IgG4-related disease and pleural effusion: a systematic review

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that rarely affects the pleura, with pleural effusion (PE) reported in only 4% of cases. The characteristics of PE in patients with IgG4-RD are unknown. The objectives of this systematic review were to document the histological and biochemical characteristics of PF and pleural tissue, assess its clinical course, and determine the most effective treatments for the management of PE.

A PRISMA literature search was conducted for published articles describing the characteristics of PE in IgG4-RD and discussing the approach to PE in this setting.

A total of 46 articles [55 patients and 57 pleural fluid (PF) samples] were included. Median age was 66 years (range, 28-86 years), with a male/female ratio of 2.9:1. PE was predominantly right-sided or bilateral (81.3%) and usually occupied <2/3 of the hemithorax (78.9%). PF generally had a serous appearance (84.2%) and was an exudate in 94.6% of cases with predominance (≥50%) of mononucleated cells in 96% (24/25). A predominance of eosinophils (≥10%) was observed in 40% (4/10 cases). As many as 66.7% of patients presented values of adenosine deaminase (ADA) ≥35 U/L (18/27), pH values remained within normal range 7.35-7.45 (15.4%) in only two patients. Three patients had glucose values <60 mg/dL (12.5%) and the PF of two patients was a chylothorax. Pleural biopsy was consistent with diagnosis in 95.6% of cases (43/45). In total, 92.7% of patients (51/55) received treatment with corticosteroids, and 9 (17.6%) received immunosuppressants. Of the four cases left untreated, 2 underwent chest drainage. Clinical course was benign in 97.7% of patients (43/44; a patient died of unknown causes).

Patients with IgG4-RD and PE are usually men over 50 years of age with small/moderate, right-sided or bilateral PE. PF is most commonly a lymphocytic exudate with elevated ADA values. Pleural biopsy can help establish diagnosis. Treatment with corticosteroids, combined or not with immunosuppressants, was usually effective.