Detection of in vivo IgG1 antinuclear antibodies may have diagnostic utility in oral biopsies from patients with suspected chronic ulcerative stomatitis or systemic autoimmune connective tissue disease.

Diagnosis of immune mediated diseases involving the oral cavity often relies on evaluating biopsied H&E stained tissue and direct immunofluorescence. Patients with chronic ulcerative stomatitis (CUS) or systemic autoimmune connective tissue diseases (ACTDs) may show immune deposits within epithelial nuclei. The IgG subclasses associated with these in vivo ANA reaction patterns are not well defined. We performed a retrospective chart review to determine whether IgG1 and IgG4 were preferentially deposited in oral biopsies interpreted as CUS or systemic ACTD. Among 45 cases identified, 24 (53%) showed IgG, IgG1, and IgG4. IgG and IgG1 were present in 17 cases (37%), while one case (2%) showed IgG1 and IgG4 without IgG. Notably, at least one of the biopsies from 11 cases (24%) demonstrated IgG1 in epithelial nuclei in the absence of IgG or IgG4. These findings indicate that detecting IgG1 may improve diagnostic sensitivity for CUS and ACTDs in oral biopsies.