Anti-BP180 NC16A IgG Titres as an Indicator of Disease Activity and Outcome in Asian Patients with Bullous Pemphigoid.

INTRODUCTION: Anti-BP180 IgG titres were observed to parallel disease activity in case series of bullous pemphigoid (BP). This study aimed to examine whether anti-BP180 titres are an indicator of disease severity, clinical course and outcome in Asian patients with BP.

MATERIALS AND METHODS: This was a prospective observational study conducted between March 2005 and March 2008 in the Immunodermatology Clinic at the National Skin Centre, Singapore. Disease activity and anti-BP180 IgG titres were measured 4-weekly for 12 weeks and during disease flares and clinical remission. Associations between anti-BP180 titres and disease activity, disease flare, clinical remission and cumulative prednisolone dose were examined.

RESULTS: Thirty-four patients with newly diagnosed BP were recruited. Median follow-up duration was 3 years. Notable correlations between disease activity and anti-BP180 titres were at baseline (r = 0.51, P = 0.002), and disease flare (r = 0.85, P <0.001). Lower titres at Week 12 were associated with greater likelihood of clinical remission (P = 0.036). Post hoc, patients with anti-BP180 titres above 87.5 U/mL at time of diagnosis who reached remission within 2 years of diagnosis received significantly higher cumulative doses (mg/kg) of prednisolone (median, 72.8; range, 56.5 to 127.1) than those with titres <87.5 U/mL (median, 44.6; range, 32.5 to 80.8); P = 0.025).

CONCLUSION: Anti-BP180 titres may be a useful indicator of disease activity at time of diagnosis and at disease flare. Lower titres at Week 12 may predict greater likelihood of clinical remission. Titres above 87.5 U/mL at time of diagnosis may suggest the need for higher cumulative doses of prednisolone to achieve remission within 2 years.