Rituximab (RTX) is a monoclonal antibody against CD20, commonly used in the treatment of hematological malignancies and autoimmune diseases. The use of RTX is related to the development of hypogammaglobulinemia and infections. Aim of this review is to summarize the evidence supporting the association of specific risk factors with the development of hypogammaglobulinemia and infections post-RTX. Immunological complications are more common in patients with malignant diseases as compared to non-malignant diseases. Moreover, the use of more than one dose of RTX, maintenance regimens, low pre-treatment basal immunoglobulin levels and the association with Mycophenolate and purine analogues represent risk factors for the development of hypogammaglobulinemia. The number of RTX courses, the evidence of low IgG levels for more than 6 months, the use of G-CSF, the occurrence of chronic lung disease, cardiac insufficiency, extra-articular involvement in patients with rheumatoid arthritis, low levels of IgG and older age have been correlated with a higher risk of infections. Even though the heterogeneity of the studies in terms of study population age and underlying disease, RTX schedules as well as differences in pre-treatment or concomitant therapy doesn't allow drawing definitive conclusions, the study of the literature highlight the association of specific risk factors with the occurrence of hypogammaglobulinemia and/or infections. A long term randomized controlled clinical trial could be useful to define a personalized evidence-based risk management plan for patients treated with RTX.

DiGeorge syndrome (DGS) is a primary immunodeficiency characterized by various degrees of T-cell deficiency. In partial DGS (pDGS), other risk factors could predispose to recurrent infections, autoimmunity, and allergy. The aim of this study was to assess the effect of different factors in the development of infections, autoimmunity, and/or allergy in patients with pDGS. We studied 467 pDGS patients in follow-up at Great Ormond Street Hospital. Using a multivariate approach, we observed that palatal anomalies represent a risk factor for the development of recurrent otitis media with effusion. Gastroesophageal reflux/dysphagia and asthma/rhinitis represent a risk factor for the development of recurrent upper respiratory tract infections. Allergy and autoimmunity were associated with persistently low immunoglobulin M levels and lymphopenia, respectively. Patients with autoimmunity showed lower levels of CD3+, CD3+CD4+, and naïve CD4+CD45RA+CD27+ T lymphocytes compared with pDGS patients without autoimmunity. We also observed that the physiological age-related decline of the T-cell number was slower in pDGS patients compared with age-matched controls. The age-related recovery of the T-cell number depended on a homeostatic peripheral proliferation of T cells, as suggested by an accelerated decline of the naïve T lymphocytes in pDGS as well as a more skewed T-cell repertoire in older pDGS patients. These evidences suggest that premature CD4+ T-cell aging and lymphopenia induced spontaneous peripheral T-cell proliferation might contribute to the pathogenesis of autoimmunity in patients with pDGS. Infections in these patients represent, in most of the cases, a complication of anatomical or gastroenterological anomalies rather than a feature of the underlying immunodeficiency.

Objectives: This study aimed to assess the clinical characteristics, treatment and outcomes of the multisystem inflammatory syndrome in children (MIS-C) following COVID-19 in five different geographical regions of Iran. Methods: In this multicenter observational study, patients <21 years were included between March 2020 and October 2021. By Disease Control and Prevention (CDC) checklist, demographic characteristics, comorbidities, clinical signs and symptoms, laboratory and radiology findings, and treatment were collected. Statistical analysis was using Chi-square and t-test in STATA₁₄. Results: In total 225 patients with median age of 55 (26–96) months were included that 59.56% boys. 57.33% were admitted to the PICU with a median of 7 days (4–10). 95.56% of patients were discharged with recovery and the rest died. All of the patients in our study were included based on the MIS-C criteria. However, some patients had Kawasaki symptoms, so we compared the clinical and epidemiological characteristics of the two groups. Conjunctival injection, cervical lymphadenopathy>1.5 cm diameter, and strawberry tongue in Kawasaki-like MIS-C patients were higher than of MIS-C patients, and this difference was significant(p<0.001). The most common comorbidity was obesity (24.86%). Most patients tested for COVID-19 and about 60% of the patients had a positive test by serology or reverse transcription-polymerase chain reaction (RT-PCR). Gastrointestinal (88.89%) and hematologic signs (84.44%) were most common. Most drugs used in patients were IVIG and steroids. 88.07% and 61.29% of the patients had at least one problem in echocardiography and lung CT, respectively. Conclusions: The best outcome was seen in patients who were treated with both IVIG and steroids on the first days of admission. Myocarditis was common in two groups of patients. According to most patients had echocardiography abnormal, screening of heart function is recommended for patients.

Asthma is a heterogeneous chronic respiratory disease characterized by an increased burden of infections. Respiratory tract infections associated with an increased risk for asthma especially when occurring in the first months of life, also represent the most common cause of asthma exacerbations. The association between asthma and the increased frequency of infections and microbiota dysbiosis might be explained by a common mechanism, such as an underlying immune system defect. Apart from the well-established association between primary immunodeficiencies and asthma, several alterations in the immune response following infection have also been observed in asthmatic patients. An impairment in lung epithelial barrier integrity exists and is associated with both an increased susceptibility to infections and the development of asthma. Asthmatic patients are also found to have a deficient interferon (IFN) response upon infection. Additionally, defects in Toll-like receptor (TLR) signaling are observed in asthma and are correlated with both recurrent infections and asthma development. In this review, we summarize the common pathophysiological background of asthma and infections, highlighting the importance of an underlying immune system defect that predispose individuals to recurrent infections and asthma.