Alterations in the basement membrane zone in pili annulati hair follicles as demonstrated by electron microscopy and immunohistochemistry.
BACKGROUND
Pili annulati is a rare autosomal dominant inherited hair shaft abnormality in which clinical examination reveals alternating light and dark bands leading to a shiny appearance of the hair. The clinically light bands are the abnormal areas due to cavities within the cortex. The pathogenesis remains unknown.


OBJECTIVE
To investigate the expression of the basement membrane zone (BMZ) components in pili annulati hair follicles of the scalp.


METHODS
Transmission electron microscopy (TEM) was carried out on scalp sections of six individuals with pili annulati and six controls. Longitudinal sections of scalp tissues from four individuals with pili annulati and six normal controls were studied by immunohistochemistry with a panel of monoclonal antibodies to the following BMZ components: alpha(6)beta(4) integrin, laminin 5, LH39 antigen, laminin 1, collagen IV and collagen VII.


RESULTS
Using TEM, pili annulati scalp specimens exhibited a reduplicated lamina densa in the region of the root bulb in comparison with the single thin electron-dense band in controls. Using immunohistochemistry, there was a wavy BMZ in pili annulati follicles with antibodies to components of the lamina lucida, lamina densa and anchoring fibrils, whereas the BMZ in control hair follicles was as a smooth linear band. The expression of the hemidesmosome-associated alpha(6)beta(4) integrin was linear in both pili annulati and control hair follicles.


CONCLUSIONS
Our results suggest that the genetic defect may be a mutation in proteins involved in signalling and regulation of formation and degradation of the lamina densa and sublamina densa region resulting in abnormal assembly or remodelling of the BMZ.
Giehl
K A
KA
Department of Dermatology, Ludwig-Maximilian-University, 80337 Munich, Germany.
Ferguson
D J P
DJ
Dean
D
D
Chuang
Y H
YH
Allen
J
J
Berker
D A R D
DA
Tosti
A
A
Dawber
R P R
RP
Wojnarowska
F
F
D000328:Adult; D000911:Antibodies, Monoclonal; D001485:Basement Membrane / Q000473:pathology; D005260:Female; D018859:Hair Follicle / Q000002:abnormalities* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008854:Microscopy, Electron / Q000379:methods; D008875:Middle Aged; D012535:Scalp / Q000473:pathology
D000911:Antibodies, Monoclonal