IgG4‐related skin disease

Renal Manifestations of IgG4-Related Disease: A Concise Review

IgG4-related disease (IgG4-RD) is an immune-mediated disorder marked by fibro-inflammatory masses that can infiltrate multiple organ systems. Due to its relatively recent discovery and limited understanding of its pathophysiology, IgG4-related disease may be difficult to recognize and is consequently potentially underdiagnosed. Renal involvement is becoming regarded as one of the key features of this disease. To date, the most well-recognized renal complication of IgG4-related disease is tubulointerstitial nephritis, but membranous glomerulonephritis, renal masses, and retroperitoneal fibrosis have also been reported. This concise review has two objectives. First, it will briefly encapsulate the history, epidemiology, and presentation of IgG4-related disease. Second, it will examine the reported renal manifestations of IgG4-related disease, exploring the relevant histology, imaging, clinical features, and treatment considerations. This synthesis will be highly relevant for nephrologists, rheumatologists, general internists, and renal pathologists to raise awareness and help improve early recognition of IgG4-related kidney disease (IgG4-RKD).

The "great imitator": IgG4-related disease of the oral cavity. Two case reports and scoping review

This study aimed to review the lesser-known intraoral manifestations of immunoglobulin G4-related disease (IgG4-RD). In this paper we report an unprecedented case of oral IgG4-RD mimicking angiolymphoid hyperplasia with eosinophilia (ALHE), and another case presenting as plasma cell gingivitis. We then performed a scoping review of published cases of IgG4-RD involving the oral cavity. The following data were collected for each case: age, sex, intraoral site(s) involved, clinical appearance, imaging features, serum IgG4 values, histopathology, treatment, and follow-up duration. Fifty-one cases of oral IgG4-RD were published in literature. The hard palate and jaw bones were the two main locations reported, while the histological identification of a IgG4/IgG plasma cells ratio ≥40% was fundamental for diagnosis. Conversely, the pathological features of storiform fibrosis and obliterative phlebitis were not common. Future reports regarding oral IgG4-RD should report clear adherence to the recognized international diagnostic criteria of the disease.

IgG4-related disease: an update on pathology and diagnostic criteria with a focus on salivary gland manifestations

Immunoglobulin G4-related disease (IgG4-RD) is a multi-organ disorder characterized by a highly variable clinical presentation depending on the affected organ/s, extent of tumefactive fibroinflammatory lesions, and associated functional impairment. The disease pursues a chronic, relapsing, often asymptomatic course and hence may pose a significant diagnostic challenge. Diagnostic delay can lead to progressive fibrosis and irreversible organ damage resulting into significant morbidity and even mortality. Given its broad clinical spectrum, physicians of all specialties may be the first clinicians facing this diagnostic challenge. Outside the pancreatobiliary system, the head and neck represents the major site of IgG4-RD with variable organ-specific diffuse or mass-forming lesions. In up to 75% of cases, elevated serum IgG4 levels are observed, but this figure possibly underestimates the fraction of seronegative cases, as the disease manifestations may present metachronously with significant intervals. Together with negative serology, this can lead to misdiagnosis of seronegative cases. A standardized nomenclature and diagnostic criteria for IgG4-RD were established in 2012 and revised in 2020 facilitating scientific research and expanding the range of diseases associated with IgG4 abnormalities. In addition to orbital pseudotumor, dacryoadenitis, Riedel thyroiditis, sinonasal manifestations, and rare miscellaneous conditions, IgG4-related sialadenitis is one of the most frequent presentations in the head and neck region. However, controversy still exists regarding the relationship between sialadenitis and IgG4-RD. This review focuses on the clinicopathological features of IgG4-related sialadenitis and its contemporary diagnostic criteria.

Giant Ulcer with Necrosis on Right Vulva, Groin, and Thigh-- A Case of Necrotizing Fasciitis Associated with Erythematous Pemphigus

Necrotizing fasciitis is a rare, severe, rapidly progressing disease with a high mortality rate. We report a case of a 72-year female with erythematous pemphigus who developed erythema, swelling and ulceration on right vulva, groin, and thigh. The early clinical manifestations of the patient were nonspecific and easily misdiagnosed as cellulitis. However, upon the occurrence of ulceration and necrosis, deep fungal infection, pyoderma gangrenosum or lymphoproliferative disorders were considered. The pathology suggested IgG4-related diseases, plasmacytoma et al. But at last, surgical exploration and postoperative pathology confirmed the diagnosis of necrotizing fasciitis. The patient recovered after multiple aggressive surgical debridement procedures and antibiotic therapy and the patient has been followed up for 2 years without recurrence. Clinicians should be vigilant about the possibility of necrotizing fasciitis in patients with erythema, pain, rapid ulceration of skin and soft tissue, particularly in immunocompromised individuals with long-term use of immunosuppressive agents. It is crucial for saving life by early multi-disciplinary consultation, prompt diagnosis, and aggressive treatment.

Immunoglobulin G4-Related Disease of the Intestine: A Clinicopathological Entity to Be Considered

Background and Objectives: Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized immune-mediated, systemic condition of unknown etiology, associated with fibroinflammatory lesions. Diagnosis is set in the presence of IgG4-positive plasma cell infiltration of the involved tissue and elevated serum IgG4 levels. However, approximately 30% of patients have normal serum IgG4 levels. IgG4-RD may affect several organs, including the pancreas, bile ducts, mesentery, retroperitoneum, and salivary glands, but the involvement of the gastrointestinal tract is uncommon. Materials and Methods: The case series of 4 patients with IgG4-RD involving the intestinal tract was observed in the period of 2017-2022. Colorectal and ileal biopsy specimens were stained with hematoxylin and eosin and immunohistochemical techniques using monoclonal antihuman IgG4 primary antibody. Diagnosis of IgG4-RD was based on the presence of >50 cells/ HPF and IgG4/IgG ratio >40 confirmed by two pathologists. Results: IgG4-RD was set in patients previously diagnosed as affected by Crohn's disease. Conclusions: Systematic IgG4 immunohistochemical staining should be considered in the diagnostic workup of patients with gastrointestinal strictures, mimicking Crohn's disease. The exact prevalence of the condition is likely more frequent than reported and should be defined by a large series of consecutive patients.

An 8-year follow-up of IgG4-related skin disease presented with generalized ALHE-like eruptions: successful treatment of glucocorticoid and cyclophosphamide

Immunoglobulin gamma (IgG) type 4-related disease (IgG4-RD) is a chronic immunologic systemic disorder that could affect multiple organs, which may cause irreversible organ damage or even death. Skin involvement is rare and associated especially with systemic disease. The dermatologist must be equipped to recognize IgG4-RD to prevent delayed identification and treatment. This case reports a very rare case of IgG4-related skin disease (IgG4-RSD) presenting with a generalized angiolymphoid hyperplasia with eosinophilia (ALHE)-like lesions in a middle-aged male patient with no other organ involvement. He was treated with oral glucocorticoid and cyclophosphamide, which resulted in complete remission. No relapse and disease progression were seen with a follow-up for 8 years.

Cutaneous plasmacytosis Characterized by Head Plaques: An Unusual Case Report of a 57-Year-Old Male

Cutaneous plasmacytosis (CP) is a rare disorder of uncertain etiology. We report an unusual and rare case of CP in a 57‑year‑old male who presented with popular nodules all over the body, accompanied by head plaques. Pathological biopsy of the skin revealed large infiltration of mature plasma cells within the dermis. Elevated serum IgG4 concentrations were found. Immunohistochemical analysis confirmed the polyclonal nature of the plasma cells. The diagnosis of CP was established. Steroid therapy was administered at a dose of 20 mg/day. After 1 month of treatment, the patient's eruption showed regression. These findings remind dermatologists to include CP in their clinical differential diagnosis of patients with head plaques. Meanwhile, clinicians should carefully that individuals diagnosed with CP at risk for malignant transformation.

IgG4-Related Disease Manifested as Cutaneous Plasmacytosis: A Case Report

BACKGROUND

IgG4-related disease (IgG4-RD) is a rare fibroinflammatory disease that has a high tendency to misdiagnosis in clinics.

CASE PRESENTATION

A 48-year-old man developed a rash with progressive itching 3 years ago after hormone therapy for an ocular "inflammatory pseudotumor". The disease condition of this patient involved multiple organs which involved the skin. The patient was misdiagnosed with other diseases during the period of hospitalization, leading to poor therapeutic effects and repeated skin lesions. The dermatopathological report indicated plasma cell proliferative disorder, with IgG4/IgG exceeding 40% and abnormally elevated serum IgG4 levels. After the patient was diagnosed with IgG4-RD, a series of treatments improved skin lesions, relieved other symptoms, and decreased serum IgG4 levels.

CONCLUSION

IgG4-RD is a highly misdiagnosed disease that deserves the attention of physicians. The patient we reported could be considered a representative case of IgG4-RD that presents with skin lesions. For patients with suspected IgG4-RD, serum IgG4 testing should be performed, and further imaging, serological tests, and pathology examinations are needed to exclude malignancy, infection, and autoimmune diseases.

Possible Ambiguity in Interpretation Between Immunoglobulin G4-Related Disease (IgG4-RD) and Sarcoidosis in a Post-COVID-19 Pandemic

A 36-year-old lady presented with fever, cough, maculopapular rash, painless sialadenitis, episcleritis, and arthralgia of more than 10 months, occurring in episodes since she tested positive for COVID-19 in 2020. Her symptoms were well controlled with corticosteroid and immunosuppressant therapy. Her clinical presentation and findings on bronchoscopy resembled that of sarcoidosis. However, the bronchial biopsy histopathology ruled out sarcoidosis. An increased serum immunoglobulin G4 level and its possible association with COVID-19 raises the question of whether the possibility of immunoglobulin G4-related disease (IgG4-RD) could be entertained.

A Rare Case Report of Periorbital Pseudolymphoma

Pseudolymphoma (PSL) of the orbit is a benign lymphoid hyperplasia (LH). It is a rare disease with an extensive range of known causative agents. LH is further classified into "reactive" (RLH) and "atypical" (ALH) types. It clinically presents as a single or a few plaques and/or nodular lesions, particularly on the head, neck, and upper trunk. It must be differentiated from orbital malignant lymphoma. In this report, we present a case of a 58-year-old Pakistani female with an asymptomatic recurrent right periorbital swelling for three years. It was clinically diagnosed as an angiotensin-converting enzyme (ACE) inhibitor-induced angioedema as it responded to stopping the ACE inhibitor; however, after four months, the patient again started to develop right periorbital swelling. An incisional biopsy revealed perivascular and periadnexal infiltration of lymphocytes, plasma cells, and a few neutrophils along with pigmentary incontinence. The formation of multiple lymphoid follicles and infiltration by monomorphic lymphoid cells in deeper skeletal muscle fibers were also observed. Immunohistochemistry (IHC) showed polyclonality and low Ki-67 labeling (20%), corresponding to periorbital RLH. Our objective in this study is to highlight the importance of considering PSL as a differential diagnosis in periorbital swelling. We also suggest that recurrent angioedema may lead to PSL.

IgG4-related skin disease responsive to thalidomide

IgG4-related skin disease is a rare, immune-mediated disorder characterized by tissue infiltration with IgG4+ plasma cells, along with elevated serum IgG4. We describe a patient treated successfully with thalidomide.

The Role of IgG4 in Autoimmunity and Rheumatic Diseases

The distinguishing of the IgG4-related disease (IgG4-RD) from among other rheumatic diseases has brought attention to the IgG4 subclass of immunoglobulins. It is the least numerous subclass among immunoglobulins G. In general, IgG4 is considered to be non-inflammatory and tolerance inducing, due to its unique structure. However, in IgG4-RD this antibody plays a pathogenic role in activation of the fibrinogenesis and of the inflammatory process; there are also suggestions that it may be a marker of an abnormal inflammatory response. The importance of IgG4 for the pathogenesis of allergic diseases, with a vital role of its ratio to immunoglobulin E (IgE/IgG4 ratio), has been known for years. The role of IgG4 in the course and pathogenesis of rheumatic diseases is still being researched and is not yet fully understood. Increased IgG4 levels have been revealed in rheumatoid arthritis, although no clear link between this phenomenon and disease activity has been demonstrated. There are articles on the potential importance of IgG4 concentration (of both elevated and decreased serum levels) in Sjogren’s syndrome. Additionally, anti-nuclear IgG4 antibody significant titers have been detected in SLE patients, and it has been suggested that the effect of these antibodies on complement consumption and the production of proinflammatory cytokines may play a role in inhibiting the progression of SLE. IgG4 plays a role in autoimmune diseases other than rheumatic diseases, such as pemphigus, bullous pemphigoid, idiopathic membranous glomerulonephritis, or myasthenia gravis, but also in helmints infections. Research shows the importance of IgG4 in malignancy of neoplasms. Melanoma cells are known to stimulate IgG4 production through a modified Th2-based inflammatory response. The role of this immunoglobulin in cholangiocarcinoma is also considered as possible. The aim of this review article is to discuss the current knowledge of IgG4 not only from the perspective of the IgG4-RD but also from a point of view of other autoimmune diseases with particular emphasis on rheumatic diseases.

Ossifying fibrous epulis as an IgG4-related disease of the oral cavity: a case report and literature review

Background

Fibrous sclerosing tumours and hypertrophic lesions in IgG4-related disease (IgG4-RD) are formed in various organs throughout the body, but disease in the oral region is not included among individual organ manifestations. We report a case of ossifying fibrous epulis that developed from the gingiva, as an instance of IgG4-RD.

Case presentation

A 60-year-old Japanese man visited the Department of Oral and Maxillofacial Surgery, Gunma University Hospital, with a chief complaint of swelling of the left mandibular gingiva. A 65 mm × 45 mm pedunculated tumour was observed. The bilateral submandibular lymph nodes were enlarged. The intraoperative pathological diagnosis of the enlarged cervical lymph nodes was inflammation. Based on this diagnosis, surgical excision was limited to the intraoral tumour, which was subsequently pathologically diagnosed as ossifying fibrous epulis. Histopathologically, the ossifying fibrous epulis exhibited increased levels of fibroblasts and collagen fibres, as well as infiltration by numerous plasma cells. The IgG4/IgG cell ratio was > 40%. Serologic analysis revealed hyper-IgG4-emia (> 135 mg/dL). The patient met the comprehensive clinical diagnosis criteria and the American College of Rheumatology and European League Against Rheumatism classification criteria for IgG4-RD. Based on these criteria, we diagnosed the ossifying fibrous epulis in our patient as an IgG4-related disease. A pathological diagnosis of IgG4-related lymphadenopathy was established for the cervical lymph nodes. Concomitant clinical findings were consistent with type II IgG4-related lymphadenopathy.

Conclusions

A routine serological test may be needed in cases with marked fibrous changes (such as epulis) in the oral cavity and plasma cells, accompanied by tumour formation, to determine the possibility of individual-organ manifestations of IgG4-related disease.

T-Cell-Driven Fibroinflammation Inducing Follicular Dedifferentiation in Alopecia Areata and IgG4-Modified Disease

ABSTRACT

The definition of IgG4-related diseases incorporates a broad range of systemic diseases particularly a subset dominated by fibroinflammation. CD4+cytotoxic T cells have emerged as the major driving force for the fibroinflammation, and the pathogenetic role of IgG4 still remains to be determined. Cutaneous involvement is uncommon and is not well defined as elevated tissue IgG4 plasma cells are not a specific marker and prominent cutaneous fibroinflammation is often absent in cutaneous disease. We report the case of a patient with longstanding alopecia universalis and severe atopic dermatitis who presented with diffuse induration and mottled dyspigmentation of his scalp. Multiple scalp biopsies revealed diffuse interfollicular fibroinflammation and IgG4 plasma cells with induction of distinctive dedifferentiated follicles not seen in alopecia areata. This complex case may provide insight into the role of specific subsets of T cells not only in respect to the fibroinflammation linked to IgG4-related diseases but also the capacity to modify disease, follicular stem cell activation, immune privilege, cytotoxicity in alopecia areata, and the presence of atopy that may have contributed to the pathogenesis of this case.

Skin diseases in Asian individuals that you do not want to miss: A selection of unique or relatively more common conditions in Asian populations

The Asian population currently constitutes a simple majority of the global population, comprising nearly 60%. The percentage of the US population that identifies as Asian is expected to grow to 41 million by the year 2050, making up an eventual 9% of the US population. As the world and US populations of Asian individuals increase, the demand for dermatologic care from this population will increase, requiring dermatologists to become more familiar with the diagnosis and treatment of Asian-specific skin characteristics and diseases. In this contribution, we review skin conditions specific to or relatively more common in Asian patients to help recognition and management of diseases in an increasing Asian patient population. We discuss prurigo pigmentosa, primary cutaneous plasmacytosis, lipodystrophia centrifugalis abdominalis infantilis, Epstein-Barr viru-positive T- and natural killer-cell lymphoproliferative disorders, acquired bilateral nevus of Ota-like macules, and Behҫet disease.

Urticarial vasculitis

Urticarial vasculitis is a rare clinicopathologic entity that is characterized by chronic or recurrent episodes of urticarial lesions. Skin findings of this disease can be difficult to distinguish visually from those of chronic idiopathic urticaria but are unique in that individual lesions persist for ≥24 hours and can leave behind dusky hyperpigmentation. This disease is most often idiopathic but has been linked to certain drugs, infections, autoimmune connective disease, myelodysplastic disorders, and malignancies. More recently, some authors have reported associations between urticarial vasculitis and COVID-19, as well as influenza A/H1N1 infection. Urticarial vasculitis can extend systemically as well, most often affecting the musculoskeletal, renal, pulmonary, gastrointestinal, and ocular systems. Features of leukocytoclastic vasculitis seen on histopathologic examination are diagnostic of this disease, but not always seen. In practice, antibiotics, dapsone, colchicine, and hydroxychloroquine are popular first-line therapies, especially for mild cutaneous disease. In more severe cases, immunosuppressives, including methotrexate, mycophenolate mofetil, azathioprine, and cyclosporine, as well as corticosteroids, may be necessary for control. More recently, select biologic therapies, including rituximab, omalizumab, and interleukin-1 inhibitors have shown promise for the treatment of recalcitrant or refractory cases.

Does a Subset of Localized Chronic Fibrosing Vasculitis Represent Cutaneous Manifestation of IgG4-Related Disease/a Histologic Pattern of IgG4-Related Skin Disease? A Reappraisal of an Enigmatic Pathologic Entity

Localized chronic fibrosing vasculitis (LCFV) is a rare cutaneous fibroinflammatory and vasculitic process of poorly defined etiology. Furthermore, controversy remains as to whether LCFV represents a primary pathologic process or a histologic pattern. The current case documents a 52-year-old male patient with a scrotal mass and clinical history of a retroperitoneal mass as well as a previously resected tumor of the right submandibular salivary gland displaying morphologic features of eosinophilic angiocentric fibrosis. Histologic examination of the resected scrotal mass revealed a tumefactive lesion characterized by focally storiform fibrosis, obliterative phlebitis, tissue infiltration by IgG4-positive plasma cells, and leukocytoclastic vasculitis. Apart from the leukocytoclastic vasculitis, the scrotal lesion demonstrated characteristic morphologic features of an IgG4-related disease (IgG4-RD). In recognition of the combined histologic findings of both LCFV and IgG4-RD in the scrotal mass, it was postulated that a subset of LCFV cases might represent cutaneous manifestations of IgG4-RD or a new histologic pattern of IgG4-related skin disease (IgG4-RSD). The literature analysis of previously reported LCFV cases appeared to lend credence to this hypothesis. Pathologists should be aware of this new histologic pattern of IgG4-RSD as judicious consideration for additional studies might potentially detect an unexpected systemic IgG4-RD in the patient, particularly in cases of LCFV displaying storiform fibrosis associated with plasma cell infiltrate.

Punctate Purpura Complicated with Immunoglobulin G4-related Disease

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition affecting multiple organs; however, the involvement of skin lesions is rare. We herein report a 65-year-old man who presented with pruritic punctate purpura on both legs and elevated liver enzyme levels. Computed tomography showed enlargement of the pancreas and thickening of the bile duct wall. Magnetic resonance cholangiopancreatography showed diffuse irregular constriction of the main pancreatic duct, stricture of the lower common bile duct, and dilation after confluent stricture. A histopathologic examination of the pancreas and his enlarged salivary gland showed infiltration of IgG4-positive plasma cells. Ultimately, the patient was diagnosed with IgG4-RD.

Visual impairment in immunoglobulin G4-related disease: A case report

The present study reports on the case of a 50-year-old male with sinusitis, diplopia, secretory otitis media and skin eczema for >14 years. The patient presented with visual impairment in both eyes and subxiphoid pain on admission to the First Affiliated Hospital of China Medical University (Shenyang, China). Orbital CT revealed a slightly thickened left inferior rectus muscle. Due to a periocular mass, enlarged lymph nodes, elevated serum immunoglobulin G4 (IgG4) levels and enriched IgG4-positive plasma cells in the lymph nodes, the diagnosis of IgG4-related disease (IgG4-RD), possibly involving at least 10 organs, was established. Following treatment with methylprednisolone, the serum IgG4 levels decreased to normal and binocular vision returned to normal. Unlike previously reported cases, the present case exhibited no swollen masses around the optic nerve. The purpose of the present case report was to improve the understanding of IgG4-RD.

Immunoglobulin-G4-related skin disease

Immunoglobulin-G4-related disease (IgG4-RD) is an autoimmune-mediated spectrum of diseases, characterized by infiltration of IgG4+ plasma cells into one or multiple organs, with the pancreas being the most commonly affected organ. The disease mostly affects middle-aged to elderly men. Diagnosis requires an integration of clinical, radiologic, pathologic, and serologic studies. Histologically, there is an increased infiltration of IgG4+ plasma cells, elevated ratio of IgG4+/IgG plasma cells of more than 40%, and a storiform pattern of fibrosis. There may be eosinophilia, along with elevated IgG4 levels. IgG4-RD can mimic several diseases and should be differentiated from inflammatory and neoplastic processes. Recently, there has been increased awareness of cutaneous involvement by IgG4-RD either as an isolated lesion or primary involvement or as a secondary involvement from a systemic disease. Clinically, cutaneous IgG4+-related disease presents as papules, plaques, and nodules involving the head and neck areas. We have provided a systematic review of the literature of this new and challenging entity of cutaneous IgG4-RD.

Extramedullary Hematopoiesis: An Unusual Finding in Angiolymphoid Hyperplasia With Eosinophilia

Extramedullary hematopoiesis is the process of blood cell synthesis occurring outside the medulla of the bone marrow. During fetal development, extramedullary hematopoiesis is considered physiological; however, it is considered pathologic when occurring outside the neonatal period. Angiolymphoid hyperplasia with eosinophilia (ALHE) describes a lesion characterized histologically by plump endothelial cells associated with a mixed inflammatory infiltrate of lymphocytes, plasma cells, mast cells, and eosinophils. This report describes an adolescent boy with an isolated preauricular facial lesion. After excision, histopathology confirmed a diagnosis of ALHE with the additional finding of trilineage extramedullary hematopoiesis. To the authors' knowledge, this is the first reported case of extramedullary hematopoiesis in ALHE.

Skin-Associated B Cells in Health and Inflammation

Traditionally, the skin was believed to be devoid of B cells, and studies of the skin immune system have largely focused on other types of leukocytes. Exciting recent data show that B cells localize to the healthy skin of humans and other mammalian species with likely homeostatic functions in host defense, regulation of microbial communities, and wound healing. Distinct skin-associated B cell subsets drive or suppress cutaneous inflammatory responses with important clinical implications. Localized functions of skin-associated B cell subsets during inflammation comprise Ab production, interactions with skin T cells, tertiary lymphoid tissue formation, and production of proinflammatory cytokines but also include immunosuppression by providing IL-10. In this review, we delve into the intriguing new roles of skin-associated B cells in homeostasis and inflammation.

IgM Plasma Cells Reside in Healthy Skin and Accumulate with Chronic Inflammation

Antibodies are key to cutaneous host defense and inflammation. Despite their importance, the mechanisms by which skin antibodies are sustained are poorly described. Here, we identified that, in addition to antibody production in lymphoid tissues, plasma cells reside in healthy mouse and human skin. In naïve mice, IgM was the predominant isotype produced in skin. Skin plasma cells developed independently of T cells and microbiota. Importantly, chronic skin inflammation promoted the massive accumulation of IgM-secreting cells, and cutaneous immunization directed both T cell-dependent and -independent antigen-specific IgM-secreting cells into skin. Unlike their counterparts in lymphoid tissues, cutaneous IgM-secreting cells were completely dependent on survival factors such as a proliferation-inducing ligand or B cell-activating factor, which were constitutively expressed and upregulated during inflammation in skin. Our data support a model in which skin plasma cells supply natural and adaptive IgM to the cutaneous environment, thereby supporting homeostatic skin barrier functions and providing defense against pathogen intrusion. Our results are also of potential relevance for manipulation of cutaneous plasma cells in inflammatory skin diseases or cutaneous plasma cell malignancies.

IgG4-related disease coexisting with autoimmune haemolytic anaemia

An 85-year-old man presented with a pale appearance and generalised pruritic papules. Laboratory investigations disclosed eosinophilia, autoimmune haemolytic anaemia, mixed hyperbilirubinaemia, cholestasis and elevated serum IgG4 levels. Abdominal sonography and CT showed progressive dilatation of biliary trees, with diffuse pancreatic enlargement and a subtle capsule-like low-density rim around the pancreatic head and body. Endoscopic retrograde cholangiopancreatography found no stone-related biliary obstruction, while endoscopic transpapillary biopsy demonstrated chronic inflammation only. Nevertheless, the diagnosis of IgG4-related disease with coexisting autoimmune haemolytic anaemia was presumed. The clinical picture and laboratory abnormalities improved after administration of moderate dose of methylprednisolone.