HLA antigens in 88 cases of rheumatic fever observed in Martinique

Acute rheumatic fever and rheumatic heart disease

Acute rheumatic fever (ARF) is the result of an autoimmune response to pharyngitis caused by infection with group A Streptococcus. The long-term damage to cardiac valves caused by ARF, which can result from a single severe episode or from multiple recurrent episodes of the illness, is known as rheumatic heart disease (RHD) and is a notable cause of morbidity and mortality in resource-poor settings around the world. Although our understanding of disease pathogenesis has advanced in recent years, this has not led to dramatic improvements in diagnostic approaches, which are still reliant on clinical features using the Jones Criteria, or treatment practices. Indeed, penicillin has been the mainstay of treatment for decades and there is no other treatment that has been proven to alter the likelihood or the severity of RHD after an episode of ARF. Recent advances - including the use of echocardiographic diagnosis in those with ARF and in screening for early detection of RHD, progress in developing group A streptococcal vaccines and an increased focus on the lived experience of those with RHD and the need to improve quality of life - give cause for optimism that progress will be made in coming years against this neglected disease that affects populations around the world, but is a particular issue for those living in poverty.

Post-infectious group A streptococcal autoimmune syndromes and the heart

There is a pressing need to reduce the high global disease burden of rheumatic heart disease (RHD) and its harbinger, acute rheumatic fever (ARF). ARF is a classical example of an autoimmune syndrome and is of particular immunological interest because it follows a known antecedent infection with group A streptococcus (GAS). However, the poorly understood immunopathology of these post-infectious diseases means that, compared to much progress in other immune-mediated diseases, we still lack useful biomarkers, new therapies or an effective vaccine in ARF and RHD. Here, we summarise recent literature on the complex interaction between GAS and the human host that culminates in ARF and the subsequent development of RHD. We contrast ARF with other post-infectious streptococcal immune syndromes - post-streptococcal glomerulonephritis (PSGN) and the still controversial paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), in order to highlight the potential significance of variations in the host immune response to GAS. We discuss a model for the pathogenesis of ARF and RHD in terms of current immunological concepts and the potential for application of in depth "omics" technologies to these ancient scourges.

Some of the People, Some of the Time

Acute rheumatic fever is a major cause of heart disease in large parts of the world, but it remains unknown why only a small fraction of those who are infected with rheumatogenic group A streptococci develop an abnormal immune response that leads to acute rheumatic fever. An understanding of the mechanisms underlying host susceptibility can provide important insights into pathogenesis that in turn can inform new treatments. Extensive searches for susceptibility factors have been undertaken, including human leukocyte antigens, B-cell alloantigens, and cytokine genes. Although significant associations have been found between genetic factors and acute rheumatic fever, study results often conflict with each other. This review explores current understanding about host susceptibility to acute rheumatic fever and provides an overall perspective to the number of studies that have recently addressed this subject.

Rheumatic fever and rheumatic heart disease: genetics and pathogenesis

Molecular mimicry between streptococcal and human proteins is considered as the triggering factor leading to autoimmunity in rheumatic fever (RF) and rheumatic heart disease (RHD). Here, we present a review of the genetic susceptibility markers involved in the development of RF/RHD and the major immunopathological events underlying the pathogenesis of RF and RHD. Several human leucocyte antigen (HLA) class II alleles are associated with the disease. Among these alleles, HLA-DR7 is predominantly observed in different ethnicities and is associated with the development of valvular lesions in RHD patients. Cardiac myosin is one of the major autoantigens involved in rheumatic heart lesions and several peptides from the LMM (light meromyosin) region were recognized by peripheral and intralesional T-cell clones from RF and RHD patients. The production of TNF-alpha and IFN-gamma from heart-infiltrating mononuclear cells suggests that Th-1 type cytokines are the mediators of RHD heart lesions while the presence of few interleukin-4 producing cells in the valve tissue contributes to the maintenance and progression of the valvular lesions.

The role of HLA molecules in susceptibility to chronic rheumatic heart disease

Only a small fraction of the streptococcal pharyngitis progress to rheumatic carditis, which implies that environmental, host and microbial factors interact to cause an aberrant immune response against the antigens of the microorganism that cross-react with cardiac tissues. Although there are numerous studies and a general consensus on the relation between human leucocyte antigen (HLA) class II antigens and rheumatic heart disease (RHD), the details and the culprit antigens are still controversial. The study was undertaken to examine 100 patients with chronic RHD and 100 controls for HLA class I and class II antigens for differences in prevalence. All samples were typed at the HLA-DRB1/3/4/5 and DQB1 loci by the sequence-specific primer (PCR-SSP) method at low resolution. For HLA class I antigens, HLA-B13 frequency was marginally increased in patients with RHD compared to controls without reaching statistical significance. For class II antigens, RHD patients had higher frequencies for HLA-DRB1*01 (RHD 24%, controls 10%), DRB1*04 (RHD 35%, controls 26%), DRB1*07 (RHD 18%, controls 11%) and HLA-DQB1*02 (RHD 32%, controls 17%) without reaching statistical significance, and significantly lower frequencies for DRB1*13 (Pc < 0.003, OR: 5.69), DRB5* (Pc < 0.003, OR: 33) and DRB3* (Pc = 0.03, OR: 2.66) compared to controls. It was concluded that host, microbial and environmental factors collude to create acute rheumatic fever (RF) and chronic rheumatic valve disease. The HLA-DRB1*13, DRB5* and DRB3* were protective against the development of rheumatic valve damage.

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.

10-year educational programme aimed at rheumatic fever in two French Caribbean islands

BACKGROUND

In less developed countries, rheumatic fever still occurs. We started a long-term educational programme in two French Caribbean islands that was directed at the public and at health-care workers to see whether we could reduce the incidence of rheumatic fever.

METHODS

Our 10-year programme started in 1981 in Martinique and Guadeloupe, and was based in the community and in clinics and hospitals. The programme established a registry of all cases of primary and secondary rheumatic fever (diagnosed by Jones' modified criteria), with systematic hospital admission of children. We graded carditis as severe, mild, or subclinical, and acute glomerulonephritis was defined by oedema, proteinuria, and haematuria for less than 3 months. The educational part of the programme targeted the public and health-care workers, including doctors, with written information distributed in schools or via radio and television broadcasts or videotapes. For the public, the benign clinical presentation of the initial streptococcal infection was contrasted with the severity of later heart disease.

FINDINGS

The first months of the programme led to a 10-20% increase in the number of rheumatic fever cases admitted to hospital, because of the renewed attention paid to the disease. Therefore we took 1982 as the baseline year. In 1982-83 the incidence of rheumatic fever was 19.6 per 100 000 inhabitants aged under 20 in Martinique, and 17.4 per 100 000 in Guadeloupe. In 100 Martinique children and 97 Guadeloupe children in 1982-83, 40 and 71% had carditis, respectively (severe in 10 and 32%). Rheumatic fever was preceded by symptomatic sore throat in 52 and 41% of cases, respectively. The disease was not seen in children with active streptococcal cutaneous infections. Disease frequency was highest in the poorest areas and families, a finding that persisted over time. The programme was associated with a progressive decline in the frequency of rheumatic fever: final reduction of 78% in Martinique and 74% in Guadeloupe. The frequency of carditis also fell. Apart from two outbreaks in one hospital, the frequency of acute glomerulonephritis also declined; 31% of cases had had sore throat, while 56% had skin infections. The cost of the programme during the 4 most intensive years was FFr 250 000 (US$ 44 500) in each island. The cost of childhood rheumatic fever, excluding late sequelae, was initially (in 1982) about FFr 7.8 million (US$ 1426 000). The cost fell to an average of Ffr 550 000 (US$ 100 000) per year in 1991-92.

INTERPRETATION

A rapid decline in rheumatic fever incidence was achieved at modest cost. Such a programme needs to be continued because of the risk of disease resurgence.

Group A streptococcal antigens and superantigens in the pathogenesis of autoimmune arthritis

Evidence from repeated clinical observations and from a variety of experimental approaches implicates group A streptococci in the pathogenesis of the autoimmune arthritides. Several streptococcal antigens and superantigens have now been characterized and their properties suggest that they may be involved in the mechanisms which underlie these diseases, although other antigens and superantigens yet to be discovered may also be involved. The association between group A streptococcal infection and autoimmune arthritis offers a useful model for providing a long-elusive understanding of the role of bacterial infection in the pathogenesis of autoimmune disease.

Rheumatic fever and the HLA complex. A cosegregation study

BACKGROUND

Considering the controversial results published in the literature concerning associations between human leukocyte antigens (HLA) and rheumatic fever (RF), the purpose of the present study was to investigate by means of cosegregation analysis the participation of HLA genes in susceptibility to RF.

METHODS AND RESULTS

The sample reported here was composed of 51 affected and 66 healthy individuals belonging to 22 genetically informative families. The comparison (chi 2 goodness-of-fit test) of the observed numbers of identical-by-descent (IBD) HLA haplotypes among all affected individuals (siblings, cousins, and uncle/nephew and grandparent/grandchild type of pairs) with the expected ones under the assumption of independent segregation of HLA alleles and the presumptive RF susceptibility gene gave a value of P = .088. Since the number of subjects studied was relatively small and the rejection level obtained was near the usual .05 significance level, we calculated the expected HLA IBD scores in the 13 pairs of affected sibs of our sample for all possible frequencies of the presumptive RF susceptibility gene. This analysis allowed clear rejection of a recessive mode, considering susceptibility gene frequencies lower than 20%, whereas the observed values fitted very well a dominant mode of inheritance, with penetrance (K) values varying between 0.5 and 0.9 and a frequency of the susceptibility gene of at least 1%.

CONCLUSIONS

The present data support the hypothesis of an RF susceptibility gene within or very near the HLA complex.

Association of HLA class I and class II antigens with rheumatic fever in a Turkish population

The distribution of class I and class II HLA antigens of 100 Turkish patients with rheumatic fever, 77 of whom had cardiac involvement, was examined. We compared the results with a control group of identical origin. The frequency of HLA A10 and HLA B35 antigens were found significantly higher in patients with rheumatic fever (p < 0.05, p < 0.01, respectively). The frequency of HLA A10 and HLA DRw11 in patients with cardiac involvement were significantly higher than in those without cardiac involvement (p < 0.05, p < 0.01, respectively). On the other hand, HLA Cw2 antigen frequency was found significantly higher in patients without cardiac involvement than in those with rheumatic heart disease (p < 0.05). We support the concept that rheumatic fever is an immunological reaction to group A, beta hemolytic streptococci in individuals who have genetic predisposition.

HLA and rheumatic fever in Turkish Children

We report the results of research on human leukocyte allo-antigen (HLA) and rheumatic fever (RF), the first published study to be carried out among Turkish children with RF. Ninety-three Turkish children, aged between 6 and 16 years (mean: 8 +/- 2.6), with RF participated in the study. Of the total, 26 patients had their first attack and 39 had acute rheumatic activity at the time of registration. The results demonstrate (1) negative but not significant association between HLA-A2 and RF; (2) a positive association between HLA-DR4 and RF (p less than 0.001); (3) a significant association between HLA-DR4 and carditis, but not with isolated arthritis. These results corroborate the concept of race-specific genetically determined familial susceptibility to the development of rheumatic heart disease.