Demonstration of eosinophil chemotactic factor in the blister fluid of patient with incontinentia pigmenti

Incontinentia pigmenti: a review and update on the molecular basis of pathophysiology

Incontinentia pigmenti is an uncommon X-linked dominant disorder, lethal in the majority of affected males in utero and variably expressed in females. Cutaneous manifestations are classically subdivided into 4 stages: vesicular, verrucous, hyperpigmented, and atrophic. Various hair and nail abnormalities, dental anomalies, and ophthalmologic and neurologic deficits are associated with the disorder. The gene for incontinentia pigmenti has been mapped to Xq28. Recently, mutations in the NEMO/IKKgamma gene located at Xq28 have been found to cause expression of the disease. Knockout mice heterozygous for NEMO/IKKgamma gene deficiency develop a clinical phenotype very similar to that of incontinentia pigmenti. NEMO/IKKgamma is an essential component of the newly discovered nuclear factor kappaB (NF-kappaB) signaling pathway. When activated, NF-kappaB controls the expression of multiple genes, including cytokines and chemokines, and protects cells against apoptosis. The mechanism by which NEMO/IKKgamma deficiency causes, via the NF-kappaB pathway, the phenotypical expression of the disease has recently been elucidated. In addition, the newest research findings on eosinophil recruitment through eotaxin release by activated keratinocytes are described in the review. Finally, anhidrotic ectodermal dysplasia with immunodeficiency, a disorder allelic to incontinentia pigmenti, is discussed together with implications on the current understanding of NF-kappaB function. (J Am Acad Dermatol 2002;47:169-87.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants will have a comprehensive and current understanding of incontinentia pigmenti, including its typical and uncommon clinical and histopathologic characteristics, diagnostic assessment, and current management strategies. Additionally, participants will gain the most current knowledge of the genetic and molecular basis of cutaneous pathomechanism.

Expression of eotaxin, an eosinophil-selective chemokine, parallels eosinophil accumulation in the vesiculobullous stage of incontinentia pigmenti

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis primarily affecting female children. The initial vesiculobullous stage of IP is characterized clinically by inflammatory papules, blisters, and pustules, and histopathologically by acanthosis, keratinocyte necrosis, epidermal spongiosis and massive epidermal eosinophil infiltration. The cause of this multisystem disease is attributed to the mutations of an X-linked regulatory gene, termed nuclear factor-kappaB essential modulator (NEMO). The exact mechanism of epidermal eosinophil accumulation has not yet been determined. We explored the possible role of an eosinophil-selective, nuclear factor-kappaB-activated chemokine, eotaxin, in the accumulation of eosinophils in the initial stage of the disease. Monoclonal antibody (6H9) specific for human eotaxin strongly labelled the suprabasal epidermis of IP skin, paralleling the upper epidermal accumulation of eosinophils, but did not label the epidermis of normal skin or lesional skin from patients with other inflammatory skin diseases not characterized by prominent eosinophil accumulation, namely dermatitis herpetiformis and selected cases of atopic dermatitis lacking significant numbers of eosinophils. In addition, endothelial cells in lesional skin of IP also exhibited strong expression of eotaxin, which correlated with perivascular and intravascular eosinophil infiltration. We also examined the in vitro effects on epidermally derived eotaxin of several cytokines that were nuclear factor-kappaB-activated and/or known to induce eotaxin expression. In normal human keratinocytes, proinflammatory cytokines either independently (IL-1alpha) or synergistically (tumour necrosis factor-alpha (TNF-alpha)/ interferon-gamma (IFN-gamma) and TNF-alpha/IL-4) up-regulated eotaxin expression. These studies suggest that release of cytokines during the initial inflammatory stage of IP induces epidermal expression of eotaxin, which may play a role in the epidermal accumulation of eosinophils.

Extensive vesiculobullous eruption following limited ruby laser treatment for incontinentia pigmenti: a case report

A 3-year-old girl with incontinentia pigmenti was referred for treatment of pigmented whorled macules on the trunk and limbs. Initially ruby laser therapy was only given to the legs. Wound healing was delayed. Two months later the patient developed extensive vesicles and erosions restricted to pigmented macules in both treated and untreated areas. Conservative treatment, including 2 weeks hospitalization, improved acute inflammation, but the remaining pigmentation was darker than originally seen. The apparent reappearance of an early cutaneous manifestation of this syndrome, seemingly triggered by laser therapy, would suggest such treatment is contraindicated.

Eosinophilic and neutrophilic spongiosis: clues to the diagnosis of immunobullous diseases and other inflammatory disorders

When eosinophils or neutrophils are found within the epidermis in concert with edema, the pattern is known as eosinophilic or neutrophilic spongiosis. Although eosinophilic spongiosis has been accepted as a clue to the diagnosis of blistering disorders for some time, the fact that either pattern can serve as a clue to the diagnosis of a variety of disorders, including immunobullous diseases, is less widely known. Herein, we review the types of inflammatory skin diseases, including spongiotic dermatitides, subepidermal vesicular dermatitides, intraepidermal vesicular dermatitides, and perivascular or diffuse dermatitides, that display intraepidermal eosinophils and neutrophils. We also review the known mechanisms that explain in part why intraepidermal granulocytes are commonly found in this diverse group of skin diseases.

Localization of eosinophil granule major basic protein in incontinentia pigmenti

We report a case of incontinentia pigmenti and demonstrate the deposition and localization of eosinophil major basic protein (MBP) in the vesicular stage of this neurocutaneous syndrome. The initial stage of incontinentia pigmenti is histologically characterized by intraepidermal vesicles associated with eosinophilic spongiotic dermatitis. Pathologic examination of a lesional tissue specimen from our patient demonstrated epidermal necrosis, spongiosis, and vesicle formation. Indirect immunofluorescence with affinity-chromatography purified antibody to human eosinophil granule MBP demonstrated many intact eosinophils within vesicles and scattered throughout the epidermis and dermis, and extracellular deposition of granular MBP in the tissue. The characteristic finding of extensive tissue eosinophilia in incontinentia pigmenti, as well as the new finding of extracellular deposition of an eosinophil granule protein in lesional tissue, suggests the involvement of eosinophils in the pathogenesis of the disease.

Incontinentia pigmenti: eosinophil chemotactic activity of the crusted scales in the vesiculobullous stage

To investigate the mechanisms underlying eosinophil infiltration into the epidermis in incontinentia pigmenti (IP), we studied the eosinophil chemotactic activity in extracts of the crusted scales from three patients with IP in the vesiculobullous stage. Eosinophil chemotactic activity was detected in the eluates from a Sephadex G-75 chromatography column between the vitamin B12 and phenol red markers. The chemotactic activity was heat-stable and resistant to enzyme digestion, and recovered after ether extraction at low pH. Leukotriene B4 (LTB4) was demonstrated in the fractions with high eosinophil chemotactic activity. These findings suggest that LTB4 plays an important role in the accumulation of eosinophils within the epidermis in IP, in the vesiculobullous stage. Blood eosinophilia, however, may not be induced by the eosinophil chemotactic factors in the scales.