Multisystem Inflammatory Syndrome in Children Associated with Severe Acute Respiratory Syndrome Coronavirus 2: A Systematic Review

OBJECTIVE

To develop a more comprehensive description of multisystem inflammatory syndrome in children (MIS-C), a novel syndrome linked to severe acute respiratory syndrome coronavirus 2, by conducting a systematic analysis of studies from different settings that used various inclusion criteria.

STUDY DESIGN

MIS-C studies were identified by searching PubMed and Embase as well as preprint repositories and article references to identify studies of MIS-C cases published from April 25, 2020, through June 29, 2020. MIS-C study metadata were assessed and information on case demographics, clinical symptoms, laboratory measurements, treatments, and outcomes were summarized and contrasted between studies.

RESULTS

Eight studies were identified representing a total of 440 MIS-C cases. Inclusion criteria varied by study: 3 studies selected patients diagnosed with Kawasaki disease, 2 required cardiovascular involvement, and 3 had broader multisystem inclusion criteria. Median age of patients by study ranged from 7.3 to 10 years, and 59% of patients were male. Across all studies, the proportion of patients with positive results for severe acute respiratory syndrome coronavirus 2 reverse transcriptase-polymerase chain reaction tests ranged from 13% to 69% and for serology, from 75% to 100%. Patients with MIS-C had high prevalence of gastrointestinal (87%), dermatologic/mucocutaneous (73%), and cardiovascular (71%) symptoms. Prevalence of cardiovascular, neurologic, and respiratory system involvement significantly differed by study inclusion criteria. All studies reported elevated C-reactive protein, interleukin-6, and fibrinogen levels for at least 75% of patients in each study.

CONCLUSIONS

This systematic review of MIS-C studies assists with understanding this newly identified syndrome and may be useful in developing a refined, universal case definition of MIS-C.

Attenuated live vaccine usage affects accurate measures of virus diversity and mutation rates in avian coronavirus infectious bronchitis virus

The full-length genomes of 11 infectious bronchitis virus (IBV) field isolates from three different types of the virus; Massachusetts (Mass), Connecticut (Conn) and California (CAL) isolated over a 41, 25 and 8 year period respectively, were sequenced and analyzed to determine the mutation rates and level of polymorphisms across the genome. Positive selection was not detected and mutation rates ranged from 10(-4) to 10(-6)substitutions/site/year for Mass and Conn IBV types where attenuated live vaccines are routinely used to control the disease. In contrast, for CAL type viruses, for which no vaccine exists, positive selection was detected and mutation rates were 10 fold higher ranging from 10(-2) to 10(-3)substitutions/site/year. Lower levels of genetic diversity among the Mass and Conn viruses as well as sequence similarities with vaccine virus genomes suggest that the origin of the Mass and all but one of the Conn viruses was likely vaccine virus that had been circulating in the field for an unknown but apparently short period of time. The genetic data also identified a recombinant IBV isolate with 7 breakpoints distributed across the entire genome suggesting that viruses within the same serotype can have a high degree of genetic variability outside of the spike gene. These data are important because inaccurate measures of genetic diversity and mutation rates could lead to underestimates of the ability of IBV to change and potentially emerge to cause disease.

Genomic structure and functional characterization of the promoter region of human IkappaB kinase-related kinase IKKi/IKKvarepsilon gene

The inducible IkappaB kinase (IKKi/IKKepsilon) is a recently described serine-threonine kinase that activates the transcription factors NFkappaB, interferon regulatory factor-3 (IRF3) and CCAAA/enhancer-binding protein (C/EBPdelta). Several inflammatory agents have been shown to induce the expression of the IKKi gene in macrophages and other cell types but the mechanism is unknown. We have found that the IKKi expression was constitutive in human chondrocytes from OA cartilage and a human chondrocytic cell line C28/I2 but was up-regulated by the inflammatory cytokines TNFalpha or IL-1betain an NFkappaB-dependent manner. To understand the constitutive and inducible expression of the IKKi gene we localized the transcription start site (TSS), cloned and sequenced a 2 kb genomic DNA fragment 5' of the TSS and characterized the putative promoter region (PPR), and identified the motifs therein that are required for basal and cytokine-induced IKKi gene promoter activity. We found that IKKi core promoter was TATA-less and by using PCR generated deletion mutants of the PPR we found that the cis-elements responsible for basal transcriptional activity were located between -51 and -100 bp upstream of the TSS while the cytokine response elements were located distally between -501 and -1000 bp upstream of the TSS. The DNA region containing the cytokine response elements had two kappaB sites as the most relevant regulatory motifs. The results of site-directed mutagenesis revealed that the kappaB site located between -833 and -847 bp upstream of the TSS was biologically functional and required for cytokine-induced IKKi promoter activity in human chondrocytes and HeLa cells. The silence of the other kappaB site (-816/-802) was positional, rather than sequence-specific. Over-expression of NFkappaB p65 mimics the TNFalpha-induced activation of the IKKi promoter. Also the gel shift assay suggested that NFkappaB p65 is responsible for activation of the IKKi promoter. These data for the first time characterize the promoter region and provide further insights into the transcriptional regulation of IKKi in human chondrocytes and other cell types.

Eight-month prospective study of 14 patients with hospital-acquired severe acute respiratory syndrome

OBJECTIVE

To define the clinical characteristics and clinical course of hospital-acquired severe acute respiratory syndrome (SARS).

PATIENTS AND METHODS

This 8-month prospective study of 14 patients with hospital-acquired SARS in Taipei, Taiwan, was conducted from April through December 2003.

RESULTS

The most common presenting symptoms in our 14 patients with hospital-acquired SARS were fever, dyspnea, dizziness, malaise, diarrhea, dry cough, muscle pain, and chills. Lymphopenia and elevated serum levels of lactate dehydrogenase (LDH) and C-reactive protein (CRP) were the most common Initial laboratory findings. Initial chest radiographs revealed various pattern abnormalities and normal results. Five of the 14 patients required mechanical ventilation. The need for mechanical ventilation was associated with bilateral lung involvement on the initial chest radiograph and higher peak levels of LDH and CRP. Clinical severity of disease varied from mild to severe. At 8 months after disease onset, patients with mild or moderate SARS had normal findings or only focal fibrosis on chest high-resolution computed tomography. However, bilateral fibrotic changes remained in the 4 patients who had recovered from severe SARS, 1 of whom had mild restrictive ventilatory impairment. One patient with severe SARS died; she was elderly and had other comorbidities. Five additional patients had reduced diffusing capacity.

CONCLUSION

The clinical picture of our patients presenting with hospital-acquired SARS revealed atypical pneumonia associated with lymphopenia, elevated serum levels of LDH, rapid clinical deterioration, and lack of response to empirical antibiotic therapy. Substantially elevated levels of LDH and CRP correlated with severe illness requiring mechanical ventilatory support. In those receiving mechanical ventilation, pulmonary function was only mildly reduced at 6 to 8 months after acute illness, consistent with the natural history of acute respiratory distress syndrome due to other causes.

Prostate gland differentiation in females

Severe acute respiratory syndrome (SARS) is an infectious condition caused by the SARS-associated coronavirus (SARS-CoV), a new member in the family Coronaviridae. To evaluate the lung pathology in this life-threatening respiratory illness, we studied postmortem lung sections from 8 patients who died from SARS during the spring 2003 Singapore outbreak. The predominant pattern of lung injury in all 8 cases was diffuse alveolar damage. The histology varied according to duration of illness. Cases that were 10 or fewer days in duration demonstrated acute phase diffuse alveolar damage (DAD), airspace edema, and bronchiolar fibrin. Cases with a time course greater than 10 days showed organizing phase DAD, type II pneumocyte hyperplasia, squamous metaplasia, multinucleated giant cells, and acute bronchopneumonia. In acute DAD, pancytokeratin staining was positive in hyaline membranes along alveolar walls and highlighted the absence of pneumocytes. Multinucleated cells were shown to be both type II pneumocytes and macrophages by pancytokeratin, TTF-1, and CD68 staining. SARS-CoV RNA was identified by RT-PCR in 7 of 8 cases in fresh autopsy tissue and in 8 of 8 cases in formalin-fixed, paraffin-embedded lung tissue including the one negative case in fresh tissue. Understanding the pathology of DAD in SARS patients may provide the basis for therapeutic strategies. Further studies of the pathogenesis of SARS may reveal new insights into mechanisms of DAD.