Role of BIOCHIP Indirect Immunofluorescence Test in Cutaneous Vesiculobullous Diseases

BIOCHIP mosaics for indirect immunofluorescence in cutaneous vesiculobullous diseases provide antibody profiles in a single run and can be an alternative to performing multistep assays. There is scanty data regarding their utility. BIOCHIP tests performed over 4 years were compared with biopsy and/or direct immunofluorescence (DIF). Of 209 BIOCHIP tests, 108 were positive. Pemphigus vulgaris and Bullous pemphigoid were the commonest. Dsg3 was the commonest positive substrate in pemphigus group (86%) with 100% sensitivity. Intercellular space pattern on BIOCHIP primate esophagus was seen only in 49%. BP 180 was the commonest positive substrate in pemphigoid (95%) with 78% sensitivity. In 68 cases, corresponding biopsy/DIF was available with concordance of 89% in pemphigus and 93% in pemphigoid groups. In 40 cases where BIOCHIP was positive without biopsy/DIF, 97.5% were concordant with clinical diagnosis. Among the negative results, 13 had biopsy/DIF that were diagnostic. The overall positivity of BIOCHIP was 92% for pemphigus and 84% for pemphigoid groups. Indirect immunofluorescence by BIOCHIP method shows good concordance with histopathology/DIF. However, the sensitivity of some of the substrates varies. It is an effective screening tool to identify cases requiring further ELISA/immunoblots or where biopsy is not feasible.