Kawasaki syndrome and concurrent Coxsackie virus B3 infection

We describe two previously healthy children who were hospitalized in the same period in different departments of our University with clinical signs of Kawasaki syndrome, which were treated with intravenous immunoglobulins and acetylsalicylic acid: in both cases, Coxsackie virus infection was concurrently demonstrated by enzyme-linked immunosorbent assay, and complement fixation test identified antibodies to serotype B3. In the acute phase, both patients presented hyperechogenic coronary arteries, but no cardiologic sequels in the mid term. The etiological relationship between Kawasaki syndrome and Coxsackie viruses is only hypothetical; however, the eventual identification of ad hoc environmental triggers is advisable in front of children with Kawasaki syndrome, with the aim of optimizing epidemiological surveillance and understanding the intimate biological events of this condition.

Discrimination between incomplete and atypical Kawasaki syndrome versus other febrile diseases in childhood: results from an international registry-based study

OBJECTIVES

Kawasaki syndrome (KS) is an acute systemic vasculitis of unknown origin predominantly affecting young children. Early diagnosis is crucial to prevent cardiac complications. However, the differential diagnosis of patients with the incomplete or atypical form of the disease poses a heavy challenge for the paediatrician. Our aim was to evaluate the prevalence of incomplete and atypical cases among children with KS and to identify clinical and laboratory variables that may help differentiate incomplete and atypical KS from other febrile diseases at this age.

METHODS

We established an international registry to recruit patients with KS, including those with incomplete and atypical forms. The control group included age-matched febrile children admitted to the hospital with a variety of diseases mimicking KS. The aim was to define clinical or laboratory clues to help in the discrimination of incomplete and atypical KS patients from others.

RESULTS

Two hundred and twenty-eight patients with incomplete KS (78%) and atypical KS (22%) were compared to 71 children with other febrile diseases. Patients with incomplete and atypical KS presented a statistically significant higher frequency of mucosal changes, conjunctivitis, extremity abnormalities and perineal desquamation compared to the group of other febrile diseases. In addition, C-reactive protein and platelet counts were significantly higher in incomplete and atypical KS compared to the other group.

CONCLUSIONS

This is the largest series of incomplete and atypical KS patients of non East-Asian ancestry: we suggest that in patients with the aforementioned clinical features and laboratory evidence of systemic inflammation in terms of increased C-reactive protein and platelet counts an echocardiogram should be performed and diagnosis of KS considered.

Calcineurin inhibitor treatment of intravenous immunoglobulin-resistant Kawasaki disease

OBJECTIVE

To describe the clinical course and outcome of 10 patients with Kawasaki disease (KD) treated with a calcineurin inhibitor after failing to respond to multiple therapies.

STUDY DESIGN

Demographic and clinical data were prospectively collected using standardized case report forms. T-cell phenotypes were determined by flow cytometry, and KD risk alleles in ITPKC (rs28493229), CASP3 (rs72689236), and FCGR2A (rs1801274) were genotyped.

RESULTS

Intravenous followed by oral therapy with cyclosporine (CSA) or oral tacrolimus was well tolerated and resulted in defervescence and resolution of inflammation in all 10 patients. There were no serious adverse events, and a standardized treatment protocol was developed based on our experiences with this patient population. Analysis of T-cell phenotype by flow cytometry in 2 subjects showed a decrease in circulating activated CD8(+) and CD4(+) T effector memory cells after treatment with CSA. However, suppression of regulatory T-cells was not seen, suggesting targeting of specific, proinflammatory T-cell compartments by CSA.

CONCLUSION

Treatment of refractory KD with a calcineurin inhibitor appears to be a safe and effective approach that achieves rapid control of inflammation associated with clinical improvement.

Genetic susceptibility to Kawasaki disease: analysis of pattern recognition receptor genes

Kawasaki disease (KD) is a systemic vasculitis of unknown etiology occurring in infants and children. Several lines of evidence suggested the importance of genetic factors and infectious triggers for the pathogenesis of KD. We have reported that oral administration of a pure NOD1 ligand induces coronary arteritis in mice without fail. Since NOD1 is one of the pattern recognition receptors (PRRs) which play important roles in the innate immunity for the detection of microbial substances and induce inflammatory responses, we have investigated the association of PRR genes with the development of KD. Forty-six tagging-SNPs in 19 PRR genes were genotyped in Japanese KD patients (n=356, consisting of two groups) and controls (n=215). The genotypes and allele frequencies of each SNP or haplotype were compared between KD patients and controls. As a result, we did not find any genes with strongly contributed to the development of KD. A haplotype, G-T-C-C, in the NOD1 gene, was associated with lower risk for KD development (KD 1st group versus controls: 23.2% versus 35.3%, Pc=0.0385). The second-round case-control study in KD group 2 demonstrated that a haplotype, T-T-C-G-A-C, in the NLRP1 gene was associated with a higher risk for KD development (4.9% versus 1.2%, Pc=0.035). From the association analysis of SNPs and haplotypes of 19 PRR genes, NOD1 and NLRP1 seemed to partly contribute to the development of KD. Further analysis with larger samples of another independent set would be needed to find confirmative results.

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.

The role of atorvastatin in regulating the immune response leading to vascular damage in a model of Kawasaki disease

Superantigens have been implicated in a number of diseases including Kawasaki disease (KD), a multi-system vasculitis resulting in coronary artery aneurysms. We have characterized a murine disease model in which coronary arteritis is induced by a novel superantigen found in Lactobacillus casei cell wall extract (LCWE). Using this animal model of KD, we have identified three pathogenic steps leading to coronary artery aneurysm formation. These steps include T cell activation and proliferation, production of the proinflammatory cytokine tumour necrosis factor (TNF)-α and up-regulation of matrix metalloproteinase 9 (MMP-9), an elastolytic protease. In addition to their cholesterol-lowering effects, 3-hydroxy-3-methylglutaryl (HMG) coenzyme A (CoA) reductase inhibitors (statins) have pleotropic immunomodulatory properties. Thus, we examined the effect of atorvastatin in modulating each of these three critical pathogenic processes leading to aneurysm formation in the disease model. Atorvastatin inhibited lymphocyte proliferation in response to superantigen stimulation in a dose-dependent manner. This inhibition was also observed for production of soluble mediators of inflammation including interleukin (IL)-2 and TNF-α. The inhibitory effect on proliferation was rescued completely by mevalonic acid, confirming that the mechanism responsible for this inhibitory activity on immune activation was inhibition of HMG-CoA reductase. Similarly, TNF-α-induced MMP-9 production was reduced in a dose-dependent manner in response to atorvastatin. Inhibition of extracellular-regulated kinase (ERK) phosphorylation appears to be the mechanism responsible for inhibition of MMP-9 production. In conclusion, atorvastatin is able to inhibit critical steps known to be important in the development of coronary aneurysms, suggesting that statins may have therapeutic benefit in patients with KD.

Polymorphism in the promoter of the CCL5 gene (CCL5G-403A) in a cohort of North Indian children with Kawasaki disease. A preliminary study

OBJECTIVES

Kawasaki disease (KD) is a common vasculitic disorder and a leading cause of acquired heart disease in children. However, there is a paucity of information on KD from developing countries. The clinical phenotype of KD in India is different from that in the West. In this study, we investigated the association of a promotor gene variant of chemokines like chemokine ligand 5 (CCL5) and a deletion in chemokine receptor CCR5 (which is a common receptor for CCL5, macrophage inhibitory protein 1α and 1β), in a cohort of North Indian children with KD.

METHODS

CCL5 G-403A and CCR5Del 32 gene variants were genotyped in the KD cohort (n=40) and in healthy controls (n=100) using the PCR-RFLP assay. Logistic regression analysis was performed in order to examine the association of these variants with KD, with special reference to those with direct (on echocardiography) or indirect (on myocardial scintigraphy) evidence of coronary involvement.

RESULTS

No significant difference in genotype or allele frequency of CCL5 G-403A variant was observed between patients and controls. However, patients with evidence of coronary involvement had a higher frequency of the minor allele CCL5 -403A (p<0.004; OR- 2.25, 95%CI: 1.13-4.46). CCR5 Del 32 variant was found to be monomorphic (minor allele frequency <0.05) in our cohort.

CONCLUSIONS

CCL5 -403A variant may be associated with coronary involvement in North Indian children with KD. Our results, however, have to be replicated on a larger sample before any definitive conclusions can be drawn.

Microparticles and Kawasaki disease: a marker of vascular damage?

BACKGROUND

Microparticles (MPs) are increased in diseases characterised by endothelial injury. Kawasaki disease (KD) damages the endothelium provoking life-threatening involvement of coronary arteries.

OBJECTIVES

To compare KD MPs vs. controls. METHODS. Thirty KD and 20 controls were enrolled. MPs were stained with monoclonal antibodies against platelets, endothelial cells (EC), monocytes, T and B cells, neutrophils, and quantified by FACS.

RESULTS

The total number of MPs was significantly increased in KD versus controls (193x105±0.6x105 vs. 94x105±0.9x105 million/ml plasma p=0.01) and vs. KD after IVIG therapy (132x105±0.4x105million/ml plasma p=0.01). EC and T cells were the major source of MPs in KD (72x105±1x105 vs. 3x105±0.9x105million/ml plasma for T cells p=0.005; 76x105±0.7x105 vs. 45x105±0.4x105 million/ml plasma for EC p<0.02) followed by MPs derived from platelets (13x105±0.3x105 vs. 3x105±0.9x105 million/ml plasma p=0.028). Cell-derived MPs B were 17x105±0.4x105 vs. 20x105±0.8x105million/ml plasma in controls (p=0.7). No significant differences were observed in KD MPs derived from monocytes and neutrophils. After IVIG administration, a significant decrease of MPs derived from platelets (3x105±0.2x105 million/ml plasma p=0.03), EC (9x105±0.4x105 million/ml plasma p=0.01), T cells (72x105±1x105 million/ml plasma p=0.02) and B cells (7x105±0.3x105 million/ml plasma p=0.02) was observed.

CONCLUSIONS

The number of KD MPs is significantly increased and EC and T cells are the major source. MPs may develop from endothelial damage and cell activation. Their role as markers of disease activity or as contributors to endothelial derangement in KD has to be further investigated.

Defective FOXP3 expression in patients with acute Kawasaki disease and restoration by intravenous immunoglobulin therapy

OBJECTIVES

The aims of this study were: 1) to investigate forkhead box P3 (FOXP3) expression in patients with Kawasaki disease (KD), exploring possible differences during the acute phase and after defervescence; 2) to evaluate a possible association of the FOXP3 single nucleotide polymorphism (SNP) 543 (SNP ID: rs2232367) with KD.

METHODS

FOXP3 expression was evaluated on 8 children with KD and 15 healthy children by flow cytometry and Real-Time polymerase chain reaction (RT-PCR). FOXP3 SNP 543 was genotyped by denaturing high-performance liquid chromatography (DHPLC) and sequencing on DNA samples from 58 additional children with KD and 114 healthy donors.

RESULTS

The frequencies of CD4+CD25 +FOXP3+ regulatory T cells were significantly (p=0.0002) lower during the acute phase of KD than in sex- and age-matched healthy donors (median % + SD: 4.8+/-1.3 vs. 7.7+/-1.7) and a similar tendency was revealed for FOXP3 mRNA transcripts (p<0.0001). FOXP3 expression increased significantly, at both protein and mRNA levels, after intravenous immunoglobulin (IVIG) therapy treatment and achieving complete remission of disease (at least 48 hrs; median 9.5 days, range 2-30). Of the 58 patients screened, only one female subject (1.7%) carried the presence of 543 SNP in heterozygosis (C>T; for a total of 1 allele out of 88), with no difference between KD patients and controls (0.0%, 0/203 alleles).

CONCLUSIONS

Our data reinforce the notion of an impaired immunoregulation in KD, suggesting also a role of IVIG treatment in modifying the Treg compartment. FOXP3 SNP 543 does not seem to be involved in susceptibility to KD in Italian children.

Altered immunoglobulin A and M levels associated with changes in BAFF and APRIL after administration of intravenous immunoglobulin to treat Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute vasculitis of unknown etiology. Immunoregulatory abnormalities have been thought to contribute to its pathogenesis. Although treatment with intravenous immunoglobulin (IVIG) effectively prevents significant cardiac morbidity, the mechanism by which IVIG produces an effect in KD has yet to be fully elucidated.

OBJECTIVE

To investigate the effects of IVIG on the immune system of patients with KD.

PATIENTS AND METHODS

Eleven patients with KD (mean [SD] age, 2.2 [1.5] years) were enrolled in this prospective study and treated with high-dose IVIG therapy (2 g/kg in 1 or 2 infusions) during the acute phase of the disease. We examined immunological changes, with special reference to Ig levels and 2 previously unassessed cytokines: B cell-activating factor belonging to the tumor necrosis factor family (BAFF), and a proliferation-inducing ligand (APRIL).

RESULTS

Clinical symptoms disappeared quickly in all cases, with no coronary artery abnormalities. IgA and IgM levels responded more rapidly than previously reported and reached a peak between the 3rd and 10th day after the start of IVIG treatment. The mean (SD) BAFF level was high before IVIG treatment (3234 [1904] pg/mL) and decreased significantly (1085 [257] pg/mL) after IVIG treatment, whereas the mean (SD) APRIL level before IVIG treatment (18.0 [10.0] ng/mL) rose significantly (120.6 [41.2] ng/mL). A significant inverse correlation between BAFF and APRIL was observed in patients with KD.

CONCLUSIONS

These results suggest that IVIG may affect the pathogenesis of KD through alteration of BAFF/APRIL.

Involvement of innate and adaptive immunity in a murine model of coronary arteritis mimicking Kawasaki disease

Kawasaki disease (KD) is the most common cause of acquired cardiac disease and acute vasculitis in children in the developed world. Injection of a cell wall extract isolated from Lactobacillus casei (LCCWE) into mice causes a focal coronary arteritis that histopathologically mimics the coronary lesions observed in KD patients. In this study we used this model to investigate the participation of T cells, B cells, and dendritic cells (DC) in the development of coronary arteritis. RAG1(-/-), B cell(null), and wild-type (WT) mice were injected with a single dose of LCCWE (500 microg/mouse i.p.). None of the RAG1(-/-) mice developed coronary arteritis, whereas 70% of WT and 100% of B cell(null) mice developed coronary lesions, indicating that T cells were required for lesion formation. When splenocytes isolated from LCCWE-treated mice were restimulated with LCCWE, we observed significant IFN-gamma secretion in WT but not in RAG1(-/-) mice. Immunohistochemical staining showed F4/80(+) macrophages, activated MIDC-8(+) myeloid DCs (mDC), plasmacytoid DCs, and colocalization of CD3(+) T cells with mDCs in coronary artery lesions, suggesting an Ag-driven process. T cells but not B cells are required for LCCWE-induced coronary arteritis. Similar to human lesions, the coronary lesions contain macrophages, activated mDCs, and plaslmacytoid DCs all in close proximity to T cells, further strengthening the relevance of this mouse model to the immunopathology of coronary disease in KD. These studies are consistent with the interpretation that macrophages and DCs may collaborate with T cells in the pathological mechanisms of coronary arteritis.

Immunoglobulin V(H) chain gene analysis of peripheral blood IgM-producing B cells in patients with Kawasaki disease

PURPOSE

Kawasaki disease is a systemic vasculitis, and its etiology and pathogenesis are still not clear. Our study was undertaken to investigate the characteristics of the activation of B cells in the peripheral blood of Kawasaki disease (KD) patients and evidence of stimulation by superantigens.

MATERIALS AND METHODS

Blood samples were obtained from three patients (2 males, 1 female) with KD, who were admitted to our Hospital, Seoul, Korea. The mean age was 1.2 years. Distribution of B cells was studied in the acute and subacute phases of KD patients. From the RNA of B cells, we obtained complementary DNA (cDNA) and performed polymerase chain reaction (PCR). To determine the oligoclonal expansion of immunoglobulin M (IgM) V(H) family, we cloned and sequenced the PCR products from each group and analyzed DNA.

RESULTS

In the peripheral blood of acute phase patients, T cells were significantly decreased (p < 0.05), whereas B cells were significantly increased (p < 0.05). When the first PCR was done on the B cell chains, V(H)1 to V(H)6 were all found to be expressed. The number of micro gene clones obtained from 3 patients was 312, and they belonged to V(H)3, V(H)4 and V(H)5 family. M99686 germ line was most frequently used and the next most frequently used, were X92224/J, L21967 and L21964. A similar order was seen in patients. Among the clones, 20 sets of clones showed the same base sequence and this was frequent between V(H)2 and V(H)5. There was one set, which showed almost the same base sequence between different patients, and the homology was 99.5%. Twenty sets of clones that had the same base sequence showed high similarity to the germ line (94 - 100%). Among these, the clones that utilized the M99686 germ line were 4 sets which were most frequent. The 3-dimensional structure of one of these clones showed typical beta, sheet structure of immunoglobulin chains.

CONCLUSION

The IgM transcripts expressed by the B cells in the peripheral blood of KD patients in the acute phase of the disease clearly showed an oligoclonal expansion, suggesting that KD is caused not by stimulation of a superantigen, but rather by a conventional antigen.

Incomplete Kawaski disease: are we missing it?

Kawasaki disease, also known as mucocutaneous lymph node syndrome or infantile polyarteritis nodosa is an acute febrile vasculitis of unknown etiology with a predilection for coronary arteries and potential for aneurysm formation. In Incomplete Kawasaki disease, children with fever lack the sufficient number of criteria to fulfill the epidemiologic case definition and are diagnosed when coronary artery disease is detected. We present a case report of a one and a half years old girl who came with features of incomplete Kawasaki disease, high grade fever, irritability, history of conjunctivitis and cracking of lips. She was investigated and had a platelet count of 902 x 10(9)/L, ESR was 71 mm/hr and CRP was also raised to 12.8 mg/l. Cardiac evaluation and echocardiography was done which showed dilated coronary arteries >3mm on the left side and 4mm on the right side with early aneurysmal changes. She was treated with immunoglobulin and aspirin and improved.

[Causes and mechanisms of systemic vasculitides]

Multiple mechanisms contribute to the pathogenesis of systemic vasculitides: 1. vasculitides resulting from the deposition of circulating immune complexes, comprising polyarteritis nodosa associated with hepatitis B virus infection, cryoglobulinemia associated systemic with vasculitides, mainly the consequence of hepatitis C virus infection, and Schonlein Henoch purpura, which results from the deposition in the mesangium and vessels of IgA forming complexes; 2. vasculitides associated with anti-neutrophil cytoplasm antibodies (ANCA), comprising Wegener's granulomatosis associated with anti-proteinase 3 ANCA, and microscopic polyangiitis and Churg-Strauss syndrome, associated with anti-myeloperoxydase ANCA. The pathogenic role of ANCA has been demonstrated in vitro and in vivo in the case of anti-myéloperoxydase antibodies, whereas it has only been demonstrated in vitro in the case of anti-proteinase 3 antibodies; 3. polyarteritis nodosa unrelated to viral infection results from rheologic phenomenon that explain the localisation of vasculitis lesions at the bifurcation of arteries and the presence of microaneurysm.

[Immunological aspects of Kawasaki disease]

Kawasaki disease is an acute illness of early childhood primarily affecting coronary arteries accompanied by aneurysms. In his first report of 50 patients in Japanese in 1967, Dr. Tomisaku Kawasaki suggested interesting immunological abnormalities of Kawasaki disease, occasional appearances of autoantibodies and proliferations of reticuloendothelial cells in cervical lymph nodes. This review briefly summarizes the aberrations in the immune systems of patients with Kawasaki disease, in antibody production and in responses of macrophage and monocyte.

[Biochemical and immunological laboratory findings in Kawasaki disease]

There is no specific diagnostic test for Kawasaki disease, but certain laboratory findings are characteristics. In acute phase of Kawasaki disease, neutrophils with toxic granules, CRP, ESR are elevated. The platelet count is generally normal in the 1st week of illness and rapidly increases by the 2nd-3rd week of illness. The hepatic transaminases, total cholesterol, LDL, and total bilirubin are increased in the acute stage. On the other hand, total protein, albumin and sodium are generally decreased during 1st-2nd week of illness. Sterile pyuria and cerebrospinal fluid pleocytosis may be present. Moreover, the cytokines, the growth factors, and the adhesion molecules are elevated according to the intensity of vasculitis.

[Changes and significance for regulatory factors for signal pathways of Toll-like receptors in immunological pathogenesis of Kawasaki disease]

OBJECTIVE

Many clinical evidences and epidemiologic data in the past suggested that Kawasaki disease (KD) is correlated with an acute immune dysfunction caused by infection. In our preliminary study, Toll-like receptor 4 signal pathway, which could activate nuclear transcription factor-kappaB and induce excessive product of proinflammatory cytokines, chemokines and co-stimulatory molecules, was observed to be significantly activated during acute phase of Kawasaki disease. But the causative factors and regulatory mechanism are still unknown. In this study, the authors further investigated the changes and significances of regulatory factors for signal pathway of Toll-like receptors (TLRs) in immunological pathogenesis of Kawasaki disease.

METHODS

Forty-eight children with KD, sixteen children with infectious disease (ID) and sixteen age-matched healthy children were studied. Reverse-transcription PCR (RT-PCR) and real-time PCR were used to evaluate the expression levels of regulatory and effective factors in toll-like receptor 4 (TLR4) signal pathways and proinflammatory factors in peripheral blood monocyte/macrophage (MC). The expression of TLR4 protein in MC was analyzed by flow cytometry.

RESULTS

(1) Expression levels of TLR4, MD-2, MyD88, IRAK-4, TRAF6, TAK1, TAB1 and TAB2 mRNA in KD group were elevated significantly during acute phase (P < 0.05). (2) Transcription levels of regulatory factors PRAT4B and STAP2 in patients with KD or ID were found to be higher than those in the healthy volunteers (P < 0.05), but no significant differences in these parameters were detected between KD patients and ID patients (P > 0.05). Transcription levels of regulatory factors such as FLN29, RP105 and MD-1 were up-regulated to some extents and expression level of DAP12 mRNA in KD patients were found to be lower than that in normal controls (P < 0.05), while all of the four regulatory factors were found to be lower than those in ID patients (P < 0.05). Expressions of proinflammatory cytokines such as L-1beta, IL-6 and TNF-alpha in KD patients were significantly higher than those in ID patients (P < 0.05). (3) Stimulation with lipopolysaccharide (LPS) elevated remarkably the expressions of regulatory factors PRAT4B and STAP2 in KD patients or healthy volunteers (P < 0.05). All of the four negative-regulatory factors were found to be significantly up-regulated after stimulation with LPS in controls (P < 0.05). No responses to LPS were observed in expression of FLN29, RP105 and MD-1 mRNA in KD patients (P > 0.05), except for increased transcription of DAP12. (4) The levels of PRAT4B and STAP2 mRNA in KD patients with coronary artery lesion (KD-CAL(+)) were detected to be higher than those in KD patients without coronary artery lesion (KD-CAL(-)) during acute phase (P < 0.05), while those of FLN29, RP105 and MD-1 in KD-CAL(+) group were lower than that in the latter (P < 0.05). No significant difference in DAP12 mRNA expression level was detected between the two groups (P > 0.05). Expressions of proinflammatory cytokines and TLR4 protein on surface of CD14-positive cells in KD-CAL(+) group were found to be higher than those in KD-CAL(-) group [(11.9 +/- 2.4)% vs. (6.5 +/- 1.7)%, P < 0.05].

CONCLUSION

Disturbance of negative-regulatory factors may be one of the factors causing aberrant immunological function in KD.

Persistent monocytosis after intravenous immunoglobulin therapy correlated with the development of coronary artery lesions in patients with Kawasaki disease

BACKGROUND AND PURPOSE

This study was conducted to investigate whether changes in the complete blood count (CBC)/differential count (DC) and C-reactive protein (CRP) were correlated to Kawasaki disease (KD) with coronary artery lesions (CALs).

METHODS

A retrospective analysis was performed of all children with KD at Chang Gung Memorial Hospital at Kaohsiung from 2001 to 2006. KD patients were divided into those with and without CALs for testing of correlations with changes in CBC/DC and CRP levels.

RESULTS

A total of 147 patients were enrolled for this analysis. Serial CBC/DC and CRP measurements and echocardiographic data for determination of CAL formation were obtained before and after intravenous immunoglobulin (IVIG) treatment. There were 44 (29%) KD patients having CAL formation (>3 mm in diameter of internal lumen). There was no significant difference in terms of age distribution and major diagnostic criteria between KD patients with and without CALs. Male KD patients, however, had a significantly higher rate of CAL formation (p=0.009). In multivariate logistical regression analysis, persistent monocytosis after IVIG treatment was the only factor significantly correlated to CAL formation (p=0.003).

CONCLUSIONS

Of the febrile routine measurements of CBC/DC and CRP in KD, persistent monocytosis after IVIG treatment was correlated to CAL formation. Further studies to clarify the mechanism of monocytosis may help prevent the CALs of KD.

Transient thrombocytopenia with large platelets in Kawasaki disease

Kawasaki disease (KD) is a multisystem disorder of unknown origin and usually associated with thrombocytosis. The authors describe a case of KD exhibiting thrombocytopenia with markedly large platelets. Among the 173 KD cases, 3 cases exhibited thrombocytopenia. One of these showed cardiac involvement with giant aneurysm of the coronary artery (33%), while only 1 of the remaining 170 cases exhibited cardiac involvement without thrombocytopenia (0.6%). The authors believe that it is important for clinicians to be aware that thrombocytopenia may occur during the course of KD and that this may be a more active condition when compared with thrombocytosis.

Polymorphism of Fc gamma RIIa may affect the efficacy of gamma-globulin therapy in Kawasaki disease

We evaluated whether there is a possible relationship between the effectiveness of gamma-globulin treatment for patients with Kawasaki disease (KD) and the polymorphism of Fcgamma RIIa, IIIb, and IIIa. Genomic DNA was extracted from whole blood collected from 56 patients with KD who received gamma-globulin treatment. The genotypes for Fcgamma RIIIb-NA(1, 2), Fcgamma RIIa-H/R131, and FcgammaRIIIa-F/V158 were determined to investigate the association between these polymorphisms and the development of coronary lesions (CALs). Twenty-three percent of patients with the HH allele for the Fcgamma RIIa polymorphism progressed to CALs, compared with 60% with the HR and RR alleles. HR and RR alleles may be a predictor of the progression of CALs in KD before the initiation of gamma-globulin therapy.

The characterization of cerebrospinal fluid and serum cytokines in patients with Kawasaki disease

BACKGROUND

The central nervous system (CNS) inflammation of Kawasaki disease (KD) has not been sufficiently evaluated in spite of the complications of irritability and CSF pleocytosis.

PATIENTS AND METHODS

Cerebrospinal fluid (CSF) and serum inflammatory cytokine values were simultaneously examined in 10 patients (2.6 +/- 2.1 year of age) during the acute phase. They were all irritable and demonstrated mild consciousness disturbance.

RESULTS

The CSF IL6 was elevated (>3.0 pg/mL) in 6 patients, and 4 of them showed higher CSF than serum values. The CSF sTNFR1 was elevated (>0.5 microg/mL) in 6 patients, and 1 showed higher CSF than serum values. These CSF cytokine (IL6; 81.4 +/- 192.8 pg/mL, sTNFR1; 1.1 +/- 0.8 microg/mL) and CSF/serum ratio (IL6; 2.8 +/- 5.2, sTNFR1 0.4 +/- 0.4) in patients with KD were the same as those of patients with acute encephalitis/acute encephalopathy.

CONCLUSIONS

The differences in the inflammatory cytokine value between CSF and serum suggest that the degree of systemic vasculitis is different between CSF and the circulating blood, and some patients with KD showed a higher degree of CSF inflammation.

Ruptured pediatric posterior cerebral artery aneurysm 9 years after the onset of Kawasaki disease: a case report

CASE REPORT

A 12-year-old boy who had a history of Kawasaki disease 9 years ago experienced a subarachnoid hemorrhage by ruptured right posterior cerebral artery aneurysm. On day 1 operation, as the aneurysm was very fragile and bled easily, two intraoperative ruptures, including a very premature rupture, were encountered. As a result, a left hemiparesis especially severe in the left hand was caused by the right anterior thalamic infarction due to the occlusion of a thalamo-perforating artery arising near the neck of the aneurysm.

DISCUSSION

The histopathological examination of the intraoperative excised aneurysmal dome disclosed the thickening of the endothelial inner due to the endothelial hypertrophy and the invasion of inflammatory cells. This finding of the aneurysm was partially mimicking the finding of the coronary artery of the patients with Kawasaki disease. The combination of cerebral aneurysm and Kawasaki disease has never been reported until now, and the etiology of the aneurysm of this patient is unclear.

Increased CD11b expression on polymorphonuclear leucocytes and cytokine profiles in patients with Kawasaki disease

Clinical evidence implicates polymorphonuclear leucocytes in the pathogenesis of vasculitis in Kawasaki disease. We examined modulation of expression of adhesion molecules (CD11b and CD62L) on polymorphonuclear leucocytes and how this expression is related to serum cytokine concentrations. In 18 patients with Kawasaki disease and 15 control subjects, adhesion molecule expression was determined by two-colour immunofluorescence staining of blood leucocytes and flow cytometry. Eight cytokines and chemokines were also measured. In patients with Kawasaki disease, mean fluorescence intensity for CD11b before giving intravenous immunoglobulin was significantly higher than in normal subjects (P<0 x 005). After intravenous immunoglobulin, mean fluorescence intensity for CD11b decreased significantly. With coronary artery lesions present, mean CD11b fluorescence intensity was significantly higher than without coronary artery lesions (P=0 x 005 before intravenous immunoglobulin; P=0 x 024 after intravenous immunoglobulin). No differences were seen in CD62L expression on polymorphonuclear leucocytes between patients with Kawasaki disease and normal subjects. CD11b expression on polymorphonuclear leucocytes correlated positively with serum interleukin (IL)-6, IL-10, granulocyte colony-stimulating factor, percentage of neutrophils among white cells and C-reactive protein. Polymorphonuclear leucocytes from patients with Kawasaki disease showed increased CD11b expression, which was associated with increased serum cytokines and appeared to be related to coronary artery lesions.

The IL-10 (-627 A/C) promoter polymorphism may be associated with coronary aneurysms and low serum albumin in Korean children with Kawasaki disease

Kawasaki disease (KD) is an acute febrile vasculitic syndrome of unknown etiology that preferentially affects the coronary artery. Interleukin-10 (IL-10) is a key proinflammatory cytokine, and a polymorphism near the major transcriptional start site of the IL-10 gene was shown to influence IL-10 production in vitro. This study investigated the association of the IL-10 promoter polymorphism with KD and its clinical parameters in Korean children. A total of 194 children with congenital heart disease (CHD) and 95 children with KD were included in this study. IL-10 (-627 A/C) polymorphism genotypes were determined using the single-base extension method. There was no difference in the allele frequencies of IL-10 (-627 A/C) polymorphism between CHD children and KD children. KD children with one or two copies of the IL-10 (-627C) allele showed significantly lower albumin levels (p = 0.020) and higher frequencies of early coronary artery aneurysm [62.22% versus 37.78%, adjusted odds ratio (aOR) = 3.50, 95% confidence interval (CI): 1.50-8.16] compared with KD children with the common IL-10 (-627A) allele. These findings suggest that the IL-10 (-627 A/C) promoter polymorphism might be a genetic marker for the risk of early coronary artery complication in KD.

New developments in the search for the etiologic agent of Kawasaki disease

PURPOSE OF REVIEW

The aim of this article is to review recent developments in the search for the etiologic agent of Kawasaki disease.

RECENT FINDINGS

Two recently proposed theories of Kawasaki disease etiology, the toxic shock syndrome toxin-1 hypothesis and the coronavirus NL-63 hypothesis, have been studied extensively and have been disproven. Surprisingly, IgA plasma cells infiltrate inflamed tissues in acute Kawasaki disease, including the coronary artery, and are oligoclonal, or antigen-driven. Synthetic versions of predominant IgA antibodies in acute Kawasaki disease arterial tissue bind to an antigen present in acute Kawasaki disease ciliated bronchial epithelium and in a subset of macrophages in acute inflamed Kawasaki disease tissues. Light and electron microscopic studies of the antigen in acute Kawasaki disease ciliated bronchial epithelium indicate that the Kawasaki disease-associated antigen localizes to cytoplasmic inclusion bodies that are consistent with aggregates of viral protein and associated nucleic acid.

SUMMARY

The identification of cytoplasmic inclusion bodies in acute Kawasaki disease ciliated bronchial epithelium has provided direction for future Kawasaki disease etiology studies. Transmission electron microscopic examination of glutaraldehyde-fixed medium-sized bronchi from acute Kawasaki disease fatalities and analysis of the protein and nucleic acid components of the inclusions should provide important information about these inclusion bodies and speed the identification of the specific etiologic agent of Kawasaki disease.

Kawasaki-like syndrome possibly associated with immune reconstitution inflammatory syndrome in an HIV-positive patient

The occurrence of Kawasaki disease is unusual in adults. We report a Kawasaki-like syndrome in a middle-aged HIV-positive man who had recently begun effective antiretroviral therapy. Onset of a significant inflammatory response after initiation of antiretroviral therapy prompted a diagnosis of Kawasaki-like syndrome associated with immune reconstitution inflammatory syndrome.

TNF-alpha is necessary for induction of coronary artery inflammation and aneurysm formation in an animal model of Kawasaki disease

Kawasaki disease is the most common cause of multisystem vasculitis in childhood. The resultant coronary artery lesions make Kawasaki disease the leading cause of acquired heart disease in children in the developed world. TNF-alpha is a pleiotropic inflammatory cytokine elevated during the acute phase of Kawasaki disease. In this study, we report rapid production of TNF-alpha in the peripheral immune system after disease induction in a murine model of Kawasaki disease. This immune response becomes site directed, with migration to the coronary arteries dependent on TNF-alpha-mediated events. Production of TNF-alpha in the heart is coincident with the presence of inflammatory infiltrate at the coronary arteries, which persists during development of aneurysms. More importantly, inflammation and elastin breakdown in the coronary vessels are completely eliminated in the absence of TNF-alpha effector functions. Mice treated with the TNF-alpha-blocking agent etanercept, as well as TNFRI knockout mice, are resistant to development of both coronary arteritis and coronary aneurysm formation. Taken together, TNF-alpha is necessary for the development of coronary artery lesions in an animal model of Kawasaki disease. These findings have important implications for potential new therapeutic interventions in children with Kawasaki disease.

Arthritis presenting during the acute phase of Kawasaki disease

OBJECTIVE

To define the prevalence, pattern, and clinical course of arthritis presenting at the time of diagnosis of Kawasaki disease.

STUDY DESIGN

A single-center, retrospective study of 414 consecutive patients diagnosed with Kawasaki disease between January 1997 and December 2002 was performed. Standardized clinical assessments, laboratory and imaging test results, and treatment regimens were reviewed. The clinical, laboratory, treatment response, and coronary outcome data were analyzed for children with and without arthritis.

RESULTS

The prevalence of arthritis was 7.5% (31/414). In the 31 children with arthritis, 55% had oligoarticular involvement and 45% had polyarticular involvement. In both of these groups, the large joints were predominantly involved. Some 88% of the children with arthritis responded to standard intravenous immunoglobulin therapy for acute Kawasaki disease and did not require additional medications. The children with arthritis had significantly increased levels of inflammatory markers, but their demographical and clinical features were otherwise similar to those of the children without arthritis, including coronary outcome, with the same proportion (13%) of children from each group having coronary artery lesions (z-score > or = 2.5).

CONCLUSIONS

Arthritis is a short-lived phenomenon included in the clinical spectrum of acute Kawasaki disease. Children with arthritis have evidence of increased systemic inflammation but otherwise share the same clinical features, response to treatment, and coronary outcomes as patients without arthritis. Most cases of arthritis resolve without additional therapeutic intervention.

Prediction of intravenous immunoglobulin unresponsiveness in patients with Kawasaki disease

BACKGROUND

In the present study, we developed models to predict unresponsiveness to intravenous immunoglobulin (IVIG) in Kawasaki disease (KD).

METHODS AND RESULTS

We reviewed clinical records of 546 consecutive KD patients (development dataset) and 204 subsequent KD patients (validation dataset). All received IVIG for treatment of KD. IVIG nonresponders were defined by fever persisting beyond 24 hours or recrudescent fever associated with KD symptoms after an afebrile period. A 7-variable logistic model was constructed, including day of illness at initial treatment, age in months, percentage of white blood cells representing neutrophils, platelet count, and serum aspartate aminotransferase, sodium, and C-reactive protein, which generated an area under the receiver-operating-characteristics curve of 0.84 and 0.90 for the development and validation datasets, respectively. Using both datasets, the 7 variables were used to generate a simple scoring model that gave an area under the receiver-operating-characteristics curve of 0.85. For a cutoff of 0.15 or more in the logistic regression model and 4 points or more in the simple scoring model, sensitivity and specificity were 86% and 67% in the logistic model and 86% and 68% in the simple scoring model. The kappa statistic is 0.67, indicating good agreement between the logistic and simple scoring models.

CONCLUSIONS

Our predictive models showed high sensitivity and specificity in identifying IVIG nonresponders among KD patients.

[The role of activation of toll-like receptors in immunological pathogenesis of Kawasaki disease]

OBJECTIVE

A great deal of clinical evidence and epidemiologic data suggest that Kawasaki disease (KD) is correlated with an acute regulating imbalance of immunology. Lots of evidences in the past suggested that nuclear transcription factor-kappaB and preinflammation factors were up-regulated significantly in patients with KD. But the causative factors are still unknown. Toll-like receptors (TLRs) is a type I trans-membrane protein which could recognize ligands of pathogen microbes, activate the nuclear transcription factor-kappaB and promote gene transcription of pre-inflammation factors and co-stimulatory molecules on cell surface. Aberrant activation of signal pathway of TLRs could interfere with autoimmune tolerance and cause autoimmune diseases. The study was designed to investigate the role of signal transduction of TLRs on immunological pathogenesis of KD.

METHODS

Sixteen children with KD and 16 age-matched health children were studied. Reverse-transcription PCR (RT-PCR) and real-time PCR were used to evaluate the levels of TLRs 1 - 10, MD-2, MyD88, IL-1beta, IL-6 and IL-8 mRNA expressions in peripheral blood mononuclear cells, and expressions of TLRs 2, 4 and co-stimulatory molecules such as CD80 and CD86 in monocyte/macrophage were analyzed by flow cytometry.

RESULTS

(1) Compared with control group, the protein and mRNA levels of TLR4 in KD group were up-regulated significantly [(Real-time PCR: 325.22 +/- 50.34 vs. 2.20 +/- 0.23, P < 0.01); (flow cytometry: 15.96% +/- 5.94% vs. 3.21% +/- 0.62%, P < 0.01)], the difference being not significant as to other TLRs. (2) Transcriptional levels of MD-2 and Myd88 were significantly up-regulated in acute phase of KD (P < 0.01), and down-regulated after the treatment with intravenous gamma globulin therapy. (3) Expressions of co-stimulatory molecules and cytokines in monocyte/macrophage during acute phase of KD were higher than those of control group (P < 0.01).

CONCLUSION

Expressions of TLRs 4, MD-2 and Myd88 were up-regulated during acute phase in KD, suggesting that aberrant activation of TLRs 4 might be one of the initiating factors of immune aberrance in KD.

Macrophage activation syndrome as the presenting manifestation of rheumatic diseases in childhood

We describe 3 patients who presented with features of macrophage activation syndrome (MAS) at the time of presentation of systemic lupus erythematosus (SLE), systemic juvenile idiopathic arthritis, and Kawasaki disease. Immunohistochemical studies in the patient with SLE demonstrated extensive expression of CD163 on hemophagocytic macrophages, suggesting a possible role as a marker of MAS.

[Changes in CD69, CD25 and HLA-DR expressions in peripheral blood T cells in Kawasaki disease]

OBJECTIVE

The study was designed to investigate the changes in CD(69), CD(25) and HLA-DR expressions in peripheral blood T cell in Kawasaki disease (KD).

METHODS

The authors detected CD(69), CD(25) and HLA-DR expressions in peripheral blood T cell by using flow cytometry. The patients who met the diagnostic criteria for KD comprised sixteen boys and fifteen girls (4 - 60 months of age; mean, 26 +/- 18 months). All received intravenous gammaglobulin at a dose of 1 g/(kg.d), for 2 days and oral aspirin at a dose of 30 - 50 mg/(kg.d). In case of persistent fever, a repeated dose of intravenous gammaglobulin or I.V. methylprednisolone at a dose of 20 mg/(kg.d) for three daily doses was attempted. The authors tested blood samples from 17 healthy controls consisting of nine boys and eight girls (3 - 84 months of age; mean, 25 +/- 18 months) and the samples from 31 patients.

RESULTS

The percentage of peripheral blood CD(3)(+) T lymphocyte was (54.4 +/- 9.0)% in acute stage of KD and (65.0 +/- 7.0)% in healthy controls. There was a significant difference between the two groups (P < 0.001). The values of CD(69)(+) [(11.2 +/- 12.6)%, vs. (0.6 +/- 0.4)%], CD(25)(+) [(9.2 +/- 3.5)% vs. (3.9 +/- 1.8)%] and HLA-DR(+) [(8.3 +/- 5.0)% vs. (4.3 +/- 2.3)%] in KD patients were markedly increased compared to those of the healthy controls. After intravenous gammaglobulin treatment, the percentage of CD(3)(+)CD(69)(+) and CD(3)(+)CD(25)(+) significantly decreased [CD(3)(+)CD(69)(+): (14.0 +/- 13.0)% vs. (1.6 +/- 1.2)%, P < 0.05; CD(3)(+)CD(25)(+): (7.8 +/- 4.1)% vs. (2.0 +/- 0.6)%, P < 0.01]. However, the CD(3)(+) T lymphocytes increased [(50.8 +/- 5.0)% vs. (64.9 +/- 5.5)%, P < 0.01]. There was no significant difference in expression of CD(3)(+) T lymphocyte cell activating markers between coronary artery disease group and normal coronary artery group in KD cases (P > 0.05).

CONCLUSION

CD(3)(+) T cell activation in the early and middle stages is involved in the mechanism responsible for cardiovascular injury.

Development of serum IgM antibodies against superantigens of Staphylococcus aureus and Streptococcus pyogenes in Kawasaki disease

To serologically determine the association of microbial superantigens and the pathogenesis of Kawasaki disease (KD), we conducted a case-control study. Serum IgG and IgM antibodies against staphylococcal enterotoxin A (SEA), SEB, SEC, toxic shock syndrome toxin-1 (TSST-1), and streptococcal pyrogenic exotoxin A (SPEA) were measured by an enzyme-linked immunosorbent assay in 293 serum samples from 65 KD patients on clinical days 1-28 and 120 control samples. The administration of immunoglobulin products, which contain high concentrations of IgG antibodies against all the superantigens, directly elevated antitoxin IgG antibodies in KD patients. In contrast, antitoxin IgM antibodies were not detected in immunoglobulin products. Actually, we found a significant elevation of IgM antibodies against SEA in KD patients in the first (median titre: 0.020, P < 0.01 versus control), second (0.024, P < 0.001), third (0.030, P < 0.001) and fourth (0.038, P < 0.001) weeks, compared to the controls (0.015). Significant differences of IgM antibodies were also true for SEB, TSST-1, and SPEA throughout the first to fourth weeks, and for SEC throughout the second to fourth weeks. The prevalence of KD patients having high IgM titres (> mean + 2SD of control values) to the 5 superantigens was increased with the clinical weeks, and reached 29-43% of KD subjects at the fourth week. This is the first study that describes kinetics of IgM antibodies against superantigens and clarifies the serological significance throughout the clinical course of KD. Our results suggest that multiple superantigens involve in the pathogenesis of KD.

Cloning the arterial IgA antibody response during acute Kawasaki disease

Kawasaki disease (KD) is the most common acquired cardiac disease in children in developed nations. The etiology of KD is unknown but likely to be a ubiquitous microbial agent. Previously, we showed that oligoclonal IgA plasma cells infiltrate coronary arteries and other inflamed tissues in acute KD. We demonstrated that a synthetic Ab made using an alpha H chain sequence prevalent in acute KD arterial tissue detected Ag in acute KD coronary arteries, lung, and other inflamed tissues and that Ag localized to cytoplasmic inclusion bodies in the acute KD ciliated bronchial epithelium. In this study, we synthesized a panel of mAbs from alpha and kappa chain sequences present in the KD arterial wall and tested the Abs for binding to acute KD tissues. We report that all of the synthetic mAbs that bind to acute KD tissues detect Ag in cytoplasmic inclusion bodies in the acute KD ciliated bronchial epithelium. Abs made from alpha sequences that were prevalent in KD arterial tissue show stronger binding to acute KD tissues than Abs made from less prevalent sequences. These findings highlight the likely importance of the inclusion bodies in the etiopathogenesis of acute KD, confirm that the IgA Ab response in acute KD is Ag driven, and demonstrate the usefulness of cloning the Ab response in diseased tissues to identify disease-relevant Ags.

[Reactivation of the scar of BCG vaccination in Kawasaki's disease: clinical case and literature review]

Kawasaki disease is an acute febrile multisystemic vasculitis affecting children that can affect the coronary arteries. Routine BCG vaccination in Mexico leads to a 99% coverage in infants younger than 1 year. We present a case of Kawasaki disease with skin lesions at the site of BCG. Clinicians should be aware of this clinical manifestation that could help diagnose atypical or incomplete cases of the disease.

Coeliac disease in patients with Kawasaki disease. Is there a link?

OBJECTIVE

Kawasaki disease (KD) is an acute febrile systemic vasculitis, mainly affecting infants and young children. Immunological abnormalities during the acute phase of KD have been described extensively. However, the occurrence of a second immunological disorder in a patient with a history of KD is rarely reported. We evaluated the presence of autoimmune thyroiditis and coeliac disease (CD) in patients with KD diagnosis.

METHODS

Ninety consecutive children (57 males and 33 females, median age 5.2 yr, age range 1.6-14.1 yr) with KD were evaluated. All patients were evaluated for thyroid function (thyroid-stimulating hormone, thyroxine and triiodothyronine), anti-thyroglobulin (TgA) and anti-peroxidase (TPOA) antibodies, and antigliadin, anti-endomysium and antitransglutaminase antibodies. CD was confirmed by jejunal biopsy if the specific antibody profile was positive. One hundred and fifty Italian children, matched for age and sex and from the same geographic area, acted as controls.

RESULTS

A total of five patients (three boys, two girls; 5.5%; P<0.05) were found positive for coeliac antibodies. In all of these patients the diagnosis of CD was confirmed histologically. Regarding thyroid function and autoantibodies, no patient showed subclinical hypothyroidism or autoimmune thyroiditis. No differences in the familial occurrence of autoimmune diseases between KD patients and controls were found (9.1 and 7.9%, respectively).

CONCLUSIONS

Our data showed a higher prevalence of CD in children with KD, and this suggests that children with KD should be monitored carefully for CD. However, there was no increase in the prevalence of autoimmune thyroid diseases in patients with KD or the familial occurrence of autoimmune diseases.

Selective expansion of CD16highCCR2- subpopulation of circulating monocytes with preferential production of haem oxygenase (HO)-1 in response to acute inflammation

Monocytes are composed of two distinct subpopulations in the peripheral blood as determined by their surface antigen expressions, profiles of cytokine production and functional roles played in vivo. We attempted to delineate the unique functional roles played by a minor CD16(high)CCR2(-) subpopulation of circulating monocytes. They produced significant levels of interleukin (IL)-6 and tumour necrosis factor (TNF)-alpha, but very low levels of IL-10 upon in vitro stimulation. Characteristic profiles of cytokine production were confirmed by stimulating purified subpopulations of monocytes after cell sorting. It was noteworthy that freshly isolated CD16(high)CCR2(-) monocyte subpopulations produced significant levels of haem oxygenase (HO)-1, whereas the major CD16(low)CCR2(+) subpopulation produced little. These results were contrary to the generally accepted notion that the CD16(high)CCR2(-) monocyte subpopulation plays a predominantly proinflammatory role in vivo. The CD16(high)CCR2(-) subpopulation increased in Kawasaki disease and influenza virus infection. In accord with this, HO-1 mRNA expression by mononuclear cells was significantly increased in these illnesses. These results indicate that CD16(high)CCR2(-) subpopulations are of a distinct lineage from CD16(low)CCR2(+) monocytes. More importantly, they may represent a monocyte subpopulation with a unique functional role to regulate inflammation by producing HO-1 in steady state in vivo.

Expression of CD180, a toll-like receptor homologue, is up-regulated in children with Kawasaki disease

Kawasaki disease (KD) is an acute febrile illness in childhood characterized by the formation of aneurysms in coronary arteries. It is believed that KD is caused by infectious agents because of its epidemic waves and high incidence of familial occurrence. Because an increase in the levels and dysfunction of B cells in peripheral blood was reported in KD, we investigated the expression of cluster of differentiation 180 (CD180), a toll-like receptor homologue, in the B cells of children with KD, and in those with bacterial or viral infections. The percentages of CD180 positive B cells were significantly higher in children with KD or viral infections than in those with bacterial infections or in healthy controls. When the expression levels of CD180 were compared by using the mean fluorescent intensity ratio of patients to healthy controls, the level of CD180 expression was also significantly up-regulated in children with KD or viral infections. To clarify the effect of viral infection on the expression of CD180, B cells were stimulated with poly inosinic-cytidyric acid [poly(IC)], a synthetic double-stranded RNA. Poly(IC) clearly enhanced CD180 expression in B cells in vitro, both at the protein and messenger RNA levels. These results suggest that similar mechanisms may be involved in the up-regulation of B cell CD180 expression in patients with either KD or viral infections.