Immunohistochemical and serological evidence for the role of streptococcal proteinase in acute post-streptococcal glomerulonephritis

BACKGROUND

We have previously demonstrated the preferential secretion of streptococcal proteinase or streptococcal pyrogenic exotoxin B (SPEB) by nephritic strains of Group A streptococci isolated from the skin or throat of patients with acute poststreptococcal glomerulonephritis (APSGN).

METHODS

To further explore the possible role of SPEB in APSGN, we performed ELISA studies to detect anti-SPEB antibodies in the sera of patients with APSGN, acute rheumatic fever (ARF), scarlet fever (SF) and normal children. Using ELISA, anti-SPEB titers on acute and convalescent APSGN sera were measured to determine immunity to APSGN. We also performed immunofluorescence studies on APSGN and non-APSGN kidney biopsies to probe for the presence and localization of SPEB.

RESULTS

Our data show that anti-SPEB antibodies are present in APSGN sera and antibody titers are significantly higher than in ARF, SF and normal sera. Anti-SPEB titers tend to rise acutely and decrease with time but do not reach baseline after one year. When kidney biopsies were probed with rabbit anti-SPEB antibody, 12 of 18 (67%) of the APSGN cases were positive while only 4 of 25 (16%) of the non-APSGN cases were positive.

CONCLUSIONS

In summary, we were able to demonstrate unique reactivity to SPEB in human sera and kidney biopsies of APSGN suggesting a significant role of this toxin in the pathogenesis of acute post-streptococcal glomerulonephritis.

Potential infectious disease complications of upper respiratory tract infections

Upper respiratory tract infections (URTIs), particularly otitis media and sinusitis, are prevalent among children. With recurrent URTIs there is an increased likelihood of sequelae. Suppurative complications associated with URTIs, although rare, must be treated rapidly to prevent serious morbidity and mortality. Further, increase in antimicrobial resistance may be accompanied by an increased risk for complications because infecting pathogens may be more difficult to eradicate.

Nutritional factors associated with rheumatic fever

The determinants for a child with group A beta-haemolytic streptococcal throat infection (BHS infection) to develop rheumatic fever (RF) remain unclear. In this case-control study, we deal with BHS infected children to examine whether nutritional factors are related to RF. In a RF hospital in Dhaka (Bangladesh) we examined 218 consecutive out-patients who had antecedent BHS infection. Sixty of them met the updated Jones criteria for RF (cases) while 104 did not (controls). Fifty-four possible RF patients were excluded. We used anthropometric measurements and a food frequency questionnaire to assess nutritional factors. Higher risk of RF was observed for low height for age (odds ratio 3.82, 95% confidence interval 1.73-8.42); low weight for age (2.41, 1.12-5.57); low upper arm circumference for age (3.76, 1.87-7.89); and low consumption of eggs (3.81, 1.95-7.63), milk (2.60, 1.36-5.08), chicken (2.62, 1.35-5.21), pulses (1.98, 1.03-3.84), fruits 2.29, 1.20-4.45), and ruti (home-made bread) (3.15, 1.61-6.34). Reduced risk was observed for soybean oil consumption (0.28, 0.12-0.62). The significant association of upper arm circumference and eggs persisted after adjustment for multiple sociodemographic confounders. The association of ruti and soybean oil appeared to be suggestive (0.05 < p < 0.1). Protein-energy malnutrition is likely to be associated with RF. The protective effect of moderate consumption of eggs and soybean oil may support other published work which suggests that the anti-inflammatory substance present in these food items may prevent maturation of the rheumatic process.

Infectious causes of arthritis in adolescents

Although most joint pain in adolescents is secondary to injury, inflammatory arthritis, mechanical problems, and other causes, infectious causes of arthritis should always be considered. Infections may cause arthritis by direct infection, reactive disease, or immune-mediated mechanisms. This chapter reviews common infectious causes of arthritis and also recognizes the difficulties in distinguishing categories.

Acute rheumatic fever. Still a challenge

At the end of the 20th century, after an apparent decline, acute rheumatic fever (ARF) now constitutes a great challenge for developed and developing countries. It is caused by a group A beta-hemolytic Streptococcus upper airways infection, but the exact pathogenetic mechanisms are not yet clear. The role of the immune system in the pathogenesis of ARF is understood better than genetic host factors. ARF can mimic many other diseases, and the diagnosis is based on clinical criteria. It is still overdiagnosed and underdiagnosed in different settings. Penicillin has greatly contributed to the reduction in the incidence and recurrence of this disease. Current schemes of prophylaxis, however, present many problems, and failures are common. Future efforts to reduce the burden of this disease should induce public health measures the vaccine strategies.

Acute rheumatic fever in adults: a resurgence in the Hasidic Jewish community

OBJECTIVE

To describe a series of adults diagnosed with acute rheumatic fever (ARF).

METHODS

Retrospective chart review of 14 patients age > 18 years with suspected ARF between 1990 and 1994 in a private rheumatology practice setting. Four additional patients treated at our medical center were included in the study.

RESULTS

Twelve patients met Jones criteria for rheumatic fever and were included in the study. Of these, only 3 had a childhood history of rheumatic fever. All had recent onset of arthritis and a history of antecedent sore throat. Only 4 patients, however, had throat cultures positive for B-hemolytic streptococcus. Nine patients were Hasidic Jews. Four patients had carditis. One patient had erythema marginatum, while chorea and subcutaneous nodules were not seen. Nine patients improved taking nonsteroidal antiinflammatory drugs or acetylsalicylic acid; 3 required steroid treatment to control severe arthritis.

CONCLUSION

Our clinical experience suggests that ARF occurs frequently, especially among Hasidic Jewish adults. Due to the disabling nature of the arthritis and the significant incidence (33%) of carditis, strict adherence to penicillin prophylaxis guidelines is indicated.

[A resurgence of rheumatic fever. New causes or old attitudes?]

Bearing in mind that in the last years there has been an increase in rheumatic fever episodes, the authors evaluate the cases recently observed in the department. The data of 3 children born and living in Portugal, the first known outbreak of rheumatic fever observed between June 93 and March 94, were examined. One case presented polyarthritis, another polyarthritis and carditis and the third chorea and carditis. In just one case was the diagnosis of rheumatic fever considered in the beginning, and over-all, failures in the diagnosis and treatment of tonsillitis, and in echocardiographic diagnosis were detected. In view of these examples, the authors conclude that the increasing incidence and morbidity of rheumatic fever is more probably due to forgetfulness of old attitudes than to new causes. Delay in the diagnosis and errors in secondary prophylaxis may influence long term results.

Anticardiolipin antibodies in acute rheumatic fever and chronic rheumatic heart disease: is there a significant association?

OBJECTIVE

The incidence and significance of IgG and IgM anticardiolipin antibodies (aCLa) in patients with acute rheumatic fever (ARF), chronic rheumatic heart disease (CRHD) and streptococcal pharyngitis have been investigated in order to determine whether these antibodies play an important role in the pathogenesis and if they are markers that can be used to confirm disease activity.

METHODS

An enzyme-linked immunosorbent assay was used to measure the IgG and IgM aCLa levels. aCLa levels of patients were considered positive if they were greater than 3.0 standard deviations above the mean for healthy children.

RESULTS

No significant difference in aCLa levels was found between patients with rheumatic fever or streptococcal pharyngitis and healthy controls, and aCLa concentrations did not correlate with the acute phase reactant levels.

CONCLUSIONS

aCLa in patients with ARF and CRHD do not appear to be markers of disease activity, and our data suggest that aCLa do not play an important role in the pathogenesis of rheumatic fever.

Repertoire of transcribed peripheral blood T-cell receptor beta chain variable-region genes in acute rheumatic fever

Patients with severe group A streptococcal infections have abnormalities in the Vbeta repertoire of peripheral blood T cells that are consistent with superantigen stimulation by cytoplasmic membrane proteins. The purpose of this study was to determine whether similar changes in Vbeta repertoire could be found for patients with acute rheumatic fever (ARF). The mean Vbeta repertoire of peripheral blood T cells in nine hospitalized ARF patients was similar to that of 34 controls and did not change during 6 months of follow-up in 6 of the ARF subjects. We were unable to detect changes in the Vbeta repertoire of peripheral blood T cells from patients with ARF that could be attributed to the influence of a superantigen.

Rheumatic fever prophylaxis using benzathine penicillin G (BPG): two- week versus four-week regimens: comparison of two brands of BPG

OBJECTIVE

This prospective study was aimed at answering two important questions: 1) Is a biweekly schedule of 1.2 million U intramuscular benzathine penicillin G (BPG) superior to a 4-week one in the prevention of upper respiratory Group A beta-hemolytic streptococcal (GABHS) infections and rheumatic fever (RF) recurrences? 2) Is there a difference in the bioavailability of BPG obtained from different manufacturers?

METHODOLOGY

Three hundred sixty rheumatic patients aged 4 to 20 years were randomly assigned to either a biweekly (190 patients) or 4-week (160 patients) BPG prophylactic schedule and were followed-up monthly for 2 years by clinical examination, throat swab culture for GABHS and measurement of antistreptolysin O titer to detect GABHS infection and/or recurrences of RF (according to revised Jones' Criteria). Thereafter, 34 rheumatic subjects, aged 8 to 16 years were randomly assigned to receive a 4-week injection of 1.2 million U of either a locally manufactured BPG brand (22 patients) or an imported one (12 patients). Sera of all patients were tested for penicillin level by plate diffusion method on days 1, 2, 3, 4, 5, 6, 7, 14, 21, and 28 after the intramuscular injection of BPG.

RESULTS

The GABHS infection rate was found to be 0.2% and 0.3% for patients on the biweekly and 4-week BPG schedules, respectively, with no significant differences between them. However, the RF recurrence rate/patient/year for the 4-week schedule patients (0.12) was double that for the biweekly schedule ones (0.06). Estimation of the bioavailability of the two different brands of BPG demonstrated a difference in their pharmacokinetics and a decrease in the serum penicillin concentration below the minimum inhibitory concentration 3 weeks after the injection of either brand.

CONCLUSION

Although a biweekly schedule may not be superior in preventing upper respiratory GABHS infection, it may play a role in preventing the sequelae of such infections. The short duration of penicillinemia explains the superiority of the 2-week schedule in RF prophylais. The difference in the pharmacokinetics of penicillin brands might contribute to the high recurrence rate of RF reported in Egypt.

Three- versus four-week administration of benzathine penicillin G: effects on incidence of streptococcal infections and recurrences of rheumatic fever

OBJECTIVE

To investigate the effects of 3-week versus 4-week administration of benzathine penicillin G (BPG) on the incidence of Group A streptococcal infections and the recurrences of rheumatic fever (RF).

STUDY DESIGN

We started, in 1979, randomly allocating all patients with RF to a 3-week or 4-week BPG prophylaxis program. They were examined at the RF clinic, every 3 to 6 months, and at any time they did not feel well. During 1979 to 1989, throat cultures and sera for antistreptolysin O and streptozyme titers were obtained at each clinic visit. Chest radiographs, electrocardiogram, color Doppler echocardiograms, and acute phase reactants were obtained.

SUBJECTS

Two hundred forty-nine patients fulfilled the revised Jones criteria and were followed until December 1991: 124 in the 3-week and 125 in the 4-week program. Their age, sex, weight, percentage with history of RF, severity of cardiac involvement, follow-up duration, and compliance to program were comparable. Eight hundred eighty throat cultures were collected in the 3-week program and 770 were collected in the 4-week program. Six hundred sixteen and 627 sera were determined in each program for antistreptolysin O, and 582 and 592 sera for streptozyme titers.

RESULTS

True streptococcal infections occurred in both programs: 39 infections in the 3-week program, and 59 infections in the 4-week program (7.5 vs 12.7 per 100 patient-years). Four infections with no antibody response occurred in the 3-week program, and three such infections in the 4-week program. Nine RF recurrences occurred in 8 patients in the 3-week program, and 16 recurrences in 16 patients in the 4-week program. Prophylaxis failure occurred in 2 of 124 patients in the 3-week program, and in 10 of 125 patients in the 4-week program (0.25 vs 1.29 per 100 patient-years). The overall recurrences/infections rate in each program was comparable, 13.6% vs 15.5%, but the recurrences/ infections rate due to prophylaxis failure was higher in the 4-week program than in the 3-week program, 3.0% versus 9.7%.

CONCLUSIONS

This 12-year prospective and controlled study documented that streptococcal infections and RF recurrences occurred more often in the 4-week program than in the 3-week program. The risk of prophylaxis failure was fivefold greater in the 4-week program than in the 3-week program.

Epidemic streptococcal disease among Army trainees, July 1989 through June 1991

Outbreaks of group A streptococcal infection occurred at four of seven US Army basic training installations between 1 July 1989 and 30 June 1991. Study data were collected through a respiratory disease surveillance program and on-site epidemiologic investigations. Although hospitalizations were frequent (range, 191-334) during each outbreak, average rates of hospitalization were low (2.4-4.8 hospitalizations/1000 trainees/week). Outbreak-associated morbidity included streptococcal toxic shock syndrome (2 cases, 1 fatal), acute rheumatic fever (6), acute glomerulonephritis (1), scarlet fever (1), and numerous other invasive sequelae. Four serotypes of Streptococcus pyogenes (M-1, -3, -5, and -18) were identified; M-18 caused significant disease at 2 installations. Disease control was rapidly achieved through prophylaxis programs using benzathine penicillin G in nonallergic trainees. These outbreaks extend other reports that document an evolution of the nature and severity of circulating S. pyogenes in the United States.

Guideline maintenance and revision. 50 years of the Jones criteria for diagnosis of rheumatic fever

OBJECTIVE

To understand better the factors that led to revisions of the Jones criteria, a widely used diagnostic guideline for diagnosis of rheumatic fever.

DESIGN

The original publication of the Jones criteria and the four revisions were examined to identify changes. A computer software maintenance paradigm was applied, and modifications were categorized as corrective (error correction), perfective (enhancements in response to user needs), or adaptive (responses to new knowledge).

RESULTS

Modifications of the Jones criteria were primarily corrective and perfective. Disease characteristics, originally characterized as major manifestations, were subsequently categorized as minor manifestations and vice versa. Twenty years after the initial publication, a requirement was added to enhance specificity (evidence for antecedent streptococcal infection). Descriptions of rheumatic manifestations became more detailed over time to eliminate ambiguous definitions and provide information to help clinicians decide about borderline cases. This emphasis on corrective and perfective maintenance contrasts with an expectation that adaptive changes would predominate, as with most knowledge-based systems. In fact, despite 50 years of technologic and methodologic advances in medicine, only echocardiography and new antibody testing contributed new knowledge that bears on the diagnosis of rheumatic fever.

CONCLUSIONS

Corrective and perfective maintenance can be avoided by making effective use of knowledge that exists at the time a guideline is published. Despite the apparent durability of the Jones criteria, carefully structured, evidence-based guidelines should require less corrective and perfective maintenance. Adaptive maintenance can be anticipated if the quality of evidence or the level of consensus that supports each recommendation is explicitly recorded.

Rheumatic fever

The incidence of RF and RHD in the tropics remains high, with a high proportion of children suffering from carditis with the first attack. Severe, incapacitating haemodynamic disturbances occur early. Many patients are seen with established RHD at their first visit, and the default rate is high. Poverty, overcrowding, poor transport facilities, understaffed and overburdened clinics, and poor follow-up add to the problem. A genetic predisposition to develop RHD appears to be important in certain countries like India, Egypt and Turkey, but no work to show this has been done in black Africa. Secondary prophylaxis remains the most practical means of controlling the disease in the tropics. Compliance with long-term prophylaxis depends on organized and concerted efforts of physicians, other health personnel, parents, teachers, and the community.

[What is happening to acute rheumatic fever?]

Rheumatic fever is an inflammatory disease of the heart, joints, central nervous system and subcutaneous tissues that develops after a nasopharyngeal infection by one of the group A beta-haemolytic streptococci. The pathogenesis remains an enigma. As the disease has been less florid and some of the more characteristic manifestations less common in developed countries, it has become more difficult to establish the diagnosis on clinical grounds. Rheumatic fever and its sequellae are still active in developing countries. Carditis is a dominant feature of this social disease. Renewed educational efforts concerning this preventable disorder are needed among both physicians and the public.

Infectious arthropathies and other rheumatologic manifestations of infectious diseases

Infectious agents have been implicated in the pathogenesis of many rheumatologic diseases. In most of these diseases, including those in which specific organisms are known to play a role, the details of pathogenesis remain incompletely defined. Recent studies have aimed to isolate bacterial and viral pathogens from patients with rheumatic diseases, efforts have been made to further define the host immune response to infection, and there have been attempts to develop improved methods of diagnosis and treatment of infectious diseases affecting the musculoskeletal system. This review discusses recent studies on the association of infection with illnesses affecting the joints and musculoskeletal system, with an emphasis on the rheumatic diseases of childhood.

[Rheumatic chorea: a still actual pathology?]

Sidenham's chorea represents one of the gold standards of rheumatic fever. Its identification however has recently become more difficult, owing to the progressive decrease of rheumatic fever itself. Nevertheless this pathology disturbing both the child and the family, easily dominated by a suitable therapy, is still topical: we report 8 cases, 5 males and 3 females running from 7 to 13 years of age, admitted to our pediatric Division from 1988 to 1992, with typical symptomatology and fair clinical evolution.

Characterization of unique human TCR V beta specificities for a family of streptococcal superantigens represented by rheumatogenic serotypes of M protein

The M protein of Streptococcus pyogenes plays a major role in the virulence of these bacteria. Members of the M protein superfamily are characterized by the presence of tandem segments of repeated amino acid sequences. The NH2-terminal end of the M proteins is a hypervariable region that harbors the type-specific epitopes of the molecule. Pepsin cleaves the molecule into a highly conserved carboxyl terminal half and a variable amino terminal portion referred to as pep M. In some individuals, infection with certain serotypes of group A streptococci is followed by autoimmune disorders such as rheumatic fever and acute glomerulonephritis. The serotypes of M protein that show a high degree of association with acute rheumatic fever are referred to as rheumatogenic serotypes. We have reported that one such serotype, type 5, is a superantigen to human T cells, specifically stimulating T cells bearing V beta 2, V beta 4, and V beta 8 elements. Here we extend our studies by examining other rheumatogenic serotypes for superantigenic properties. Studies with types 6, 18, 19, and 24 M proteins revealed that they are all superantigens to human T cells. The specificity to V beta 4 was shared by the rheumatogenic M proteins tested; however, each pep M serotype has its unique characteristic set of V beta specificity and these are distinct from those reported for the streptococcal pyrogenic exotoxins. The non-rheumatogenic serotype, pep M2, only stimulated V beta 2-bearing T cells. This study establishes that the structurally related M proteins represent a family of streptococcal superantigens analogous to the structurally related family of staphylococcal enterotoxin superantigens.