By Disease Name > Linear IgA Disease

Linear IgA Disease

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•IgA = the predominant immunoglobulin of the secretory immune system
•IgA1 subclass (vs. mucosal IgA2)

 

clinical:

•rare;  average age of onset >60
•oral lesions present in 70% of cases (common in CBDC as well)
•the pattern of annular bullae is said to be characteristic
•clinical manifestations variable:  can present with phenotypic characteristics of EBA epidemolysis bullosa acquisita, DH dermaitis herpetiformis, BP, or CP cicatrical pemphigoid

 

histology:

•sub-epidermal blister, neutrophils (virtually indistinguishable from DH and CBDC chronic bullous disease of childhood)
•DIF:  linear IgA at DE junction
•IIF: circulating anti-BMZ antibodies in 60-70%

 

pathology:

•multiple antigens:
•roof of salt split – 97kd (= identical to part of the extracellular domain of BP2 antigen)
•dermal side of salt split – a 290kd antigen which is different than type VII collagen

 

 

ddx:

•Bullous Pemphigoid but BP has: linear IgG along BMZ; circulating IgG in 60-70%
•Dermatitis Herpetiformis but in DH: oral lesions uncommon; granular IgA at dermal papillary tips; no circulating antibodies that bind to skin
•EM; bullous LE
•drug induced linear IgA bullous dermatosis (vancomycin, lithium)

 

CHRONIC BULLOUS DISEASE OF CHILDHOOD

•may be same disease occurring in different age group  (<5 years old)
•circulating IgA antibodies binding to same antigens;  identical pattern of homogenous linear IgA deposits
•rare;  HLA-B8

 

clinical:

•tense blisters on inflammatory base;  most frequently in the perineum and perioral region
•often in cluster giving a “cluster of jewels” appearance