Enfermedad relacionada con IgG4, según criterios ACR/EULAR 2019 sin evidencia de IgG4 en sangre / IgG4-related disease according to ACR/EULAR 2019 criteria without evidence of IgG4 in blood

INTRODUCCIÓN. La enfermedad relacionada con IgG4 es una patología fibroinflamatoria multiorgánica, de origen desconocido, que simula trastornos malignos, infecciosos e inflamatorios. Los criterios del American College of Rheumatology y la European League against Rheumatism 2019, son útiles para el diagnóstico diferencial de ésta enfermedad cuando se no se cuenta con evidencia de inmunoglobulina G4 en sangre. CASO CLÍNICO. Paciente hombre de 45 años de edad, nacido en Ambato-Ecuador, con ingreso en noviembre del 2017, en emergencias del Hospital de Especialidades Carlos Andrade Marín, con presencia de tos con hemoptisis leve, febrícula, astenia, pérdida de peso e hiporexia de dos semanas de evolución. Se realizó múltiples exámenes, tras observar infiltrados pulmonares intersticiales, con elevación de inmunoglobulina G en suero, negativas para malignidad; se sospechó de enfermedad relacionada a inmunoglobulina G4. Se ampliaron los estudios para descartar otras patologías más prevalentes y cuyo diferencial es primordial. Se inició tratamiento con prednisona y micofenolato con buena respuesta clínica; durante dos años. DISCUSIÓN. La evidencia científica registró que el hallazgo más importante en la enfermedad relacionada con inmunoglobulina G4 fue un aumento de sus niveles séricos. La recurrencia de la enfermedad en un órgano afectado o la aparición de un nuevo órgano involucrado pudo conducir al diagnóstico en el caso presentado. CONCLUSIÓN. La enfermedad relacionada con inmunoglobulina G4 al ser una patología heterogénea, inmunomediada, al simular otras afecciones puede retrasar el diagnóstico; se debe tener una alta sospecha clínica, si al excluir otros procesos infecciosos, autoinmunes y/o eoplásicos, hay evidencia de patología fibroesclerosante multiorgánica sin causa establecida.

INTRODUCTION. IgG4-related disease is a multiorgan fibroinflammatory pathology of unknown origin that mimics malignant, infectious, and inflammatory disorders. The criteria of the American College of Rheumatology and the European League against Rheumatism 2019 are useful for the differential diagnosis of this disease when there is no evidence of immunoglobulin G4 in blood. CLINICAL CASE. 45-year-old male patient, born in Ambato-Ecuador, with admission in November 2017, in the emergency room of the Hospital de Especialidades Carlos Andrade Marín, with the presence of cough with mild hemoptysis, fever, asthenia, weight loss and hyporexia of two weeks of evolution. Multiple tests were performed, after observing interstitial pulmonary infiltrates, with elevated serum immunoglobulin G, negative for malignancy; immunoglobulin G4-related disease was suspected. Studies were extended to rule out other more prevalent pathologies whose differential is paramount. Treatment with prednisone and mycophenolate was started with good clinical response; for two years. DISCUSSION. The scientific evidence recorded that the most important finding in immunoglobulin G4-related disease was an increase in its serum levels. Recurrence of the disease in an affected organ or the appearance of a new involved organ could have led to the diagnosis in the presented case. CONCLUSION. Immunoglobulin G4-related disease, being a heterogeneous, immune-mediated pathology, by simulating other conditions may delay diagnosis; a high clinical suspicion should be maintained if, when other infectious, autoimmune and/or neoplastic processes are excluded, there is evidence of multiorgan fibrosclerosing pathology without established cause.

Serum immunoglobulin free light chains and their association with clinical phenotypes, serology and activity in patients with IgG4-related disease.

The clinical utility of serum immunoglobulin free light chains (sFLC) in IgG4-related disease (IgG4-RD) is unknown. Herein we evaluated their association with clinical phenotypes, serology and activity in patients with IgG4-RD. Cross-sectional study that included 45 patients with IgG4-RD, and as controls 25 with Sjögren's syndrome (SS) and 15 with sarcoidosis. IgG4-RD patients were classified in clinical phenotypes: pancreato-hepato-biliary, retroperitoneum/aorta, head/neck-limited and Mikulicz/systemic; as well as proliferative vs. fibrotic phenotypes. We assessed the IgG4-RD Responder Index (IgG4-RD RI) at recruitment and measured IgG1, IgG4, κ and λ sFLC serum levels by turbidometry. sFLC levels were similar among IgG4-RD, SS and sarcoidosis groups. Regarding the IgG4-RD patients, the mean age was 49 years, 24 (53.3%) were men and 55.5% had activity. Eight (17.7%) belonged to pancreato-hepato-biliary, 6 (13.3%) to retroperitoneum/aorta, 14 (31.1%) to head/neck-limited, 16 (35.5%) to Mikulicz/systemic phenotypes, whereas 36 (80%) to proliferative and 9 (20%) to fibrotic phenotypes. High κ sFLC, λ sFLC and κ/λ ratio were present in 29 (64.4%), 13 (28.9%) and 13 (28.9%) of IgG4-RD patients, respectively. There were no differences in sFLC among IgG4-RD phenotypes. κ sFLC and κ/λ ratio correlated positively with the number of involved organs and IgG4-RD RI. Patients with renal involvement had higher κ sFLC and λ sFLC. The AUC for κ sFLC and λ sFLC, for renal involvement was 0.78 and 0.72, respectively. Active IgG4-RD had higher levels of κ sFLC and more frequently a high κ/λ ratio. The AUC for κ sFLC and κ/λ ratio for predicting active IgG4-RD was 0.67 and 0.70, respectively. sFLC correlated positively with IgG1 and IgG4 levels. sFLC may be useful as a biomarker of disease activity as well as multiorgan and renal involvement. In particular, a high κ/λ ratio may identify patients with active disease.

Pseudotumor retroperitoneal como apresentação de doença relacionada à IgG 4: relato de caso / Retroperitoneal pseudotumor as a presentation of IgG4-related disease: a case report

Apresentamos um caso de doença relacionada à IgG4 devido às suas várias formas de apresentação clínica e dificuldades diagnósticas, objetivando acrescentar à literatura científica essa apresentação atípica. Trata-se de um homem de 65 anos com dor abdominal, febre e sintomas urinários. Exames laboratoriais inocentes para processo infeccioso agudo. Em tomografia computadorizada de abdome, evidenciou-se pseudotumor em região retroperitoneal, envolvendo ureter, veia e artéria ilíacas. Foi submetido à ressecção cirúrgica, tendo sido confirmado o diagnóstico de doença relacionada à IgG4 pela imuno-histoquímica. Iniciou tratamento com glicocorticoide com melhora clínica importante, seguindo em acompanhamento ambulatorial.

This is a case report of IgG4-related disease because of its wide variety of clinical presentations and difficulties in diagnosis, aiming at adding this atypical presentation to scientific literature. It is a case of a 65-year-old man with abdominal pain, fever and urinary symptoms. Laboratory tests were naive for acute infectious processes. In a computed tomography of the abdomen, retroperitoneal pseudotumor involving ureter, and iliac vein and artery was found. The patient underwent surgical resection, and the diagnosis of IgG4-related disease was confirmed by immunohistochemistry. The treatment was begun with glucocorticoids, with important clinical improvement. He was followed in outpatient settings.