To determine the prevalence and outcome of intravenous gamma-globulin (IVIG) retreatment in patients with Kawasaki disease (KD). Multicenter, retrospective survey of all children with KD evaluated at nine clinical centers across North America during a 15-month period. Data were available for 378 patients. At 48 h after completion of the initial IVIG infusion, 50 patients (13.2%) remained febrile, 29 (58.0%) of whom were retreated with IVIG, including 4 (13.8%) with coronary artery abnormalities before their first IVIG infusion. Among 25 retreated patients with a normal baseline echocardiogram, 5 (20.0%) developed coronary abnormalities and were termed "treatment failures." Among the 323 patients with a normal baseline echocardiogram, only 9 (2.8%) were treatment failures; treatment failure occurred in 4 of 282 (1.4%) patients who became afebrile post-IVIG and in 5 of 41 (12.2%) patients with persistent or recrudescent fever after their first course of IVIG therapy (P=0.002). The overall prevalence of new coronary abnormalities in KD patients treated with IVIG and aspirin remains low. Persistent or recrudescent fever after the first course of IVIG was associated with an increased risk of treatment failure (P=0.002). IVIG retreatment in patients who remain febrile after the first course of IVIG is now common (58.0%), although the efficacy of this practice requires assessment with a randomized trial.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with substantial cardiovascular implications. Although infection with SARS-CoV-2 is usually mild in children, some children later develop a severe inflammatory disease that can have manifestations similar to toxic shock syndrome or Kawasaki disease. This syndrome has been defined by the US Centers for Disease Control and Prevention as multisystem inflammatory syndrome in children. Although the prevalence is unknown, >600 cases have been reported in the literature. Multisystem inflammatory syndrome in children appears to be more common in Black and Hispanic children in the United States. Multisystem inflammatory syndrome in children typically occurs a few weeks after acute infection and the putative etiology is a dysregulated inflammatory response to SARS-CoV-2 infection. Persistent fever and gastrointestinal symptoms are the most common symptoms. Cardiac manifestations are common, including ventricular dysfunction, coronary artery dilation and aneurysms, arrhythmia, and conduction abnormalities. Severe cases can present as vasodilatory or cardiogenic shock requiring fluid resuscitation, inotropic support, and in the most severe cases, mechanical ventilation and extracorporeal membrane oxygenation. Empirical treatments have aimed at reversing the inflammatory response using immunomodulatory medications. Intravenous immunoglobulin, steroids, and other immunomodulatory agents have been used frequently. Most patients recover within days to a couple of weeks and mortality is rare, although the medium- and long-term sequelae, particularly cardiovascular complications, are not yet known. This review describes the published data on multisystem inflammatory syndrome in children, focusing on cardiac complications, and provides clinical considerations for cardiac evaluation and follow-up.

We report the isolation of a novel antimicrobial peptide, bass hepcidin, from the gill of hybrid striped bass, white bass (Morone chrysops) × striped bass (M. saxatilis). After the intraperitoneal injection of Micrococcus luteus and Escherichia coli, the peptide was purified from HPLC fractions with antimicrobial activity against Escherichia coli. Sequencing by Edman degradation revealed a 21‐residue peptide (GCRFCCNCCPNMSGCGVCCRF) with eight putative cysteines. Molecular mass measurements of the native peptide and the reduced and alkylated peptide confirmed the sequence with four intramolecular disulfide bridges. Peptide sequence homology to human hepcidin and other predicted hepcidins, indicated that the peptide is a new member of the hepcidin family. Nucleotide sequences for cDNA and genomic DNA were determined for white bass. A predicted prepropeptide (85 amino acids) consists of three domains: a signal peptide (24 amino acids), prodomain (40 amino acids) and a mature peptide (21 amino acids). The gene has two introns and three exons. A TATA box and several consensus‐binding motifs for transcription factors including C/EBP, nuclear factor‐κB, and hepatocyte nuclear factor were found in the region upstream of the transcriptional start site. In white bass liver, hepcidin gene expression was induced 4500‐fold following challenge with the fish pathogen, Streptococcus iniae, while expression levels remained low in all other tissues tested. A novel antimicrobial peptide from the gill, bass hepcidin, is predominantly expressed in the liver and highly inducible by bacterial exposure.

Tomisaku Kawasaki published the first English-language report of 50 patients with Kawasaki disease (KD) in 1974. Since that time, KD has become the leading cause of acquired heart disease among children in North America and Japan. Although an infectious agent is suspected, the cause remains unknown. However, significant progress has been made toward understanding the natural history of the disease and therapeutic interventions have been developed that halt the immune-mediated destruction of the arterial wall. We present a brief history of KD, review progress in research on the disease, and suggest avenues for future study.Kawasaki saw his first case of KD in January 1961 and published his first report in Japanese in 1967. Whether cases existed in Japan before that time is currently under study. The most significant controversy in the 1960s in Japan was whether the rash and fever sign/symptom complex described by Kawasaki was connected to subsequent cardiac complications in a number of cases. Pathologist Noboru Tanaka and pediatrician Takajiro Yamamoto disputed the early assertion of Kawasaki that KD was a self-limited illness with no sequelae. This controversy was resolved in 1970 when the first Japanese nationwide survey of KD documented 10 autopsy cases of sudden cardiac death after KD. By the time of the first English-language publication by Kawasaki in 1974, the link between KD and coronary artery vasculitis was well-established.KD was independently recognized as a new and distinct condition in the early 1970s by pediatricians Marian Melish and Raquel Hicks at the University of Hawaii. In 1973, at the same Hawaiian hospital, pathologist Eunice Larson, in consultation with Benjamin Landing at Los Angeles Children's Hospital, retrospectively diagnosed a 1971 autopsy case as KD. The similarity between KD and infantile periarteritis nodosa (IPN) was apparent to these pathologists, as it had been to Tanaka earlier.What remains unknown is the reason for the simultaneous recognition of this disease around the world in the 1960s and 1970s. There are several possible explanations. KD may have been a new disease that emerged in Japan and emanated to the Western World through Hawaii, where the disease is prevalent among Asian children. Alternatively, KD and IPN may be part of the spectrum of the same disease and clinically mild KD masqueraded as other diseases, such as scarlet fever in the preantibiotic era. Case reports of IPN from Western Europe extend back to at least the 19th century, but, thus far, cases of IPN have not been discovered in Japan before World War II. Perhaps the factors responsible for KD were introduced into Japan after the World War II and then reemerged in a more virulent form that subsequently spread through the industrialized Western world. It is also possible that improvements in health care and, in particular, the use of antibiotics to treat infections caused by organisms including toxin-producing bacteria reduced the burden of rash/fever illness and allowed KD to be recognized as a distinct clinical entity.Itsuzo Shigematsu, Hiroshi Yanagawa, and colleagues have conducted 14 nationwide surveys in Japan. These have indicated that: 1) KD occurred initially in nationwide epidemics but now occurs in regional outbreaks; 2) there are ∼5000 to 6000 new cases each year; 3) current estimates of incidence rates are 120 to 150 cases per 100 000 children <5 years old; 4) KD is 1.5 times more common in males and 85% of cases occur in children <5 years old; and 5) the recurrence rate is low (4%). In 1978, David Morens at the Centers for Disease Control and Prevention published a case definition based on Kawasaki's original criteria. The Centers for Disease Control and Prevention developed a computerized database in 1984, and a passive reporting system currently exists in 22 states. Regional investigations and national surveys suggest an annual incidence of 4 to 15 cases per 100 000 children <5 years of age in the United States.The natural history of KD reveals that coronary artery aneurysms occur as a sequela of the vasculitis in 20% to 25% of untreated children. Echocardiography can be successfully used to detect coronary artery dilatation and aneurysms in virtually all patients. Patients with no acute phase coronary artery changes detected by echocardiogram are clinically asymptomatic at least 10 years later. The Japanese Ministry of Health has established a registry of 6500 children who will be followed longitundinally to determine the natural history of the illness. No similar registry of patients exists in the United States.Studies of KD pathogenesis show a progression of arterial lesions accompanying KD vasculitis and a number of immunoregulatory changes, including a deficiency of circulating CD8+ suppressor/cytotoxic T cells; an abundance of circulating B cells spontaneously producing immunoglobulins; and circulating, activated monocytes. Biochemical and immunologic evidence suggests endothelial cell activation and injury. Although the cause of KD remains unknown, clinical trials have established effective therapies, despite the absence of a proven cause. Intravenous immunoglobulin (IVIG) plus aspirin lowers the rate of coronary artery aneurysms from 20% to between 3% and 5%. In 1988, the Committee on Infectious Diseases of the American Academy of Pediatrics endorsed IVIG treatment as recommended therapy for KD. Questions remain regarding treatment of patients who fail to respond to an initial dose of IVIG. The role of steroids or other antiinflammatory agents in the treatment of KD is controversial.Areas for further research include: 1) a more sensitive case definition that includes laboratory and echocardiographic data, as well as clinical signs and symptoms; 2) development of a diagnostic test based on the biology of inflammation and acute endothelial cell damage that, in the absence of the causative agent, could be used to identify children with KD;...