• Written By: Kelvin Kam-lung Chong, MBChB, MRCS, FCOphth, FHKAM

    Given the recent surge in interest in using IgG4 positivity to evaluate orbital disorders, the authors sought to determine the clinicopathological characteristics of patients with ocular adnexal infiltration of IgG4-positive plasma cells.

    They prospectively classified 24 patients with ocular adnexal lymphoplasmacytic infiltrative lesions, including those with sclerosing inflammation and reactive lymphoid hyperplasia, based on their IgG4-related status - IgG4 related, indeterminate or unrelated - using two criteria.

    Patients with an elevated serum level of IgG4 of 135 mg/dL or greater and an IgG4:IgG ratio of infiltrating plasma cells of 30 percent or greater were classified as IgG4-related; 10 patients met this criteria. Five patients who met one but not both criteria were considered "indeterminate," and nine patients who did not meet either criteria were classified as IgG4-unrelated.

    Patients in the IgG4-related group more frequently had bilateral ocular adnexal lesions (P = 0.02), allergic diseases (P = 0.01) and elevated IgE serum levels (P = 0.01). Additionally, three patients in the IgG4-related group had polyclonal hypergammaglobulinemia, six had systemic lymphadenopathy or salivary gland enlargement and one developed autoimmune pancreatitis. Patients in the IgG4-unrelated group did not have these abnormalities.

    The authors conclude that ocular adnexal IgG4-related lymphoplasmacytic infiltrative disorder has different patterns of tissue involvement and systemic disease associations and possibly different prognoses than IgG4-unrelated lesions.

    Whether treatment response to irradiation or recurrence upon steroid cessation and future transformation to ocular adnexal lymphoma occur more frequently in the IgG4-related group still needs to be verified with larger numbers of patients and longer follow-up. The presence of IgG4-related features in serum and biopsy may reflect systemic immunological imbalance or activation, the underlying pathophysiology of which is still under investigation.