Clinical features and capillary zone electrophoresis analysis of 10 patients with extremely elevated serum IgG4 levels

Abstract

Introduction and aims

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated condition often marked by elevated serum IgG4 levels and diverse clinical presentations, making diagnosis challenging, especially in patients without visible signs. This study aimed to summarize the characteristics of capillary zone electrophoresis (CZE) changes caused by high serum concentrations of immunoglobulin G4 (IgG4), provide experience and data for clinical practice, and identify patients with suspected IgG4-related disease (IgG4-RD) through the details of CZE changes.

Materials and methods

Ten patients with extremely elevated serum IgG4 levels were enrolled in this study. The clinical characteristics of these 10 patients were summarized, and the characteristics of CZE were analyzed.

Results

All 10 patients were men aged 32–82 years; of them, five had an obvious mass or lymph node enlargement on the body surface, while the remaining five patients had kidney lesions, enlarged lymph nodes in the mediastinum, and pancreatic tail occupation. The IgG4 values of the 10 patients were 15.3–80.6 g/L, 7.61–40.10 times higher than the upper limit of the reference range. The IgG levels were elevated in all cases, whereas the immunoglobulin A (IgA) and immunoglobulin M (IgM) levels were normal. The beta2 peak in CZE disappeared in all 10 cases. Instead, a broad basal bulge appeared where beta2 and gamma were connected and fused with the gamma region. With increasing IgG4 concentrations, the peak value of the bulge in this region increased.

Conclusion

The presence of a beta-gamma bridge in CZE, excluding the increases in IgA and IgM, indicates the presence of high serum IgG4 concentrations.