Anti-desmocollin autoantibodies in nonclassical pemphigus

BACKGROUND

Despite the established pathogenic role of anti-desmoglein (Dsg) antibodies in classical pemphigus, the significance of autoantibodies to another desmosomal cadherin, desmocollin (Dsc) is at present unknown. No consistent immunoassay for immunoglobulin (Ig) G autoantibodies to Dscs has been developed.

OBJECTIVES

The aim of this study was to develop reliable assays to detect anti-Dsc autoantibodies.

METHODS

We expressed soluble recombinant proteins (RPs) of human Dsc1-3 in mammalian cells and examined sera of various types of pemphigus, including 79 paraneoplastic pemphigus (PNP) sera, by novel enzyme-linked immunosorbent assays (ELISAs) using the RPs. We also performed ELISAs of Dsc baculoproteins and used the complementary DNA (cDNA) transfection method, and compared the results with those of mammalian ELISAs.

RESULTS

Through mammalian ELISAs, IgG autoantibodies to Dsc1, Dsc2 and Dsc3 were detected in 16.5%, 36.7% and 59.5% of PNP sera, respectively, and considerable numbers of pemphigus herpetiformis (PH) and pemphigus vegetans (PVeg) sera reacted strongly with Dsc1 and Dsc3. Mammalian ELISAs were highly specific and more sensitive than baculoprotein ELISAs or the cDNA transfection method. Several Dsc-positive sera, particularly PH sera, showed no reactivity with Dsgs. The reactivity of PNP serum and PVeg serum with Dscs was not abolished by pre-absorption with Dsg RPs.

CONCLUSIONS

The results of these novel ELISAs indicated that IgG anti-Dsc autoantibodies were frequently detected and potentially pathogenic in nonclassical pemphigus.

Necrotizing fasciitis caused by Cryptococcus neoformans in a patient with pemphigus vegetans

Cryptococcosis occurs most often in immunocompromised people. The cutaneous features of cryptococcosis include papules, pustules, nodules, subcutaneous swelling, abscesses, molluscum contagiosum-like or tumour-like lesions, cellulitis, blisters, ulcers and very rarely, necrotizing fasciitis (NF). NF is a destructive soft-tissue infection that is most typically caused by group A streptococci or by a combination of facultative and anaerobic bacteria. We present the case of a 55-year-old woman with pemphigus vegetans, who developed cryptococcal NF in the legs. She had been treated with immunosuppressants including plasmapheresis and pulse therapy with steroid and cyclophosphamide. Cryptococcal NF localized to the legs is very rare. Because diagnosis and treatment of cryptococcal infection is often delayed, clinicians should be aware of the possibility of cryptococcal infection when antibacterial therapy is not effective in an immunocompromised patient.

Induction of cutaneous delayed hypersensitivity reactions in mice sensitized with intragastrically administered hapten: activation of Langerhans cells in the sensitization and elicitation phases

BACKGROUND

As seen in atopic dermatitis, allergic diseases often produce lesions both in the gastrointestinal tract and the skin, suggesting the involvement of an immunological relationship between the two organs in the pathogenesis.

OBJECTIVES

To study the role of gastric and epidermal Langerhans cells (LCs) in the sensitization and elicitation phases, respectively, of cutaneous delayed-type hypersensitivity (DTH) reactions to intragastrically administered hapten.

METHODS

BALB/c mice, which were subjected to intragastric administration of trinitrochlorobenzene 5 days previously, received an elicitative challenge of the same hapten to the ear skin. Sections of the ear were immunostained for CD4 and CD8. Epidermal sheets of the ear and epithelial sheets of the forestomach were immunostained for I-A and observed under a confocal laser scanning microscope.

RESULTS

Cutaneous DTH reactions were induced in mice, as demonstrated by an increase in ear thickness and a prominent infiltration of CD4+ and CD8+ lymphocytes at 24-36 h after the elicitative challenge. In the elicitation phase, epidermal LCs showed a significant increase in size, indicating in vivo activation, at 24 h. In the sensitization phase, gastric LCs increased in size at 2 h, became round at 6 h, and decreased in number at 24 h, possibly representing the sequential events of LC activation and migration from the epithelium.

CONCLUSIONS

The present study demonstrated that gastric LCs and epidermal LCs were activated in vivo in the sensitization and elicitation phases, respectively, of cutaneous DTH reactions in orally sensitized mice.