Utility of oral mucosa as a substrate for the serodiagnosis of pemphigus: A descriptive analysis.

BACKGROUND: The indirect immunofluorescence test is useful in the serodiagnosis of pemphigus. As indirect immunofluorescence titers correlate with disease activity in pemphigus, it is often used as a monitoring tool. The sensitivity of indirect immunofluorescence depends on the substrate used, and the preferred substrates are monkey esophagus for pemphigus vulgaris and normal human skin for pemphigus foliaceus. AIMS: We evaluated oral mucosa as a substrate for indirect immunofluorescence in pemphigus. METHODS: Fifty patients with pemphigus (40 with pemphigus vulgaris and ten with pemphigus foliaceus) and 50 controls were enrolled for study. Demographic and clinical details were recorded and indirect immunofluorescence using two substrates (oral mucosa and normal human skin) was carried out in serial dilution. Desmoglein (Dsg) 1 and 3 enzyme-linked immunosorbent assay was also evaluated simultaneously. RESULTS: Indirect immunofluorescence was positive in 40 patients (80%) with oral mucosa substrate and 34 patients (68%) with normal human skin substrate. Circulating antibodies were detected with oral mucosa in 33 (82.5%) of the 40 pemphigus vulgaris patients and in 26 (65%) patients using normal human skin. Antibodies were detected in eight of the ten pemphigus foliaceus patients (80%) with normal human skin and in seven (70%) patients with oral mucosa. Dsg enzyme-linked immunosorbent assay was positive in 45 (90%) patients, and 37 of these were also indirect immunofluorescence positive with oral mucosa. In the five Dsg enzyme-linked immunosorbent assay-negative patients, indirect immunofluorescence with oral mucosa was positive in three. LIMITATIONS: A comparison of oral mucosa with monkey esophagus could not be performed. CONCLUSION: Oral mucosa is a suitable and sensitive substrate for indirect immunofluorescence in pemphigus. Further studies comparing the sensitivity of indirect immunofluorescence using oral mucosa with monkey esophagus are recommended.

Serration pattern analysis as a practical adjunct tool for categorization of subepidermal autoimmune blistering diseases.

BACKGROUND: Serration pattern analysis helps in the classification of subepidermal autoimmune blistering disorders; more precisely, it helps to differentiate epidermolysis bullosa acquisita from other subepidermal autoimmune blistering disorders. Most of the published reports of this tool have come from a single center. OBJECTIVES: The objectives of the study were to study the utility of serration pattern analysis in classifying subepidermal autoimmune blistering disorders. METHODS: Seventy five cases of subepidermal autoimmune blistering disorders were enrolled in this prospective study. A three millimeter punch biopsy was taken from the perilesional skin or mucosa for direct immunofluorescence; indirect immunofluorescence was carried out using salt-split skin. Subclassification of subepidermal autoimmune blistering disorders was done based on direct immunofluorescence, indirect immunofluorescence on salt-split skin, indirect immunofluorescence using knockout skin and serration pattern analysis findings. RESULTS: Indirect immunofluorescence was positive in 68 cases; 14 cases showed a dermal staining pattern while the rest showed either an epidermal or a combined pattern. All patients with epidermal or combined staining patterns showed "n" serrated pattern on direct immunofluorescence. Nine patients with dermal staining on indirect immunofluorescence also revealed an "n" serration pattern on direct immunofluorescence indicating the diagnosis of anti-p200 pemphigoid, and the rest showed a "u" serrated pattern. Three patients with negative indirect immunofluorescence showed "u" serration on direct immunofluorescence while the rest showed "n" serration. LIMITATIONS: ELISA and immunoblotting could not be performed due to resource constraints. CONCLUSION: Based on indirect immunofluorescence and serration pattern analysis, classification of the majority of patients with subepidermal autoimmune blistering disorders was possible in our study. Pattern recognition is a cost-effective tool and can be easily learnt. It is recommended to be practiced in all laboratories where facilities for advanced immunological diagnosis are unavailable.