Vasculitides associated with IgG antineutrophil cytoplasmic autoantibodies in childhood

Rituximab pediatric drug development: Pharmacokinetic and pharmacodynamic modeling to inform regulatory approval for rituximab treatment in patients with granulomatosis with polyangiitis or microscopic polyangiitis

Anti-neutrophil cytoplasmic antibody-associated vasculitides granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) are rare, potentially organ- and life-threatening autoimmune conditions affecting adult and pediatric patients. An open-label phase II study was conducted to determine safe and effective dosing regimens of rituximab in pediatric patients with GPA/MPA. To determine the selection of an appropriate dose regimen in children for induction and maintenance, a population pharmacokinetic approach was used (nonlinear mixed-effect modeling), combining pediatric data with data from adults with GPA/MPA. The time course of B-cell depletion was assessed in both populations. The exposure-effect relationship was assessed by logistic regression. Twenty-five pediatric patients (80% female patients; age range, 6-17 years) were enrolled in the trial and received the induction regimen of intravenous rituximab 375 mg/m² weekly for 4 weeks, which resulted in a similar exposure to that of adults. Based on pharmacokinetic modeling, a maintenance dosing regimen of 250 mg/m² administered twice over 14 days followed by 250 mg/m² every 6 months is expected to result in similar rituximab exposure as that of adults receiving the approved maintenance dose of 500 mg administered twice over 14 days followed by 500 mg every 6 months. The time course of B-cell depletion was similar between the pediatric and adult populations, supporting the similarities in response in both populations and allowing extrapolation to patients less than 6 years old. Using a partial extrapolation approach helped identify safe and effective dosing regimens of rituximab in pediatric patients with GPA/MPA and lead to regulatory approval.

Phase IIa Global Study Evaluating Rituximab for the Treatment of Pediatric Patients With Granulomatosis With Polyangiitis or Microscopic Polyangiitis

OBJECTIVE

To assess the safety, tolerability, pharmacokinetics, and efficacy of rituximab (RTX) in pediatric patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA).

METHODS

The Pediatric Polyangiitis Rituximab Study was a phase IIa, international, open-label, single-arm study. During the initial 6-month remission-induction phase, patients received intravenous infusions of RTX (375 mg/m2 body surface area) and glucocorticoids once per week for 4 weeks. During the follow-up period, patients could receive further treatment, including RTX, for GPA or MPA. The safety, pharmacokinetics, pharmacodynamics, and exploratory efficacy outcomes with RTX were evaluated.

RESULTS

Twenty-five pediatric patients with new-onset or relapsing disease were enrolled at 11 centers (19 with GPA [76%] and 6 with MPA [24%]). The median age was 14 years (range 6-17 years). All patients completed the remission-induction phase. During the overall study period (≤4.5 years), patients received between 4 and 28 infusions of RTX. All patients experienced ≥1 adverse event (AE), mostly grade 1 or grade 2 primarily infusion-related reactions. Seven patients experienced 10 serious AEs, and 17 patients experienced 31 infection-related AEs. No deaths were reported. RTX clearance correlated with body surface area. The body surface area-adjusted RTX dosing regimen resulted in similar exposure in both pediatric and adult patients with GPA or MPA. Remission, according to the Pediatric Vasculitis Activity Score, was achieved in 56%, 92%, and 100% of patients by months 6, 12, and 18, respectively.

CONCLUSION

In pediatric patients with GPA or MPA, RTX is well tolerated and effective, with an overall safety profile comparable to that observed in adult patients with GPA or MPA who receive treatment with RTX. RTX is associated with a positive risk/benefit profile in pediatric patients with active GPA or MPA.

Granulomatosis with Polyangiitis in Adolescence: Two Distinct Presentations

Introduction. Granulomatosis with polyangiitis (GPA) is a rare disease in pediatric age. We report two cases with distinct presentations. Case Reports. A seventeen-year-old male with prolonged febrile syndrome, cough, and constitutional symptoms. CT-scan showed cavitated lesions of the lung and bronchial biopsy a necrotizing inflammatory process. The remaining investigation revealed hematoproteinuria and positive C-ANCA and anti-PR3. Complications: Bilateral acute pulmonary thromboembolism, splenic infarction, and extensive popliteal and superficial femoral deep vein thrombosis. He was treated with corticosteroids, immunoglobulin, rituximab, and anticoagulation. Rituximab was maintained every six months during the first two years. Control angio-CT was performed with almost complete resolution of previous findings. In a twelve-year-old female with inflammatory signs of the limbs, investigation showed myositis of the thigh and tenosynovitis of the wrist, normocytic normochromic anemia (Hg 9.4 g/dL), mild elevation of inflammatory markers, and high creatine kinase. During hospitalization, she presented an extensive alveolar hemorrhage associated with severe anemia and positive C-ANCA and anti-PR3. Clinical deterioration prompted intravenous methylprednisolone pulses and plasmapheresis. Induction therapy with rituximab and prednisolone showed good results. Rituximab was maintained every six months, for 18 months, with gradual tapering of corticoids. Discussion. GPA is a systemic disease with variable clinical presentation and severity. Pediatric patients have similar clinical manifestations to adults but different frequencies of organ involvement; constitutional symptoms are also more common. We highlight the different presentation of these two cases, as well as the need for an individualized approach. Rituximab has been used for both induction-remission and maintenance therapy, with good results, particularly in young patients.

Immune deposits in skin vessels of patients with acute hemorrhagic edema of young children: A systematic literature review

BACKGROUND

Acute hemorrhagic edema of young children is a benign skin-limited vasculitis mainly affecting children 2 to 24 months of age, which is often considered the infantile variant of immunoglobulin A vasculitis (Henoch-Schönlein purpura). In most cases, the diagnosis is made on a clinical basis without a skin biopsy.

METHODS

A systematic review of the literature was performed to examine the reported prevalence of vascular immune deposits in skin biopsies of patients with acute hemorrhagic edema of young children.

RESULTS

Testing for vascular immune deposits was performed in 75 cases (64 boys and 11 girls aged from 3.5 to 72, median 11 months) published between 1970 and 2018. Vessel wall deposition of complement C3 was seen in 40 cases. Immunoglobulin M (N = 24), immunoglobulin A (N = 21), immunoglobulin G (N = 13), and immunoglobulin E (N = 3) were less frequently detected. Gender, age, clinical features, and disease duration were not statistically different in cases with and without vessel wall deposition of immunoglobulin A.

CONCLUSION

Immune deposits in skin vessels, most frequently complement C3, are common in subjects with acute hemorrhagic edema of young children, providing furhter evidence that acute hemorrhagic edema, immunoglobulin A vasculitis, and pauci-immune vasculitides are different entities.

Epidemiology and clinical features of childhood-onset anti-neutrophil cytoplasmic antibody-associated vasculitis: a clinicopathological analysis

BACKGROUND

This study was performed to determine the clinical features and outcomes of childhood-onset anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), particularly microscopic polyangiitis (MPA).

METHODS

A retrospective Japanese multicenter study was performed in patients diagnosed with AAV before 16 years of age.

RESULTS

Of 49 patients with AAV, 36 were female. The diagnoses were as follows: MPA (n = 38, 78%), granulomatosis with polyangiitis (GPA; n = 9, 18%), eosinophilic granulomatosis with polyangiitis (EGPA; n = 1, 2%), and other (n = 1, 2%). The median age at onset was 10.7 years, and median time to diagnosis was 2.0 months. Twenty-seven (55%) patients were identified through a school urinary screening program. Initial symptoms included fever and fatigue (45%), and renal (71%), pulmonary (29%), ocular (20%), and mucocutaneous involvement (22%). Although 27 (55%) patients achieved remission and none had died at the last follow-up, at least one recurrence occurred in 13 (48%) patients after a median of 48 months and was more common in patients with GPA (P < 0.01). After a median follow-up of 43 months, seven (14%) patients (all with MPA) progressed to end-stage renal disease (ESRD).

CONCLUSIONS

Childhood-onset AAV has an estimated prevalence of 3.41-4.28 per million children and is characterized by female predominance and high frequency of detection in school urinary screening programs. More than 10% of patients with childhood-onset AAV still progress to ESRD without achieving remission. Histological chronicity is a factor associated with ESRD.

Cutaneous Manifestations of Small-Vessel Leukocytoclastic Vasculitides in Childhood

In childhood, cutaneous small-vessel vasculitides include Henoch-Schönlein syndrome, a systemic vasculitis, and Finkelstein-Seidlmayer syndrome, a skin-limited vasculitis. Both Henoch-Schönlein and Finkelstein-Seidlmayer syndromes are seen more frequently in white or Asian compared with black children and occur especially in winter and spring with a male-to-female ratio of approximately 2:1. In everyday clinical practice, both conditions are diagnosed on clinical grounds without histological confirmation. The characteristic cutaneous hallmarks of Henoch-Schönlein syndrome include a purpuric rash in all and a subcutaneous edema in approximately every second case, which are often preceded by non-specific red or pink macular elements that mimic a non-itching urticarial rash. Recent data point out that Henoch-Schönlein children often present further cutaneous findings such as Köbnerization, Rumpel-Leede capillary fragility phenomenon, and blistering eruptions. Children with Finkelstein-Seidlmayer syndrome are usually ≤24 months of age and not ill-appearing. They present with (a) large, round, red to purpuric plaques (often with a targetoid appearance) predominantly over the cheeks, ears, and extremities and (b) often tender non-pitting edema of the distal extremities, ears, and face (without pruritus). Both in Henoch-Schönlein syndrome and Finkelstein-Seidlmayer syndrome, there is often scrotal involvement. The cutaneous findings remit without sequelae within 2 months in Henoch-Schönlein and 3 weeks in Finkelstein-Seidlmayer syndrome.

[Childhood vasculitis]

BACKGROUND

The primary vasculitides are rare conditions in childhood. The most common disease subtypes are Schönlein-Henoch purpura and Kawasaki's syndrome, which frequently have a self-limiting course. In the majority of vasculitides, the etiology remains unknown. Environmental exposure, including infections, is suspected to trigger an autoinflammatory response in predisposed individuals.

GOAL

The aim of this review is to present the various aspects of childhood vasculitis.

MATERIALS AND METHODS

Reviews and special original papers on childhood vasculitis, published classification criteria and current therapy guidelines were reviewed and summarized.

RESULTS

The classification of vasculitides in childhood has been modified from the previous adult Chapel Hill classification for vasculitides in 2008. Most therapy recommendations for children are adapted from results of studies in adults. This review covers the current classifications, pathogenesis, clinical manifestations and therapy recommendations for children.

DISCUSSION

Although etiology and pathogenesis of many vasculitides in childhood are still unknown, clarifying diagnostic methods and effective therapeutic options are available. The knowledge about various forms of disease manifestation may contribute to an early diagnosis and timely initiation of treatment, which may prevent devastating irreversible impairment.

Vasculitis: do we know more to classify better?

The systemic vasculitides are a heterogeneous group of disorders characterized by the inflammation of blood vessels. The development and implementation of advanced diagnostic tests and genetic studies have resulted in substantial improvement in our understanding of vasculitis pathogenesis, resulting in the revision of the nomenclature and classification for vasculitis. Multicenter, collaborative studies are currently underway to develop improved diagnostic criteria. In this review, the major nomenclature and classification systems for vasculitides are summarized, with special emphasis on those emerging from the recent 2012 Chapel Hill Consensus Conference (CHCC).

Clinical characteristics and outcomes of childhood-onset ANCA-associated vasculitis: a French nationwide study

BACKGROUND

Data on anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis are scarce in children. The current study is aimed at describing the clinical features and outcomes of childhood-onset ANCA-associated vasculitis (AAV).

METHODS

We conducted a retrospective French multicentre study involving patients in whom AAV was diagnosed before the age of 18 years. Inclusion criteria were (i) granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) according to classification criteria of the European League Against Rheumatism/Paediatric Rheumatology European Society, and (ii) ANCA positivity. Patient and renal survival were analysed.

RESULTS

Among 66 children included, 80% were female, 42% had GPA and 58% MPA including renal-limited vasculitis, 67% were pANCA+ and 33% cANCA+. The mean incidence of reported cases increased to 0.45 per million children/year in the period 2006-10. Median age at diagnosis was 11.5 years, and median time to diagnosis was 1 month. Initial symptoms included fever and fatigue (79%), skin lesions (41%), arthritis (42%), pulmonary (45%) and renal involvement (88%). Clinical features were similar between GPA and MPA with the exception of upper airway impairment (28%) specific of GPA. Ninety percent of the patients achieved remission after induction treatment. After a median follow-up of 5.2 years, 4 patients (6%) died, corresponding to a mortality rate of 1.2 per 100 person-years, and 22 patients (34%) developed end-stage renal disease (ESRD). Renal survival was 74, 70 and 59% at 1, 5 and 10 years, respectively. In a multivariable Cox regression model, baseline glomerular filtration rate, ethnic origin, histopathological classification and era of treatment were associated with the occurrence of ESRD. Relapse-free survival was 57% at 5 years and 34% at 10 years of follow-up. Patient and renal outcome did not significantly differ between GPA and MPA.

CONCLUSION

Childhood-onset AAV is a rare disease characterized by female predominance, delayed diagnosis, frequent renal impairment and a high remission rate. Baseline GFR and new histopathological classification system are strong predictors of ESRD. Renal survival in childhood AAV has improved over time.

[A rapidly progressive orbital tumor in a seven-year-old girl revealing a primitive systemic vasculitis]

Orbital tumor lesions in pediatric population encompass a wide range of pathological processes, which are very different in etiology and prognosis. They usually require an emergency in histological diagnosis because of their quick growth. Beside malignant and benign tumors, the inflammatory pseudo-tumors group included dysimmune orbital involvement secondary to systemic vasculitis such as granulomatosis with polyangiitis (ex-Wegener's granulomatosis). We report the case of a seven-year-old girl suffering from a severe primitive ANCA vasculitis, revealed by an orbital mass.

Current perspectives on ophthalmic manifestations of childhood rheumatic diseases

Inflammatory eye diseases are an important manifestation of many pediatric rheumatologic conditions. Early screening and diagnosis are imperative as these illnesses can not only result in significant visual morbidity but are also an indicator of systemic inflammation. Time to presentation of ocular inflammation varies significantly and can range from many years prior to the onset of systemic symptoms to well after the diagnosis of the rheumatologic disorder. Due to this variability in presentation, careful monitoring by an ophthalmologist is vital to preventing ocular complications and preserving vision. Both local and systemic immunosuppressive medications have been effective in the management of ocular disease. In this review, we will focus on the known ophthalmologic manifestations of common pediatric rheumatologic diseases and discuss recent advances in therapeutic considerations for these conditions.

ANCA-associated glomerulonephritis/systemic vasculitis in childhood: clinical features-outcome

BACKGROUND

Antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis and systemic vasculitis (AAGNV) is uncommon in childhood.

METHODS

This is a retrospective study of AAGNV cases diagnosed over a 13-year period in a tertiary pediatric nephrology department.

RESULTS

Thirteen cases of AAGNV were identified: seven Wegener granulomatosis (WG) and six microscopic polyangiitis (MPA). Acute renal failure/nephrotic range proteinuria (NRP) was found in 77 % of the patients (4 with WG, all with MPA). Eleven (85 %) patients showed necrotizing glomerulonephritis (NGN), with ≥50 % crescents identified in nine patients (69 %) (4 with WG, 5 with MPA). Treatment with methylprednisolone, cyclophosphamide and plasma exchange resulted in extra-renal remission and antibody reduction in all patients and renal function improvement/stabilization in 77 % of the patients. Three patients, all without oliguria at presentation and few sclerotic lesions, had normal renal function at follow-up. Chronic kidney disease (CKD) stages 2 and 3-4 were observed in four (WG) and three (MPA) patients, respectively. Three patients (23 %) developed end stage renal disease: two were MPA patients with severe presentation (markedly impaired glomerular filtration rate, oliguria, NRP, crescentic NGN, glomerular sclerosis) and one was a WG patient with extensive interstitial fibrosis/tubular atrophy.

CONCLUSIONS

Severe renal involvement was more common in children with MPA than WG. Treatment with methylprednisolone, cyclophosphamide and plasma exchange induced extra-renal remission/serological response and renal function improvement/stabilization. Markedly decreased GFR, oliguria, NRP, and chronic glomerular lesions at presentation were predictors of poor outcome.

Microscopic polyangiitis in a girl with severe anemia and no respiratory symptoms

ANCA-positive microscopic polyangiitis is a rare in children. We reported an 11-year-old girl without respiratory symptoms with sever anemia which shows signs of hemolytic anemia in test data. Chest X-ray and computed tomography scans suggested alveolar hemorrhage. The patent developed night hypoxia and moderate proteinuria. Serum MPO-antibody was highly positive and renal biopsy demonstrated segmental necrosis or crescent formation. A diagnosis of microscopic polyangiitis was made. She responded to pulsed methylprednisolon and pulsed Endoxan therapy. Microscopic polyangitiis should be considered early in the differential diagnosis of patients presenting with anemia of an unknown origin.

Biomarkers of endothelial cell activation: candidate markers for drug-induced vasculitis in patients or drug-induced vascular injury in animals

There is a pressing need for vascular biomarkers for studies of drug-induced vasculitis in patients and drug-induced vascular injury (DIVI) in animals. We previously reviewed a variety of candidate biomarkers of endothelial cell (EC) activation (Zhang et al., 2010). Now we update information on EC activation biomarkers from animal data on DIVI and clinical data of vasculitic patients, particularly patients with primary antineutrophil cytoplasmic autoantibody (ANCA)-associated small vessel vasculitis (primary AAVs), including Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome and necrotizing crescentic glomerulonephritis. Drug-associated ANCA-positive small vessel vasculitis (drug-AAVs) can closely resemble primary AAVs, suggesting the large overlap between primary idiopathic systemic vasculitis and drug-induced vasculitis. AAVs in patients and DIVI in animals vary considerably; however, there is close resemblance between AAVs and DIVI in some respects: (1) the immunopathogenetic mechanisms (activation of primed neutrophils, ECs and T cells by ANCA in patients and activation of ECs, mast cells, and macrophages by drugs in animals); (2) the morphologic changes (fibrinoid necrosis of the vessel wall and neutrophilic infiltration); (3) the preferable sites (small arteries, arterioles, capillaries and venules); and (4) elevation of vascular biomarkers suggestive of an endothelial origin. The present review discusses soluble and cell component biomarkers and provides a rationale for the potential utility of EC activation biomarkers in nonclinical and clinical studies during new drug development. Further investigation, however, is needed to assess their potential utility.

Concomitant thrombotic thrombocytopenic purpura and ANCA-associated vasculitis in an adolescent

Thrombotic thrombocytopenic purpura (TTP) rarely occurs with systemic vasculitis. A 17-year-old girl presented with non-bloody diarrhea, menorrhagia, and syncope. She had severe anemia (hemoglobin = 3.8 g/dl), thrombocytopenia (platelet = 7,000/mm(3)), and acute kidney injury (serum creatinine, Cr = 2.3 mg%). Peripheral smear examination confirmed the presence of microangiopathic hemolytic anemia. Additionally, she had a positive anti-nuclear antibody (1:1600) and normal complement levels. We considered the diagnosis of TTP, possibly associated with systemic lupus erythematosus, and promptly initiated pulse methylprednisolone and daily 3-4 l of plasma exchange therapy. Following resolution of her thrombocytopenia in 48 h, we performed a kidney biopsy that revealed diffuse proliferative, focal crescentic, and necrotizing glomerulonephritis with mild IgG immunofluorescence staining. Concomitantly, autoimmune work-up was significant for positive perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA = 1:640) and decreased von Willebrand factor cleaving protease activity (<5%). A final diagnosis of TTP with microscopic polyangiitis (p-ANCA-mediated) was made and treatment with daily oral cyclophosphamide and prednisone resolved her renal injury over 2 months (follow-up Cr = 1.0 mg%). Our case highlights the importance of identifying systemic disorders such as ANCA-associated vasculitis with TTP.