IgG4-related disease: a rheumatologist's perspective.

OBJECTIVES: Given that the clinical features of several IgG4-related diseases (IgG4-RD) can mimic those of autoimmune disorders, the aim of this study was to find possible distinguishing characteristics that would help us identify such cases from the pool of patients in a rheumatology clinic. METHODS: From our clinic's medical records, we identified patients who fulfilled the recently published diagnostic criteria for IgG4-RD. We recorded their presenting features, co-morbid conditions, laboratory, radiologic and histologic findings as well as their treatment and outcome. RESULTS: We identified 11 cases of IgG4-RD: 4 cases of IgG4-related autoimmune pancreatitis (AIP), 5 cases of IgG4-related retroperitoneal fibrosis (RPF)/ periaortitis, 2 cases of IgG4-related sialadenitis and one of IgG4-related interstitial nephritis. 5 out of the 11 patients had been diagnosed with an autoimmune disease, namely rheumatoid arthritis (RA), Sjogren's syndrome (SS) and antiphospholipid syndrome (APS). 3 out of 11 patients were subsequently diagnosed with neoplastic disorders. All patients with IgG4-related AIP had raised CRP levels at presentation. Presenting features of RPF/periaortitis patients were constitutional symptoms, abnormal renal function, hypertension and back pain. Patients with IgG4-related sialadenitis had clinical features mimicking SS. The majority of patients had a favourable response to steroids. CONCLUSIONS: We present common IgG4-RD presentations in the setting of a rheumatology clinic. Increased awareness may avoid delay in diagnosis.

Interstitial lung disease in a patient with antisynthetase syndrome and no myositis.

Interstitial lung disease in patients with antisynthetase syndrome and no evidence of myositis is rare and may precede other disease manifestations. We report a patient who initially presented with symptoms primarily related to lung involvement. The diagnosis of the antisynthetase syndrome without myositis was made many months later when he developed a characteristic hand rash (mechanic's hands), which was confirmed by positive antibodies to Jo-1. With treatment, both the hand rash and the interstitial lung disease improved. Antisynthetase syndrome should be considered in patients presenting with interstitial lung disease with no evidence of myositis. Appropriate laboratory testing with measurement of specific autoantibodies may help in the early diagnosis and treatment of the syndrome.

Autoimmune manifestations in common variable immunodeficiency.

Common variable immunodeficiency (CVID) is a disorder characterized by decreased serum immunoglobulin concentrations and increased incidence of recurrent infections. Interestingly 20-25% of patients with CVID develop clinical features suggestive of an autoimmune disease. Although this association is well established, the immunodeficiency background of CVID patients manifesting autoimmune disorders is often overlooked. This study describes three CVID patients displaying a variety of autoimmune manifestations. The pathophysiologic mechanisms of autoimmunity in CVID are also reviewed.