ABSTRACT
BACKGROUND: A novel chemiluminescent enzyme immunoassay (CLEIA) was recently developed to quantify autoantibodies specific for desmogleins (Dsgs) and BP180, the target antigens of pemphigus and pemphigoid. This assay is automated and highly accurate and efficient. OBJECTIVE: To validate the use of the CLEIA for detection of autoantibodies during the clinical courses of patients with pemphigus and pemphigoid. METHODS: To define cut-off values for Dsg1, Dsg3, and BP180, we evaluated 47 serum samples from patients with pemphigus foliaceus (PF), 59 from those with pemphigus vulgaris (PV), 52 from those with bullous pemphigoid (BP), and 995 from healthy individuals. We also evaluated any fluctuations in CLEIA titers according to disease activity during the clinical course of 10 cases each of PF, PV, and BP. We used clinical symptom scores, the pemphigus disease area index (PDAI) and the bullous pemphigoid disease area index (BPDAI), to evaluate disease activity. RESULTS: The cut-off values for the CLEIA titers determined by the Youden index were 15.4U/mL for Dsg1, 14.9U/mL for Dsg3, and 16.8U/mL for BP180. CLEIA titers fluctuated in parallel with the PDAI/BPDAI scores in 28 of the 30 cases with PF, PV, or BP. Although the CLEIA and enzyme-linked immunosorbent assay (ELISA) values in the same samples differed substantially in some cases, the concordance rates of positive/negative results between the CLEIA and ELISA were 96% for Dsg1, 97% for Dsg3, and 96% for BP180. CONCLUSION: The CLEIA, a newly developed, highly effective autoantibody detection system, is as reliable as ELISA for evaluation of the clinical courses of pemphigus and pemphigoid.
Subject(s)
Autoantibodies/blood , Immunoenzyme Techniques/methods , Luminescent Measurements/methods , Pemphigoid, Bullous/diagnosis , Pemphigus/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Autoantigens/immunology , Child , Child, Preschool , Desmoglein 1/immunology , Desmoglein 3/immunology , Enzyme-Linked Immunosorbent Assay , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Non-Fibrillar Collagens/immunology , Pemphigoid, Bullous/blood , Pemphigoid, Bullous/immunology , Pemphigus/blood , Pemphigus/immunology , Reproducibility of Results , Sensitivity and Specificity , Young Adult , Collagen Type XVIIABSTRACT
OBJECTIVES: To confirm that sera from some BP patients reactive exclusively to the BP230 and to study the clinical and immunological characteristics of this condition. MATERIALS AND METHODS: BP patients were divided into three groups: BP reactive only to BP230 (BP230-BP), BP reactive to both BP180 and BP230 (BP180-BP230-BP) and BP reactive only to BP180 (BP180-BP), based on the results of standard ELISAs for BP180 and BP230. Clinical features were statistically analyzed among the three groups. Then, targeted epitopes in each group were studied by immunoblotting and novel ELISAs using three domain-specific BP230 recombinant proteins. RESULTS: Forty-one, 65 and 47 of 153 BP patients were categorized as BP230-BP, BP180-BP230-BP and BP180-BP, respectively. Clinically, BP230-BP patients showed significantly lower severity, less need of systemic steroids and better responses to various treatments, suggesting that BP230-BP is a milder condition. Immunoblotting and ELISAs of domain-specific BP230 recombinant proteins indicated that, while BP180-BP230-BP sera reacted with all three domains of BP230, BP230-BP sera reacted more frequently with epitopes in the BP230 C-terminal domain. CONCLUSION: We propose a new disease entity, named anti-BP230-type BP, in which anti-BP230 antibodies might be pathogenic and react specifically with the BP230 C-terminal domain. While anti-BP230 antibodies in BP180-BP230-BP seem to be produced via intermolecular epitope spreading, anti-BP230 antibodies in BP230-BP are considered to be produced by different mechanisms.
