IgG anti-laminin-332 autoantibodies are present in a subset of patients with mucous membrane, but not bullous, pemphigoid.
BACKGROUND
Antiepiligrin cicatricial pemphigoid is a mucosal-predominant subepidermal blistering disease associated with an increased relative risk of cancer. In contrast to prior reports showing that anti-laminin (L)-332 autoantibodies are a reliable marker for patients with antiepiligrin cicatricial pemphigoid, a recent report suggested that as many as 40% of patients with bullous pemphigoid (BP) have IgG reactive with this laminin isoform.


OBJECTIVE
We sought to determine whether patients with BP possess circulating IgG anti-L-332 autoantibodies.


METHODS
Sera from 100 adults with BP were analyzed by indirect immunofluorescence testing of intact skin, immunoblot studies of human keratinocyte (HK) extracts, and a new L-332 enzyme-linked immunosorbent assay. Sera showing reactivity suggestive of anti-L-332 autoantibodies in these assays were further analyzed in immunoblot studies of HK extracellular matrix and immunoprecipitation studies of biosynthetically radiolabeled HK extracts.


RESULTS
IgG from all patients with BP bound intact epidermal basement membrane by indirect immunofluorescence microscopy and immunoblotted bullous pemphigoid antigen-1, -2, or both in HK extracts. None of these sera immunoblotted L-332 in HK extracts, although 13 did score above the cut point of a new IgG(4) L-332 enzyme-linked immunosorbent assay (sensitivity = 0.91, specificity = 0.98, Youden index = 0.89). Further analysis of sera from these 13 patients found: (1) all had IgG that bound the epidermal side of 1 mol/L NaCl split skin by indirect immunofluorescence microscopy; (2) none immunoblotted L-332 purified from HK extracellular matrix; and (3) none immunoprecipitated L-332 from biosynthetically radiolabeled HK extracts.


CONCLUSIONS
The basis of false-positive enzyme-linked immunosorbent assay determinations for anti-L-332 IgG among patients with BP is unknown.


CONCLUSIONS
Anti-L-332 autoantibodies remain a reliable marker for patients with antiepiligrin cicatricial pemphigoid.
Lazarova
Zelmira
Z
Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Salato
Valerie K
VK
Lanschuetzer
Christoph M
CM
Janson
Marleen
M
Fairley
Janet A
JA
Yancey
Kim B
KB
D001323:Autoantibodies / Q000097:blood*; D015815:Cell Adhesion Molecules / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D009092:Mucous Membrane; D010391:Pemphigoid, Bullous / Q000097:blood*; D000097794:Kalinin
D001323:Autoantibodies; D015815:Cell Adhesion Molecules; D007074:Immunoglobulin G; D000097794:Kalinin