Bullous pemphigoid associated with systemic lupus erythematosus: the discrimination of antibasement membrane zone antibody

The significance of preclinical anti-BP180 autoantibodies

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering disease. Although the pathomechanism of BP onset has yet to be elucidated in detail, BP autoantibodies targeting two hemidesmosomal components, BP180 and BP230, are known to play a pivotal role in BP pathogenesis. Thus, the detection and measurement of BP autoantibodies are necessary for diagnosing BP and monitoring the disease activity. Immune assays such as immunofluorescence microscopy, immunoblotting, and ELISAs using BP180 and BP230 detect BP autoantibodies in most BP cases with high specificity; however, BP autoantibodies are sometimes detected in BP patients before the onset of this disease. BP autoantibodies that are detected in patients without typical tense blisters are defined as “preclinical BP autoantibodies”. These preclinical BP autoantibodies are detected even in a low percentage of normal healthy individuals. Although the importance of preclinical BP autoantibodies remains elusive, these autoantibodies might be a potential risk factor for subsequent BP development. Therefore, previous comparative epidemiological studies have focused on the prevalence of preclinical BP autoantibodies in populations susceptible to BP (e.g., the elderly) or in diseases with a higher risk of comorbid BP. This mini-review summarizes the literature on the prevalence of preclinical BP autoantibodies in patients with various conditions and diseases, and we discuss the significance of preclinical BP autoantibody detection.

Diffuse Bullous Eruptions in an Elderly Woman: Late-Onset Bullous Systemic Lupus Erythematosus

Vesiculobullous eruptions in the elderly represent a diverse range of varying pathophysiologies and can present a significant clinical dilemma to the diagnostician. Diagnosis requires a careful review of clinical history, attention to detail on physical and histomorphological examination, and appropriate immunofluorescence testing. We describe the case of a 73-year-old female who presented to our hospital with a painful blistering skin rash developed over 2 days. Examination of the skin was remarkable for numerous flaccid hemorrhagic bullae on a normal-appearing nonerythematous skin involving both the upper and lower extremities. Histopathology of the biopsy lesion showed interface change at the epidermo-dermal region with subepidermal blister formation, mild dermal fibrosis, and sparse interstitial neutrophilic infiltrate. Immunohistological analysis was significant for positive IgG basement membrane zone antibodies with a dermal pattern of localization on direct immunofluorescence and positive IgG antinuclear antibodies on indirect immunofluorescence. Evidence of antibodies to type VII collagen suggested the diagnosis of epidermolysis bullosa acquisita versus bullous systemic lupus erythematosus (BSLE). A diagnosis of BSLE was made based on positive American College of Rheumatology criteria, acquired vesiculo-bullous eruptions with compatible histopathological and immunofluorescence findings. This case illustrates one of many difficulties a physician encounters while arriving at a diagnosis from a myriad of immunobullous dermatoses. Also, it is important for internists and dermatologists alike to be aware of and differentiate this uncommon and nonspecific cutaneous SLE manifestation from a myriad of disorders presenting with vesiculobullous skin eruptions in the elderly.

Relationship between target antigens and major histocompatibility complex (MHC) class II genes in producing two pathogenic antibodies simultaneously

In this report,we present 15 patients with histological and immunopathologically proven pemphigus vulgaris (PV). After a mean of 80 months since the onset of disease, when evaluated serologically, they had antibodies typical of PV and pemphigoid (Pg). Similarly, 18 patients with bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP) were diagnosed on the basis of histology and immunopathology.After a mean of 60 months since the onset of disease, when their sera were evaluated they were found to have Pg and PV autoantibodies. In both groups of patients the diseases were characterized by a chronic course, which included several relapses and recurrences and were non-responsive to conventional therapy. The major histocompatibility complex class II (MHC II) genes were studied in both groups of patients and phenotypes associated typically with them were observed. Hence, in 33 patients, two different pathogenic autoantibodies were detected simultaneously. The authors provide a computer model to show that each MHC II gene has relevant epitopes that recognize the antigens associated with both diseases. Using the databases in these computer models, the authors present the hypothesis that these two autoantibodies are produced simultaneously due to the phenomena of epitope spreading.

Bullous Pemphigoid

Bullous pemphigoid (BP) is a chronic, autoimmune, blistering disease observed primarily in the elderly population. Several clinical variants have been described, including classic (bullous), localised, nodular, vegetating, erythrodermic, erosive, childhood and drug-induced forms. Autoantibodies target the BP230 and BP180 antigens, located in the hemidesmosomal complex of the skin basement membrane zone. Subsequent complement activation recruits chemical and cellular immune mediators to the skin, ultimately resulting in blister formation. Both autoantibodies and complement may be detected by various immunofluorescent, immune electron microscopy and molecular biology techniques. Recent trials suggest that potent topical corticosteroids should be considered as first-line therapy. Tetracycline with or without nicotinamide may benefit a subset of patients with mild BP. Oral corticosteroids should rarely exceed 0.75 mg/kg/day and corticosteroid-sparing agents may be useful for recalcitrant disease.