Immunofluorescence study of pemphigus from north India.

Both serum studies by indirect immunofluorescence (IIF) tests and skin biopsy examination by direct immunofluorescence (DIF) were performed on 22 cases of pemphigus with clinically active lesions. Twenty cases had pemphigus vulgaris and two, pemphigus foliaceus. The majority of cases (70%) were between 21 and 60 years old; the mean age was 39.5 ± 12.7 years. There was no sex predilection. DIF showed the positive fluorescence of intercellular cement substance (ICS) of the epidermis in all 22 cases (100%). IgG was positive in 77.27%, followed sequentially by C3C (50%), IgA (45.45%), and IgM (36.36%). Six cases (27.27%) also showed granular immunoglobulin and/or complement deposits at the dermoepidermal junction. IIF detected serum antiepithelial antibodies in 18 cases (81.81%) using human esophagus as substrate. Most of these cases (88.88%) showed IgG type of antibodies; the other 11.11% exhibited IgA and IgM in low concentrations. 1+ titer positivity was observed in 15 cases. This study demonstrates the value of DIF for a definitive diagnosis of pemphigus. However, it is also important to appreciate that immunofluorescence is not a substitute for histopathology, but rather complementary to it.