From the Research
An IgG4 level of 125 mg/dL is actually within the normal reference range and does not require specific treatment, as it is only mildly elevated and not diagnostic of IgG4-related disease (IgG4-RD) without characteristic clinical and histopathological findings. This level is not indicative of IgG4-RD, which typically requires levels above 135 mg/dL along with specific clinical and histopathological findings, as noted in studies such as 1. If the patient has no symptoms or clinical manifestations suggestive of IgG4-RD, such as:
- Autoimmune pancreatitis
- Retroperitoneal fibrosis
- Salivary/lacrimal gland enlargement simple monitoring with repeat IgG4 levels in 3-6 months is appropriate, as IgG4 levels alone are not diagnostic, with approximately 5% of healthy individuals having elevated levels, and some patients with confirmed IgG4-RD may have normal levels, as discussed in 2 and 3. If the patient develops symptoms concerning for IgG4-RD, further evaluation including:
- Imaging
- Possibly biopsy of affected organs would be warranted, followed by consideration of glucocorticoid therapy, typically prednisone 0.6 mg/kg/day, if IgG4-RD is confirmed, as suggested by 4 and 5.