Idiopathic plasmacytic lymphadenopathy: A conceptual history along with a translation of the original Japanese article published in 1980.

The current consensus on Castleman disease is that it is a group of several distinct lymphoproliferative disorders with different underlying pathogenesis and clinical outcomes. In 1980, Mori et al. proposed the concept of idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia (IPL), a disease of unknown etiology, characterized by severe polyclonal hypergammaglobulinemia and generalized superficial lymphadenopathy. After Frizzera et al.'s landmark report in 1983, the term multicentric Castleman disease (MCD) gradually became established, and for a time, IPL was regarded as identical to MCD. However, with the subsequent recognition of human herpesvirus 8 (HHV8)-related MCD in the 1990s and the contributions by Kojima et al. in the 2000s, in which non-HHV8-related MCD (now called idiopathic MCD) was at least subclassified into IPL and others (non-IPL), it is now clear that the original distinctiveness of IPL is still maintained in MCD, which is a diverse collection of diseases.

Continuous hypergammaglobulinemia and proteinuria after the recovery of the visceral Leishmaniasis: a case report.

BACKGROUND: Kidney involvement of visceral Leishmaniasis is previously reported, but knowledge is limited. Hypergammaglobulinemia is common in visceral leishmaniasis patients. Whether hypergammaglobulinemia after leishmaniasis depletion can cause kidney injury is not well reported yet. CASE PRESENTATION: We reported a patient who recovered from visceral Leishmaniasis but showed persistent hypergammaglobulinemia and elevated urinary protein. Kidney biopsy showed glomerular hypertrophy with mild segmental mesangial proliferation without tubulointerstitial involvement in light microscopy. No immune complex deposit was found in the mesangial area by neither immunofluorescent staining nor electronic microscope. Increased lysosomes were observed in proximal tubules by electronic microscope. Valsartan was administered to decrease urinary protein, and no immune-suppressive therapy was added. The urinary protein and serum IgG level gradually dropped, and serum creatinine level remained stable during three- month follow up. CONCLUSIONS: Hypergammaglobulinemia is unlikely to cause renal structural or functional damage in the short term. Angiotensin blockade significantly reduced urine protein, with a minor effect on IgG elimination.

Telbivudine on IgG-associated hypergammaglobulinemia and TGF-ß1 hyperactivity in hepatitis B virus-related liver cirrhosis.

As debate rumbles on about whether anti-hepatitis B virus (HBV) nucleos(t)ide analogue treatments modulate host immune system during end-stage liver diseases, we studied effects of two potent anti-HBV agents, telbivudine or entecavir, on humoral immune activities including cytokine secretion, immunoglobulin production, and IgG-Fc agalactosylation, which is known to induce proinflammatory responses, in liver cirrhosis. Serum IgG-Fc N-glycan structures in patients with HBV-related liver cirrhosis, who had received either telbivudine treatment or entecavir treatment for at least 48 weeks were analyzed using liquid chromatography tandem-mass spectrometry. Levels of cytokines and each immunoglobulin isotype were measured using enzyme-linked immunosorbent assays. Results showed that 48 weeks of entecavir treatment caused HBV DNA loss, alanine aminotransferase normalization, and an amelioration of hypergammaglobulinemia in cirrhotic patients; however, telbivudine treatment, though possessing similar efficacies on HBV suppression and an improvement in liver inflammation to entecavir treatment, did not mitigate IgG-related hypergammaglobulinemia. Levels of IgG and transforming growth factor (TGF)-ß1 in sera of the cirrhotic patients before and during treatment were positively correlated. In vitro assays revealed that telbivudine treatment induced TGF-ß1 expression in human macrophagic cells. Moreover, recombinant TGF-ß1 treatment stimulated cell proliferation and IgG overproduction in human IgG-producing B cell lines. Finally, we found that telbivudine treatment enhanced the proportion of serum IgG-Fc agalactosylation in cirrhotic patients, which was associated with enhanced levels of TGF-ß1 and IgG. In conclusion, telbivudine therapy was associated with TGF-ß1 hyperactivity, IgG-related hypergammaglobulinemia, and IgG-Fc agalactosylation in HBV-related liver cirrhosis.

Abdominal aortic aneurysm as an IgG4-related disease.

The objectives of this study were to evaluate patients with aortic abdominal aneurysm (AAA) with regard to immunoglobulin (Ig)G4-related disease (IgG4-RD). IgG4-RD represents a recently defined condition comprised of a collection of disorders characterized by IgG4 hypergammaglobulinemia, the presence of IgG4-positive plasma cells in organs affected with fibrotic or sclerotizing changes and typical histopathological features. It was identified as a possible cause of vasculitis in large vessels. Studies have been published on a possible association between inflammatory aortic or cardiovascular disease and IgG4-RD. We examined 114 patients with AAA requiring surgery in order to identify findings which are characteristic of IgG4-RD. Aneurysm samples from seven patients showed histopathological features consistent with IgG4-RD and the presence of IgG4+ plasma cells. Only two of these seven patients showed elevated IgG4 serum levels higher 1·35 g/l. In five of the patients, the concentration of serum IgG4 was lower than 1·20 g/l, with the number of IgG4+ plasma cells being higher than 50/high-power field. These findings were consistent with AAA being a heterogeneous group of inflammatory diseases with different pathogenesis.

Caracterización histológica y clínica de pacientes con enfermedad relacionada con inmunoglobulina G4 en un centro de alta complejidad en Cali, Colombia / Histological and clinical characteristics of cases of immunoglobulin G4-related disease in a tertiary hospital, in Cali, Colombia

Introducción: La enfermedad relacionada con inmunoglobulina G4 (IgG4) ha sido reconocida durante la última década. Es una condición fibroinflamatoria con capacidad de comprometer casi cualquier órgano. El diagnóstico requiere la confirmación histológica, clínica y paraclínica. En Colombia, este es el estudio con mayor número de casos. Objetivo: Describir las características clínicas e histopatológicas de los pacientes diagnosticados con enfermedad relacionada con IgG4 en la Fundación Valle del Lili. Métodos: Estudio observacional descriptivo retrospectivo. Se revisaron los registros clínicos y patológicos de pacientes a quienes se les diagnosticó enfermedad relacionada con IgG4 en la institución. Se utilizó estadística descriptiva. Resultados: Entre 2013 y 2016 se diagnosticaron 16 pacientes. La mediana de edad fue 44 años, rango intercuartílico 30-58 y 10 (62,5%) fueron mujeres. La presentación clínica más común fue la asociación de masa+síntomas constitucionales+síntomas relacionados con el sitio de localización 43,8% (n=7). No hubo predominancia por algún órgano. En la histopatología todos presentaron infiltrado linfoplasmocitario y fibrosis estoriforme, el 75% flebitis obliterante; en todos los casos se evidenció≥10 células/CAP de IgG4+ y el 81% tuvieron una razón de IgG4+/IgG+>50%. Conclusión: Dada la baja sospecha y el amplio espectro clínico, se cree que existe un subdiagnóstico de la enfermedad. De acuerdo a nuestros hallazgos se recomienda que ante la presencia de infiltrado linfoplasmocitario, fibrosis estoriforme o flebitis obliterante en la evaluación histológica, se solicite inmunohistoquímica para IgG e IgG4, cuya positividad deberá ser correlacionada con estudios complementarios para la confirmación diagnóstica

Introduction: Immunoglobulin G4 (IgG4)-related disease has been described in the last decade. It is a fibro-inflammatory condition capable of affecting almost every organ and diagnosis requires both clinical and paraclinical confirmation. We present the largest study to date in Colombia. Objective: To describe the clinical and histopathological characteristics of patients diagnosed with IgG4-related disease at the Fundación Valle del Lili. Methods: Observational-descriptive retrospective study. The clinical and pathological records of patients diagnosed with IgG4-related disease at the Fundación Valle del Lili were reviewed and a descriptive statistical analysis made. Results: From 2013-2016, 16 patients were diagnosed. Median age was 44 years (RIC 30-58) and 10 (62.5%) were women. The most common clinical presentation was a combination of a tumefactive mass, constitutional symptoms and site-related symptoms (43.8%) (n=7). No preference for any organ was seen. Histopathology revealed all cases had dense lymphoplasmacytic infiltrate and storiform-type fibrosis; 75% also had obliterative phlebitis. In all cases≥10 cells/HPF of IgG4+ were found and 81% had a ratio of IgG4+/IgG+>50%. Conclusion: IgG4-related disease appears to be underdiagnosed, probably due to its broad clinical spectrum as well as a low index of awareness among clinicians. We recommend that, when dense lymphoplasmacytic infiltrates, storiform-type fibrosis or obliterative phlebitis are found, immunohistochemistry for IgG and IgG4should be requested. Positive results then must be correlated with complementary studies to confirm the disease

Urological manifestations of the disease related to immunoglobulin G4. / Manifestaciones urológicas de la enfermedad relacionada con la inmunoglobulina G4

Immunoglobulin G4 related disease (IgG4-RD) is a fibro-inflammatory disease of unknown etiology, characterized by lesions in the form of tumors, elevated serum IgG4 levels, plasma cells with significant IgG4 infiltration, accompanied by phlebitis obliterans and fibrosis. This disease usually has multiorgan disease, including pancreas, biliary tract, salivary glands, peri orbital tissues, kidneys, lungs, lymph nodes and retro peritoneum. IgG4-RD mainly affects men with a predominance of age by young adults until old age. The clinical manifestations of IgG4-RD, depend mainly on the organs affected and the response to steroids. His forecast is not yet clear. Within the affected urogenital organs can be observed kidney, retroperitoneum, ureter, bladder, urachus, testis/epididymis, paratesticular region, prostate and urethra.

La enfermedad relacionada con la inmunoglobulina G4 (ER-IgG4) es una enfermedad fibroinflamatoria de etiología desconocida, la cual se caracteriza por presentar lesiones en forma de tumoraciones, concentraciones séricas aumentadas de IgG4 y células plasmáticas con una infiltración importante de IgG4, junto con flebitis obliterante y fibrosis. Esta enfermedad suele tener afección multiorgánica, incluyendo el páncreas, el tracto biliar, las glándulas salivares, los tejidos periorbitarios, los riñones, los pulmones, los ganglios linfáticos y el retroperitoneo. La ER-IgG4 afecta principalmente a hombres, con un predominio de edad por los adultos jóvenes y hasta la vejez. Las manifestaciones clínicas de la ER-IgG4 dependen principalmente de los órganos afectados y de la respuesta a los esteroides. Su pronóstico aún no es del todo claro. Dentro de los órganos urogenitales afectados pueden incluirse el riñón, el retroperitoneo, el uréter, la vejiga, el uraco, el testículo/epidídimo, la región paratesticular, la próstata y la uretra.

Evaluación de la zona gamma del proteinograma por electroforesis: correspondencia clínico-patológica / Evaluation of protein electrophoresis in the gamma zone: clinicopathological correspondence / Avaliação da área gamma do proteinograma por eletroforese: correspondência clínico-patológica

El proteinograma por electroforesis (PxE) sérico es solicitado para detectar modificaciones del perfil proteico. El objetivo del trabajo fue evaluar las alteraciones de la zona gammaglobulina y su correspondencia con distintos estados clínico-patológicos. Se incluyeron 7.259 pacientes (1-89 años) a los que en 2013 se les solicitó PxE. Según el trazado densitométrico, en la zona gammaglobulina se reconocieron diferentes grupos: hipogammaglobulinemia (<0,60 g/dL), hipergammaglobulinemia policlonal (≥1,80 g/dL), banda monoclonal (BM) y bandas oligoclonales. Prevaleció la hipergammaglobulinemia policlonal (4,2%), seguida por BM (1,4%) e hipogammaglobulinemia (0,8%). Hipergammaglobulinemia policlonal (>3 g/dL) se observó en: hepatitis autoinmune, cirrosis, síndrome de Sjögren, enfermedad mixta del tejido conectivo, HIV, hepatitis C y enfermedad de Castleman. El hallazgo de BM correspondió a 47% de pacientes con gammapatía monoclonal de significado incierto y 40% con mieloma múltiple; el 0,5% fueron casos nuevos. Con hipogammaglobulinemias, en adultos prevaleció la inmunosupresión terapéutica (55%), seguida por diabetes/síndrome metabólico/hipotiroidismo (23%); en niños, 22% por inmunosupresión y 78% con hipogammaglobulinemia no clasificada como inmunodeficiencia primaria. Se concluye que en 6,4% de los PxE se observó alteración de la zona gammaglobulina; prevaleció la hipergammaglobulinemia policlonal. En 1 de cada 200 PxE se pesquisó un paciente con BM. El hallazgo de hipergammaglobulinemia policlonal o BM se correspondió con distintos estados clínico-patológicos.

Serum protein electrophoresis (PEP) is requested to screen changes in the protein profile. The aim of this study was to evaluate alterations in the gamma globulin zone and correspondence with various clinical and pathological states. 7259 patients were included (1-89 years of age) who had been requested a PEP in 2013. According to the densitometric tracing, in the gamma globulin zone different groups were recognized: hypogammaglobulinemia (<0.60 g/dL), polyclonal hypergammaglobulinemia (≥1,80 g/dL), monoclonal band (MB) and oligoclonal band. The polyclonal hypergammaglobulinemia prevailed (4.2%), followed by MB (1.4%) and hypogammaglobulinemia (0.8%). Polyclonal hypergammaglobulinemia (>3 g/dL) was observed in autoimmune hepatitis, alcoholic cirrhosis, Sjögren's syndrome, mixed connective tissue disease, HIV, hepatitis C and Castleman's disease. The MB finding corresponded to a 47% of patients with monoclonal gammopathy of undetermined significance and 40% with multiple myeloma; 0.5% were new cases. In adults, hipogammaglobulinemias prevailed in therapeutic immunosuppression cases (55%), followed by patients with diabetes/ metabolic syndrome/ hypothyroidism (23%); in children, 22% with immunosuppression and 78% corresponded to hipogammaglobulinemias not classified as primary immunodeficiency. To conclude, an alteration in the gamma globulin zone was observed in 6.4% of PEP. In 1 out of 200 PEP MB was found. The finding of polyclonal hypergammaglobulinemia or MB corresponded to different clinicopathological states.

O proteinograma por eletroforese (PXE) sérico é solicitado para detectar modificações no perfil proteíco. O objetivo do trabalho foi avaliar as alterações da área gammaglobulina e sua correspondência com diversos estados clínico-patológicos. Incluíram-se 7259 pacientes (1-89 anos) aos quais, em 2013, foi solicitado um PxE. De acordo com o traçado densitométrico, na área gammaglobulina, diferente grupos foram reconhecidos: hipogammaglobulinemia (<0,60 g/dL), hipergammaglobulinemia policlonal (≥1,80 g/dL), banda monoclonal (BM) e bandas oligoclonais. Prevaleceu a hipergammaglobulinemia policlonal (4,2%), seguida por BM (1,4%) e hipogammaglobulinemia (0,8%). Hipergammaglobulinemia policlonal (>3 g/dL) foi observada em: Hepatite autoimune, cirrose, síndrome de Sjögren, doença mista do tecido conjuntivo, HIV, hepatite C e doença de Castleman. O achado de BM correspondeu a 47% de pacientes com gammapatia monoclonal de significado indeterminado e 40% com mieloma múltiplo; 0,5% eram casos novos. Com hipogammaglobulinemias em adultos prevaleceu a imunossupressão terapêutica (55%), seguida por diabete/síndrome metabólica/hipotireoidismo (23%); em crianças, 22% por imunossupressão e 78% com hipogammaglobulinemia não classificados como imunodeficiência primária. Conclui-se que em 6,4% dos PxE foi observada alteração da área gammaglobulina; prevaleceu a hipergammaglobulinemia policlonal. Em 1 de cada 200 PxE foi encontrado um paciente com BM. O achado de hipergammaglobulinemia policlonal ou BM se correspondeu com diferentes estados clínico-patológicos.

Overlap of IgG4-related Disease and Multicentric Castleman's Disease in a Patient with Skin Lesions.

A 59-year-old man presented with multiple dark red erythemas with induration, anemia, and polyclonal hypergammaglobulinemia. A skin biopsy revealed the infiltration of lymphocytes and plasma cells and he was initially diagnosed with multicentric Castleman's disease (MCD). Glucocorticoid treatment was only partially effective. Four years later, the patient's bilateral lacrimal glands gradually became enlarged and a biopsy revealed dense lymphocyte and plasma cell infiltration with an IgG4+/IgG+ plasma cell ratio of 70%. The patient was diagnosed with IgG4-related disease (RD). Rituximab only had a slight effect. This case demonstrates that overlapping features of IgG4-RD and MCD may present in a single patient, which suggests a shared pathogenesis.

Multicentric Castleman disease mimicking IgG4-related disease: A case report.

A 50-year-old woman was referred to our hospital for shoulder joint stiffness. She had a history of polyclonal hypergammaglobulinemia and an elevated C-reactive protein level. Her laboratory data revealed an elevated serum immunoglobulin G4 (IgG4) level, hypergammaglobulinemia, and rheumatoid factor positivity in the absence of anticyclic citrullinated peptide antibody. [18F]-Fluorodeoxyglucose positron emission tomography showed significant [18F]-fluorodeoxyglucose uptake in multiple lymph nodes (axillary, hilar, para-aortic, and inguinal). Biopsy of the inguinal lymph node showed expansion of the interfollicular areas by heavily infiltrating plasma cells, consistent with multicentric Castleman disease (MCD). Immunohistochemical analysis revealed a 37.3% IgG4-positive:IgG-positive plasma cell ratio, indicating overlapping IgG4-related disease. However, serological cytokine analysis revealed elevated levels of interleukin-6 (9.3 pg/ml) and vascular endothelial growth factor (VEGF) (1210 pg/ml), which are compatible with MCD. Corticosteroid treatment resolved the serological and imaging abnormalities. IgG4-related disease can mimic MCD, and it is crucial to distinguish between these two diseases. Serum interleukin-6 and VEGF levels may help to discriminate MCD from IgG4-related disease.

Characterization of Cutaneous Plasmacytosis at Different Disease Stages.

BACKGROUND/AIMS: Cutaneous plasmacytosis is rare and still not well understood. A retrospective study was made of 9 Chinese patients with 1- to 15-year histories of biopsy-proven cutaneous plasmacytosis diagnosed between 2003 and 2015. METHODS: Patient records and archival photographs helped establish the pattern and duration of skin lesions, and skin biopsy specimens provided additional data. RESULTS: The mean age at diagnosis was 46.4 years. Two patients had lesions within 1 year of developing the disease, and 4 had lesions lasting longer than 5 years. One patient had lymphadenopathy of the neck that was later determined to be Castleman disease. Three patients had elevated IgG4 levels; only 2 had increased IgG4+ cells in skin tissues. Flexural accentuation was prominent. Four patients had elevated IgG levels, and 1, with an IgG level >5,000 mg/dL, developed systemic plasmacytosis (later confirmed as Castleman disease). The level of IgG4 subclass was related to disease duration, whereas IgG4+ plasma cells in tissues seemed irrelevant. CONCLUSION: Routine laboratory tests, especially measurement of IgG4 levels, may be useful for following patients with cutaneous plasmacytosis. Because of the retrospective nature of our study, we could only evaluate the results of a single IgG4 test for each patient, but the results pointed to cutaneous plasmacytosis in all 9 patients, who had different stages of the disease. Serial skin biopsies may also be helpful for gauging disease progress. Although IgG4-related disease was not established in any of these patients, long-term follow-up is warranted for all patients.

Detection of serum IgG4 levels in patients with IgG4-related disease and other disorders.

OBJECTIVE: Elevated serum IgG4 levels are an important hallmark for diagnosing IgG4-related disease (IgG4-RD), but can also be observed in other diseases. This study aimed to compare two different testing methods for IgG4: ELISA and nephelometric assay. Both assays were used to measure serum IgG4 concentrations, and to assess the prevalence of high serum IgG4 levels in both IgG4-RD and non-IgG4-RD diseases. METHODS: A total of 80 serum samples were tested using the nephelometric assay and ELISA method that we established. Serum IgG4 concentrations were determined by ELISA for 957 patients with distinct diseases, including 12 cases of IgG4-RD and 945 cases of non-IgG4-RD. RESULTS: IgG4 levels from 80 selected serum samples examined by ELISA were in agreement with those detected using the nephelometry assay. Meanwhile, the serum IgG4 concentrations measured by ELISA were also consistent with the clinical diagnoses of patients with IgG4-RD during the course of disease. The Elevated levels of serum IgG4 (>1.35 g/L) were detected in all IgG4-RD (12/12) patients, and the prevalence of high IgG4 serum levels was 3.39% in non-IgG4-RD cases. Among them, the positive rates of serum IgG4 were 2.06% in patients with carcinoma and 6.3% in patients with other non-IgG4 autoimmune diseases. CONCLUSION: Our established ELISA method is a reliable and convenient technique, which could be extensively used in the clinic to measure serum IgG4 levels. High levels of IgG4 were observed in IgG4-RD. However, this phenomenon could also be observed in other diseases, such as carcinomas and other autoimmune diseases. Thus, a diagnosis of IgG4 disease cannot only be dependent on the detection of elevated serum IgG4 levels.

Levo-1-methyl tryptophan aggravates the effects of mouse hepatitis virus (MHV-A59) infection.

Mice infected with mouse hepatitis virus A59 (MHV-A59) develop autoantibodies (autoAb) to liver and kidney fumarylacetoacetate hydrolase (FAH) with a concomitant enhancement of transaminases and release of alarmins such as uric acid and high-mobility group box protein 1 (HMGB1). Tryptophan catabolism is an endogenous mechanism that restricts excessive immune responses, thereby preventing immunopathology. Since indoleamine-2,3-dioxygenase (IDO) is the key and rate-limiting enzyme of tryptophan catabolism, the aim of this work was to explore whether specific inhibition of IDO by Levo-1-methyl tryptophan (MT) could affect MHV actions. Results showed that MT strongly enhanced the hypergammaglobulinemia induced by the virus, as well as anti-MHV Ab and uric acid release. Moreover, infected mice treated with MT did express anti-FAH autoAb and high levels of serum HMGB1. Survival of MHV-infected animals treated with MT was severely reduced compared with that of MHV-infected mice or controls only treated with MT. Furthermore, histological liver examination indicated that MT induced fibrosis in MHV-infected animals, whereas MT itself increased uric acid levels without shortening the animal life Thus, under our experimental conditions, results indicated an exacerbated response to MHV infection when IDO was blocked by MT.

Hyperimmunoglobulinemia E and efficacy of elimination diet in two patients with Schnitzler syndrome.

BACKGROUND: Schnitzler syndrome (SS) is a rare clinical entity characterized by chronic recurrent urticarial rash, monoclonal IgM gammopathy, intermittent fever and other symptoms. In this report, we present the cases of two patients with SS: a male and a female aged 50 and 49 years, respectively. Both patients had hyperimmunoglobulinemia E and showed good response to elimination diet. METHODS: The patients had chronic urticaria, IgM gammopathy and an elevation of the serum levels of inflammation markers. Total IgE levels were found to be high (2000 U/ml and 540 U/ml, respectively). No underlying causes for hyperimmunoglobulinemia E (allergy, parasites, etc.) were revealed. The first patient did not respond to the treatment with antihistamines, while the second one responded only to high doses. The response to prednisolone in the second patient was incomplete. RESULTS: Following a strict elimination diet resulted in marked improvement in skin lesions in both patients. In one of our patients we observed a decrease in IgE and IgM levels after a 3 week diet. The systemic symptoms persisted and improved only after adding pefloxacin, followed by a 3-day empirical course of intravenous prednisone in the first patient and a course of plasmapheresis in the second one. CONCLUSION: The high serum levels of total IgE may be associated with chronic urticaria activity, severe disease course and a poor response to treatment with antihistamines, and may be considered a possible marker of a subset of patients with SS showing a good response to the restriction diet. In general, we can assume that elimination diet can have an influence on the skin lesions and other symptoms of SS as well as on total IgE and IgM levels, but such association, the underlying mechanisms and the reasons for excessive IgE synthesis should be investigated in further studies.

Crystalglobulinemia with fulminant course with cylinder-like bodies on peripheral blood smear.

A 63-year-old woman presented to our hospital with fever, purpura and pain in both legs and died 4 days after admission. Her blood smear and skin biopsy showed cylinder-like bodies (20×120 µm). She was diagnosed to have monoclonal gammopathy (IgG, lambda type). An autopsy revealed cylinder-like bodies in the vasculature of various organs. We noted a proliferation of atypical plasma cells in her bone marrow, suggesting pre-existing myeloma. Crystalglobulinemia is a rare manifestation of hypergammaglobulinemia that can cause multiple embolisms of the small vessels, and this resulted in the patient's fulminant course. The identification of cylinder-like bodies in the peripheral blood may help in reaching a diagnosis in such cases.

Sudden cardiac death due to coronary artery involvement by IgG4-related disease: a rare, serious complication of a rare disease.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic disorder characterized by multiorgan fibrosis with IgG4-producing plasma cells, increased IgG4 serum concentration, and responsiveness to steroid therapy. Involvement of the pancreas, salivary glands, orbit, aorta, and other sites has been well documented in the literature; however, there have been limited reports of cases involving the coronary arteries. We report the case of a 53-year-old Hispanic man who was brought to the emergency center and diagnosed with sudden cardiac death. Autopsy was subsequently performed, revealing multiorgan involvement by IgG4-RD, including involvement of the coronary arteries. The inflammation and fibrosis, in combination with concomitant atherosclerotic disease, resulted in severe stenosis of the coronary arteries. Two of the coronary arteries were further occluded by thrombosis. These factors led to cardiac hypoperfusion, myocardial infarction and, ultimately, sudden cardiac death. Fatal involvement of the coronary arteries has not been previously reported, raising a new concern for a severe complication of IgG4-RD.

Current concept, diagnosis and pathogenesis of autoimmune pancreatitis as IgG4-related disease.

Recently, autoimmune pancreatitis, a pancreatic manifestation of IgG4-related disease (IgG4-RD) has been recognized as a novel clinical entity associated with massive infiltration of IgG4-positive cells. The first international symposium on IgG4-RD endorsed the comprehensive nomenclature as IgG4-RD, which the Japanese research committee supported by the Ministry of Health, Labor and Welfare of Japan proposed in 2009, and proposed the individual nomenclatures for each organ system manifestations and the international pathologic consensus in 2011. In addition to the pathological consensus, the Japanese comprehensive diagnostic criteria (CDC) for IgG4-RD for general use, and several organ specific criteria for the organ specified physicians have been proposed; the International Consensus Diagnostic Criteria and the revised clinical diagnostic criteria in 2011 by Japan Pancreas Society (JPS-2011) for type1 AIP, the Clinical Diagnostic Criteria 2012 for IgG4-sclerosing cholangitis (IgG4-SC-2012), the diagnostic criteria for IgG4-positive Mikulicz's disease by the Japanse Society for Sjogren's syndrome, and Diagnostic criteria for IgG4-related kidney disease by the Japanese Society of Nephrology. Although the pathogenic mechanism still remains unclear, we have proposed a hypothesis of the pathogenic mechanism; abnormal innate and acquired immunity, regulatory T cells, and B cells on abnormal genetic backgrounds may be involved in the development of IgG4-cholangiopathy. Further studies are necessary to clarify the pathogenesis including genetic backgrounds, disease specific antigens, and the role of IgG4.