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Myocarditis
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
The disease is clearly an aberrant immune response to the streptococcus. Antigenic similarities between certain streptococcal wall components and cardiac connective tissue led to the concept of ‘molecular mimicry’ for rheumatic fever. Streptococcal antigens invoke a brisk antibody response. High titres of ASO haemolysin are used to diagnose acute rheumatic fever. It has been convincingly demonstrated that molecular mimicry between Streptococcus pyogenes antigen and human proteins lead to autoimmune reactions both humoral and cell mediated causing rheumatic heart disease. Cardiac valves, left atrial appendage (LAA) and myocardium reveal variable infiltration by lymphocytes. CD4+ T-cells are most likely the ultimate effectors of chronic valve lesions. They can recognize Streptococcal M5 protein peptides and produce various inflammatory cytokines such as TNF-α, IFN-γ, IL-10, IL-4 which could be responsible for progressive fibrotic valvular lesions. Cross-reactivity between cardiac myosin and group A β haemolytic Streptococcal M protein has also been demonstrated. The disease predominantly affects the valvular endocardium culminating in valve deformity.
Nephrology, including fluid and electrolytes
Published in Jagdish M. Gupta, John Beveridge, MCQs in Paediatrics, 2020
Jagdish M. Gupta, John Beveridge
10.10. Which of the following statements is/are true of post-streptococcal glomerulonephritis?More than 10% of children develop chronic renal failure.Hypertensive encephalopathy is a recognized complication.ASO titre is the most useful marker of streptococcal infection.Life-long penicillin prophylaxis is recommended.Abnormalities of serum complement usually persist for more than 3 months.
The kidneys
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Immunofluorescence microscopy of renal biopsy material in cases of acute diffuse glomerulonephritis typically reveals granular deposition of immunoglobulin (usually mainly IgG) and components of complement in the glomerular capillary walls (see Figure 14.14B). These findings, together with the detection by electron microscopy of dense subepithelial deposits, are strongly suggestive of the deposition of immune complexes. As acute glomerulonephritis usually follows a streptococcal infection it is likely that antibodies to streptococcal products, appearing a week or so after the infection, combine with streptococcal antigens still present in the plasma, thus providing immune complexes that would, at first, be formed in the presence of antigen excess. In keeping with this there are usually low levels of serum complement components, consistent with the activation of complement by an antigen–antibody reaction, and serum antistreptolysin O (ASO) titres are usually high, indicating previous streptococcal infection. It is not understood why certain types of group A streptococci, notably Griffiths types 12, 4, 1, 25, and 49, are nephritogenic, whereas other types and other microorganisms are not.
Acute kidney injury after arterial switch operation: incidence, risk factors, clinical impact – a retrospective single-center study
Published in Renal Failure, 2023
Anton Puzanov, Vadym Tkachuk, Andriy Maksymenko
There is a big discrepancy between CPB and cross-clamp time impact in articles, dedicated to post-cardiac surgery AKI. The deleterious effect of CPB and cross-clamp on renal function is multifactorial and well-known and they are regarded as potentially modifiable risk factors [13,14]. CPB provokes AKI development, mostly due to kidneys' intraoperative hypoperfusion, non-pulsatile blood flow, and release of inflammatory mediators [15]. In adults both CPB and cross-clamp, times are independent AKI risk factors [16,17]. In the pediatric population, a threshold of 120 min of CPB was shown to increase the risk of AKI after cardiac surgery [5]. However, practically all ASO patients usually have at least 2 h of perfusion. Previous studies of AKI in patients after ASO did not find significant correlations between CPB and cross-clamp times and AKI development risk [1,3,4]. Basu suggested, that it shows limitations of applying data drawn from all-surgical and all-lesion types to specific surgical lesions [2]. However, in our study cross-clamp time was an independent predictor of severe AKI development, which is an original finding in our study. We proposed cutoff value of cross-clamp time for severe AKI risk based on ROC-curve analysis, although with low sensitivity and specificity values.
Epidemiology and Clinical Characteristics of Henoch–Schönlein Purpura Associated with Streptococcal Infection in 217 Children in Hubei Province, China
Published in Fetal and Pediatric Pathology, 2022
Jun Chen, Jian-gang Wu, Ying Cheng, Hong-bo Hu
We performed a comparison between the present series and other series published in the literature of patients with HSP (Table 3). Similar to previous studies [1, 8, 9, 11, 12], HSP occurred most frequently at age of 5 to 10 in our study. Males were affected more than females (ratio M:F = 1.33:1). These findings were in accord with studies that have reported male predominance [1, 8–10, 12]. According to our results, HSP occurred mostly in spring and winter, and lower in summer, which was consistent with the report of Anhui Province in China [1]. The reason may be that Hubei and Anhui are both provinces in central China and their geographical locations are very close. Based on bacterial culture and ASO titers, Streptococcus was the common infectious agent identified in 217 cases (15.1%) from 1437 HSP cases. The frequency of streptococcal infection in HSP children was 17.08% in Anhui, China [1], 47.5% in Shandong, China [8], 13.8% in Turkey [9], and 13.3% in Saudi Arabia [10]. Obviously, our findings fall within the aforementioned range and were similar to most other reports [1, 9, 10].
The role of discoidin domain receptor 2 in the renal dysfunction of alport syndrome mouse model
Published in Renal Failure, 2021
Yuya Sannomiya, Shota Kaseda, Misato Kamura, Hiroshi Yamamoto, Hiroyuki Yamada, Masataka Inamoto, Jun Kuwazuru, Saki Niino, Tsuyoshi Shuto, Mary Ann Suico, Hirofumi Kai
Next, we measured the mRNA expression of inflammatory cytokines in the kidney tissue of CON ASO- and DDR2 ASO-treated AS mice. The mRNA expression levels of Il-1β, Il-6 and Kc (Il-8 mouse homolog) were not changed in the kidneys of DDR2 ASO-treated AS mice compared with CON ASO-treated mice (Figure 4(A-C)). Mcp1, which is related to macrophage infiltration, is inhibited by DDR2 ASO (Figure 4(D)). We measured the expression of renal fibrosis markers α-Sma, Tgf-β and Col1a1 in CON ASO- and DDR2 ASO-treated AS mice. Interestingly, DDR2 ASO suppressed the expression of Col1a1 but not α-Sma and Tgf-β (Figure 4(E-G)). However, Masson-trichrome staining revealed that DDR2 ASO did not improve renal fibrosis (Figure 4(H)). These results suggest that although DDR2 ASO suppressed some cytokines and fibrosis marker, it did not improve the renal pathology of AS.