The significance of tubulointerstitial lesions in childhood Henoch-Schönlein nephritis

Clinical and histological comparison of IgA nephritis and renal IgA vasculitis

BACKGROUND

Immunoglobulin A (IgA) nephritis (IgAN) and renal IgA vasculitis (IgAV) show renal IgA deposits, but whether these two diseases are distinct entities or a spectrum of the same condition is under debate. In this study, we add perspective by contrasting the clinical course and histological presentation using the Oxford classification and the National Institutes of Health lupus nephritis activity index (LN-AI) and chronicity index (LN-CI) in IgAN and IgAV.

METHODS

In this single-centre, retrospective study, kidney biopsies of 163 adult patients with IgAN and 60 adult patients with IgAV were compared according to the Oxford MEST-C score, LN-AI and LN-CI. At the time of biopsy, clinical presentation was compared in terms of age, arterial hypertension, diabetes mellitus, extrarenal manifestations, estimated glomerular filtration rate, proteinuria and urine sediment. IgAV patients and all IgAN patients with crescents received immunosuppressive treatment. After biopsy, kidney function was followed until patients reached end-stage renal disease (ESRD) or they died.

RESULTS

The clinical course and kidney histology differ in IgAN and IgAV. IgAV patients showed more microhaematuria and nephritic sediment, while IgAN patients had a greater history of arterial hypertension, more proteinuria and a higher risk for ESRD. These clinical differences were associated with histological differences, as kidney biopsies of IgAN patients were characterized by glomerulosclerosis and tubular atrophy while kidney biopsies of IgAV patients were characterized by endocapillary hypercellularity and crescents. Overall, tubular atrophy and an LN-CI ≥4 were associated with a higher risk for ESRD in IgAN and IgAV.

CONCLUSION

Our study supports the notion that IgAN and IgAV follow distinct courses, suggesting that they require different treatment strategies. Moreover, we make a point that the Oxford classification and LN-CI can be useful in categorizing and predicting long-term prognosis not only in IgAN, but also in IgAV.

Comparison of clinical, pathological and long-term renal outcomes of children with Henoch-Schonlein purpura nephritis and IgA nephropathy

PURPOSE

To compare clinical, pathological, and long-term renal outcomes of children with Henoch-Schonlein purpura nephritis (HSPN) and IgA nephropathy (IgAN).

METHODS

The medical records of patients diagnosed as HSPN and IgAN during childhood were evaluated retrospectively. HSPN and IgAN groups were compared in terms of gender, age, upper respiratory infection history, blood pressure; presence of nephrotic and/or nephritic syndrome; hemoglobin level, leukocyte count, C-reactive protein (CRP), serum albumin (sAlb), creatinine, complement 3 (sC3), complement 4 (sC4) and immunoglobulin A (sIgA) levels; estimated glomerular filtration rate (eGFR) and proteinuria levels; and renal pathology findings at the onset of disease; total follow-up time; and blood pressure, eGFR and proteinuria levels at the last visit.

RESULTS

Fifty-four patients were enrolled in the study [38 (70%) HSPN and 16 (30%) IgAN]. The median follow-up time was 60.5 and 72.0 months in HSPN and IgAN groups, respectively (p > 0.05). The HSPN and IgAN groups were also not different in terms of gender, age at the onset; leukocyte count, eGFR, sC3-sC4-sIgA levels; and the presence of endocapillary, extracapillary and mesangial proliferation, tubular atrophy, interstitial fibrosis and IgA, IgM, C3 accumulation in renal tissue. Upper respiratory tract infection history was more common in children with IgAN (8/16 vs 8/38, p = 0.045). sAlb (3.96 ± 0.58 vs 4.40 ± 0.46 g/dL, p = 0.005), hemoglobin (12.1 ± 1.3 vs 13.3 ± 1.2 g/dL, p = 0.004,) and the incidence of mesangial IgG deposition (15/38 vs 11/16, p = 0.049) were lower, while CRP (16.3 ± 7.2 vs 7.8 ± 4.4 mg/L, p = 0.002) and proteinuria (72.1 ± 92.4 vs 34.2 ± 37.9 mg/m2/24 h, p = 0.041) was higher in HSPN group at the onset of disease. Proteinuria and eGFR were similar between the two groups at last visit.

CONCLUSION

Children with HSPN and IgAN have little clinical and histological differences in our population. The most prominent difference at presentation with nephritis was higher proteinuria in HSPN probably associated with inflammation due to systemic vasculitis. Long-term renal outcome was good in both HSPN and IgAN.

Efficacy and Safety of Tacrolimus in the Treatment of Pediatric Henoch-Schönlein Purpura Nephritis

BACKGROUND

Children with severe Henoch-Schönlein purpura nephritis (HSPN) may progress to end-stage renal disease without appropriate treatment.

OBJECTIVE

This study aimed to investigate the efficacy and safety of tacrolimus combined with glucocorticoids in the treatment of pediatric HSPN.

METHODS

A total of 87 HSPN patients with urinary protein ≥ 0.75 g/24 h received standard of care, including angiotensin II receptor blockers/angiotensin-converting enzyme inhibitors and glucocorticoids. Patients were divided into three groups and additionally received tacrolimus (n = 30), cyclophosphamide (n = 31), or mycophenolate mofetil (MMF) (n = 26). We monitored outcome measures, including proteinuria, hematuria, and renal function and analyzed the efficacy and side effects in each group.

RESULTS

At 2-month follow-up, the overall efficacy was 93.3%, 83.9%, and 61.5% for tacrolimus, cyclophosphamide, and MMF, respectively (P < 0.05). Urinary protein significantly decreased for all groups. Urinary red blood cell counts significantly decreased for patients treated with tacrolimus (P < 0.001) and cyclophosphamide (P < 0.05), whereas no significant decrease was seen for those receiving MMF (P = 0.09). Although urine β2-microglobulin significantly decreased following 2 months of treatment with all medications, efficacy was greater with tacrolimus than with cyclophosphamide and MMF (P < 0.001). Major adverse events were respiratory and urinary infections, with MMF having the highest infection rate. The cyclophosphamide group also experienced additional adverse events, including arrhythmia, hemorrhagic cystitis, leukocytosis, thrombocytopenia, and hyperglycemia.

CONCLUSIONS

These results indicate that tacrolimus is more effective at reducing proteinuria and hematuria and improving renal function, with relatively milder side effects, in the treatment of pediatric HSPN.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2200055323, retrospectively registered on January 7, 2022.

Patient Outcomes of Henoch-Schönlein Purpura Nephritis According to the New Semiquantitative Classification

Background: A new semiquantitative classification (SQC) for pediatric Henoch-Schönlein nephritis (HSN) was defined recently. The outcomes of pediatric HSN patients are reevaluated according to the new classification. Methods: Primary kidney biopsies from 80 HSN patients were scored using the new SQC. The International Study of Kidney Disease in Children (ISKDC) and SQC classifications were compared in terms of the patient outcomes. Outcomes were defined as: Outcome A (n = 44) patients with no sign of renal disease, Outcome B (n = 32) patients with minor urinary abnormalities, and Outcome C (n = 4) patients with active renal disease. Results: The patients with outcome C had significantly higher biopsy scores and chronicity indices than patients in group A. There was no significant difference in areas under the curve between total biopsy SQC scores and ISKDC findings. Conclusions: Our results suggest that the modified SQC is not more sensitive than ISKDC classification for predicting the outcome in HSN cases.

Prediction of renal outcome in Henoch-Schönlein nephritis based on biopsy findings

BACKGROUND

In Henoch-Schönlein nephritis (HSN), a risk factor for unfavorable outcome is prolonged proteinuria, but the value of renal biopsies in prognosis assessment is debatable.

METHODS

We evaluated serial renal biopsies from 26 HSN patients. Follow-up biopsy occurred at median 2.1 years after diagnostic biopsy. Patients formed two groups at the follow-up biopsy: patients without proteinuria (group I; n = 11) and with proteinuria (group II; n = 15). Biopsies underwent evaluation according to three classifications: International Study of Kidney Disease in Children (ISKDC), Oxford (MEST-C), and semiquantitative classification (SQC) including an activity and chronicity score. Analysis also included expression of pro-fibrotic (alpha-smooth muscle actin and vimentin) and inflammatory (P-selectin glycoprotein ligand-1) molecules in the diagnostic biopsy specimens. Definition of unfavorable outcome was active renal disease or reduced renal function at last follow-up.

RESULTS

Between the biopsies, SQC chronicity score increased in 22 (85%) patients, whereas activity score and ISKDC grade decreased in 21 (81%) and 17 (65%), respectively. Of the MEST-C parameters, endocapillary proliferation (from 83 to 13%; p < 0.001) and crescents (from 63 to 25%; p = 0.022) showed significant reduction, and segmental glomerulosclerosis (from 38 to 79%; p = 0.006) significant increment. These changes occurred similarly in groups I and II. Expression of the pro-fibrotic and inflammatory molecules showed no clinically significant differences between groups I and II. None in group I and five (33%) patients in group II had unfavorable outcome (p = 0.053).

CONCLUSIONS

Our results suggest that follow-up biopsies provide limited additional information to clinical symptoms in HSN outcome prediction.

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.

Tubulointerstitial Infiltration of M2 Macrophages in Henoch-Schönlein Purpura Nephritis Indicates the Presence of Glomerular Crescents and Bad Clinical Parameters

Henoch-Schönlein purpura (HSP) is the most common systemic vasculitis in children, and renal involvement (HSP nephritis, HSPN) is a severe manifestation. HSPN is histologically classified by the International Study of Kidney Disease in Children (ISKDC) based on mesangial hypercellularity and the extent of glomerular crescents. Macrophages, categorized as M1 or M2, frequently infiltrate in various glomerular and tubulointerstitial diseases and infiltration of specific subtypes is associated with disease progression. Therefore, to identify whether infiltration of M1 or M2 macrophages has clinical significance, we quantified the subtypes of macrophages in 49 HSPN specimens and correlated the counts with histologic features and clinical parameters. Higher tubulointerstitial M2 counts were associated with chronic renal failure (CRF), ISKDC classes III-IV, and crescents (P<0.001, 0.002, 0.001). Glomerular M2 counts were significantly related to ISKDC classes III-IV and crescents (area under curve, AUC 0.804, 0.833). Tubulointerstitial M2 counts were associated with CRF, ISKDC classes III-IV, and crescents (AUC 0.872, 0.778, 0.830). Tubulointerstitial M2 counts also revealed higher AUC than tubulointerstitial M1 counts for CRF (P=0.036) and ISKDC classes III-IV (P=0.047). Glomerular M2 counts revealed higher AUC than glomerular M1 counts for ISKDC classes III–IV (P=0.024). Tubulointerstitial M2 counts were the most powerful parameter for CRF (AUC 0.872) and revealed even higher AUC than ISKDC classification (AUC 0.716) with borderline significance (P=0.086) for CRF. In summary, tubulointerstitial M2 counts were a superior parameter to tubulointerstitial M1 counts and even to ISKDC classification indicating the presence of CRF.

Henoch-schonlein Purpura Nephritis with Renal Interstitial Lesions

Objective

To investigate the clinical pathology and prognosis & outcome of Henoch-Schonlein purpura nephritis (HSPN) with renal interstitial lesions.

Methods

All 148 patients were analyzed for clinical, renal pathological, and prognostic features. Patients with no, mild, and moderate- severe renal tubulo-interstitial lesions were included in group A, B and C, respectively.

Results

The estimated glomerular filtration rate (eGFR) of group B was significantly lower than that of group A. The levels of serum creatinine and blood urea nitrogen in group C were significantly higher than those in groups A and B. Clinical type II was correlated with pathological types II and IIIa; pathological type IV and IIIb were correlated with clinical type VI and IV. There were significant differences in the level of red blood cells in urinary sediment, levels of urine occult blood and in the prognosis among the 3 groups.

Conclusion

Clinically, Type II is the most common cause; pathologically, Type IIIa is more common. The severity of renal tubulo-interstitial lesions is positively correlated with a decline in renal function and GFR. There is a correlation between the severity of renal tubulo-interstitial lesions and the severity of hematuria. Most patients with HSPN have a good prognosis.

Presentation of pediatric Henoch-Schönlein purpura nephritis changes with age and renal histology depends on biopsy timing

BACKGROUND

This study correlates the clinical presentation of Henoch-Schönlein purpura nephritis (HSPN) with findings on initial renal biopsy.

METHODS

Data from 202 pediatric patients enrolled in the HSPN registry of the German Society of Pediatric Nephrology reported by 26 centers between 2008 and 2014 were analyzed. All biopsy reports were re-evaluated for the presence of cellular crescents or chronic pathological lesions (fibrous crescents, glomerular sclerosis, tubular atrophy >5%, and interstitial fibrosis >5%).

RESULTS

Patients with HSPN with cellular glomerular crescents were biopsied earlier after onset of nephritis (median 24 vs 36 days, p = 0.04) than those without, whereas patients with chronic lesions were biopsied later (57 vs 19 days, p < 0.001) and were older (10.3 vs 8.6 years, p = 0.01) than those without. Patients biopsied more than 30 days after the onset of HSPN had significantly more chronic lesions (52 vs 22%, p < 0.001), lower eGFR (88 vs 102 ml/min/1.73m², p = 0.01), but lower proteinuria (2.3 vs 4.5 g/g, p < 0.0001) than patients biopsied earlier. Children above 10 years of age had lower proteinuria (1.98 vs 4.58 g/g, p < 0.001), lower eGFR (86 vs 101 ml/min/1.73m², p = 0.002) and were biopsied significantly later after onset of nephritis (44 vs 22 days, p < 0.001) showing more chronic lesions (45 vs 30%, p = 0.03). Proteinuria and renal function at presentation decreased with age.

CONCLUSIONS

In summary, we find an age-dependent presentation of HSPN with a more insidious onset of non-nephrotic proteinuria, impaired renal function, longer delay to biopsy, and more chronic histopathological lesions in children above the age of 10 years. Thus, HSPN presents more like Immunoglobulin A (IgA) nephritis in older than in younger children.

The ISKDC classification and a new semiquantitative classification for predicting outcomes of Henoch-Schönlein purpura nephritis

BACKGROUND

Histological findings from primary kidney biopsies were correlated with patient outcomes in a national cohort of paediatric Henoch-Schönlein nephritis (HSN) patients.

METHODS

Primary kidney biopsies from 53 HSN patients were re-evaluated using the ISKDC (International Study of Kidney Disease in Children) classification and a modified semiquantitative classification (SQC) that scores renal findings and also takes into account activity, chronicity and tubulointerstitial indices. The ISKDC and SQC classifications were evaluated comparatively in four outcome groups: no signs of renal disease (outcome A, n = 27), minor urinary abnormalities (outcome B, n = 18), active renal disease (outcome C, n = 3) and renal insufficiency, end-stage renal disease or succumbed due to HSN (outcome D, n = 5). For the receiver operating characteristic and logistic regression analyses, outcomes A and B were considered to be favourable and outcomes C and D to be unfavourable. The median follow-up time was 7.3 years.

RESULTS

The patients with an unfavourable outcome (C and D), considered together due to low patient numbers, had significantly higher total biopsy SQC scores and activity indices than those who had a favourable one (groups A and B). The chronicity and tubulointerstitial indices differed significantly only between group C + D and group A. The difference in areas under the curve between the total biopsy SQC scores and ISKDC findings was 0.15 [p = 0.04, normal-based 95% confidence interval (CI) 0.007-0.29, bias-controlled 95% CI -0.004 to 0.28].

CONCLUSIONS

Our results suggest that the modified SQC is more sensitive than ISKDC classification for predicting the outcome in HSN cases.