LEKTI demonstrable by immunohistochemistry of the skin: a potential diagnostic skin test for Netherton syndrome.
BACKGROUND
Netherton syndrome (NS) is a rare autosomal recessive condition characterized by ichthyosiform erythroderma, trichorrhexis invaginata and atopic manifestations. Confirming the diagnosis may be difficult in the early stages. Mutations in the SPINK5 gene which encodes for the serine protease inhibitor LEKTI are associated with NS. These mutations create premature termination codons which result in absent or abnormal expression of LEKTI in patients with NS.


OBJECTIVE
To investigate the expression of LEKTI in the skin of patients with NS in comparison with normal controls and patients with other skin conditions, namely atopic dermatitis, psoriasis and nonbullous ichthyosiform erythroderma.


METHODS
Immunohistochemistry was performed on skin sections from four patients with NS, four normal controls, four with atopic dermatitis, two with psoriasis and two with nonbullous ichthyosiform erythroderma, using a primary rabbit polyclonal antibody against LEKTI.


RESULTS
LEKTI was localized to the stratum granulosum in normal skin. All four skin sections from patients with NS showed absent or very reduced staining for LEKTI. Staining in the other disorders showed positive LEKTI expression in varying patterns.


CONCLUSIONS
NS can be difficult to diagnose especially in the early stage, which can lead to inappropriate treatments particularly if it is misdiagnosed as atopic dermatitis. Immunohistochemistry of skin with an antibody against LEKTI is a potentially useful diagnostic test for NS.
Ong
C
C
Department of Paediatric Dermatology, Institute of Child Health, 30 Guildford Street, London WC1N 1EH, U.K. c.ong@ich.ucl.ac.uk
O'Toole
E A
EA
Ghali
L
L
Malone
M
M
Smith
V V
VV
Callard
R
R
Harper
J I
JI
D000293:Adolescent; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000175:diagnosis / Q000378:metabolism; D003937:Diagnosis, Differential; D006197:Hair / Q000002:abnormalities*; D006801:Humans; D006967:Hypersensitivity / Q000235:genetics / Q000378:metabolism; D016113:Ichthyosiform Erythroderma, Congenital / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D017490:Ichthyosis, Lamellar / Q000175:diagnosis / Q000378:metabolism; D007124:Immunoenzyme Techniques; D053491:Proteinase Inhibitory Proteins, Secretory; D011565:Psoriasis / Q000175:diagnosis / Q000378:metabolism; D000074163:Serine Peptidase Inhibitor Kazal-Type 5; D015842:Serine Proteinase Inhibitors / Q000378:metabolism; D012867:Skin / Q000378:metabolism*; D013577:Syndrome
D002352:Carrier Proteins; D053491:Proteinase Inhibitory Proteins, Secretory; C120650:SPINK5 protein, human; D000074163:Serine Peptidase Inhibitor Kazal-Type 5; D015842:Serine Proteinase Inhibitors