Purpose This study aimed to assess the effect of COVID-19 on patients with IEIs, the potentially at-risk population, regarding the clinical course, complications, severity, and outcomes. Methods This two-phase study was conducted on patients from three referral immunodeficiency centers in Iran. At phase one, 98 IEI patients with COVID-19 infection were evaluated by telephone follow-up (TFU). At phase two, the demographic, clinical, and laboratory records of clinically confirmed 33 IEI patients with COVID-19 infection were collected and analyzed. Results At phase one, 16.3% represented COVID-19 infection without any report of pediatric intensive care unit (PICU) admission or death. During the second phase, combined immunodeficiency (CID) (42.4%) and predominantly antibody deficiencies (PADs) (33.3%) were the predominant immune defects. Atopy (27.3%) and lung disorders (27.3%) were the frequent pre-existing comorbidities. Organomegaly (p=0.030) and renal disorders (p=0.033) were significantly associated with the development of respiratory insufficiency. Cyanosis, tachypnea, intercostal retraction, and seizure were the chief complaints of patients who were more likely to progress respiratory insufficiency (p<0.05), being admitted to the PICU (p<0.05), and/or deceased (p<0.05). Laboratory evaluation revealed a marked positive correlation between D-Dimer (p=0.045), prothrombin time (p=0.045), C-reactive protein (p=0.041), proteinuria (p=0.013), ferritin (p=0.020), metabolic acidosis (p=0.003), and troponin (p=0.049) level with mortality. We detected a significant association between the chest X-ray pattern of COVID-19 infection with PICU admission (p=0.023) and death (p=0.046). Conclusion In the current study, patients with CID and PAD were introduced as patients at high risk of COVID-19 infection, who may need extra protective and therapeutic measurements.

Background Defective Cernunnos gene in nonhomologous end‐joining (NHEJ) pathway of the DNA repair is responsible for radiosensitive severe combined immunodeficiency (SCID). Herein, presented a new patient with Cernunnos deficiency and summarized the clinical, immunological, and molecular features of reported patients in the literature. Case The patient was a 6‐month‐old female born to consanguineous parents. She presented with long‐lasting fever, diarrhea, poor feeding, and restlessness. She had suffered from recurrent fever of unknown origin and multiple episodes of oral candidiasis. In the physical examination, microcephaly, failure to thrive, oral candidiasis, pustular rash on fingers, and perianal ulcers, but no dysmorphic feature were observed. The immunologic workup revealed lymphopenia, neutropenia, normocytic anemia, low T‐ but normal B‐ and natural killer (NK)‐ cells, low immunoglobulin (Ig)G, and normal IgA, IgM, and IgE. The T‐cell receptor excision circle (TREC) was low and the lymphocyte transformation test (LTT) was abnormal to mitogens and antigens. She was diagnosed with T − B + NK + SCID and improved by intravenous immunoglobulin along with antimicrobials. A homozygous splice site variant, c.390 + 1G > T, at the intron 3 of the NHEJ1 , was identified and the diagnosis of Cernunnos deficiency was established. However, while a candidate for hematopoietic stem cell transplantation, she developed sepsis and died at 11 months of age. Conclusions Cernunnos deficiency should be considered as a differential diagnosis in patients with microcephaly, growth retardation, recurrent infections, T‐cell defects, and hypogammaglobulinemia. The normal B‐cell level in the index patient is an unexpected finding in Cernunnos deficiency which requires further evaluation.

Background Mendelian susceptibility to mycobacterial disease (MSMD) is an uncommon disorder with increased susceptibility to less virulent mycobacteria including bacillus Calmette-Guérin (BCG). Fibrosing mediastinitis (FM) is also a rare condition defined by excessive fibrotic reactions in the mediastinum. So far, some infectious organisms and autoimmune diseases have been introduced as possible etiologies of FM. However, no study has ever discussed the possible association of BCG infection and FM. Case presentation In this study, we report a 3-year-old female presenting with persistent fever, weakness, and bloody diarrhea in addition to mediastinal lymphadenopathy, hepatosplenomegaly, and pleural and pericardial effusion. Further examinations established a diagnosis of MSMD based on her clinical condition, immunologic data, positive tests for mycobacterial species, positive family history, and genetic study (IL12RB1 gene, c.G1193C, p.W398S). A year and a half later, she was referred with submandibular lymphadenitis and underwent immunologic work-up which revealed high inflammatory indices, a slight reduction in numbers of CD3 + and CD4 + cells as well as elevated CD16/56 + cell count and hyperimmunoglobulinemia. Purified protein derivative (PPD), QuantiFERON, and gastric washing test were all negative. Her chest computed tomography (CT) scan revealed suspicious para-aortic soft tissue and her echocardiography was indicative of strictures in superior vena cava and pulmonary veins. She further underwent chest CT angiography which confirmed FM development. Meanwhile, she has been treated with anti-mycobacterial agents and subcutaneous IFN-γ. Conclusion In summary, we described a novel case of MSMD in a child presenting with granulomatous FM possibly following BCG infection. This is the first report introducing aberrant BCG infection as the underlying cause of FM. This result could assist physicians in identifying early-onset FM in suspicious cases with MSMD. However, more studies are required to support this matter.