Interleukin-1 Beta-Mediated Sex Differences in Kawasaki Disease Vasculitis Development and Response to Treatment

OBJECTIVE

Kawasaki disease (KD) is the leading cause of acute vasculitis and acquired heart disease in children in developed countries. Notably, KD is more prevalent in males than females. We previously established a key role for IL (interleukin)-1 signaling in KD pathogenesis, but whether this pathway underlies the sex-based difference in susceptibility is unknown. Approach and Results: The role of IL-1 signaling was investigated in the Lactobacillus casei cell wall extract-induced experimental mouse model of KD vasculitis. Five-week-old male and female mice were injected intraperitoneally with PBS, Lactobacillus caseicell wall extract, or a combination of Lactobacillus caseicell wall extract and the IL-1 receptor antagonist Anakinra. Aortitis, coronary arteritis inflammation score and abdominal aorta dilatation, and aneurysm development were assessed. mRNA-seq (messenger RNA sequencing) analysis was performed on abdominal aorta tissue. Publicly available human transcriptomics data from patients with KD was analyzed to identify sex differences and disease-associated genes. Male mice displayed enhanced aortitis and coronary arteritis as well as increased incidence and severity of abdominal aorta dilatation and aneurysm, recapitulating the increased incidence in males that is observed in human KD. Gene expression data from patients with KD and abdominal aorta tissue of Lactobacillus caseicell wall extract-injected mice showed enhanced Il1b expression and IL-1 signaling genes in males. Although the more severe IL-1β-mediated disease phenotype observed in male mice was ameliorated by Anakinra treatment, the milder disease phenotype in female mice failed to respond.

CONCLUSIONS

IL-1β may play a central role in mediating sex-based differences in KD, with important implications for the use of anti-IL-1β therapies to treat male and female patients with KD.

[Previous or coincident infections with suspected Kawasaki disease. Should we change our approach?]

INTRODUCTION

Kawasaki disease (KD) is a multisystem vasculitis associated with coronary artery abnormalities. Infections could be a trigger of the inflammation. The main aim of this study was to describe the presence of infections in children with KD, and to analyse the clinical characteristics and the presence of coronary abnormalities in these cases.

PATIENTS AND METHODS

A retrospective study was performed within the Kawasaki Diseases Network (KAWA-RACE (2011-2016). An analysis was performed that included patients with positive microbiological findings (PMF) during the acute phase, as well as those with a previous recent infection (PRI) during the 4 weeks preceding KD diagnosis.

RESULTS

The study included total of 621 children with KD, with PMF being found in 101 (16.3%) patients, and a PRI in 107 (17.2%). Significantly less echocardiographic abnormalities were found in the in the group with a PRI, when compared to those without a PRI (23 vs. 35%, P=.01) and also a lower proportion of overall coronary artery lesions (16 vs. 25%, P=.054). No significant differences were found in the proportion of aneurysms in either of these groups (PRI or PMF) when compared to those without infection.

CONCLUSIONS

In the present study, no differences were found in the incidence of coronary aneurysms in either of the groups, with or without PRI or PMF. Therefore, if KD is suspected, appropriate treatment should be started despite having a confirmed infection.

Profile of resistance to IVIG treatment in patients with Kawasaki disease and concomitant infection

INTRODUCTION

Kawasaki disease (KD) can be associated with concomitant viral or bacterial infections. Children with persistent or recurrent fever 36 hours after the end of intravenous immunoglobulin (IVIG) are considered to be resistant to treatment and are at increased risk for coronary complications. Although concomitant infection does not affect coronary outcome, it is unknown how it influences the response to IVIG treatment.

METHODOLOGY

Retrospective cohort study between 2008 and 2016 in a tertiary pediatric university hospital, including 154 children, of which 59 (38%) had concomitant infection.

RESULTS

Children with concomitant infection were more likely to have fever 48 hours after initial IVIG treatment (36% vs 20%, p = 0.05) and to be treated with a second dose (33% vs 18%, p = 0.04). Children with infection had higher C-reactive protein at the time of diagnosis (148 vs 112 mg/L, p = 0.04), and 48 hours after IVIG administration (111 vs 59 mg/L, p = 0.003). Nevertheless, there was no statistically significant difference in the prevalence of coronary complications (Z-score > 2.5) between children with and without concomitant infection (36% vs 39%, p = 0.68).

CONCLUSION

Children with KD and concomitant infection are more likely to have persistent fever and elevated inflammatory markers after treatment. This association increases the likelihood of receiving a second dose of IVIG but not the risk of coronary complication. Accordingly, prospective studies to distinguish true IVIG resistance from infection induced persistent fever is warranted.

Kawasaki disease in association with urinary tract infection

We report a 2-month-old infant with E. coli urinary tract infection, who did not respond to antibiotic therapy. She later developed clinical features fulfilling criteria of Kawasaki disease (KD), and was treated with intravenous immunolglobulin and aspirin. KD should be considered in the differential diagnosis in patients who present with infection and do not respond to antibiotic therapy.

Bacille Calmette Guérin (BCG) can induce Kawasaki disease-like features in programmed death-1 (PD-1) gene knockout mice

OBJECTIVES

Various genetic variants of inhibitory immune signals have been suspected as feasible causes of Kawasaki disease (KD). We investigated the associative role of programmed death-1 (PD-1) gene in the pathogenesis of KD by injecting bacilli Calmette Guérin (BCG) to PD-1 gene knockout (PD-1KO) mice.

METHODS

In order to induce KD-like clinical manifestations in young PD-1KO mice, intradermal injection of the bacilli Calmette Guérin (BCG) was performed twice on the abdominal skin with a 4-week interval. For defining the role of BCG, heat shock protein (HSP) 65 was challenged. In addition, Staphylococcus aureus was adopted as a microorganism that does not contain HSP65 structure. One month after the second injection, heart, liver, and kidneys were removed and examined.

RESULTS

PD-1KO mice showed KD-like features including prolonged fever for more than 5 days, erythematous swelling on soles, tail skin desquamation, and gallbladder (GB) hydrops. Inflammatory cell aggregation and intimal proliferation in at least more than one coronary artery was found in all PD-1KO mice whereas scanty coronary lesion was found in wild type (WT) mice. When the PD-1KO mice were injected twice with HSP65, coronary arterial lesions similar to those seen after BCG injection were observed. Inflammatory reactions in other organs including hepatic arteries, renal arteries, and biliary arteries were also observed in PD-1KO mice.

CONCLUSIONS

Our data suggest that PD-1 gene may be one of the genetic predispositions of KD and antigens containing HSP65 structure could be a triggering factor of KD by our animal model of KD.

[Etiologic agent of Kawasaki disease]

Clinical and epidemiologic features suggest infectious agent or agents as a possible cause of Kawasaki disease; however, the etiology of Kawasaki disease still remains unknown. A number of microorganisms including bacteria, viruses, rickettsiae etc. were hypothesized as an etiology of the illness. Unfortunately, no specific agent that provides reproducible evidence has yet reported. The differences of histology between vasculitic disorders indicate the differences of etiology and pathogenesis. The histological characteristics that abnormal activation of monocytes/macrophages is caused in the vascular lesions of Kawasaki disease can be of help when considering the etiology of Kawasaki disease.

[Kawasaki disease and infection]

Kawasaki disease (KD) is an acute multisystemic vasculitis. Although some infectious agents are highly suspected the etiology of KD remains unknown. Various bacteria such as, Streptococcus pyogenes, Staphylococcus aureus, and Yersinia pseudotuberculosis have been implicated in etiology of KD. However, modern molecular techniques failed to identify the positive relation between these agents and etiology of KD. Recently, one hypothesis suggests that superantigens (TSS-1, SEB, SEC, SPEB, SPEC), which are produced by streptococci and staphylococci, play an important role in the cause of KD. Although several studies show that superantigens, mainly bacterial toxins and viral antigens, are involved in causing some diseases, there is no obvious evidence that superantigens are able to induce KD. Host-derived factor as well as infectious agents should be investigated to understand the immunopathogenesis of KD.

Clostridium baratii bacteremia associated with Kawasaki syndrome. First case report

We experienced a case of a 3-year-old boy who presented signs and symptoms of Kawasaki syndrome. Two blood culture sets were processed by the hospital microbiology laboratory using a standard blood culturing system. The anaerobic bottles gave a positive result at day 3 after inoculation. The biochemical profiles produced by the RapID ANA II System showed that the organism was Clostridium baratii with a probability of 99%. Our case highlights the importance of C. baratii as a potential human pathogen and reports the associations with manifestations, which, to our knowledge, have not been previously described concomitantly with a clostridial infection.

Similarities of Kawasaki disease and Yersinia pseudotuberculosis infection epidemiology

Although an infectious etiology is strongly suspected in Kawasaki disease (KD), an etiologic agent has not yet been identified. By reviewing epidemiologic data published in past decades, this work highlights a higher incidence of KD when populations were exposed to the risk of Yersinia pseudotuberculosis infection. This hitherto unnoticed element reinforces the hypothesis whereby this bacterium might contribute to the development of KD in some cases.

The role of superantigens of group A Streptococcus and Staphylococcus aureus in Kawasaki disease

PURPOSE OF REVIEW

Since the first suggestion of a superantigen hypothesis for Kawasaki disease over a decade ago, debate on the aetiology remains inconclusive. This article reviews recent publications that address the role of superantigens of group A Streptococcus and Staphylococcus aureus in the pathogenesis of Kawasaki disease.

RECENT FINDINGS

Over the past few years, new superantigens produced by group A Streptococcus and S. aureus have been increasingly identified, bringing the total known number to more than 30. Several studies on T-cell Vbeta repertoires and seroloepidemiology have demonstrated evidence for the involvement of single or multiple superantigens produced by the two pathogens. The associated superantigens differed in those studies, including streptococcal pyrogenic toxins A and C, staphylococcal enterotoxins A-C, and toxic shock syndrome toxin 1. These disparate findings suggest that the inflammation of Kawasaki disease does not result from a single agent but rather a final common inflammatory pathway in genetically susceptible individuals after numerous infectious agents.

SUMMARY

Certain staphylococcal and streptococcal superantigens are suggested to be responsible for the development of Kawasaki disease. A better understanding of the precise role of the causative agents will lead to accurate diagnosis, more targeted therapy and an improvement of coronary outcomes.

[Yersinia pseudotuberculosis type 4a infection meeting the diagnostic criteria for Kawasaki disease complicated by disseminated intravascular coagulation]

We report a case of Yersinia pseudotuberculosis (Y. ptbc) infection complicated by disseminated intravascular coagulation (DIC) that presented as Kawasaki disease (KD). A 9-year-old girl had been well until two days before, when she developed a fever, exanthem, and abdominal pain. An erythematous macular rash was observed in the perineum, and she had a strawberry tongue. The patient was admitted to Kawasaki Medical School Hospital because the macular rash spread over her entire body, and edema of her hands and conjunctivitis subsequently developed. Echo cardiography showed dilation of the left coronary artery. Thrombocytopenia and an elevated total fibrin degeneration product level were noted on the third hospital day, and the prothronmbin and partial-thromboplastin times were prolonged. Her clinical presentation was typical of KD and DIC. A stool culture and a blood culture were negative. Serologic tests were positive for antibodies to Y. ptbc. The antibody titer against Y. ptbc-derived mitogen was not elevated after her recovery. Y. ptbc infection should be considered in an older child whose clinical findings fulfill the criteria for KD complicated by DIC.

Kawasaki disease and toxic shock syndrome--at last the etiology is clear?

A decade after the superantigen hypothesis for KD was first suggested, it has still not been either proven or refuted conclusively. Although initial optimism for the hypothesis was quashed by a series of published papers apparently refuting the idea, in the last few years there have been a number of good studies providing evidence in support of the superantigen hypothesis. Whether this renewed enthusiasm is justified will hopefully become clear in the near future. Ultimately, accurate diagnosis, more targeted treatment, and preventative strategies depend on the unraveling of the immunopathogenesis of this disease.

Relation of streptococcal pyrogenic exotoxin C as a causative superantigen for Kawasaki disease

We previously reported that the frequency of TCRBV2 and TCRBV6S5-bearing T-cells was high in patients in the acute phase of Kawasaki disease (KD) and that streptococcal pyrogenic exotoxin C (SPE-C) was a potent stimulator of these TCRBV-bearing T-cells. To further elucidate the pathogenesis of KD, we examined the T-cell receptor (TCR) repertoire, human leukocyte antigen (HLA)-DRB1 genotype, and antibody responses to recombinant(r) SPE-C in patients with KD. We also performed in vitro stimulation with rSPE-A and rSPE-C of peripheral blood mononuclear cells from healthy donors and characterized the reacting T-cells. The percentage of T-cells bearing TCRBV2 and TCRBV6S5 was high in patients in the acute stage of KD. rSPE-C stimulation of PBMC from healthy donors induced expansion of TCRBV2 and TCRBV6S5-bearing T-cells. Furthermore, serum levels of anti-SPEC antibodies, which did not display antimitogenic activity, were higher in patients with acute KD than in age-matched controls. The frequencies of the DRB1*04051, 0406, and 0901 were high, whereas that of the DRB1*1101 was low among patients with KD as compared with the healthy adults.

Characteristic profile of intestinal microflora in Kawasaki disease

To investigate whether the ecology of the intestinal microflora may change in the acute phase of Kawasaki disease (KD), the distribution pattern was studied of common micro-organisms in feces from 20 patients with KD, 20 patients with acute febrile diseases (disease control) and 20 healthy children. KD patients had a significantly lower (p < 0.001) incidence of Lactobacillus (2/20, 10%) than disease control patients (16/20, 80%) and healthy children (14/20, 70%). KD patients had no significant incidences of other microbial genera, compared with both disease control and healthy children.

CONCLUSION

The results suggest that a lack or loss of the beneficial Lactobacillus genus in the enteric microflora may occur during the acute phase of KD.

Kawasaki syndrome associated with group A streptococcal and Epstein-Barr virus co-infections

We present a case of Kawasaki syndrome complicated by coronary aneurysm in a 6-year-old boy with laboratory evidence of group A streptococcal infection and infectious mononucleosis. The case demonstrates that evidence of acute infection in a patient with features suggestive of Kawasaki syndrome should not exclude a diagnosis of the latter. Immunoglobulin therapy should be considered seriously in highly suggestive cases, even if diagnostic criteria are not fulfilled.

Prevalence of superantigen-secreting bacteria in patients with Kawasaki disease

OBJECTIVES

To assess the prevalence of superantigen secreting bacteria in children with acute Kawasaki disease (KD) relative to control patients.

STUDY DESIGN

Bacterial cultures were obtained in a blinded fashion from the throat, rectum, and groin of 45 patients with untreated acute KD and 37 febrile control patients from 6 centers in the United States. Cultures were processed for the presence of superantigen-producing bacteria at a central laboratory.

RESULTS

Staphylococci or streptococci that produced superantigens (TSST-1, SEB, SEC, SPEB, SPEC) were isolated from 25 of 45 patients with KD (56%) as compared with 13 of 37 (35%) control patients (P =.078). Because SEB- and SEC-producing Staphylococcus aureus have not been associated with KD and because they do not induce a Vbeta2+ T-lymphocyte response, we analyzed the difference between groups relative to superantigens TSST-1 or SPEB/SPEC production. TSST-1 secreting S aureus or SPEB/SPEC producing group A streptococci were isolated from 20 of 45 (44%) patients with KD compared with 7 of 37 (19%) control patients (P =.019).

CONCLUSIONS

The overall isolation rates of superantigen (TSST-1, SPEB, SPEC, SEB, SEC) producing bacteria between patients with KD and febrile control patients were not statistically significant. However, future studies should further examine the potential role of Vbeta2-stimulatory superantigens (TSST-1 and SPEB/SPEC) in KD.

Kawasaki disease: is it caused by an infectious agent?

Kawasaki disease (KD) is an acute systemic febrile illness of unknown aetiology, predominantly affecting children under five years of age. Initially described in 1967 by Tomisaku Kawasaki, it is now the most common cause of acquired heart disease in children in the developed world. Although normally self-limiting, KD is associated with a range of complications, the most important of which is the development of life-threatening coronary artery abnormalities. Here, we examine the evidence supporting the concept that KD is caused by an infectious agent. Various infectious agents--including bacterial, viral and Rickettsial organisms--have been implicated as potential causes, as have certain immunological agents such as bacterial toxin-mediated superantigens, allergens such as anionic detergents and house-dust mites, and some chemicals (including heavy metals). Following extensive research, however, no links between any of these individual agents and the disease have been established irrefutably. Despite this, most of the epidemiological and immunological evidence currently available indicates that the causative agent is most likely to be infectious in nature; and additional evidence highlights the likelihood that development of KD is multifactorial in nature, requiring certain genetic and immunological factors, and possibly a vector.

Failure to demonstrate Chlamydia pneumoniae in cardiovascular tissue from children with Kawasaki disease

Chlamydia pneumoniae has been associated with atherosclerosis and myocardial infarction in adults. Coronary artery tissues of five fatal cases of Kawasaki disease were examined by PCR; none was positive.

Kawasaki syndrome: the Iranian experience

Experience with 50 cases of Kawasaki syndrome in the Islamic Republic of Iran is presented. The syndrome occurred mostly in winter and spring with a 2.1:1 male:female ratio. In 72% of cases, the disease occurred between 1 and 5 years of age, and 80% had an antecedent viral or bacterial illness. Eight patents (16%) had microbiological evidence of infection and 19 (38%) had clinical evidence. Five patients had clinical and radiological evidence of sinusitis. Leukocytosis, neutrophilia, bandaemia, elevated erythrocyte sedimentation rate, positive C-reactive protein, reversed albumin/globulin ratio and increased antistreptolysin O titre were other indications of infection and inflammation. Male gender, prolonged fever, white blood cell count > 15,000/mm3 and absolute granulocyte count > 10,000/mm3 were significant risk factors for the development of coronary artery disease (10 patients).

Evidence for the involvement of bacterial superantigens in psoriasis, atopic dermatitis, and Kawasaki syndrome

A growing body of evidence implicates streptococcal and staphylococcal superantigens in the development of psoriasis, atopic dermatitis and Kawasaki syndrome. In each of these illnesses, an abnormal state of immunologic activity is observed. Superantigens, which have a unique ability to activate large numbers of lymphocytes, are likely to contribute to these disorders in a number of ways. The demonstrated activities of bacterial superantigens include increasing the number of circulating lymphocytes, with activation of autoreactive subsets, upregulation of tissue homing receptors on circulating lymphocytes, and local activation of immune cells within affected tissues. Through these and other mechanisms, superantigens have a proven ability to induce high levels of inflammatory cytokines and/or initiate autoimmune responses that contribute to the development of skin and vascular disorders. Though development of the illnesses discussed in this review are highly complex processes, superantigens may well play a critical role in their onset or maintenance. Understanding superantigen function may elucidate potential therapeutic strategies for these disorders.

Characterization and distribution of a new enterotoxin-related superantigen produced by Staphylococcus aureus

Staphylococcal enterotoxins (SEs) are a family of structurally related pyrogenic exotoxins consisting of the five prototypic SEs (types A to E) and three newly characterized SEs (types G to I) produced by Staphylococcus aureus (S. aureus). They also work as superantigens and cause food poisoning and shock symptoms in humans. In this study, we cloned a new variant gene of the seg and characterized its superantigenic properties and distribution among the clinical isolates of S. aureus. The gene encodes a 233 amino acid protein which is highly homologous to SEG (97.7%). The variant SEG (SEGv) expressed by the cloned gene exerted mitogenic activity on human peripheral blood mononuclear cells at the concentration of 100 pg/ml. T cells bearing Vbeta3, 12, 13.1, 13.2, 14 and 15 were preferentially expanded after stimulation with the recombinant protein. The mRNA of the variant seg gene was detected in the total RNA of the organisms bearing this gene. By PCR, 27 out of 48 clinical isolates of S. aureus (56%) possessed either the seg or variant seg gene. These findings suggest that SEG, or SEGv, is one of the most frequently produced superantigen exotoxins by S. aureus and may participate in the inflammatory process of the host by activating a distinct set of Vbeta families of T cells.

Infectious exanthems and unusual infections

Invasive disease due to group A beta-hemolytic streptococci (GABHS) can be divided into 3 categories of disease: streptococcal toxic shock syndrome (strepTSS), necrotizing fasciitis, and other invasive GABHS disease. Patients with strepTSS may have multiorgan failure within hours of presentation. Clindamycin and penicillin G should be used in combination for treatment of invasive GABHS disease. The mortality rate for menstrual staphylococcal toxic shock syndrome has decreased with early recognition and treatment, and removal of hyperabsorbent tampons from the market. Kawasaki syndrome (KS) is the most common cause of acquired heart disease in children in the U. S., and atypical forms have a higher mortality rate than typical KS. Hantavirus pulmonary syndrome is a zoonosis with an 80% mortality rate if the diagnosis is not made on first presentation and patients return to the hospital in shock. Children and adolescents with Lyme disease have an excellent prognosis and respond well to antimicrobial therapy. Cat scratch disease (CSD) is caused by Bartonella henselae and is transmitted by flea-infested kittens. CSD lymphadenopathy typically resolves spontaneously in 2ñ3 months; however, there is a 50% likelihood of resolution in 1 month if patients receive a 5-day treatment course with azithromycin.

Isolation of a Kawasaki disease-associated bacterial sequence from peripheral blood leukocytes

BACKGROUND

The clinical and epidemiologic features of Kawasaki disease (KD) suggest an infectious etiology, but the agent(s) remains unknown. We aimed to isolate the causative bacterial gene from peripheral blood leukocytes of patients with acute KD.

METHODS

Nested polymerase chain reaction (PCR) assay was used to amplify the bacterial 16S ribosomal RNA gene (rDNA). The amplified DNA were cloned into a plasmid vector and sequenced. Phylogenetic analysis was performed with clustal W program and the neighbour-joining method.

RESULTS

First, the PCR reagents were examined by the PCR assay using conservative primers and we found more than 10 16S rDNA sequences contaminating the reagents. We then examined five KD patients using the PCR assay, excluding the contaminated sequences, and obtained five 16S rDNA sequences as possible KD-associated sequences. The primers specific to each 16S rDNA sequence were synthesized and used for specific PCR assays. Only the PCR assay specific to the 16S rDNA sequence termed 16S71-33 did not show any false positives with the control DNA from non-KD patients. The 16S71-33 sequence was positive in three of 20 patients with acute KD before gamma-globulin therapy, but it became negative after therapy. The phylogenetic analysis showed a new species of the genus Corynebacterium as the origin of the 16S71-33 sequence.

CONCLUSIONS

These data show that an infectious KD agent is traced in peripheral leukocytes and that a new Corynebacterium species may be responsible for KD in some cases. The true frequency and the role of the new Corynebacterium in KD would be clarified by measuring specific antibodies to it.

Staphylococcus aureus isolates from patients with Kawasaki disease express high levels of protein A

Kawasaki disease (KD) is an acute vasculitis of young children that can be complicated by coronary artery abnormalities. Recent findings suggest that a superantigen(s) may play an important role in stimulating the immune activation associated with the disease, although the origin of this superantigen(s) is unclear. Staphylococcus aureus, isolated from the rectum or pharynx of patients with KD, secretes toxic shock syndrome toxin 1 (TSST-1). The KD isolates express low levels of other exoproteins compared to isolates from patients with toxic shock syndrome (TSS). Thus, it was previously suggested that the KD isolates may be defective in the global regulatory locus agr (for accessory gene regulator), which positively regulates these factors (D. Y. M. Leung et al., Lancet 342:1385-1388, 1993). Here we describe another characteristic of KD isolates. When considered collectively, the KD isolates were found to express higher levels of staphylococcal protein A than the TSS isolates, another characteristic of an agr-defective phenotype. This correlated with a higher level of spa mRNA in these isolates. In contrast, the KD and TSS isolates expressed comparable levels of TSST-1, consistent with previous findings (D. Y. M. Leung et al., Lancet 342:1385-1388, 1993). Analysis of RNAIII transcript levels and nucleotide sequence analysis of the RNAIII-coding region suggested that the KD isolates are not defective in RNAIII, the effector molecule of the agr regulatory system. However, induction of RNAIII transcription in the KD isolates did not result in a dramatic decrease in the amount of spa mRNA, as has been reported for other strains (F. Vandenesch, J. Kornblum, and R. P. Novick, J. Bacteriol. 173:6313-6320, 1991).

Kawasaki syndrome-like illness associated with infection caused by enterotoxin B-secreting Staphylococcus aureus

Two children had symptoms and clinical signs that were characteristic of the diagnostic criteria for Kawasaki syndrome, temporally associated with Staphylococcus aureus bacteremia. One child initially had focal osteomyelitis that was evident clinically and radiographically, and radiographic evidence of multifocal osteomyelitis was noted at follow-up. The blood-borne S. aureus isolates from these two patients secreted staphylococcal enterotoxin B and were negative for toxic shock syndrome toxin. Staphylococcal and streptococcal superantigens may play a role in the pathogenesis of some cases of Kawasaki syndrome or Kawasaki syndrome-like illness.

Staphylococcus aureus isolated from Kawasaki disease patients hyper-releases extracellular protein A

S. aureus isolates from patients with Kawasaki disease (KD) release high levels of extracellular protein A (SpA), as compared to S. aureus in other diseases. The molecular weight of this released protein A is about 70 kDa. Extracellular KD SpA purified by affinity chromatography possessed the same amino acid sequence at the NH2-terminal IgG binding region and the same antigenic specificity as recombinant and cell-wall-bound SpA preparations. The size of DNA fragments containing the spa gene from S. aureus KD strains was 160-165 kb. All of these DNA fragments contained the igb portion encoding the IgG-binding region of KD SpA. Significantly higher molecular size of the SpA molecules hyper-released in the stationary-phase culture and the lack of production of other exo-proteins allow us to speculate that S. aureus isolated from patients with KD have mutations occurring in the agr locus.

Suppression of coronary vasculitis in a murine model of Kawasaki disease using an angiogenesis inhibitor

Coronary arteritis can be induced in C57BL/6 mice with a single intraperitoneal (ip) injection of Lactobacillus casei cell fragments. Histologic sections resemble the vasculitis and aneurysms observed in the medium-sized coronary arteries of children with Kawasaki disease. Since endothelial cells could play an important role in the development of vasculitis, a recently described angiogenesis inhibitor that is not an immunosuppressive agent, AGM-1470 (derived from Aspergillus fumigatus), was used to evaluate its therapeutic potential in this model. A total of 32 mice were administered 0.5 mg of sterile L. casei preparation ip on day 0 and randomized to either a treatment (AGM-1470, 27mg/kg sc alternate days) or a control (vehicle only) protocol. Hearts were harvested on day 14 (early disease) or at the end of the study on day 28 (established disease). Histologic sections were scored blindly for vasculitis. Day 14 sections from both protocols manifested only minimal disease, indicating that the vasculitis had not yet matured. By day 28, the AGM-1470 group had significantly less coronary vasculitis than the control group (0.7 vs 2.6, p < 0.005, respectively). These studies suggest that endothelial cells may play an active role in this pathologic process and that angiogenesis inhibitors, such as AGM-1470, could be useful tools for the treatment and understanding of vasculitis.

Association of toxic shock syndrome toxin-secreting and exfoliative toxin-secreting Staphylococcus aureus with Kawasaki syndrome complicated by coronary artery disease

Kawasaki syndrome (KS) has been reported to be associated with selective expansion of Vbeta2+ T cells and either staphylococcal toxic shock syndrome toxin-1 or streptococcal pyrogenic exotoxin C in uncomplicated cases. However, there have been no previous studies on the role of superantigens in KS associated with coronary artery disease, the major complication of this illness. The present study characterized bacteria isolated from three acute KS patients who developed coronary artery disease. Staphylococcus aureus secreting either TSST-1 (n = 3) or exfoliative toxin A (n = 1), both known to stimulate expansion of Vbeta2+ T cells, were isolated from all three patients. The percent Vbeta2+ T cells was determined in three patients with coronary artery disease. On presentation, one patient demonstrated reduction, whereas the other two showed expansion, of Vbeta2+ T cells. Repeat analyses of the latter two children showed their percent Vbeta2+ T cells to decrease toward normal. These observations suggest that coronary artery disease in KS may result from superantigenic stimulation of Vbeta2+ T cells. This is also the first demonstration of an association of staphylococcal exfoliative toxin with acute KS. The observation that three different bacterial toxins associated with KS are potent activators of Vbeta2+ T cells suggests an important role for this T cell subset in the pathogenesis of this autoimmune disease.

[Purification and partial characterization of a novel human platelet aggregation factor in the extracellular products of Streptococcus mitis, strain Nm-65]

In this paper, we report the purification and partial characterization of human platelet aggregation factor form the extracellular products (ECP) of Streptococcus mitis (S. mitis) isolated from a patient with Kawasaki disease (KD). Platelet aggregation reaction was carried out using platelet-rich plasma (PRP) and washed platelets suspended in ACD-PBS. The aggregation factor was designated as S. mitis-derived human platelet aggregation factor (Sm-hPAF). The results obtained were as follows. 1) Sm-hPAF was isolated by chromatography on DEAE-Sepharose CL-6 B, hydroxyapatite and Superdex 75 columns. The purified Sm-hPAF showed a single band upon SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and molecular weight of approximately 66 kDa on SDS-PAGE. The isoelectric point (pI) of Sm-hPAF was 8.5, and Sm-hPAF showed an absorption peak at 278 nm on absorption spectra. When the platelet aggregation activity of the Sm-hPAF was compared with that of ECP, the specific aggregation activity of the of Sm-hPAF was significantly increased (up to 28-fold). Sugars were not found in Sm-hPAF. The sequence of the first 15 amino-terminal amino acid residues were H.Asp-Glu-Gln-Gly-Asn-Arg-Pro-Val-Glu-Thr-Glu-Asn-Ile-Ala-Arg. The platelet aggregation activity of Sm-hPAF was inactivated by heating at 45 degrees C for 10 min. 2) PGE2 was released from platelets after incubation for 10 min with Sm-hPAF in a dose-dependent fashion. Platelet aggregation by the Sm-hPAF was totally inhibited by either PGE1, or GRGDS, but these reagents did not inhibit the platelet aggregation by collagen. 3) Histological examination of the rabbit skin sites showing an early reaction revealed increased dilatation of the veins and capillaries with cellular infiltration in the perivascular space of the dermis. Hyperplasia of the endothelial cells was noted. Degeneration of the vascular walls was observed in the later stages of the reaction. Aggregation of red cells in the vascular endothelium was also observed. Sm-hPAF was capable of producing vasculitis. 4) Twenty (76.9%) platelet-rich plasma samples (PRP) derived from 26 healthy human volunteers reacted with Sm-hPAF, but the remaining 6 PRPs were not reactive. Preliminary study suggests the existence of an inhibitory factor in plasma from nonreactive donors.

Sequence of the toxic shock syndrome toxin gene (tstH) borne by strains of Staphylococcus aureus isolated from patients with Kawasaki syndrome

To explore whether a novel staphylococcal clone or structural variant of toxic shock syndrome toxin 1 is associated with Kawasaki syndrome, six toxigenic strains of Staphylococcus aureus from Kawasaki syndrome patients were studied. The strains were divisible into two groups based on phenotypic and genotypic characteristics and are therefore unequivocally not clonal. Portions of the tstH genes of each strain were sequenced. Three were sequenced in their entirety, while the remainder were sequenced from codon 66 to codon 137 of the mature protein only. Two of the former group differed slightly in the sequences of their signal peptides relative to the sequence published for the tstH signal peptide. Those differences did not affect toxin processing or secretion. The sequenced portions of the regions encoding mature toxic shock syndrome toxin 1 were identical in all six strains and corresponded exactly to the published sequence of tstH. No evidence was found for the existence of a structural variant of tstH uniquely associated with Kawasaki syndrome.

Microbiologic studies on the small intestine in Kawasaki disease

In an attempt to elucidate the etiology of Kawasaki disease (KD), the microflora of the small intestine was investigated in 15 Japanese KD patients. The range of bacterial species adhering to the lumen of the jejunum of KD patients was quite different from that of controls. A wider variety of bacteria was isolated from jejunal biopsies in the acute phase of KD as compared with those from control children. Gram-positive cocci were isolated from KD patients predominantly. Notably, five kinds of streptococci and two kinds of staphylococci were isolated only from KD patients. Further investigation of the microflora of the small intestine of KD patients may provide clues to clarify the pathogenesis of this disease.

Characterization of Streptococcus sanguis isolated from patients with Behçet's disease

The DNA homology and cell wall sugar constituents of eight Streptococcus sanguis(-like) strains, three isolated from the patients with Behçet's disease (BD114-23, BD113-20, BD118-1), two from patients with Kawasaki disease (MCLS-1, MCLS-2), and three type and reference strains of ATCC (ATCC10556T: S. sanguis, ATCC10557: S. oralis, and ATCC10558T: S. gordonii) were analyzed. Strains BD114-23 and BD118-1 showed high DNA homology to ATCC10556T, and their cell wall constituents were identical. Conversely, BD113-20, MCLS-1, MCLS-2, and ATCC10557 showed little DNA homology to ATCC10556T and ATCC10558T, but showed approximately 50 to 60% homology to each other. The cell wall constituents of BD113-20, MCLS-1, MCLS-2, and ATCC10557, however, were somewhat different, indicating that some of the clinical isolates have different characters from those of the three ATCC strains.

Kawasaki disease associated with streptococcal infection within a family

OBJECTIVE

To describe the illness occurring in four members of a family, which had clinical and laboratory features of Kawasaki disease and streptococcal infection.

METHODOLOGY

A retrospective report of three siblings and an adult male living in one household. The children had serology, blood counts, cultures and echocardiography performed and were treated with antibiotics and gammaglobulin infusions.

RESULTS

The patients developed clinical, and exhibited laboratory, features suggesting streptococcal infection and 4/5 criteria suggesting the diagnosis of Kawasaki disease. All made a good clinical recovery but the youngest developed a coronary artery aneurysm.

CONCLUSIONS

It may be difficult to distinguish streptococcal infection and Kawasaki disease. It is possible that some cases of Kawasaki disease are precipitated by streptococcal infection.

The absence of evidence of staphylococcal toxin involvement in the pathogenesis of Kawasaki disease

To detect a causative superantigen and to clarify a possible role for staphylococci in Kawasaki disease (KD), culture supernatants of individual bacterial isolates from 11 acute-stage patients were studied. Toxic shock syndrome toxin-1 (TSST-1) and antibody to TSST-1 and enterotoxins A (SEA), B (SEB), and C (SEC) in acute (mean, day 7) and late convalescent (mean, month 15) sera from 26 patients (12 with coronary artery aneurysms) and 22 age-matched controls were measured. Only 1 of 60 supernatants was mitogenic for human lymphocytes; it was 1 of the 4 Staphylococcus aureus isolates. Mitogenicity was neutralized by sera obtained after administration of intravenous gamma globulin (mean, week 4) but not by late convalescent sera. TSST-1 was detectable in 2 of 26 acute sera and 1 of 22 control sera. No KD but 1 control serum had IgM to TSST-1. IgG seroconversion rates to TSST-1, SEA, SEB, and SEC were 10%, 15%, 21% and 16%, respectively. These data do not support the involvement of toxin-producing staphylococci in KD.

Superantigenic exotoxin production by isolates of Staphylococcus aureus from the Kawasaki syndrome patients and age-matched control children

Nineteen strains of Staphylococcus aureus were isolated from the throat or the tooth surfaces of 19 cases amongst 127 patients with Kawasaki syndrome (KS) during the acute phases and 11 S. aureus isolates were obtained from five of 17 diseased controls and six healthy controls. The production of exotoxins, particularly superantigenic toxic shock syndrome toxin-1 (TSST-1), coagulase serotype, pigment production, haemolytic activity and tryptophan auxotrophy of these isolates were compared. Among 10 KS S. aureus strains isolated in 1990-1991, five (50%) secreted TSST-1, a higher frequency than two (18%) of 11 control isolates. In contrast, none of the nine KS strains collected in 1984 produced TSST-1. Four of five TSST-1-secreting KS strains produced white or white to golden pigmentation, whereas the two control strains capable of TSST-1 production formed golden colonies. There were no noticeable differences between S. aureus strains from KS patients and control children in the production of staphylococcal exotoxins A-E, coagulase serotype, haemolysis of sheep erythrocytes and tryptophan auxotrophy. The pathological or aetiological role of a new TSST-1-secreting S. aureus clone in patients with KS was not confirmed.

Search for highly conserved viral and bacterial nucleic acid sequences corresponding to an etiologic agent of Kawasaki disease

The use of conventional methods to detect a possible infectious cause of Kawasaki disease (KD) has been unsuccessful. Using the polymerase chain reaction and DNA hybridization techniques, we have sought evidence that a known or new herpesvirus, parvovirus, or bacterial pathogen is related etiologically to KD. Peripheral blood DNA from acute KD patients was subjected to amplification and dot-blot hybridization to detect the presence of herpesvirus DNA, and acute KD peripheral blood and serum DNA were subjected to dot-blot hybridization for the presence of parvoviral DNA. All samples were negative for both herpesvirus and parvovirus DNA. In addition, we analyzed buffy-coat white blood cell DNA, synovial fluid DNA, and frozen autopsy and formalin-fixed, paraffin-embedded myocardial tissue DNA from KD patients for the presence of highly conserved bacterial 16S ribosomal RNA gene sequences with the polymerase chain reaction, and all were negative. These results argue against a direct pathogenic role for herpesviruses, parvoviruses, and bacteria in KD. This approach to the detection of highly conserved genomic sequences among broad groups of microorganisms can be adapted for the detection of other groups of microorganisms and may yet prove useful in the search for an etiologic agent of KD.

Is it infectious?

The Autumn meeting of the English Branch of The British Society for the Study of Infection was held at the Zoological Society of London. Speakers from a breadth of specialties re-examined the clinical features and pathology of some remarkably diverse illnesses and addressed the question 'Is it Infectious?'