Immunologic and clinical correlations in rheumatic fever and rheumatic heart disease

Association of lymphocyte-monocyte ratio and monocyte-to-high-density lipoprotein ratio with the presence and severity of rheumatic mitral valve stenosis

Aim: We aimed to evaluate the relationships between monocyte-to-high-density lipoprotein ratio (MHR) and lymphocyte-to-monocyte ratio (LMR) and rheumatic mitral valve stenosis (RMVS). Methodology: A total of 368 patients with mitral stenosis and 80 healthy participants were included. Patients were categorized into two groups in respect to the severity of RMVS as mild-moderate group (mitral valve area ≥1.0 cm2) and severe group (mitral valve area <1.0 cm2). Results: The MHR (10.6 ± 2.3, 11.6 ± 2.6, 13.8 ± 3.1; p < 0.001) and C-reactive protein levels (control group, nonsevere RMVS and severe RMVS groups 3.4 ± 0.7, 4.4 ± 1.1, 5.2 ± 1.4, respectively; p < 0.001) were significantly increased whereas LMR (4.51 ± 1.3, 3.57 ± 1.3, 3.14 ± 1.4; p < 0.001) levels were significantly decreased in parallel to the severity of mitral stenosis. Discussion/conclusion: MHR and LMR can be used to predict severity of RMVS.

The pattern of acute rheumatic fever in children: Experience at the children's hospital, Riyadh, Saudi Arabia

BACKGROUND

The study was carried out in Riyadh City Hospital to determine the hospital prevalence of acute rheumatic fever (ARF), its characteristics and to determine the proportion of the ARF population that have recurrent attacks.

METHODS

The study was an analysis of 83 children with ARF, admitted to the Children's Hospital, Riyadh, over a 10-year period (1994-2003). The diagnosis of ARF was based on clinical features as defined in the modified Jones criteria with evidence of recent streptococcal infection. The diagnosis of recurrence of rheumatic fever in children with rheumatic heart disease was based on the presence of one major criterion apart from carditis or two minor criteria, in addition to evidence of preceding streptococcal infection.

RESULTS

The mean age at presentation was 9 years. In 31 (37%) cases, arthritis was the only major Jones criterion. In 30 (36%) others, arthritis was associated with carditis and in 3 (4%), with chorea. Cardiac involvement was documented in 44 (53%) cases; it occurred alone in 5 (6%), with arthritis in 30 (36%), and with chorea in 9 (11%) others. Among the 44 with carditis, the pattern of cardiac involvement was valvular only (mild carditis) in 30 (68%), while it was severe in the remaining 14 (32%) cases who also had heart failure. The involvement of the mitral valve alone occurred in 26 (59%) cases in the form mitral regurgitation, while both aortic and mitral valve regurgitation were present in 11 (25%) cases, and aortic valve regurgitation alone in four (9%) others. Chorea was the only major criterion of ARF in 5 children (6%), while it occurred in association with other major criteria in 12 (15%) others. Nineteen (23%) children had recurrent attacks of ARF.

CONCLUSION

ARF continues to occur in Saudi Arabia in the period (1994-2003), despite the progress made in the socio-economic development of the country, and this is often associated with severe cardiac involvement.

Immune responsiveness during disease progression from acute rheumatic fever to chronic rheumatic heart disease

Streptococcus pyogenes causes pharyngitis in school age children, which if left untreated causes acute rheumatic fever (ARF) that later progress toward rheumatic heart disease (RHD). The pathogenesis of this disease and its progression as post infectious squeal is not well understood. In this study, percentages of CD4(+) and CD8(+) T-cells were compared among patients of ARF, RHD and Chronic RHD using flow cytometer. The production of Th1/Th2 cytokines from serum and endothelial cells of damaged and normal heart valves was also analyzed using flow cytometer. Results showed an inverse proportion of CD4(+) and CD8(+) T-cell numbers in ARF and RHD patients. Cytokine assay demonstrated a switch-over from Th1 to Th2 type, as the disease progressed. We observed significantly high IL-6 in ARF patients and high TNF-α in early RHD patients which allowed us to construct a hypothesis, that, during initial infection phase, lot of antibodies are produced (via IL-6) and TNF-α has a role in disease progression and tissue damage during RHD phase.

An animal model of chronic rheumatic valvulitis induced by formalin-killed streptococci

Rheumatic heart disease is the most severe complication of rheumatic fever. Till date, very few successful animal models of rheumatic valvular disease have been reported. This study aimed at developing a suitable animal model of chronic rheumatic valvulitis for further investigation and prevention of rheumatic heart disease. Lewis rats were immunized with one administration of formalin-killed and sonicated group A streptococci together with Complete Freund's Adjuvant every 7 days for three cycles followed by group A streptococci alone till killing. Control rats were administered adjuvants and saline. Rats in group 1 were killed 12 weeks after the initial injection. Rats in group 2 and control group were killed 24 weeks after the initial injection. Results 62.5% (5/8) of rats in group 1 developed myocarditis and 50% (4/8) developed valvulitis. Histological examination of cardiac sections showed only cellular infiltrates. In contrast, 75% (6/8) of rats in group 2 developed rheumatic-like myocarditis and 62.5% (5/8) developed chronic valvulitis. Histological manifestations of the hearts in group 2 animals involved not only acute damage such as cellular infiltrates, Aschoff-like cells, verrucous vegetation, but also chronic lesions such as fibrosis, vascular neogenesis. None of the rats (0/8) in control group presented myocarditis or valvulitis. Lewis rat repeatedly immunized with formalin-killed GAS may be a suitable animal model of chronic rheumatic valvulitis. It may be useful for future investigation of the pathogenesis and possible preventive strategies of human rheumatic heart disease.

Overexpression of transforming growth factor-beta 1 in the valvular fibrosis of chronic rheumatic heart disease

For the purpose of determining the pathogenic role of transforming growth factor-beta1 (TGF-beta 1) in the mechanism of chronic rheumatic heart disease, we evaluated the expression of TGF-beta 1, proliferation of myofibroblasts, and changes in extracellular matrix components including collagen and proteoglycan in 30 rheumatic mitral valves and in 15 control valves. High TGF-beta 1 expression was identified in 21 cases (70%) of rheumatic mitral valves, whereas only 3 cases (20%) of the control group showed high TGF-beta 1 expression (p<0.001). Additionally, increased proliferation of myofibroblasts was observed in the rheumatic valves. High TGF-beta1 expression positively correlated with the proliferation of myofibroblasts (p=0.004), valvular fibrosis (p<0.001), inflammatory cell infiltration (p=0.004), neovascularization (p=0.007), and calcification (p<0.001) in the valvular leaflets. The ratio of proteoglycan to collagen deposition inversely correlated with TGF-beta 1 expression in mitral valves (p=0.040). In conclusion, an ongoing inflammatory process, the expression of TGF-beta 1, and proliferation of myofibroblasts within the valves have a potential role in the valvular fibrosis, calcification, and changes in the extracellular matrix that lead to the scarring sequelae of rheumatic heart disease.

Comprehensive analysis of antibody responses to streptococcal and tissue antigens in patients with acute rheumatic fever

Acute rheumatic fever (ARF) is an autoimmune disease occurring in individuals following untreated group A streptococcal infection believed to be triggered by antibodies to bacterial components that cross-react with human tissues. We developed a multiplexed immunoassay for the simultaneous quantitation of antibodies to nine streptococcal-related antigens including streptolysin O (SLO), DNase B, collagen I and IV, fibronectin, myosin, group A carbohydrate, M6 protein and streptococcal C5a peptidase. Utilizing this method, we examined serum from 49 ARF, 58 pharyngitis patients and age- and sex-matched controls in samples collected at initial disease onset, and at 4 weeks, 6 months and 1 year after diagnosis. Antibody responses were significantly higher for SLO, DNase B, M6 protein, group A carbohydrate and the cross-reactive antigens collagen I and myosin in ARF compared with pharyngitis patients (P <or= 0.05). Moreover, we found significantly elevated antibody responses in the ARF patients with rheumatic heart disease to fibronectin and collagen I compared with ARF patients without heart disease. The major differences between the ARF patients with and without carditis appear to be in the immune response to the putative heart valve components, collagen I and fibronectin.

Theories of schizophrenia: a genetic-inflammatory-vascular synthesis

BACKGROUND

Schizophrenia, a relatively common psychiatric syndrome, affects virtually all brain functions yet has eluded explanation for more than 100 years. Whether by developmental and/or degenerative processes, abnormalities of neurons and their synaptic connections have been the recent focus of attention. However, our inability to fathom the pathophysiology of schizophrenia forces us to challenge our theoretical models and beliefs. A search for a more satisfying model to explain aspects of schizophrenia uncovers clues pointing to genetically mediated CNS microvascular inflammatory disease.

DISCUSSION

A vascular component to a theory of schizophrenia posits that the physiologic abnormalities leading to illness involve disruption of the exquisitely precise regulation of the delivery of energy and oxygen required for normal brain function. The theory further proposes that abnormalities of CNS metabolism arise because genetically modulated inflammatory reactions damage the microvascular system of the brain in reaction to environmental agents, including infections, hypoxia, and physical trauma. Damage may accumulate with repeated exposure to triggering agents resulting in exacerbation and deterioration, or healing with their removal. There are clear examples of genetic polymorphisms in inflammatory regulators leading to exaggerated inflammatory responses. There is also ample evidence that inflammatory vascular disease of the brain can lead to psychosis, often waxing and waning, and exhibiting a fluctuating course, as seen in schizophrenia. Disturbances of CNS blood flow have repeatedly been observed in people with schizophrenia using old and new technologies. To account for the myriad of behavioral and other curious findings in schizophrenia such as minor physical anomalies, or reported decreased rates of rheumatoid arthritis and highly visible nail fold capillaries, we would have to evoke a process that is systemic such as the vascular and immune/inflammatory systems.

SUMMARY

A vascular-inflammatory theory of schizophrenia brings together environmental and genetic factors in a way that can explain the diversity of symptoms and outcomes observed. If these ideas are confirmed, they would lead in new directions for treatments or preventions by avoiding inducers of inflammation or by way of inflammatory modulating agents, thus preventing exaggerated inflammation and consequent triggering of a psychotic episode in genetically predisposed persons.

Immunization with C5a peptidase from either group A or B streptococci enhances clearance of group A streptococci from intranasally infected mice

Group A streptococci (S. pyogenes) are responsible for pharyngitis, impetigo and several more serious diseases. Emergence of toxic shock, and necrotizing fasciitis, associated with this pathogen over the past 10 years, has generated interest in development of a vaccine, which would prevent infections and potential serious complications. The highly conserved C5a peptidase that is expressed on the surface of group A streptococcus and other streptococcal species, associated with human infections, is a prime vaccine candidate. Here, we report construction of an inactive form of the peptidase and test its potential to induce protection in mice from intranasal challenge with either serotype M1 and M49 strains of streptococci. Mice were immunized by subcutaneous administration of recombinant proteins, mixed with Alum and monophosphoryl lipid A (MPL) adjuvants. Control mice were vaccinated with tetanus toxoid in the same adjuvants. Preparations of SCPA protein were highly immunogenic in mice. Antibody directed against protein from either group A (SCPAw) or group B (SCPBw) streptococci neutralized activity associated with both enzymes. Streptococci were cleared from the oral-nasal mucosa of mice immunized with vaccine protein more rapidly than those immunized with tetanus toxoid. Moreover, immunization with either protein enhanced clearance of group A streptococci from the lung. These results suggest that parenteral vaccination with SCPBw protein will provide protection against infection by either group A or B streptococci.

amrA encodes a putative membrane protein necessary for maximal exponential phase expression of the Mga virulence regulon in Streptococcus pyogenes

The transcriptional regulator Mga activates a regulon of virulence genes important for colonization and immune evasion in GAS. Using transposon mutagenesis of a serotype M6 group A streptococcus (GAS) reporter strain KSM148, we have identified an open reading frame (ORF) designated amrA that is required for maximal activation of the Mga regulon during exponential phase. A deletion in amrA, but not in the downstream transcriptionally linked ORF Spy0798, was able to reproduce the phenotype seen in the transposon mutants. Northern analysis for mga and emm transcripts, as well as Western analysis of Mga, confirmed a reduction in mga expression leading to a decrease in transcription of the Mga-regulated emm in the amrA deletion and transposon mutants. Furthermore, both the amrA deletion mutant and an original transposon mutant could be complemented using amrA expressed from a nisin-inducible expression system. As amrA is strongly conserved across the sequenced streptococcal M types, and inactivation of amrA in an M3 serotype also resulted in reduction of emm transcripts, the role of amrA does not appear to be serotype specific. Although the specific function of AmrA is unknown, its putative membrane localization and homology to transporters involved in cell wall synthesis suggest a link between growth and virulence gene expression in GAS.

Serum intercellular adhesion molecule-1 levels in acute rheumatic fever

In order to determine the role of soluble intercellular adhesion molecule-1 (sICAM-1) in the pathogenesis and course of acute rheumatic fever (ARF), serum levels of ICAM-1 were measured in 30 patients at onset of ARF, in remission and during inactive periods of the disease (group 1), in 20 patients who had had ARF at least a year beforehand and had no evidence of exacerbation of the disease (group 2) and in 20 healthy children. Serum levels of sICAM-1 were increased in group 1, peaking in the active phase of the disease and declining during remission to the inactive phase of the disease when they were still significantly higher than in the controls, despite their ESR and fibrinogen levels having fallen to normal limits. The levels in group 2 were similar to those in the healthy controls. We consider that ICAM-1 plays a role in the pathogenesis of ARF and that improvement of ARF might best be determined by serum sICAM-1 levels, even when clinical and other laboratory test results have returned to normal, but additional studies are needed to clarify this hypothesis.

HLA class II associations with rheumatic heart disease among clinically homogeneous patients in children in Latvia

Genetic control of immune reactions has a major role in the development of rheumatic heart disease (RHD) and differs between patients with rheumatic fever (RF). Some authors think the risk of acquiring RHD is associated with the HLA class II DR and DQ loci, but other views exist, due to the various HLA-typing methods and ways of grouping cases. Our goal was to determine the relations between HLA class II alleles and risk of or protection from RF in patients with relatively homogeneous clinical manifestations. A total of 70 RF patients under the age of 18 years were surveyed in Latvia. HLA genotyping of DRB1*01 to DRB1*18 and DQB1*0201-202, *0301-305, *0401-402, *0501-504, and *0601-608 was performed using polymerase chain reaction sequence-specific primers. Data for a control group of 100 healthy individuals typed for HLA by the same method were available from the databank of the Immunology Institute of Latvia. Of the RF patients, 47 had RHD and 8 had Sydenham's chorea. We concluded that HLA class II DRB1*07-DQB1*0401-2 and DRB1*07-DQB1*0302 could be the risk alleles and HLA class II DRB1*06 and DQB1*0602-8, the protective ones. Patients with mitral valve regurgitation more often had DRB1*07 and DQB1*0401-2, and patients with multivalvular lesions more often had DRB1*07 and DQB1*0302. In Sydenham's chorea patients, the DQB1*0401-2 allele was more frequent. Genotyping control showed a high risk of RF and RHD in patients with DRB1*01-DQB1*0301-DRB1*07-DQB1*0302 and DRB1*15-DQB1*0302-DRB1*07-DQB1*0303.

Rheumatic fever-associated Streptococcus pyogenes isolates aggregate collagen

Acute rheumatic fever is a serious autoimmune sequel of Streptococcus pyogenes infection. This study shows that serotype M3 and M18 S. pyogenes isolated during outbreaks of rheumatic fever have the unique capability to bind and aggregate human basement membrane collagen type IV. M3 protein is identified as collagen-binding factor of M3 streptococci, whereas M18 isolates bind collagen through a hyaluronic acid capsule, revealing a novel function for M3 protein and capsule. Following in vivo mouse passage, conversion of a nonencapsulated and collagen-binding negative M1 S. pyogenes into an encapsulated, collagen-binding strain further supports the crucial role of capsule in mediating collagen binding. Collagen binding represents a novel colonization mechanism, as it is demonstrated that S. pyogenes bind to collagen matrix in vitro and in vivo. Moreover, immunization of mice with purified recombinant M3 protein led to the generation of anti-collagen type IV antibodies. Finally, sera from acute rheumatic fever patients had significantly increased titers of anti-collagen type IV antibodies as compared with healthy controls. These findings may suggest a link between the potential of rheumatogenic S. pyogenes isolates to bind collagen, and the presence of collagen-reactive autoantibodies in the serum of rheumatic fever patients, which may form a basis for post-streptococcal rheumatic disease. These anti-collagen antibodies may form a basis for poststreptococcal rheumatic disease.

Rheumatic fever in the 21st century

In the first half of the twentieth century, the group A streptococcus (GAS) was established as the sole etiologic agent of acute rheumatic fever (ARF). In the century's latter half, the clinical importance of variation in the virulence of strains of GAS has become clearer. Although still obscure, the pathogenesis of ARF requires primary infection of the throat by highly virulent GAS strains. These contain very large hyaluronate capsules and M protein molecules. The latter contain epitopes that are cross-reactive with host tissues and also contain superantigenic toxic moieties. In settings where ARF has become rare, GAS pharyngitis continues to be common, although it is caused by GAS strains of relatively lower virulence. These strains, however, colonize the throat avidly and stubbornly. Molecularly distinct pyoderma strains may cause acute glomerulonephritis, but they are not rheumatogenic, even though they may secondarily colonize and infect the throat. Guidelines for the diagnosis, treatment, and prevention of GAS pharyngitis and ARF are reviewed with particular reference to the prevalence of the latter in the community.

Intravenous immunoglobulin in acute rheumatic fever: a randomized controlled trial

BACKGROUND

Acute rheumatic fever (ARF) remains the leading cause of acquired heart disease in children worldwide. No therapeutic agent has been shown to alter the clinical outcome of the acute illness. Immunological mechanisms appear to be involved in the pathogenesis of ARF. Intravenous immunoglobulin (IVIG), a proven immunomodulator, may benefit cardiac conditions of an autoimmune nature. We investigated whether IVIG modified the natural history of ARF by reducing the extent and severity of carditis.

METHODS AND RESULTS

This prospective, double-blind, randomized, placebo-controlled trial evaluated IVIG in patients with a first episode of rheumatic fever, stratifying patients by the presence and severity of carditis before randomization. Patients were randomly allocated to receive 1 g/kg IVIG on days 1 and 2 and 0.4 g/kg on days 14 and 28, or they received a placebo infusion. Clinical, laboratory, and echocardiographic evaluation was performed at 0, 2, 4, 6, 26, and 52 weeks. Fifty-nine patients were treated, of whom 39 had carditis (including 4 subclinical) and/or migratory polyarthritis (n=39). There was no difference between groups in the rate of normalization of the erythrocyte sedimentation rate or acute-phase proteins at the 6-week follow-up. On echocardiography, 59% in the IVIG group and 69% in the placebo group had carditis at baseline. There was no significant difference in the cardiac outcome, including the proportion of valves involved, or in the severity of valvar regurgitation at 1 year. At 1 year, 41% of the IVIG and 50% of the placebo group had carditis.

CONCLUSIONS

IVIG did not alter the natural history of ARF, with no detectable difference in the clinical, laboratory, or echocardiographic parameters of the disease process during the subsequent 12 months.

Pharyngeal carriage of group C and group G streptococci and acute rheumatic fever in an Aboriginal population

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) represent an autoimmune response to group A streptococcal pharyngitis. In the Aboriginal population of the Northern Territory of Australia, some of the highest rates of ARF in the world have been reported, although throat carriage rates of group A streptococcus in this population are extremely low and symptomatic group A streptococcal pharyngitis is uncommon; by contrast, carriage rates of group C and G streptococci are high. Therefore, we questioned the involvement of these groups in ARF and showed that they have the potential to elicit an autoimmune response that may trigger ARF.

On defining Sydenham's chorea: where do we draw the line?

Sydenham's chorea (SC) is a major manifestation of rheumatic fever characterized by an array of neuropsychiatric symptoms that vary in severity, timing, and character. Some of the same symptoms are seen in Tourette's syndrome and childhood-onset obsessive-compulsive disorder. Genetic vulnerability appears to play a role in all three conditions. The term PANDAS (pediatric autoimmune neuropsychiatric disorder associated with streptococcus) has been introduced to describe a putative subset of obsessive-compulsive disorder and Tourette's syndrome that bears some resemblance to Sydenham's chorea. This article discusses whether PANDAS should be subsumed under Sydenham's chorea, thus expanding the diagnostic boundaries of Sydenham's chorea to include primarily neuropsychiatric presentations now classified as cases of obsessive-compulsive disorder or Tourette's syndrome. We conclude that PANDAS is a useful construct, but that it would be premature to view it as a subset of Sydenham's chorea-whether defined narrowly or broadly.

HLA class II associations with rheumatic heart disease are more evident and consistent among clinically homogeneous patients

BACKGROUND

Discrepancies in reported HLA class II associations with rheumatic heart disease (RHD) may have been due to inaccuracies of serological typing reagents and/or lack of defined clinical classification of patients analyzed. The molecular association between HLA and RHD was investigated in patients with defined clinical outcome.

METHODS AND RESULTS

Class II allele/haplotype distribution was determined in 2 groups of RHD patients (n=88) and a control group (n=59). Patients were divided into the mitral valve disease (MVD) category (ie, those with mitral regurgitation with or without mitral stenosis) and the multivalvular lesions (MVL) category, with impairment of aortic and/or tricuspid valves in addition to mitral valve damage. The MVD category (n=65) accounted for 74% of patients and included significantly fewer recurrent RF episodes compared with MVL patients (P=0.002).

CONCLUSIONS

Significant increases in DRB1*0701 and DQA1*0201 alleles and DRB1*0701-DQA1*0201 haplotypes were found in patients. Removal of the MVL patients from analysis increased the strength of HLA associations among the MVD sample. The frequency of DQA1*0103 allele was decreased and the DQB1*0603 allele was absent from the patient group, suggesting that these alleles may confer protective effects against RHD. DQ alleles in linkage disequilibrium with DR alleles appear to influence risk/protection effect: whereas the DRB1*13-DQA1*0501-3-DQB1*0301 haplotype showed a trend toward risk, the DRB1*13-DQA1*0103-DQB1*0603 haplotype was absent in the RHD sample. Our data indicate that certain class II alleles/haplotypes are associated with risk or protection from RHD and that these associations appear to be stronger and more consistent when analyzed in patients with relatively more homogeneous clinical manifestations.

[Diagnosis and treatment of rheumatic fever]

Rheumatic fever has become rare in France as in most developed countries. However, recent outbreaks have underlined the need for practitioners to remain vigilant and to maintain careful prevention. Polyarthritis and polyarthralgia are the main manifestations of rheumatic fever but they are not specific. Carditis is a major feature which affects only half the patients; cardiac ultrasonography is therefore very helpful with respect to positive and false positive diagnoses resulting from innocent murmurs. Fever, acute phase inflammatory markers, and evidence of streptococcal infection are of major importance and rheumatic fever must be disregarded in their absence. The treatment includes: 1) steroids for a 3 month-period; 2) early antibiotic treatment of streptococcal carriage; 3) long-term prophylaxis using intramuscular benzathine penicillin.