Role of mesangial fibrinogen deposition in the pathogenesis of crescentic Henoch-Schonlein nephritis in children

Individualized medication based on pharmacogenomics and treatment progress in children with IgAV nephritis

Immunoglobulin A vasculitis (IgAV) nephritis, also known as Henoch-Schönlein purpura nephritis (HSPN), is a condition in which small blood vessel inflammation and perivascular IgA deposition in the kidney caused by neutrophil activation, which more often leads to chronic kidney disease and accounts for 1%–2% of children with end-stage renal disease (ESRD). The treatment principles recommended by the current management guidelines include general drug treatment, support measures and prevention of sequelae, among which the therapeutic drugs include corticosteroids, immunosuppressive agents and angiotensin system inhibitors. However, the concentration range of immunosuppressive therapy is narrow and the individualized difference is large, and the use of corticosteroids does not seem to improve the persistent nephropathy and prognosis of children with IgAV. Therefore, individualized maintenance treatment of the disease and stable renal prognosis are still difficult problems. Genetic information helps to predict drug response in advance. It has been proved that most gene polymorphisms of cytochrome oxidase P450 and drug transporter can affect drug efficacy and adverse reactions (ADR). Drug therapy based on genetics and pharmacogenomics is beneficial to providing safer and more effective treatment for children. Based on the pathogenesis of IgAV, this paper summarizes the current therapeutic drugs, explores potential therapeutic drugs, and focuses on the therapeutic significance of corticosteroids and immunosuppressants in children with IgAV nephritis at the level of pharmacogenomics. In addition, the individualized application of corticosteroids and immunosuppressants in children with different genotypes was analyzed, in order to provide a more comprehensive reference for the individualized treatment of IgAV nephritis in children.

A Review of the Mechanism of Vascular Endothelial Injury in Immunoglobulin A Vasculitis

Immunoglobulin A (IgA) vasculitis (IgAV), also known as Henoch-Schönlein purpura, is the most common form of childhood vasculitis. It is characterized by cutaneous hemorrhage, resulting from red blood cell leakage into the skin or mucosae, possibly caused by damage to small blood vessels. These acute symptoms usually disappear without treatment. Endothelial cells are distributed on the inner surfaces of blood vessels and lymphatic vessels, and have important functions in metabolism and endocrine function, as well as being the primary targets of external stimuli and endogenous immune activity. Injury to endothelial cells is a feature of IgA vasculitis. Endothelial cell damage may be related to the deposition of immune complexes, the activation of complement, inflammatory factors, and chemokines, oxidative stress, hemodynamics, and coagulation factors. Both epigenetic mechanisms and genetic diversity provide a genetic background for endothelial cell injury. Here, research on the role of endothelial cells in allergic IgA vasculitis is reviewed.

Efficacy and safety of low-dose corticosteroid with azathioprine in the treatment of elderly-onset IgA vasculitis with nephritis

The diagnosis of elderly-onset IgA vasculitis (IgAV) and its prognosis can be difficult to ascertain because of its rarity and the frequent presence of comorbidities. Furthermore, the treatment of elderly-onset IgAV remains controversial. We report a case of IgAV in an 87-year-old patient. Renal involvement was detected early during the IgAV follow-up. He was treated with low-dose corticosteroid and azathioprine, which led to a complete remission without any adverse effects. This suggests that precise intervention with early diagnosis and careful renal follow-up may prevent renal failure and that low-dose steroids with azathioprine can be an effective treatment for elderly-onset IgAV with nephritis.

Significance of glomerular fibrinogen deposition in children with Henoch-Schönlein purpura nephritis

BACKGROUND

Henoch-Schönlein purpura nephritis (HSPN) is the most common pediatric secondary glomerular disease. This study aimed to investigate the significance of glomerular fibrinogen (Fib) deposition in children with HSPN.

METHODS

Eighty-two patients with HSPN were enrolled retrospectively at the Children's Hospital of Soochow University from January 2015 to March 2017. Patients were divided into groups according to the presence or absence and intensity of glomerular Fib deposits, and clinical and pathological features were compared among the groups.

RESULTS

Glomerular Fib deposition was observed in 64 children (78.05%), including 1 Fib± case (1.22%), 23 Fib+ cases (28.05%), 37 Fib++ cases (45.12%), and 3 Fib+++ cases (3.66%). Significantly different levels of high-sensitivity C-reactive protein (hs-CRP), D-dimer (DD), proportions of CD19 + CD23+ cells and urine microalbumin:creatinine ratios (UMA/Cr) were noted among the different Fib deposition groups (no, mild and severe). Pairwise comparison in multiple groups revealed significantly increased hs-CRP, proportion of CD19 + CD23+ cells and UMA/Cr in the severe deposition group compared with the mild and no deposition groups, and remarkably increased DD levels were noted in the severe and mild deposition groups compared with the no deposition group. The degree of glomerular Fib deposition was positively correlated with the degree of glomerular IgA deposition, and the incidence of glomerular IgG deposition in the severe deposition group was increased compared with the no deposition group.

CONCLUSION

HSPN children with glomerular Fib deposition, especially those with severe Fib deposition, exhibit more severely disordered immunologic function, inflammatory reactions and hypercoagulability; glomerular damage in these patients may also be more severe.

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 significance of tubulointerstitial lesions in childhood Henoch-Schönlein nephritis

BACKGROUND

Little information is currently available on the development of tubulointerstitial lesions in children with Henoch-Schönlein nephritis (HSN). To identify the impact of the development of tubulointerstitial changes in HSN, we retrospectively analyzed renal biopsies obtained from children with HSN.

METHODS

Twenty-eight children with HSN from whom serial renal biopsies had been obtained before and after immunosuppressive therapy were enrolled in the study. The patients were divided into two groups according to the observed change in tubulointerstitial lesion development: group I (n = 15), with stable or improved tubulointerstitial lesions, and group II (n = 13), with worsened tubulointerstitial lesions. Group II patients had longer duration of proteinuria than group I patients (3.7 ± 3.7 years vs. 1.7 ± 1.7 years, p = 0.052).

RESULTS

The change in serum albumin level was negatively correlated with the change in tubulointerstitial scores before and after treatment (γ = -0.444, p = 0.018). Group II patients showed a significant decrease in immunoglobulin G (IgG) and IgA deposits after treatment (p = 0.039 and 0.003, respectively), while group II patients did not (p = 0.458 and 0.506, respectively).

CONCLUSIONS

Although the International Study of Kidney Disease in Children classification of HSN does not include tubulointerstitial lesions, they can progress during treatment and could have significant clinical implications in association with the duration of proteinuria.

Adjuvant treatments for Henoch-Schönlein purpura nephritis in children: A systematic review

BACKGROUND

The management of Henoch-Schönlein purpura nephritis (HSPN) in childhood is controversial. Adjuvant therapies such as immunoglobulin, anticoagulants, and vitamins have been used with conventional treatments despite a lack of evidence of their efficacy.

OBJECTIVE

The aim of this study was to review the scientific literature regarding adjuvant treatments administered with conventional drugs in the treatment of childhood HSPN.

METHODS

Published articles were identified from the MEDLINE and EMBASE databases (1988-December 2008; key words: Henoch-Schönlein nephritis and Henoch-Schönlein purpura). The search was limited to published English-language studies on therapeutic options for HSPN in children.

RESULTS

A total of 12 studies were identified and included in this review; most (n = 8) were case series or retrospective studies. Studies of conventional therapy combined with adjuvant treatment should be interpreted with caution. In particular, factor XIII administration was reported to improve kidney symptoms in 1 study. Based on the results from 9 studies, no convincing evidence on intravenous immunoglobu-lin, urokinase, or anticoagulants was identified. No substantial information was available on the benefit of antiplatelet agents or heparin in treating HSPN. Integrating treatment with vitamin E was not recommended based on the results from 1 randomized controlled trial. Fish oil was reported to be effective in 1 case series.

CONCLUSIONS

Studies concerning the treatment of HSPN in children with adjuvant therapies were retrospective and recommendations were drawn from level IV evidence. One randomized controlled trial on the use of tocopherol as adjuvant treatment was identified; however, no clinical utility was reported. At present, there is no strong evidence supporting benefits with the use of adjuvant treatments.

Correlates of systemic disease in adult Henoch-Schönlein purpura: a retrospective study of direct immunofluorescence and skin lesion distribution in 87 patients at Mayo Clinic

BACKGROUND

Detection of IgM in lesional skin of adult patients with Henoch-Schönlein purpura via direct immunofluorescence (DIF) has been associated with the presence of renal disease.

OBJECTIVE

We sought to examine whether DIF findings of skin biopsy specimens and distribution of skin lesions were associated with the presence of systemic disease, including renal, gastrointestinal tract, and joint involvement.

METHODS

We performed a retrospective review of adult patients with Henoch-Schönlein purpura seen at Mayo Clinic between 1992 and 2011.

RESULTS

Of the 87 patients (mean age, 46.1 years), 51 (59%) were male. A total of 39 patients (45%) had renal disease; 32 (37%), gastrointestinal tract involvement; 39 (45%), joint involvement; and 65 (75%), some systemic involvement. In all, 61 patients (70%) had cutaneous lesions above the waist. The DIF findings showed the presence of IgA in all 87 patients (100%). In addition, findings were positive for IgM in 32 patients (37%); IgG in 3 patients (3%); C3 in 75 patients (87%); and fibrinogen in 78 patients (92%). IgM was not found to be significantly associated with renal disease (P = .10); however, absence of fibrinogen was correlated with presence of renal involvement (P = .04). No other correlations were detected between DIF findings and systemic disease. Lesions above the waist were not significantly associated with renal (P = .12) or any (P = .76) systemic involvement.

LIMITATIONS

This study is retrospective.

CONCLUSIONS

Neither IgM in lesional skin nor distribution of skin lesions above the waist was a reliable indicator of renal or systemic disease in adults with Henoch-Schönlein purpura.

Fibrinogen, acting as a mitogen for tubulointerstitial fibroblasts, promotes renal fibrosis

Fibrinogen plays an important role in blood coagulation but its function extends far beyond blood clotting being involved in inflammation and repair. Besides these crucial functions it can also promote tissue fibrosis. To determine whether fibrinogen is involved in the development of renal tubulointerstitial fibrosis we utilized the profibrotic model of unilateral ureteral obstruction in fibrinogen-deficient mice. In the heterozygotes, obstruction was associated with a massive deposition of intrarenal fibrinogen. Fibrinogen deficiency provided significant protection from interstitial damage and tubular disruption, attenuated collagen accumulation, and greatly reduced de novo expression of α-smooth muscle actin in the obstructed kidney. While no differences were found in renal inflammatory cell infiltration, fibrinogen deficiency was associated with a significant reduction in interstitial cell proliferation, a hallmark of renal fibrosis. In vitro, fibrinogen directly stimulated renal fibroblast proliferation in a dose-dependent manner. This mitogenic effect of fibrinogen was mediated by at least three different cell surface receptors on renal fibroblasts: TLR2, TLR4, and ICAM-1. Thus, our study suggests that fibrinogen promotes renal fibrosis by triggering resident fibroblast proliferation.