Uso de PCR digital para definir terapéuticas específicas y seguimiento en enfermedades autoinflamatorias / Use of digital PCR to define specific therapeutics and follow-up in autoinflammatory diseases

Las enfermedades autoinflamatorias (AIDs) son un grupo heterogéneo de desórdenes monogénicos o poligénicos, con características de disregulación inmune innata y/o adaptativa, cuyo mecanismo central es la autoinflamación pero también pueden presentarse con autoinmunidad e inmunodeficiencia. En estos últimos años el desarrollo de las tecnologías de secuenciación masiva han provocado una explosión en el descubrimiento de nuevos genes responsables de AIDs monogénicas. Esto remarca la importancia de implementar este tipo de estudios para llegar a un diagnóstico definitivo sobre todo en este grupo de patologías genéticamente muy diversas donde los fenotipos clínicos se solapan. Sin embargo, dada la presencia de variantes de significación incierta (VUS), los resultados pueden no ser concluyentes planteándose la necesidad de desarrollar pruebas funcionales para determinar la patogenicidad de dichas variantes genéticas. En nuestro grupo de trabajo estamos aplicando la PCR digital en gotas (ddPCR), una técnica cuantitativa de 3era generación altamente sensible, especifica y reproducible que no necesita de curvas de calibración, para desarrollar pruebas funcionales que permitan no sólo reclasificar variantes VUS para lograr diagnósticos definitivos sino también estudiar los mecanismos responsables de las principales AIDs que permitan una estratificación de las terapéuticas especificas a aplicar y de esta manera poder contribuir al diagnóstico, tratamiento y seguimiento de nuestros pacientes en forma personalizada. (AU)

Autoinflammatory diseases (AIDs) are a heterogeneous group of monogenic or polygenic disorders, with characteristics of inborn and/or adaptive immune dysregulation, whose central mechanism is autoinflammation but may also present with autoimmunity and immunodeficiency. In recent years the development of massive sequencing technologies has led to an exponential increase in the discovery of new genes responsible for monogenic AIDs. This emphasizes the importance of the implementation of this type of studies to make a definitive diagnosis, especially in this group of genetically very diverse diseases with overlapping clinical phenotypes. However, given the presence of variants of uncertain significance (VUS), the results may not be conclusive, raising the need to develop functional tests to determine the pathogenicity of these genetic variants. In our working group we are applying droplet digital PCR (ddPCR), a highly sensitive, specific and reproducible third generation quantitative technique that does not require calibration curves, to develop functional tests that allow not only to reclassify VUS variants to achieve definitive diagnoses but also to study the mechanisms responsible for the main AIDs that allow for the stratification of specific treatments to be used and thereby contribute to the individualized diagnosis, treatment, and follow-up of our patients (AU)

Síndrome inflamatorio multisistémico pediátrico (SIMS) asociado con el SARS-CoV-2: Un estudio de cohorte retrospectivo / SARS-CoV-2-associated pediatric multisystemic inflammatory syndrome: A retrospective cohort study

Introduccion: El Síndrome inflamatorio multisistémico pediátrico (SIMS) asociado con el SARS-CoV-2 es una enfermedad aguda acompañada de un síndrome hiperinflamatorio, con falla multiorgánica y shock, asociada a la infección por SARS CoV2, que produce alta morbilidad en la población pediátrica, que hasta el momento es la afectada por este síndrome. Objetivo: Evaluar las características diferenciales del síndrome multisistémico inflamatorio asociado al SARS-COV-2 (SIMS) en niños. Métodos: se realizó un estudio de cohorte retrospectivo. La definición de SIMS se basó en los criterios de la OMS. Los pacientes con COVID-19 relacionados temporalmente se incluyeron como controles. Resultados: se incluyeron 25 pacientes con SIMS y 75 controles. El modelo de regresión logística múltiple de las variables que mostraron ser significativas en el análisis univariado reveló que la edad ≥ 2 años (OR 24,7; IC del 95%: 1,03 -592,4; P = 0,048), la linfopenia (OR 9,03; IC del 95%: 2,05-39,7; P = 0,004), y el recuento de plaquetas <150x109 / L (OR 11,7; IC del 95%: 1,88-75,22; P = 0,009) se asociaron significativamente con SIMS. La presencia de una enfermedad subyacente pareció reducir el riesgo de SIMS (OR 0,06; IC del 95%: 0,01-0,3). Conclusión: El SIMS fue más común en pacientes mayores de 2 años y en aquellos con linfopenia o trombocitopenia. La enfermedad subyacente parece reducir el riesgo del mismo. (AU)

Introduction: SARS-CoV-2-associated pediatric multisystemic inflammatory syndrome (PMIS) is an acute disease accompanied by a hyperinflammatory syndrome, with multiorgan failure and shock associated with SARS CoV2 infection, producing high morbidity in the pediatric population, which so far is affected by this syndrome. Objective: To evaluate the differential characteristics of SARS-COV-2-associated PMIS in children. Methods: A retrospective cohort study was conducted. The definition of PMIS was based on WHO criteria. Patients with temporally related COVID-19 were included as controls. Results: 25 patients with PMIS and 75 controls were included. A multiple logistic regression model of the variables shown to be significant in univariate analysis revealed that age ≥ 2 years (OR 24.7; 95% CI: 1.03 -592.4; P = 0.048), lymphopenia (OR 9.03; 95% CI 2.05-39.7; P = 0.004), and platelet count < 150x109/L (OR 11.7; 95% CI: 1.88-75.22; P = 0.009) were significantly associated with PMIS. The presence of an underlying disease appeared to reduce the risk of PMIS (OR 0.06; 95% CI: 0.01-0.3). Conclusion: PMIS was more common in patients older than 2 years and in those with lymphopenia or thrombocytopenia. Underlying disease appears to reduce the risk of SMIS.(AU)

Hypertrophic osteoarthropathy in two children with cholestatic hepatic disease.

AIM: To describe two children with hypertrophic osteoarthropathy associated with cholestatic hepatic disease. Both patients suffered from chronic progressive cholestatic liver disease and developed digital clubbing, polyarthritis and periosteal reaction. In one of them, clinical and radiological features normalized after liver transplant. CONCLUSION: Hepatic hypertrophic osteoarthropathy is a rare disabling condition that responds poorly to conservative management, while liver transplantation appears to be the only effective therapeutic intervention.

Use of infliximab in patients with systemic juvenile idiopathic arthritis refractory to etanercept.

OBJECTIVE: To analyse the effectiveness and safety of Infliximab in a group of patients with systemic juvenile idiopathic arthritis (SJIA) who had failed treatment with etanercept in a single paediatric rheumatology clinic. METHODS: Patients with SJIA with active polyarthritis refractory to methotrexate (MTX) [> or = 20 mg/m2/week] for at least 3 months and to etanercept (up to 1 mg/kg twice weekly) for at least 6 months were included. All children received infliximab 3-10 mg per kg of body weight intravenously concomitantly with MTX 7.5-10 mg/week for 19 (2-113) weeks. Evaluation included ACR paediatric 30 criteria and presence of signs of systemic activity (fever, rash). RESULTS: Six patients were included. Three patients met ACR paediatric 30 criteria at 2 weeks (2 patients) and 10 weeks after initiation of infliximab. Improvement lasted for 4, 12, and 84 weeks respectively. The presence of fever/rash was not modified by the treatment. Infliximab was discontinued due to moderate side effects in 4 patients. No serious side effects were observed. CONCLUSIONS: Most patients with SJIA who fail to respond to etanercept may not reach sustained improvement when switched to infliximab. The only patient in our group who improved sustainedly with infliximab did not show any systemic features at the beginning of therapy. Further controlled studies are needed in order to assess efficacy of infliximab in children with refractory SJIA.

Etanercept in systemic juvenile idiopathic arthritis.

OBJECTIVE: To evaluate the effectiveness of etanercept in patients with systemic juvenile idiopathic arthritis (SJIA) refractory to methotrexate (MTX) therapy in a pediatric rheumatology practice. METHODS: Fifteen patients with SJIA with active polyarthritis refractory to higher dose MTX (> or = 20 mg/m2/week) for at least 3 months were included. Patients received etanercept 0.4 mg/Kg twice weekly concomitantly with MTX. Observed period of treatment ranged from 5 to 12 months (median 9 months). RESULTS: Improvement of ESR, swollen and limited joint counts, functional capacity, and general wellbeing was achieved by 14/15 patients. The most significant impact on these variables was observed 3 to 5 months after treatment onset. Mean time to improvement was 2 months. In the 4 patients who presented fever and rash, these signs disappeared after the beginning of etanercept treatment and reappeared during flares. Three patients showed sustained clinical and biochemical remission on low dose MTX (< or = 5 mg/m2/week). Thirteen relapses were observed in 9 (60%) patients at a mean of 7.6 months after therapy was begun. Etanercept was discontinued due to lack of efficacy in 7 patients, only after higher dose (1 mg/kg/dose) was used. MTX and corticosteroid doses were decreased during the observation period. No serious side effects were observed. CONCLUSIONS: Etanercept, in combination with MTX, demonstrated benefit soon after initiation of treatment in patients with refractory SJIA, but flares and progressive loss of effectiveness were observed with continued treatment in most patients. Sharp decreases in the dose of MTX and corticosteroids may have contributed to subsequent occurrence of flares. Changes in MTX and corticosteroids doses should probably need to be made gradually, and it is possible that patients on SJIA should continue on therapeutic doses of MTX while being on etanercept in order to maintain therapeutic benefit.

Chronic infantile neurological cutaneous and articular syndrome: two new cases with rare manifestations.

UNLABELLED: CINCA/IOMID is a systemic inflammatory disorder of unknown aetiology that resembles congenital infection and systemic juvenile chronic arthritis (JCA). This disorder is characterized by neonatal onset, persistent rash, ocular inflammatory lesions, and progressive articular and neurological involvement. We report two new patients with this syndrome. Both children presented periodic bouts of cutaneous rash, fever, organomegaly, articular involvement with typical radiological features, and developmental delay. One of the patients presented neonatal jaundice and elevation of liver enzymes; inflammatory infiltrates were observed in the liver biopsy. The other patient showed retinal vasculitis detected at age 18 mo on fundoscopy and fluorescent angiography. Therapy with azathioprine was associated with prolonged remission of this complication. In both cases, the disease was diagnosed after some delay. CONCLUSION: Early hepatitis and retinal vasculitis are rare features of CINCA/IOMID that may help differentiate this syndrome from JRA. Azathioprine may have induced the remission of vasculitis in one case.

Alteraciones de la función pulmonar en pacientes con lupus eritematoso sitémico juvenil / Alterations of pulmonary function in patients with systemic lupus erithematosus

El Lupus Eritematoso Sistémico (LES) es una enfermedad multiorgánica con frecuente afectación pulmonar. Se ha descripto la presencia de alteraciones funcionales, aún sin evidencia clínica de compromiso respiratorio. Objetivos: evaluar la incidencia de alteraciones de la función pulmonar en pacientes con LES y correlacionarlas con la presencia de síntomas respiratorios y signos radiológicos. Se analizó un grupo no seleccionado de 35 pacientes con LES con enfermedad estable. Treinta y tres mujeres, edad x 13.8 años (9-22). Se consignaron síntomas respiratorios (disnea ante medianos esfuerzos, tos crónica), actividad de la enfermedad según parámetros clínicos y bioquimicos, radiografía de tórax y pruebas de función pulmonar (PFP): espirometría, difusión de CO (DLCO), pletismografía. Resultados: de los 35 pacientes 8 (23 por ciento) presentaron sintomatología respiratoria, 10 (28.6 por ciento) alteraciones radiológicas y 20 (57 por ciento) alteraciones de la funció pulmonar. La alteración funcional más frecuente fue la disminución de la DLCO en 16/20 pacientes, aislada en 9 y asociada en 7 casos a incapacidad ventilatoria restrictiva 4/20 pacientes sólo presentaron incapacidad ventilatoria restrictiva. La pletismografía mostró disminución de la capacidad pulmonar total en 5/9 pacientes con espirometría restrictiva. Los 20 pacientes con alteraciones en PFP no presentaron diferencias significativas con los pacientes con PFP normales en los parámetros clínicos y bioquiímicos de actividad de la enfermedad. De 27 pacientes asintomáticos 12 (44,4 por ciento) presentaron alteraciones de la función pulmonar, asociadas a signos radiológicos. Los 8 pacientes con síntoma respiratorios presentaron altraciones de la funcion pulmonar, asociadas en 7 a radiografía patológica. Conclusiones: el compromiso pulmonar en LES es muy frecuente; 44,4 por ciento de pacientes sin síntomas respiratorios presentaron alteraciones de la función pulmonar.

Cholestasis in juvenile dermatomyositis: report of three cases.

This report describes 3 cases of juvenile dermatomyositis (juvenile DM) complicated by cholestasis. All 3 patients had typical features of juvenile DM, and all developed a cholestatic syndrome within the initial months of their disease. Liver biopsy revealed mixed (cytoplasmic and ductal) cholestasis with no abnormalities in the intrahepatic ducts in all 3 cases. Cholestasis improved or was completely reversible upon treatment with prednisone. In the 2 patients who could be followed up long term, no sequelae remained. The possible role of inflammation in the pathogenesis of cholestasis in juvenile DM is discussed.