Insight into the Interplay of Gd-IgA1, HMGB1, RAGE and PCDH1 in IgA Vasculitis (IgAV)

The pathogenesis of IgAV, the most common systemic vasculitis in childhood, appears to be complex and requires further elucidation. We aimed to investigate the potential role of galactose-deficient immunoglobulin A1 (Gd-IgA1), high-mobility group box 1 (HMGB1), receptor for advanced glycation end products (RAGE) and protocadherin 1 (PCDH1) in the pathogenesis of IgAV. Our prospective study enrolled 86 patients with IgAV and 70 controls. HMGB1, RAGE, Gd-IgA1 and PCDH1 in serum and urine were determined by the enzyme-linked immunosorbent assay (ELISA) method at the onset of the disease and after a six-month interval in patients and once in the control group. Serum concentrations of HMGB1, RAGE and PCDH1 and urinary concentrations of HMGB1, RAGE, Gd-IgA1 and PCDH1 were significantly higher in patients with IgAV than in the control group (p < 0.001). Concentrations of HMGB1 (5573 pg/mL vs. 3477 pg/mL vs. 1088 pg/mL, p < 0.001) and RAGE (309 pg/mL vs. 302.4 pg/mL vs. 201.3 pg/mL, p = 0.012) in the serum of patients remained significantly elevated when the disease onset was compared with the six-month follow-up interval, and thus could be a potential marker of disease activity. Urinary concentration of HMGB1 measured in the follow-up period was higher in patients with nephritis compared to IgAV without nephritis (270.9 (146.7-542.7) ng/mmol vs. 133.2 (85.9-318.6) ng/mmol, p = 0.049) and significantly positively correlated with the urine albumine to creatinine ratio (τ = 0.184, p < 0.05), the number of erythrocytes in urine samples (τ = 0.193, p < 0.05) and with the outcome of nephritis (τ = 0.287, p < 0.05); therefore, HMGB1 could be a potential tool for monitoring patients with IgAV who develop nephritis. Taken together, our results imply a possible interplay of Gd-IgA1, HMGB1, RAGE and PCDH1 in the development of IgAV. The identification of sensitive biomarkers in IgAV may provide disease prevention and future therapeutics.

Serum Levels of S100A8/A9 as a Biomarker of Disease Activity in Patients with IgA Vasculitis

S100A8/A9 protein is a well-known marker of disease activity or severity in many autoimmune and autoinflammatory diseases, but there have not been many studies about the role of S100A8/A9 in IgA vasculitis (IgAV). The aim of our study was to evaluate S100A8/A9 as a possible biomarker of activity in IgAV. We measured the serum levels of S100A8/A9 in pediatric patients with IgA vasculitis at the onset of the disease, after three months, and after six months. We compared these levels between patients with active disease, remission, and a control group, and assessed their correlation with disease activity and other markers of inflammation. Patients with active disease had significantly higher levels of serum S100A8/A9 (median ± SD) than those in the control group at the beginning of the disease (5740 ± 3157 ng/mL vs. 1447 ± 858.3 ng/mL; p < 0.0001), but also three months and six months after disease onset (p < 0.001). There was a positive correlation between S100A8/A9 serum levels and disease activity (p = 0.0003). Patients with active disease had significantly higher levels of S100A8/A9 than those in remission three months after disease onset (p = 0.0260). There was a correlation between S100A8/A9 and C-reactive protein, the C3 component of complement, ferritin, and fibrinogen. Serum levels of S100A8/A9 were also higher in patients with greater skin areas covered with rash. We demonstrated that serum levels of S100A8/A9 correlated well with disease activity and other biomarkers of inflammation in children with IgAV. According to our results, serum S100A8/A9 may be a good indicator of active disease in IgAV.

Involvement of M1-Activated Macrophages and Perforin/Granulysin Expressing Lymphocytes in IgA Vasculitis Nephritis

We investigated the polarisation of CD68+ macrophages and perforin and granulysin distributions in kidney lymphocyte subsets of children with IgA vasculitis nephritis (IgAVN). Pro-inflammatory macrophage (M)1 (CD68/iNOS) or regulatory M2 (CD68/arginase-1) polarisation; spatial arrangement of macrophages and lymphocytes; and perforin and granulysin distribution in CD3+ and CD56+ cells were visulaised using double-labelled immunofluorescence. In contrast to the tubules, iNOS+ cells were more abundant than the arginase-1+ cells in the glomeruli. CD68+ macrophage numbers fluctuated in the glomeruli and were mostly labelled with iNOS. CD68+/arginase-1+ cells are abundant in the tubules. CD56+ cells, enclosed by CD68+ cells, were more abundant in the glomeruli than in the tubuli, and co-expressed NKp44. The glomerular and interstitial/intratubular CD56+ cells express perforin and granulysin, respectively. The CD3+ cells did not express perforin, while a minority expressed granulysin. Innate immunity, represented by M1 macrophages and CD56+ cells rich in perforin and granulysin, plays a pivotal role in the acute phase of IgAVN.

HLA Polymorphisms and Clinical Manifestations in IgA Vasculitis

Studies concerning the genetic background of IgA vasculitis (IgAV), a small-vessel vasculitis occurring predominantly in childhood, have confirmed that the HLA-DRB1 gene showed a strong association with disease susceptibility. The objective was to investigate human leukocyte antigen (HLA) polymorphisms among Croatian patients with IgAV and their influence on disease susceptibility and clinical heterogeneity. Thus, 130 children with IgAV and 202 unrelated healthy individuals were enrolled in the study. Genomic DNA was extracted from whole peripheral blood, and HLA-A, -B, -DRB1 and -DQB1 gene polymorphism analysis was performed. HLA-A*03 (21.4% vs. 12.38%, p = 0.0092), HLA-B*37 (2.9% vs. 0.2%, p = 0.0054) and HLA-DRB1*12 (3.1% vs. 0.7%, p = 0.0216) alleles were significantly more frequent in IgAV patients than in controls. High-resolution typing revealed significantly higher frequency of HLA-DRB1*10:01 and -DRB1*11:03 among IgAV patients with gastrointestinal manifestations of the disease in comparison to controls (p = 0.0021 and p = 0.0301, respectively), while HLA-DRB1*14:01P occurred significantly more often in the group of patients who developed nephritis during the course of the disease (17.5% vs. 4.5%, p = 0.0006). Our results demonstrated that there is an association of HLA-A*03, HLA-B*37 and HLA-DRB1*12 alleles with susceptibility to IgAV in the examined Croatian pediatric population. Studies which aim to determine the HLA profile may contribute to the elucidation of the genetic background of autoimmune diseases, including IgAV.

The Association of HMGB1 and RAGE Gene Polymorphisms with IgA Vasculitis

High-mobility group box 1 (HMGB1) is a pleiotropic cytokine that propagates inflammation by its extracellular action of interacting with the receptor for advanced glycation end products (RAGE). Both HMGB1 and RAGE play multiple roles in the pathogenesis of a variety of inflammatory and autoimmune diseases. We investigated the association of five single-nucleotide polymorphisms (SNPs) of the HMGB1 gene (rs1412125, rs2249825, rs1045411, rs1060348, rs41369348) and four SNPs of the RAGE gene (rs1800624, rs1800625, rs2070600, rs3134940) with the susceptibility and clinical features of paediatric patients with IgA vasculitis (IgAV), also known as Henoch-Schönlein's purpura. This case‒control study included 103 children with IgAV (experimental group) and 150 age-matched healthy individuals (control group). The strength of the association between different groups and alleles or genotypes of HMGB1 and RAGE was estimated using odds ratios (ORs) and 95% confidence intervals (CIs). The HMGB1 polymorphisms rs41369348, rs1045411, rs2249825 and rs1412125 were associated with the development of generalized purpuric rash, and rs1412125 was associated with IgAV nephritis (IgAVN). The RAGE polymorphism rs2070600 might be linked to the development of arthritis in IgAV patients. There was no statistically significant association between the analysed polymorphisms and susceptibility to IgAV. This is the first study to propose an association between several HMGB1 and RAGE polymorphisms and different phenotypes in the clinical course of IgAV in a paediatric population. Further research on other polymorphisms of HMGB1 and RAGE should be conducted in a larger number of patients.

Cerebrovascular involvement in systemic childhood vasculitides

Pediatric vasculitides sometimes involve central nervous system (CNS). The manifestations are diverse, ranging from headache, seizures, vertigo, ataxia, behavioral changes, neuropsychiatric symptoms, consciousness disorders, and even cerebrovascular (CV) accidents that may lead to irreversible impairment and even death. Stroke, on the other hand despite the great progress in prevention and treatment, is still one of the leading causes of morbidity and mortality in the general population. The aim of this article was to summarize CNS manifestations and CV issues observed in primary pediatric vasculitides and the current knowledge of etiology and CV risk factors, preventive strategies, and therapeutic options in this target patient population. Pathophysiological links reveal similar immunological mechanisms involved in both pediatric vasculitides and CV events with endothelial injury and damage being the central point. From the clinical point of view, CV events in pediatric vasculitides were associated with increased morbidity and poor prognosis. If damage has already occurred, the therapeutic approach consists of good management of the vasculitis itself, antiplatelet and anticoagulation therapy, and early rehabilitation. Risk factors for acquiring cerebrovascular disease (CVD) and stroke, particularly hypertension and early atherosclerotic changes, already begin in childhood, with vessel wall inflammation contributing itself, once more emphasizing that appropriate preventive measures are certainly necessary in pediatric vasculitis population to improve their long-term outcome.

Clinical features, treatment and outcome of pediatric patients with severe cutaneous manifestations in IgA vasculitis: Multicenter international study

OBJECTIVE

IgA vasculitis (IgAV) (formerly Henoch-Schönlein Purpura, HSP) rarely causes severe skin lesions in children. The purpose of the research was to determine whether severe skin manifestations were associated with a more severe disease course.

METHODS

Severe cutaneous manifestations were defined as presence of hemorrhagic vesicles, bullae, ulcerations and/or necroses. Data were collected retrospectively from 12 international tertiary university medical centers.

RESULTS

A total of 64 patients with the most severe skin changes in IgAV/HSP and median (Q1, Q3) age of 8.08 (5.08, 11.92) years at the disease onset were compared with 596 IgAV/HSP patients without these manfiestations and median (Q1, Q3) age of 6.33 (4.50, 8.92) years. The patients with severe cutaneous manifestations were older in comparison to other patients with IgAV/HSP (p<0.001), they developed nephritis more frequently (40.6% vs. 20.6%, p = 0.001) with worse outcome of renal disease (p = 0.001). This group of patients also had higher frequencies of severe gastrointestinal complications like hematochezia, massive bleeding and/or intussusception (29.3% vs. 14.8%, p<0.001). d-dimer concentrations were significantly higher in these patients (4.60 mg/L vs. 2.72 mg/L, p = 0.003) and they had more frequent need for treatment with systemic glucocorticoids (84.4% vs. 37.2%, p<0.001) in comparison with the control group. Further multivariate analysis showed that severe cutaneous changes were associated with higher risk of developing nephritis [OR=3.1 (95%CI 1.04-9.21), p = 0.042] and severe gastrointestinal complications [OR=3.65 (95%CI 1.08-12.37), p = 0.038].

CONCLUSION

Patients with IgAV/HSP and severe skin manifestations had a more severe clinical course and more frequently required glucocorticoids compared to classic IgAV/HSP patients.

The Role of Genetic Risk Factors in Pathogenesis of Childhood-Onset Systemic Lupus Erythematosus

The pathogenesis of childhood-onset systemic lupus erythematosus (cSLE) is complex and not fully understood. It involves three key factors: genetic risk factors, epigenetic mechanisms, and environmental triggers. Genetic factors play a significant role in the development of the disease, particularly in younger individuals. While cSLE has traditionally been considered a polygenic disease, it is now recognized that in rare cases, a single gene mutation can lead to the disease. Although these cases are uncommon, they provide valuable insights into the disease mechanism, enhance our understanding of pathogenesis and immune tolerance, and facilitate the development of targeted treatment strategies. This review aims to provide a comprehensive overview of both monogenic and polygenic SLE, emphasizing the implications of specific genes in disease pathogenesis. By conducting a thorough analysis of the genetic factors involved in SLE, we can improve our understanding of the underlying mechanisms of the disease. Furthermore, this knowledge may contribute to the identification of effective biomarkers and the selection of appropriate therapies for individuals with SLE.

Semiquantitative classification (SQC) and Oxford classifications predict poor renal outcome better than The International Study of Kidney Disease in Children (ISKDC) and Haas in patients with IgAV nephritis: a multicenter study

INTRODUCTION

Several histologic classifications are used in the evaluation of IgA vasculitis nephritis (IgAVN), however, to date, no studies have determined which one has the strongest association with the severity of IgAVN and, as a consequence, its outcomes.

MATERIALS AND METHODS

Patients included in the study were diagnosed with IgAV and IgAVN in seven tertiary university medical centers in Croatia, Italy and Israel. The International Study of Kidney Disease in Children (ISKDC), Haas, Oxford, and Semiquantitative classification (SQC) classifications were used in the analysis and description of renal biopsy. Time from biopsy to outcome evaluation was a statistically significant factor in outcome prediction that was used to define the base model, and was a covariate in all the tested models.

RESULTS

Sixty-seven patients were included in this study. The SQC classification proved to be the best one in outcome prediction, followed by the Oxford classification. The ISKDC and Haas classifications could not predict renal outcome. The Oxford parameters for mesangial hypercellularity and tubular atrophy, as well as the SQC parameters for cellular crescents showed an independent statistically significant contribution to outcome prediction. High level of twenty-four hour protein excretion was associated with a higher grade in the Oxford, SQC and ISKDC classifications. Endocapillary proliferation was positively associated with the Pediatric Vasculitis Activity Score (PVAS) at diagnosis, while tubular atrophy was negatively associated.

CONCLUSION

The SQC, followed by the Oxford classification were found to provide the best classifications of renal biopsy analysis in patients to predict the outcome in patients with IgAVN. Cellular crescents, mesangial hypercellularity and tubular atrophy showed significant contributions, indicating that active and chronic variables should be included in the estimation.

Diagnostic and Management Strategies of IgA Vasculitis Nephritis/Henoch-Schönlein Purpura Nephritis in Pediatric Patients: Current Perspectives

IgA vasculitis (IgAV) or Henoch-Schönlein purpura (HSP) is the most common vasculitis in children, and nephritis (IgAVN or HSPN) is the most important and only chronic manifestation of the disease. Despite this, there are no diagnostic criteria and we rely on the European League Against Rheumatism/Paediatric Rheumatology International Trials Organization/Paediatric Rheumatology European Society-endorsed Ankara 2008 classification criteria in our daily practice. Basic investigations that should be done in every patient with IgAVN include blood pressure measurement, estimated glomerular filtration rate and urinalysis. Kidney biopsy is still the gold standard for the diagnosis of IgAVN since noninvasive confirmation of nephritis is still pending. According to the Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) recommendations, the first-line treatment for with mild forms of IgAVN is oral glucocorticoids, for patients with moderate IgAVN parenterally administrated glucocorticoids in pulsed doses, while initial treatment for patients with the most severe forms of IgAVN include pulsed doses of glucocorticoids in combination with intravenous cyclophosphamide pulses. New therapeutic options are currently being tested, aiming to reduce the production of galactose-deficient IgA₁ and autoantibodies or suppress the alternative or lectin complement pathway and blocking mesangial cell activation.

2019 ACR/EULAR classification criteria and therapy in predicting organ damage accrual in patients with childhood-onset systemic lupus erythematosus: A retrospective study over the last 29 years

OBJECTIVE

We explored damage occurrence in patients with childhood-onset SLE (cSLE) and aimed to predict the risk of organ damage occurrence in time.

METHODS

The retrospective study included patients treated for cSLE at the Centre of Reference for Pediatric and Adolescent Rheumatology of the Republic Croatia over a 29-year period.

RESULTS

The disease development of 97 patients (77 females) with cSLE was examined. The median (Q₁, Q₃) follow-up time was 6.5 (2.3, 12.0) years. SDI was determined at 5 time points (6, 12, 24, 36 months, and last follow-up). Thirty-eight patients (48%) had organ damage at the last follow-up. Prepubertal group of patients showed higher SLEDAI scores at the disease onset, while post-pubertal group had significantly lower proportion of patients with relapses. We estimated the time from the first symptom to the moment of damage and our findings suggest that it is unlikely that organ damage will occur in 50% of patients in the first 6 years since the diagnosis. The number of 2019 ACR/EULAR classification criteria at the time of diagnosis associated with SDI determined after 1 year of the follow-up period. The patients who received higher doses of glucocorticoids accumulated damage faster and mycophenolate mofetil was found to be a more frequent therapy in patients with SDI ≥3.

CONCLUSION

Knowing that damage will most likely happen after the first 6 years after diagnosis in 50% of patients enables physicians to better predict damage occurrence. High number of 2019 ACR/EULAR criteria and treatment with glucocorticoids in childhood-onset SLE are associated with damage accrual and these findings could enable us to detect patients which should be closely monitored for higher risk of damage development.

New Insights and Challenges Associated With IgA Vasculitis and IgA Vasculitis With Nephritis-Is It Time to Change the Paradigm of the Most Common Systemic Vasculitis in Childhood?

What are the challenges ahead and how have we responded so far when it comes to the non-granulomatous systemic vasculitis, characterized mainly by deposits of IgA immune complexes in the endothelium of small blood vessels-IgA vasculitis (IgAV)? That is the question to which we tried to answer. We summarized existing knowledge about epidemiology, pathogenesis, genetics, diagnostic tests and therapy in this somewhat neglected entity in pediatric rheumatology. Since etiopathogenesis of IgA vasculitis is complex, with factors other than galactose-deficient IgA₁-containing immune complexes also being important, and may involve numerous interactions between environmental and genetic factors, genomics alone cannot explain the entirety of the risk for the disease. The incidence of IgAV and nephritis varies worldwide and may be a consequence of overlapping genetic and environmental factors. In addition to the role of the HLA class II genes, some studies have pointed to the importance of non-HLA genes, and modern geostatistical research has also indicated a geospatial risk distribution, which may suggest the strong influence of different environmental factors such as climate, pathogen load, and dietary factors. The application of modern geostatistical methods until recently was completely unknown in the study of this disease, but thanks to the latest results it has been shown that they can help us a lot in understanding epidemiology and serve as a guide in generating new hypotheses considering possible environmental risk factors and identification of potential genetic or epigenetic diversity. There is increasing evidence that an integrative approach should be included in the understanding of IgA vasculitis, in terms of the integration of genomics, proteomics, transcriptomics, and epigenetics. This approach could result in the discovery of new pathways important for finding biomarkers that could stratify patients according to the risk of complications, without an invasive kidney biopsy which is still the gold standard to confirm a diagnosis of nephritis, even if biopsy findings interpretation is not uniform in clinical practice. Ultimately, this will allow the development of new therapeutic approaches, especially important in the treatment of nephritis, for which there is still no standardized treatment.

Expanding the clinical spectrum of pathogenic variation in NR2F2: Asplenia

We present a case with congenital syndromic asplenia associated with immune deficiency, glandular hypospadias and cryptorchidism. Genetic analysis identified a likely pathogenic de novo variant in NR2F2. Pathogenic NR2F2 variants have been associated with other congenital anomalies affecting the central axis, such as congenital heart disease and diaphragmatic hernia, which were not part of our patient's clinical features. The association between NR2F2 and asplenia (including glandular hypospadias and cryptorchidism) has been described in animal models and our report is the first expanding the NR2F2 clinical spectrum in humans to include asplenia.

Gastrointestinal involvement and its association with the risk for nephritis in IgA vasculitis

Background:

We analysed clinical and biochemical parameters in predicting severe gastrointestinal (GI) manifestations in childhood IgA vasculitis (IgAV) and the risk of developing renal complications.

Methods:

A national multicentric retrospective study included children with IgAV reviewed in five Croatian University Centres for paediatric rheumatology in the period 2009–2019.

Results:

Out of 611 children, 281 (45.99%) had at least one GI manifestation, while 42 of 281 (14.95%) had the most severe GI manifestations. Using logistic regression several clinical risk factors for the severe GI manifestations were identified: generalized rash [odds ratio (OR) 2.09 (95% confidence interval (CI) 1.09–4.01)], rash extended on upper extremities (OR 2.77 (95% CI 1.43–5.34)] or face [OR 3.69 (95% CI 1.42–9.43)] and nephritis (IgAVN) [OR 4.35 (95% CI 2.23–8.50)], as well as lower values of prothrombin time (OR 0.05 (95% CI 0.01–0.62)], fibrinogen [OR 0.45 (95% CI 0.29–0.70)] and IgM [OR 0.10 (95% I 0.03–0.35)]] among the laboratory parameters. Patients with severe GI involvement more frequently had relapse of the disease [OR 2.14 (CI 1.04–4.39)] and recurrent rash [OR 2.61 (CI 1.27–5.38)]. Multivariate logistic regression found that the combination of age, GI symptoms at the beginning of IgAV and severity of GI symptoms were statistically significant predictors of IgAVN. Patients in whom IgAV has started with GI symptoms [OR 6.60 (95% CI 1.67–26.06)], older children [OR 1.22 (95% CI 1.02–1.46)] with severe GI form of IgAV (OR 5.90 (95% CI 1.12–31.15)] were particularly high-risk for developing IgAVN.

Conclusion:

We detected a group of older children with the onset of GI symptoms before other IgAV symptoms and severe GI form of the IgAV, with significantly higher risk for acute and chronic complications of IgAV.

Persistence and Severity of Cutaneous Manifestations in IgA Vasculitis Is Associated with Development of IgA Vasculitis Nephritis in Children

BACKGROUND/OBJECTIVE

The purpose of this study was to evaluate the prevalence and severity of skin involvement in children with IgA vasculitis (IgAV) and its relationship with clinical and biochemical parameters and the risk of developing IgA vasculitis nephritis (IgAVN), the only cause of long-term morbidity and the main prognostic factor in IgAV patients.

METHODS

This national multicenter retrospective study included 611 patients under the age of 18 years with IgAV referred to five Croatian tertiary hospitals between 2009 and 2019. Patient data were collected from a database with systematic analysis of IgAV patients in the Croatian population.

RESULTS

Among the 611 children, 205 (33.55%) had purpura on the lower extremities, in 207 (33.88%) the rash extended on the trunk, in 149 (24.39%) it extended to the upper extremities, in 32 (5.24%) the rash was generalized, while 15 (2.47%) had the most severe skin symptoms: bullae, ulcerations, and necroses. IgAVN developed in 130 (21.28%) and persistent IgAVN (present for >3 months) in 48 (7.86%) children. Multivariate logistic regression found that presence of ulcerations and necroses (OR 3.20 [95% CI 1.03-9.91]), persistent purpura (OR 2.89 [95% CI 1.71-4.88]), and higher age (OR 1.16 [95% CI 1.09-1.23]) were significant predictors of IgAVN, whereas persistent purpura (OR 20.11 [95% CI 1.09-372.52]), male sex (OR 3.32 [95% CI 1.13-9.80]), and higher age (OR 1.15 [95% CI 1.00-1.30]) were predictors of persistent IgAVN. Among the laboratory parameters, higher serum urea (OR 1.43 [95% CI 1.03-2.00]) and reduction in activated partial thromboplastin time (OR 0.83 [95% CI 0.74-0.93]) were shown to have a significant impact on increasing the risk of persistent IgAVN.

CONCLUSION

With increasing severity and duration of cutaneous manifestations in IgAV, the risk of developing IgAVN increases, making the prognosis worse, with a greater likelihood to need more aggressive treatment.

Geospatial clustering of childhood IgA vasculitis and IgA vasculitis-associated nephritis

OBJECTIVES

Research on spatial variability of the incidence of IgA vasculitis (IgAV) in children and its potential implications for elucidation of the multifactorial aetiology and pathogenesis is limited. We intended to observe spatial variability of the incidence of IgAV and IgA vasculitis-associated nephritis (IgAVN) using modern geostatistical methods, and hypothesised that their spatial distribution may be spatially clustered.

METHODS

Patients' data were retrospectively collected from 2009 to 2019 in five Croatian University Hospital Centres for paediatric rheumatology, and census data were used to calculate the incidence of IgAV. Using spatial empirical Bayesian smoothing, local Morans' I and local indicator of spatial autocorrelation (LISA), we performed spatial statistical analysis.

RESULTS

596 children diagnosed with IgAV were included in this study, of which 313 (52.52%) were male. The average annual incidence proportion was estimated to be 6.79 per 100 000 children, and the prevalence of IgAVN was 19.6%. Existence of spatial autocorrelation was observed in both IgAV and IgAVN; however, clustering distribution differed. While IgAV showed clustering in Mediterranean and west continental part around cities, IgAVN was clustered in the northern Mediterranean and eastern continental part, where a linear cluster following the Drava and Danube river was observed.

CONCLUSION

IgAV incidence in Croatia is similar to other European countries. Spatial statistical analysis showed a non-random distribution of IgAV and IgAVN. Although aetiological associations cannot be inferred, spatial analytical techniques may help in investigating and generating new hypotheses in non-communicable diseases considering possible environmental risk factors and identification of potential genetic or epigenetic diversity.

Different histological classifications for Henoch-Schönlein purpura nephritis: which one should be used?

BACKGROUND

Nephritis is the most important chronic complication of IgA Vasculitis (IgAV)/Henoch-Schönlein purpura (IGAV/HSP) and thus the main prognostic factor of this most common childhood vasculitis. Since the prognosis and treatment selection depends on the mode of interpretation of biopsy material, in this manuscript we have presented several issues related to the uneven application of different histological classifications in IgAV/Henoch-Schönlein purpura nephritis (HSPN). The nephritis of IgAV/IGAV/HSP will be abbreviated as HSPN for this paper.

MAIN BODY

In clinical practice we use different histological classifications for HSPN. It is not known which of these classifications best correlates with severity of renal disease and renal outcome in IgAV/IGAV/HSP. One of the major problem with existing histological classifications is that there is no consensus on the implementation of biopsy in the treatment of HSPN. There is a histologic classification system conventionally used in HSPN, of the International Study of Kidney Disease in Children (ISKDC). On the other hand there is the new classification system suggested for IgA nephropathy, the Oxford classification. The latter has been validated only in IgA nephropathy. There are also two further histologic classifications of Haas and Koskela that have been developed. Current treatment strategies in HSPN are not standardised nor predominantly based on histological classification.

CONCLUSION

One of the possible solutions to problems related to the application of different histological classification in HSPN is the implementation of multicenter multinational prospective studies with joint collaboration between pediatric rheumatologists, nephrologists and nephropathologists to correlate the clinical features and outcome with the classification systems as well among the classifications. This classification should be the basis for the construction of guidelines for the treatment of patients with HSPN.

Challenges in early diagnosis of Kawasaki disease in the pediatric emergency department: differentiation from adenoviral and invasive pneumococcal disease

Early recognition and distinction of Kawasaki disease (KD) from other febrile infectious diseases is one of the biggest challenges in pediatric emergency departments (PED). The aim of this study was to assess the utility of clinical findings and routinely used laboratory parameters for early discrimination between KD, invasive pneumococcal disease (IPD) and adenovirosis (AdV). A retrospective, cross-sectional study of children aged 3-36 months consecutively admitted to the PED and diagnosed with either KD (n = 110), AdV (n = 440) or IPD (n = 122) was conducted. At first presentation to the PED, 56.3% of KD patients had none or only one clinical criterion, 31% of patients with AdV and 11% with IPD had > 2 criteria. The levels of platelets (Plt), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were higher and white blood cells (WBC) significantly lower in KD than in IPD and AdV group. The WBC < 20 ×10⁹/l showed a sensitivity of 80.9% and specificity of 79.7% in comparison to AdV. The ROC curve showed a significant, but low sensitivity for AST, ALT and Plt. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) did not show any significant diagnostic accuracy. Significant association between incomplete KD and rash, WBC < 20 ×10⁹ and Plt > 400 ×10⁹/L compared to AdV and conjuctivitis, rash and Plt > 400 × 10⁹/L, was found. Due to the time delay and nonspecific early presentation, differentiating KD from IPD and AdV is challenging. Tools used for identification of patients at risk for severe bacterial infections in PED lack sensitivity for identification of KD cases. New biomarkers are warranted for distinction of KD from IPD or AdV.