies participating in the European Pregnancy and Paediatric HIV Cohort Collaboration. Methods: Infants with perinatal HIV starting cART aged less than 6 months with at least 1 viral load measurement within 15 months of cART initiation were included. Multi-variable interval-censored flexible parametric proportional hazards models were used to assess predictors of faster virological suppression, with timing of suppression assumed to lie in the interval between last viral load at least 400 and first viral load less than 400 copies/ml. Results: Of 420 infants, 59% were female and 56% from Central/Western Europe, 26% United Kingdom/Ireland, 15% Eastern Europe and 3% Thailand; 46 and 54% started a boosted protease inhibitor-based or nonnucleoside reverse transcriptase inhibitor-based regimen, respectively. At cART initiation, the median age, CD4(+) % and viral load were 2.9 [interquartile range (IQR): 1.4-4.1] months, 34 (IQR: 24-45)% and 5.5 (IQR: 4.5-6.0) log(10) copies/ml, respectively. Overall, an estimated 89% (95% confidence interval: 86-92%) achieved virological suppression within 12 months of cART start. In multivariable analysis, younger age [adjusted hazard ratio (aHR): 0.84 per month older; P < 0.001], higher CD4(+) % (aHR: 1.11 per 10% higher; P=0.010) and lower log(10) viral load (aHR: 0.85 per log(10) higher; P < 0.001) at cART initiation independently predicted faster virological suppression. Conclusion: We observed a significant independent effect of age at cART initiation, even within a narrow 6 months window from birth. These findings support the earliest feasible cART initiation in infants and suggest that early therapy influences key virological and immunological parameters that could have important consequences for long-term health.

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

Dipeptidyl peptidase 4 (DPP4, CD26) is a serine protease that is expressed constitutively by many haematopoietic and non-haematopoietic tissues. It exists as a membrane-associated protein, as well as in an active, soluble form (herein called sDPP4), present at high concentrations in bodily fluids. Despite the proposed use of sDPP4 as a biomarker for multiple diseases, its cellular sources are not well defined. Here, we report that individuals with congenital lymphocyte immunodeficiency had markedly lower serum concentrations of sDPP4, which were restored upon successful treatment and restoration of lymphocyte haematopoiesis. Using irradiated lymphopenic mice and wild-type to Dpp4-/- reciprocal bone marrow chimeric animals, we found that haematopoietic cells were a major source of circulating sDPP4. Furthermore, activation of human and mouse T lymphocytes resulted in increased sDPP4, providing a mechanistic link between immune system activation and sDPP4 concentration. Finally, we observed that acute viral infection induced a transient increase in sDPP4, which correlated with the expansion of antigen-specific CD8+ T cell responses. Our study demonstrates that sDPP4 concentrations are determined by the frequency and activation state of lymphocyte populations. Insights from these studies will support the use of sDPP4 concentration as a biomarker for inflammatory and infectious diseases.

Objective To investigate the clinical manifestations at diagnosis and during follow-up in patients with 22q11.2 deletion syndrome to better define the natural history of the disease. Study design A retrospective and prospective multicenter study was conducted with 228 patients in the context of the Italian Network for Primary Immunodeficiencies. Clinical diagnosis was confirmed by cytogenetic or molecular analysis. Results The cohort consisted of 112 males and 116 females; median age at diagnosis was 4 months (range 0 to 36 years 10 months). The diagnosis was made before 2 years of age in 71% of patients, predominantly related to the presence of heart anomalies and neonatal hypocalcemia. In patients diagnosed after 2 years of age, clinical features such as speech and language impairment, developmental delay, minor cardiac defects, recurrent infections, and facial features were the main elements leading to diagnosis. During follow-up (available for 172 patients), the frequency of autoimmune manifestations ( P = .015) and speech disorders ( P = .002) increased. After a median follow-up of 43 months, the survival probability was 0.92 at 15 years from diagnosis. Conclusions Our data show a delay in the diagnosis of 22q11.2 deletion syndrome with noncardiac symptoms. This study provides guidelines for pediatricians and specialists for early identification of cases that can be confirmed by genetic testing, which would permit the provision of appropriate clinical management.

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.

Objective: To investigate humoral compartment at diagnosis and during follow-up in patients with 22q11.2 Deletion Syndrome (22q11DS). Methods: A retrospective and prospective multicenter study was conducted with 165 patients in the context of the Italian Network for Primary Immunodeficiencies. Patients were investigated for serum immunoglobulin, testing specific antibody titers to recall antigens and proliferative responses to phytohemagglutinin (PHA) and OKT3. Lymphocyte subsets were assessed by flow cytometric analysis. Results: The cohort consisted of 96 males and 69 females; median age at diagnosis was 4 months (range 0 to 35 years). Eighty out of 165 patients had a history of recurrent and/or severe infections and 41% patients received at least one prophylactic treatment. During follow-up the frequency of autoimmune manifestations increased, severe infections and antibiotic prophylaxis decreased. We reported hypogammaglobulinemia in 34% of patients at diagnosis, confirmed during follow-up. Total lymphocytes and T-cells subsets were decreased in most of 22q11DS patients, although these immunological abnormalities did not correlate to risk of infections. Lymphocyte proliferation in response to mitogens and antigens was normal/ in the lower levels of normality, in most of patients. Our preliminary data showed a decrease of B cell memory. Conclusions: Not only T-cell but also B- cell compartment should be routinely investigated in 22q11DS patients with an history of recurrent infections and autoimmune manifestations. These data could help to better define, in these patients, follow-up and clinical management with a specific antimicrobial treatment and/or intravenous immunoglobulin therapy.

Deficiency of the purine salvage enzyme adenosine deaminase leads to SCID (ADA-SCID). Hematopoietic cell transplantation (HCT) can lead to a permanent cure of SCID; however, little data are available on outcome of HCT for ADA-SCID in particular. In this multicenter retrospective study, we analyzed outcome of HCT in 106 patients with ADA-SCID who received a total of 119 transplants. HCT from matched sibling and family donors (MSDs, MFDs) had significantly better overall survival (86% and 81%) in comparison with HCT from matched unrelated (66%; P < .05) and haploidentical donors (43%; P < .001). Superior overall survival was also seen in patients who received unconditioned transplants in comparison with myeloablative procedures (81% vs 54%; P < .003), although in unconditioned haploidentical donor HCT, nonengraftment was a major problem. Long-term immune recovery showed that regardless of transplant type, overall T-cell numbers were similar, although a faster rate of T-cell recovery was observed after MSD/MFD HCT. Humoral immunity and donor B-cell engraftment was achieved in nearly all evaluable surviving patients and was seen even after unconditioned HCT. These data detail for the first time the outcomes of HCT for ADA-SCID and show that, if patients survive HCT, long-term cellular and humoral immune recovery is achieved.