Direct immunofluorescence analysis of oral Tzanck smears for pemphigus vulgaris: A diagnostic test.

BACKGROUND

Pemphigus vulgaris (PV) is a rare and potentially fatal autoimmune blistering disease. Direct immunofluorescence (DIF) and histopathological analysis are crucial methods for PV diagnosis, but oral tissue biopsy is difficult to perform because of the fragile characteristics of the oral mucosa. However, no well-designed diagnostic studies addressing the validity of DIF analysis of oral Tzanck smears for the diagnosis of PV exist. We aimed to design a diagnostic test based on DIF analysis combined with oral Tzanck smears and evaluate its diagnostic accuracy for PV.

METHODS

We enrolled 81 patients with oral erosive lesions, of whom 41 patients had PV and 40 were non-PV controls. Oral Tzanck smears were obtained from oral mucosal lesions and observed under a fluorescence microscope after fixing and fluorescence staining. The diagnostic efficacy indexes including sensitivity, specificity, predictive value, Youden index, diagnostic odds ratio, and likelihood ratio were calculated.

RESULTS

Of the 41 PV patients, 36 showed DIF-positive findings for oral Tzanck smears, and all 36 DIF-positive PV patients showed IgG and/or C3 deposition, with seven also showing IgA and/or IgM positivity. None of the non-PV controls showed DIF positivity. The sensitivity and specificity of DIF analysis with oral Tzanck smears were 87.80% and 100%, respectively. The area under the receiver operator characteristic curve (ROC) was 0.939, with the test demonstrating significantly high diagnostic efficacy.

CONCLUSION

DIF analysis of oral Tzanck smears is a minimally invasive and easy-to-operate technique that can assist the rapid and accurate diagnosis of PV in dental clinic.