Co-occurrence of IgA nephropathy and IgG4-Tubulointersitial nephritis effectively treated with tacrolimus: a case report

Background Cases of concurrent immunoglobulin A nephropathy (IgAN) and IgG4-related tubulointerstitial nephritis (IgG4-TIN) are rare and previous case reports have lacked important data. KDIGO suggests a treatment with systemic glucocorticoids in IgAN patients. Glucocorticoids are recommended as the first-line therapy for IgG4-TIN. The use of tacrolimus as a long-term maintenance treatment has not been described. We report the case of a man who developed IgAN and IgG4-TIN without abnormalities in extra-renal tissue, without renal function abnormalities or impairment as well, and was treated by tacrolimus as a long-term maintenance during 45 months follow-up. Case presentation A 56-year-old Chinese man first presented to our hospital with the chief complaint of foamy urine for 1 year and hematuria for 3 months, with a medical history of hypertension. Testing revealed a notable increase in serum IgG4 level without abnormalities in renal function or imaging, or in dysfunction other organs. Renal biopsy showed mesangial extracellular matrix proliferation, increased mesangial cell numbers and infiltration of plasma cells. Immunofluorescence showed mesangial positivity for IgA and C3. Immunohistochemistry staining showed widespread IgG4 and increased CD38 and CD138 expression. Electron microscopy showed immune complexes located on the tubular basement membrane. He was diagnosed with IgAN and IgG4-TIN. He received glucocorticoids, leflunomide and tacrolimus to induce remission. He was given tacrolimus as long-term maintenance treatment. When tacrolimus was temporarily withdrawn, proteinuria recurred. After resuming tacrolimus therapy, he again entered complete remission. After 45 months of therapy, he remains in complete remission and the serum IgG4 level is normal. Conclusions The finding of concurrent IgAN and IgG4-TIN without abnormalities in renal function, imaging or extra-renal tissue is rare and their coexistence may be coincidental. Long-term treatment with tacrolimus proved effective and he has remained in remission during 45 months follow-up.

Suspected IgG4-related disease of the submandibular salivary gland and periorbital soft tissue in a man with latent tuberculosis

A 77-year-old Lithuanian man presented to our institution with recurrent episodes of periorbital cellulitis, submandibular swelling and sialadenitis. Investigations revealed a positive QuantiFERON, raised inflammatory markers and normal autoimmune screen. Cross-sectional imaging showed no signs of occult malignancy, and work-up for mycobacterial infection including imaging and bronchoalveolar lavage did not show active tuberculosis. During hospitalisation, the patient developed fevers of unknown origin, which were investigated with a positron emission tomography (PET) scan and a bone marrow aspiration, without evidence of occult infection or malignancy. Serum IgG4 level was three times the upper limit of normal. The patient responded well to oral steroids but relapsed after completing a slow taper. Serum IgG4 level was three times the upper limit of normal. He had an American College of Rheumatology/European League Against Rheumatism score of 20, in conjunction with involvement of orbital and salivary tissue. Therefore, IgG4-related disease was considered the most likely diagnosis, despite prominent fevers, which are among the exclusion criteria for this diagnosis. After a multidisciplinary review including rheumatology and ophthalmology, the patient was commenced on maintenance methotrexate with remission of symptoms.

AB1036 CLINICAL MANIFESTATIONS, CLINICAL COURSE, AND OUTCOMES OF IMMUNOGLOBULIN G4 RELATED DISEASE

Background:Immunoglobulin G4 related disease (IgG4-RD) is an uncommon chronic systemic autoimmune disease, pathologically characterized by lymphoplasma cell, IgG4 plasma cell or storiform fibrosis infiltration with elevated serum IgG4 level. IgG4-RD is a new disease and not widely recognized.Objectives:The aim of this study was to describe clinical manifestations and outcomes of IgG4-RD in Thai patientsMethods:This multicenter retrospective cohort study included patients who aged ≥ 18 years and were diagnosed with IgG4-RD according to 2011 comprehensive or consensus diagnostic criteria, between 2000 and 2019 in four academic centers in Thailand. Baseline characteristic, laboratory and pathologic findings, treatments, and outcomes were systematically reviewed.Results:Of the 110 patients included, 71% were male with mean age (SD) of 59.6 (13.3) years and median disease duration (IQR) of 28.8 (14.6-53.5) months. Single organ involvement was observed in 60 patients (54.5%). The most common presenting organ involvement was the orbit (29%), followed by the salivary glands (19%), lacrimal glands (18%), bile duct (16%), and pancreas (11%). The most frequently affected organs were the orbits (34%), followed by the salivary glands (26%), lacrimal glands (20%), bile duct (19%), and lymph nodes (19%). Ninety-six percent (96%) had IgG4 level of more than 135 mg/dl at presentation. Most patients (92%) were treated with corticosteroid (CS) alone or in combination with immunosuppressive agents. Azathioprine (47%) and methotrexate (11%) were the most commonly used immunosuppressive agents. Additionally, 20% required surgery, and 6.4% underwent stent insertion. One-fourth (26%) were in remission with successfully CS tapering, while 37%, and 29% had complete, and partial response. Nevertheless, 22% relapse with median time to relapse (IQR) of 22.2 (12.8-41.1) months. Relapse was common in patients with orbital (p = 0.001) and lung (p= 0.007) involvement, and patients with longer disease duration (median 44.1 and 23.1 months, P=0.001), while serum IgG4 level was insignificantly higher in relapse group (median 1,085 vs. 850 mg/dL, p=0.28).Conclusion:IgG4-RD is a chronic systemic autoimmune disease with diverse manifestations, response to treatment, and outcomes. Most patients responded well to CS and immunosuppressive agents with notable relapse rate, while minority required surgery or mechanical intervention.References:[1]Wallace ZS, Zhang Y, Perugino CA, Naden R, Choi HK, Stone JH. Clinical phenotypes of IgG4-related Disease: an analysis of two international cross-sectional cohorts. Ann Rheum Dis. 2019;78(3):406-12.[2]Martinez-Valle F, Fernandez-Codina A, Pinal-Fernandez I, Orozco-Galvez O, Vilardell-Tarres M. IgG4- related disease: Evidence from six recent cohorts. Autoimmun Rev. 2017;16(2):168-72Acknowledgments:NoneDisclosure of Interests:None declared

Relapse predictors and serologically unstable condition of IgG4-related disease: a large Chinese cohort

Objectives Patients with IgG4-related disease (IgG4-RD) typically respond well to initial glucocorticoid therapy, but always relapse with tapered or maintenance dosage of steroid. We aimed to identify the risk factors for relapse of IgG4-RD and explore the impact of active intervention on the serologically unstable condition. Methods We performed a retrospective study of 277 IgG4-RD patients at Peking University People’s Hospital from February 2012 through February 2019. They were all followed for >4 months. The primary outcome was patient relapse. Data on recurrence of IgG4-RD symptoms, laboratory and image findings were recorded, along with information on treatment in the serologically unstable condition. Results The cumulative relapse rate was 12.86%, 27.84% and 36.1% at 12, 24 and 36 months, respectively. Younger age at onset, younger age at diagnosis, longer time from diagnosis to treatment and history of allergy were associated with relapse. Identified independent risk factors were longer time from diagnosis to treatment and history of allergy. When serum IgG4 level was 20%, 50% or 100% higher than that of the remission period, similar percentages of patients finally relapsed, regardless of whether they were in the immunosuppression intensified or non-intensified group. Median duration from serum IgG4 level instability to relapse in the intensified and non-intensified group was not statistically different. Conclusion The risk factors of relapse were longer time from diagnosis to treatment and history of allergy. Intervention in the serologically unstable condition was not helpful for reducing relapse rate.

Clinical Characteristics of 76 Patients with IgG4-Related Hypophysitis: A Systematic Literature Review

Background. IgG4-related hypophysitis (IgG4-RH) is a rare disease, and its prevalence remains unclear. In recent years, an increasing number of cases have been reported because of the increasing recognition of this disease. We aimed to summarize case reports of IgG4-RH and outline the clinical features and outcomes. Methods. We performed PubMed search of articles using the search terms “hypophysitis [AND] IgG4.” Consequently, only 54 English articles (76 cases) met Leporati’s diagnostic criteria. Results. Of the 76 cases, the ratio of men to women was 1.5 : 1, and the age at diagnosis was 54.1 ± 17.8 years. The median IgG4 concentration was 405.0 mg/dl. Anterior hypopituitarism, isolated central diabetes insipidus, and panhypopituitarism were observed in 14 (18.4%), 12 (15.8%), and 44 (57.9%) cases, respectively. The sequence of anterior hormone deficiency was as follows: gonadotropin (68.4%), ACTH (63.2%), TSH (59.2%), GH (48.7%), and prolactin (42.1%). The median number of involved organs was 1.5, and the lung (18.4%), retroperitoneum (17.1%), kidney (15.8%), submandibular glands (14.5%), and pancreas (13.2%) were the common involved organs. Elevated IgG4 concentration and normal IgG4 level were in 42 (76.4%) and 13 (23.6%) cases, respectively. Patients with elevated serum IgG4 concentration were older (60.9 ± 14.3 vs 45.6 ± 17.4, p=0.001) and male-prone (78.6% vs 40.4%, p=0.003) and had a susceptibility of multiple organ involvement (78.6% vs 35.0%, p=0.001) compared to those with normal serum IgG4 levels. Males were older at disease onset (61.5 ± 12.6 vs 42.9 ± 18.8, p<0.001) and had a higher IgG4 concentration (425.0 vs 152.5, p=0.029) and a greater number of involved organs (2.0 vs 0.0, p=0.001), while isolated hypophysitis was more prominent in female (63.3% vs 26.1%, p=0.001). Conclusion. In this review, we found that there were different characteristics between different genders. Patients with elevated serum IgG4 level in terms of some clinical features were also different from those with normal serum IgG4 level. However, the data in this review were limited by bias and confounding. Further clinical studies with larger sample sizes are warranted.

IgG4-Related Kidney Disease: A Curious Case of Interstitial Nephritis with Hypocomplementemia

IgG4-related kidney disease has been relatively newly recognized over the last two decades as a combination of an autoimmune and allergic disorder, with elevated serum IgG4 level and hypocomplementemia among its characteristic features. Here we report the case of a man with interstitial nephritis presenting with acute kidney injury and hypocomplementemia but normal serum IgG4 level and provide a literature review of IgG4-related kidney disease. This case highlights the importance of IgG4-related kidney disease as an important differential diagnosis in any patient presenting with a clinical syndrome mimicking acute interstitial nephritis with hypocomplementemia. A high index of suspicion with a low threshold for performing a native kidney biopsy would be paramount as patients do respond well to corticosteroid therapy.