To explore the diagnostic features of IgG4-related diseases (IgG4-RD).

The clinical data of IgG4-RD patients treated in the Second Hospital of Shanxi Medical University from April 2014 to September 2020 were retrospectively analyzed, and the patients were divided into a confirmed case group and a probable confirmed case group (including probable and suspected diagnosis). The differences in age, gender, duration of disease and IgG4 levels between the 2 groups were observed. The relationship between the number of organs involved and the duration of the disease was analyzed by the Spearman correlation, and the relationship between the number of organs involved and the level of IgG4 was analyzed by the Kruskal-Wallis H test.

Among the 68 patients with IgG4-RD, the male to female sex ratio was 1.27∶1, and the median age was 59(50, 65) years. In 29 cases (42.65%) and 11 cases (16.18%), mandibular and eyelid enlargement were the first clinical manifestations, respectively. Other clinical manifestations included abdominal pain, abdominal distention, jaundice, shoulder and back pain, nasal congestion, runny nose, blurred vision, pharyngeal foreign body sensation, angina, rash, shortness of breath, uroparesis were also observed, the most commonly affected organs in 37 cases (54.41%), followed by the submandibular gland in 29 cases (42.65%), pancreaticobiliary ducts in 15 cases (22.06%), lacrimal glands in 11 cases (16.18%), parotid glands in 8 cases (11.76%), and retroperitoneal fibrosis in 7 cases (10.29%). Serum IgG4 levels in 47 cases (69.12%) were more than 1 350 mg/L. Local ultrasound exploration or CT/MRI imaging may showed one or more organs with localized or diffuse enlargement, nodules, wall thickening, soft tissue shadowing next to the involved organ, and enlarged lymph nodes. At the location where 55 cases′ pathological specimens were collected, submandibular glands (29/55, 52.73%), orbital masses (11/55, 20.00%), and pancreas (8/55, 14.55%) were frequent. Pathological manifestations included lymphocytic and plasma cell infiltration, as well as eosinophilic infiltration and fibrous tissue hyperplasia in some cases. Immunohistochemical staining showed that there were 20-50/HPF, IgG4⁺ /IgG⁺ 20%-50%. Most patients improved after being treated with hormones or combined immunosuppressants. Two elderly patients died due to obstructive nephropathy and chronic renal failure. Among the 34 confirmed patients, Spearman correlation analysis revealed a significant correlation between the duration of the disease and the number of organs involved (r=0.33, P=0.005). The Kruskal-Wallis H test showed no statistically significant difference between the numbers of organs involved and IgG4 levels (H=4.73, P=0.192).

The clinical manifestations of IgG4-RD are highly heterogeneous, and the level of IgG4 cannot be used to assess the severity of the disease.