Treatments for multi-system inflammatory syndrome in children - discharge, fever, and second-line therapies

Scarce evidence exists about the best treatment for multi-system inflammatory syndrome (MIS-C). We analyzed the effects of steroids, intravenous immunoglobulin (IVIG), and their combination on the probability of discharge over time, the probability of switching to second-line treatment over time, and the persistence of fever 2 days after treatment. We did a retrospective study to investigate the effect of different treatments on children with MIS-C from 1 March 2020 to 1 June 2021. We estimated the time-to-event probability using a Cox model weighted by propensity score to balance the baseline characteristics. Thirty of 132 (22.7%) patients were initially treated with steroids alone, 29/132 (21.9%) with IVIG alone, and 73/132 (55%) with IVIG plus steroids. The probability of early discharge was higher with IVIG than with IVIG plus steroids (hazard ratio [HR] 1.65, 95% CI 1.11-2.45, p = 0.013), but with a higher probability of needing second-line therapy compared to IVIG plus steroids (HR 3.05, 95% CI 1.12-8.25, p = 0.028). Patients on IVIG had a higher likelihood of persistent fever than patients on steroids (odds ratio [OR] 4.23, 95% CI 1.43-13.5, p = 0.011) or on IVIG plus steroids (OR 4.4, 95% CI 2.05-9.82, p < 0.001). No differences were found for this endpoint between steroids or steroids plus IVIG.    Conclusions: The benefits of each approach may vary depending on the outcome assessed. IVIG seemed to increase the probability of earlier discharge over time but also of needing second-line treatment over time. Steroids seemed to reduce persistent fever, and combination therapy reduced the need for escalating treatment. What is Known: • Steroids plus intravenous immunoglobulin, compared with intravenous immunoglobulin alone for multi-system inflammatory syndrome (MIS-C) might reduce the need for hemodynamic support and the duration of fever, but the certainty of the evidence is low. What is New: • Intravenous immunoglobulin, steroids, and their combination for MIS-C may have different outcomes. • In this study, intravenous immunoglobulin increased the probability of discharge over time, steroids reduced persistent fever, while combination therapy reduced the need for second-line treatments.

Ex vivo effect of JAK inhibition on JAK-STAT1 pathway hyperactivation in patients with dominant-negative STAT3 mutations

PURPOSE

STAT1 gain-of-function (GOF) and dominant-negative (DN) STAT3 syndromes share clinical manifestations including infectious and inflammatory manifestations. Targeted treatment with Janus-kinase (JAK) inhibitors shows promising results in treating STAT1 GOF-associated symptoms while management of DN STAT3 patients has been largely supportive. We here assessed the impact of ruxolitinib on the JAK-STAT1/3 pathway in DN STAT3 patients' cells.

METHODS

Using flow cytometry, immunoblot, qPCR, and ELISA techniques, we examined the levels of basal STAT1 and phosphorylated STAT1 (pSTAT1) of cells obtained from DN STAT3, STAT1 GOF patients, and healthy donors following stimulation with type I/II interferons (IFNs) or interleukin (IL)-6. We also describe the impact of ruxolitinib on cytokine-induced STAT1 signaling in these patients.

RESULTS

DN STAT3 and STAT1 GOF resulted in a similar phenotype characterized by increased STAT1 and pSTAT1 levels in response to IFNα (CD3⁺ cells) and IFNγ (CD14⁺ monocytes). STAT1-downstream gene expression and C-X-C motif chemokine 10 secretion were higher in most DN STAT3 patients upon stimulation compared to healthy controls. Ex vivo treatment with the JAK1/2-inhibitor ruxolitinib reduced cytokine responsiveness and normalized STAT1 phosphorylation in DN STAT3 and STAT1 GOF patient' cells. In addition, ex vivo treatment was effective in modulating STAT1 downstream signaling in DN STAT3 patients.

CONCLUSION

In the absence of effective targeted treatment options for AD-HIES at present, modulation of the JAK/STAT1 pathway with JAK inhibitors may be further explored particularly in those AD-HIES patients with autoimmune and/or autoinflammatory manifestations.

Septic pulmonary emboli detected by 18F-FDG PET/CT in children with S. aureus catheter-related bacteremia

PURPOSE

The role of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) in the diagnosis of metastatic infectious foci in children with catheter-related blood stream infection has been hardly studied, although some authors have reported it benefit in the screening of metastatic foci in adult population. Septic pulmonary emboli are among the most difficult to identify, because many cases do not present pulmonary complaints or abnormal chest radiography. However, diagnosis of these foci has important therapeutic consequences. The purpose of this article is to describe the role of ¹⁸F-FDG PET/CT in the diagnosis of septic pulmonary embolism in children with S. aureus catheter-related bacteremia.

METHODS

We report 3 children with S. aureus catheter-related bacteremia and normal chest X-ray at admission, in whom ¹⁸F-FDG PET/CT led to the diagnosis of unsuspected septic pulmonary emboli, with an impact on clinical management.

RESULTS

All patients had hemophilia and implantable venous access ports and presented with fever and normal lung auscultation. Only 1 reported non-specific symptoms (undifferentiated left chest pain). All patients had normal chest X-ray on admission. Catheters were removed within 48 h after admission in 2 cases, and 5 days after admission in the last case, subsiding fever. In 2 children, paired blood cultures were not able to identify bacteremia. However, in all cases catheter tip and subcutaneous port cultures yielded S. aureus and PET/CT detected unsuspected pulmonary metastatic emboli.

CONCLUSIONS

¹⁸F-FDG PET/CT should be considered as a useful tool to diagnose septic pulmonary embolism in S. aureus catheter-related bacteremia, especially if conventional diagnostic imaging techniques have failed to reveal possible metastatic foci. Further studies are needed to clarify the usefulness of PET/CT performance in children with CRBSI.