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The basement membrane zone (BMZ) of the skin is a dynamic area of research. It is the anchoring complex joining the epidermis and derms of the skin. To best understand the importance of the different components of the BMZ, the corresponding disease states are included. The anchoring complex is composed of the hemidesmosomes, anchoring filaments, and anchoring fibrils. See the keratinocyte for more information regarding the hemidesmosome.


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The basic structure of the BMZ is an interaction between the following structures:

Component Description
Basal keratinocytes-epidermal side BP180
Basal keratinocytes-dermal side BP180/NC16A
alpha6beta4 integrin
Lamina lucida p200
Laminin 6
Lamina densa BP180
Laminin 5
Sublamina densa Collagen type VII
Dermal collagen including collagen type IV
Components spanning the BMZ
(transmembrane proteins)


Proteins Localized to the Hemidesmosome Plectin
alpha6beta4 integrin


Basement Membrane Components Type IV collagen-Lamina densa
Laminin-Lamina lucida
Heparan sulfate-Clusters on either side of LD
Bullous pemphigoid antigen-Basal cell plasma membrane
EBA antigen-Lamina densa-sublamina densa
  Bullous pemphigoid antigens
Laminin 5
Ladinin (LAD-1)
EBA antigen
Bullous Pemphigoid Antigen  
BPAg1 (230kd)
Intracellular associated with hemidesmosomes
Homology with desmoplakin
70% of BP pts have circulating Ab to this
BPAg2 (180kd)
Intra and extracellular with collagen-like domains
Also called collagen XVII
Extramembranous protion is antigenic epitope site for BP and HG
Laminin 5 Lamina lucida
Identical to epiligrin
Also called BM600, nicein, and kalinin
Antibodies found in:
Antiepiligrin cicatricial pemphigoid
Some forms of junctional EB
Uncein Anchoring filament related to laminin 5
Antibodies found in:
Overlap syndrome with features of CP and EBA
Ladinin (LAD-1) Component of anchoring filaments
Lamina lucida
Antibodies found in:
Linear IgA disease
Chronic bullous disease of childhood
EBA Antigen Within and subjacent to lamina densa
Constituent molecule of anchoring fibrils attaching BM to underlying dermis Noncollagenous domain of type VII collagen
Mainly synthesized by keratinocytes

The pathologist has a number of tools that can further identify the location of some of these structures.


Epidermal side of split Bullous pemphigoid
Pemphigoid gestationis
Lichen planus pemphigoides
Dermal side of split Epidermolysis bullosa acquisita
Anti-p200 pemphigoid
Anti-p105 pemphigoid
Both epidermal and dermal Linear IgA disease
Cicatricial pemphigoid
Bullous SLE

When these structures and proteins are studied in detail, it is easy to understand why this Salt Split Skin technique has localization of the various components to the epidermal, dermal, or both sides of the BMZ.

Molecular Interactions Autoimmune Disorder Genetic Disease Affected Gene Variant of Epidermolysis bullosa (EB)
Keratin intermediate filaments, micortubules, actin, BP180, beta4 integrin Paraneoplastic pemphigus EB with muscular dystrophy
EB Ogna ?
PLEC1 Hemidesmosomal
Keratin intermediate filaments, BP180 Bullous pemphigoid
Pemphigoid gestationis
Lichen planus pemphigoides
Linear IgA disease
Cicatricial pemphigoid
- - -
alpha6beta4 integrin, BP230, plectin, laminin Bullous pemphigoid
Pemphigoid gestationis
Lichen planus pemphigoides
Linear IgA disease
Cicatricial pemphigoid
Generalized atrophic benign EB (GABEB) COL17A1 Hemidesmosomal

beta4 integrin, BP180, NC16A, laminin 5

alpha6 integrin, BP180, plectin, laminin5

Cicatricial pemphigoid EB with pyloric atresia ITGA6
Laminin 6, alpha6beta4 integrin, BP180, type VII collagen Cicatricial pemphigoid
Bullous SLE
Herlitz Junctional EB, GABEB, Localized junctional EB LAMA3
Laminin 5 Cicatricial pemphigoid
Bullous SLE
- - -
Laminin 5, type IV collagen EBA
Bullous SLE
Dystrophic EB COL7A1 Dystrophic

Adv Dermatol 2000; 16;113-157.
Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Ninth Edition. Mosby 2004.
Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 6th Edition. McGraw-Hill. 2003.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

Commonly Used Terms

Alpha6beta4 integrin-Beta 4 integrin subunit is noncovalently bound to alpha6 subunit. Trasmembrane alpha6beta4 integrin interacts with the anchoring complex (BP180, plectin, laminin 5). Also plays a role in hemidesmosome assembly. After ligation with laminin 5, it is important for cell proliferation, differentiation, and migration.


Collagen VII-Collagen variant present in the skin basement membrane within the anchoring fibrils.


Laminin 5-Widely distributed in various epithelia. Localizes to the anchoring filaments of the lamina lucida and also within the lamina densa of the basement membrane zone.

Plectin-Cytoskeletal linker protein in skin and muscle-member of the plakin family. Located in the hemidesmosomal and hemidesmosomal plaques interacting with the cytoskeletal proteins. Separation occurs at the level of the hemidesmosomal plaque

Salt split skin assay-Normal skin incubated with 1M NaCl which separates the epidermis from dermis. The epidermal half contains the upper lamina lucida, hemidesmosomes, and BP antigen. The dermal half contains laminin 5, lamina densa, and anchoring fibrils.


Basic Principles of Disease
Learn the basic disease classifications of cancers, infections, and inflammation

Commonly Used Terms
This is a glossary of terms often found in a pathology report.

Diagnostic Process
Learn how a pathologist makes a diagnosis using a microscope

Surgical Pathology Report
Examine an actual biopsy report to understand what each section means

Special Stains
Understand the tools the pathologist utilizes to aid in the diagnosis

How Accurate is My Report?
Pathologists actively oversee every area of the laboratory to ensure your report is accurate

Got Path?
Recent teaching cases and lectures presented in conferences

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Last Updated April 10, 2006

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