Reactive granulomatous dermatitis as a histological pattern including manifestations of interstitial granulomatous dermatitis and palisaded neutrophilic and granulomatous dermatitis: a study of 52 patients

BACKGROUND

Confusion exists regarding interstitial granulomatous dermatitis (IGD) and palisaded neutrophilic and granulomatous dermatitis (PNGD).

OBJECTIVE

To determine whether IGD and PNGD are two different entities, or whether they must be considered as two subtypes of the same reactive pattern, and thus whether the unification of the nomenclature is necessary.

METHODS

Observational retrospective multicentre study of patients with IGD and PNGD evaluated between 1999 and 2019 and review of their clinical and histological features.

RESULTS

We identified 52 patients (38 women and 14 men). Clinical and histological findings of IGD were observed in 88.4% of cases. The most common cutaneous lesions were plaques/macules (IGD) or annular plaques and papules/nodules (PNGD), located mostly on the limbs and trunk. The rope sign was developed in two patients with IGD that associated autoimmune disorders. Similar associated comorbidities (75%) were found in both entities, mainly autoimmune diseases (53.8%). In IGD, the infiltrate was predominantly lympho-histiocytic. Neutrophilic infiltrates, karyorrhexis and skin lesions with limited clinical course were mainly associated with PNGD biopsies. In biopsies with a limited recurrent course, a predominant lymphocytic inflammatory infiltrate was found. Collagen degeneration was present in 75.9% of cases. The floating sign was observed only in IGD type patients (63%). Overlapping histological findings were found in one fourth of cases, especially between IGD and interstitial granuloma annulare. Interface dermatitis, apparently unrelated to drug intake, was observed in 4 cases of IGD.

CONCLUSION

We support the term reactive granulomatous dermatitis to unify both the clinical and histological findings of IGD and PNGD, and the overlapping between IGD and interstitial granuloma annulare. According to this, a spectrum of histological changes will be found depending on the clinical course of the skin lesions.

The involvement of ADAM10 in acantholysis in mucocutaneous pemphigus vulgaris depends on the autoantibody profile of each patient

BACKGROUND

Acantholysis in pemphigus vulgaris (PV) may be triggered by desmoglein (Dsg) and non-Dsg autoantibodies. The autoantibody profile of each patient results in distinct intracellular signalling patterns.

OBJECTIVES

Based on our previous findings, we aimed to elucidate whether PV acantholysis in a mouse model may be mediated by activation of a disintegrin and metalloproteinase 10 (ADAM10).

METHODS

We used three PV-IgG fractions from different patients containing high or low levels of anti-Dsg1 and anti-Dsg3 antibodies, and the presence or not of anti-desmocollin (Dsc) antibodies, using a passive transfer mouse model of PV.

RESULTS

Although all of the PV-IgG fractions produced suprabasal acantholysis, only those containing anti-Dsg1/3, but not anti-Dsc2/3 antibodies, induced ADAM10 activation in a Src-dependent way, and an increase in the epidermal growth factor (EGF) receptor ligands EGF and betacellulin (BTC). In contrast, the presence of anti-Dsc2/3 antibodies, in addition to anti-Dsg1/3, triggered earlier and ADAM10-independent epidermal detachment, with no increase in EGF and BTC, which was associated with an earlier and more intense acantholysis.

CONCLUSIONS

All PV-IgG fractions produced suprabasal acantholysis, but our results reveal that depending on the levels of anti-Dsg antibodies or the presence of non-Dsg antibodies, such as anti-Dsc, more severe cell-cell epidermal detachment will occur at different times, and in an ADAM10-dependent manner or not. Acantholysis in these different groups of patients with PV may be a consequence of the activation of specific intracellular mechanisms downstream of Autoantibodies binding to Dsg or non-Dsg proteins, and therefore more specific therapeutic approaches in PV should be used. What's already known about this topic? Suprabasal acantholysis in pemphigus vulgaris (PV) may be triggered by both desmoglein (Dsg) and non-Dsg autoantibodies. The autoantibody profile of each patient is associated with a distinct intracellular signalling pattern. What does this study add? In patients with PV with anti-Dsg3 and anti-Dsg1, but not anti-desmocollin (Dsc)3 antibodies, ADAM10 activation is induced in an Src-dependent way, together with an increase in the epidermal growth factor receptor (EGFR) ligands EGF and betacellulin. The presence of anti-Dsc3 antibodies triggers an earlier and ADAM10-independent acantholysis, without increasing EGFR ligands, and is associated with more severe epidermal detachment. Lower levels of anti-Dsc3 antibodies are associated with less severe acantholysis. What is the translational message? In some patients with PV, the severity and the timing for cell-cell detachment seem to depend on the level of anti-Dsg1/3 antibodies, although other as yet uncharacterized antibodies may also participate. These patients with PV would exhibit inhibition of acantholysis by Src, ADAM10, EGF and EGFR inhibitors. In other patients, the presence of non-Dsg antibodies, such as anti-Dsc2/3, would produce an earlier and more severe ADAM10-independent suprabasal acantholysis.

Clinical management of cutaneous adverse events in patients on targeted anticancer therapies and immunotherapies: a national consensus statement by the Spanish Academy of Dermatology and Venereology and the Spanish Society of Medical Oncology

Progress in the understanding of many tumors has enabled the development of new therapies, such as those targeted at specific molecules involved in cell growth (targeted therapies) or intended to modulate the immune system (immunotherapy). However, along with the clinical benefit provided by these new treatments, new adverse effects have also appeared. Dermatological toxicities such as papulopustular eruptions, xerosis, and pruritus are common with EGFR inhibitors. Other adverse effects have also been described with PDGFR, BCR-ABL, and MAPK tyrosine kinase inhibitors, antiangiogenic drugs, and inhibitors at immune checkpoints such as CTLA-4 and PD-1/PD-L1. Onset of these adverse effects often causes dose reductions and/or delays in administering the prescribed therapy, which can affect patient survival and quality of life. It is, therefore, important to prevent the occurrence of these adverse effects, or to treat unavoidable ones as soon as possible. This requires cooperation between medical oncologists and dermatologists. This article reviews the various dermatological toxicities associated with targeted therapies and immunotherapies, along with their diagnosis and therapeutic management.

Exploring beyond the oral mucosa in patients affected with autoimmune blistering diseases: the importance of endoscopic procedures

Autoimmune blistering diseases (AIBD) comprise several entities characterized by the presence of autoantibodies targeted against structural proteins either in desmosomes or in the dermoepidermal junction of polystratified squamous epithelium. Patients develop blisters, erosions in cutaneous surfaces or mucosas. Diagnosis is based on the characteristic mucocutaneous lesions, the typical findings on histological studies and direct immunofluorescence assays, and the presence of specific autoantibodies against the epidermal antigens. It may not be possible for dermatologists to appropriately explore the nose and throat (NT). Thus, a clinical exploration by endoscopic procedures of NT may be a useful tool during the conventional dermatological exam. The aims of this review are to draw attention to the most frequent NT manifestations in AIBD patients, and underline the utility of endoscopic procedures to achieve a more successful and rationale management of patients. Additionally, we will provide brief information related to the anatomical structures and type of epithelium in NT areas which may explain the extent and type of NT involvement in AIBD. Endoscopic exploration in AIBD patients is important for several reasons. Firstly, it will allow the real NT mucosal involvement in each patient to be determined, thus making a differential diagnosis during the endoscopic exam possible, based on the localization of mucosal lesions. Secondary mucosal morbidity can also be ruled out. Secondly, the clinical response to treatment may be established, especially in NT mucosa, as these are anatomical areas subjected to important local traumas, and physiological functions such as breathing, swallowing, speech production and phonation may be damaged. Therefore, a multidisciplinary management in AIBD is mandatory by both dermatologists and otorhinolaryngologists, adding the clinical exploration by endoscopic procedures of NT to the conventional dermatological exam in all AIBD patients, irrespective of whether they exhibit associated symptoms.

Rituximab in dermatology

Rituximab was introduced into clinical practice as a medication with considerable potential. Its use in patients with B-cell lymphoma and rheumatoid arthritis revealed numerous indications in autoimmune diseases, many of which involve the skin, thus requiring dermatologists to become familiar with both the characteristics of anti-CD20 antibodies and the role of B cells in multiple skin diseases. Thanks to these developments, we will be able to use rituximab more frequently and appropriately in our patients and draw up consensus guidelines based on large case series. In other words, establishing the indications for rituximab will make it possible to shorten disease course and reduce morbidity due to more specific drugs.

Study of oral, ear, nose and throat involvement in pemphigus vulgaris by endoscopic examination

BACKGROUND

Pemphigus vulgaris (PV) is an autoimmune blistering skin disorder characterized by the presence of suprabasal acantholysis and autoantibodies against desmoglein 3. There are two different clinical forms: mucocutaneous (MCPV) and mucosal (MPV). However, little is known about PV lesions in oral, ear, nose and throat (OENT) areas produced by the very dynamic of the anatomical structures involved in the functions of the aerodigestive tract.

OBJECTIVES

To investigate the pattern of OENT manifestations in PV, and their relationship with physiological traumatic mechanisms in stratified squamous epithelial structures.

METHODS

A prospective analysis of 40 patients diagnosed with MCPV (22 patients) or MPV (18 patients) was carried out at the University Clinic of Navarra. OENT manifestations were evaluated in all patients endoscopically. OENT involvement was divided into anatomical areas.

RESULTS

The most frequent symptom was pain, mainly on oral mucosa (87·5%). Buccal mucosa (90%), posterior wall of pharynx (67·5%), upper edge of epiglottis (85%) and nasal vestibule (70%) were the areas most frequently affected in the OENT mucosa. These localizations were related to physiological traumatic mechanisms in polystratified squamous epithelial structures.

CONCLUSIONS

OENT endoscopy should be included in the examination of all patients with PV. Knowledge of the most frequent localizations of active lesions on OENT mucosa in PV will help us to interpret more efficiently the findings from OENT endoscopy. Also, information related to traumatic physiological mechanisms on OENT areas must be offered to patients in order to avoid the appearance of new active PV lesions.

Subsequent nonmelanoma skin cancer after liver transplantation

BACKGROUND

Liver transplant recipients have a high risk of developing nonmelanoma skin cancer (NMSC). Some develop multiple NMSC.

METHODS

Patients with a follow-up of >1 year have been prospectively followed to detect NMSC. We studied the risk of developing >1 NMSC.

RESULTS

After a follow-up of 2658 patient-years (mean, 8.5 years per patient), 59/312 (19%) patients were diagnosed with NMSC. Twenty-five had >1 NMSC. The 5-year risk of developing 1 NMSC, >1 NMSC, and a subsequent NMSC (a new NMSC after a first one) were 15%, 5.5%, and 46.5%, respectively. Age >60 years and transplantation for hepatocellular carcinoma were independently associated with a higher risk of developing >1 NMSC.

CONCLUSION

NMSC are frequent complications after liver transplantation and they may show a high rate of recurrence. Older age and hepatocellular carcinoma were related to the development of multiple NMSC.

[Usefulness of bilateral sympathectomy using video-assisted thorascopic surgery in the treatment of essential hyperhidrosis]

Essential, idiopathic, or primary hyperhidrosis is defined as excessive sweating in certain areas of the body due to factors unrelated to other disease. Clinical presentation can be categorized as palmar, plantar, axillary, or craniofacial. Medical treatment (aluminium salts, iontophoresis, anticholinergic drugs, and alpha2-agonists) is of questionable effectiveness. Intradermal injections of botulinum toxin are very effective for the treatment of axillary hyperhidrosis. Surgical treatment involves resection (sympathectomy) or electrocautery (sympathicolysis) of the thoracic sympathetic chain, or compression of the sympathetic chain with clips, in all cases via video-assisted thorascopic surgery. One or more ganglia between T2 and T5 are usually resected depending on the area affected by hyperhidrosis: T2 for craniofacial hyperhidrosis, T3 and T4 for palmar hyperhidrosis, and T3 to T5 for combined palmar and axillary hyperhidrosis. The technique is very useful and is effective in those patients with primary hyperhidrosis who have not responded to conservative treatment.

[Waldenström macroglobulinemia associated with cutaneous lesions and type I cryoglobulinemia]

Waldenström macroglobulinemia is a blood dyscrasia characterized by monoclonal proliferation of B cells in the bone marrow, lymph nodes, and spleen. Patients with this disease show elevated serum levels and tissue deposition of monoclonal immunoglobulin (Ig) M produced by these aberrant cells. We present the case of a patient with Waldenström macroglobulinemia who suffered cutaneous lesions resulting from deposition of k light chains of IgM and clinical manifestations secondary to associated type I cryoglobulinemia. We discuss the different pathological cutaneous processes caused by IgM in Waldenström macroglobulinemia.

Ear, nose and throat manifestations in pemphigus vulgaris

BACKGROUND

Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. There are two clinical forms: mucosal (MPV) and mucocutaneous (MCPV). The frequency of ear, nose and throat (ENT) involvement in PV is not clearly defined. Only a few isolated individual cases have been reported.

OBJECTIVES

The objective of our study was to determine the incidence of ENT involvement in patients with PV.

PATIENTS

We studied prospectively all 16 patients diagnosed with PV and treated in the Department of Dermatology of the University Clinic of Navarra between 2001 and 2005. They were 10 cases of MPV and six cases of MCPV. All patients were evaluated for ENT manifestations by endoscopic examination.

RESULTS

Of the 16 patients, 13 presented with throat symptoms (81%), 12 pharyngeal (75%) and seven laryngeal symptoms (44%). Fourteen patients (88%) had active PV lesions on endoscopic evaluation (eight patients had active lesions on both pharyngeal and laryngeal mucosa, four had PV lesions only on laryngeal mucosa and two had PV lesions on pharyngeal mucosa). Laryngeal lesions were most commonly present in MPV patients. The frequency of nasal symptoms (38%) was lower than active PV lesions (62%) found on ENT examination. Oral symptoms and oral active PV lesions were the most frequent findings (94%). Only three patients with MCPV showed erosions on the external auditory canal.

CONCLUSIONS

As ENT endoscopy allows more extensive areas of mucosa to be examined than simple visual inspection, we recommend that it be included in the examination of all patients with PV. By obtaining more complete information concerning the extent of the disease, a more accurate diagnosis can be made, better choice of drug and dose may be decided and, ultimately, response to treatment may be improved.

[Surgical treatment of penile lymphedema associated with hidradenitis suppurativa]

Penoscrotal lymphedema is a rare disease in the developed countries, although it is relatively frequent in tropical countries. The most common cause is filariasis, although in our practice usually is associate to neoplasic and inflammatory processes, surgery, radiotherapy, hidroelectrolitic disbalances and idiopathic. We present a 22 years old patient with penoscrotal lymphedema due to hidradenitis suppurativa. After unsuccessful medical treatment, was performed a total excision of the penile skin and subcutaneous tissue to Buck's fascia. Split thickness skin grafts were used to cover the defect. Even medical management of penoscrotal lymphedema is not effective for most patients, surgery is a safe and effective procedure that gives excellent functional and cosmetic results.

Successful treatment of lichen planus with sulfasalazine in 20 patients

BACKGROUND

Lichen planus (LP) is a disturbing pruritic cutaneous disease that may have an spontaneous resolution or exhibit a more chronic course during some weeks or months.

OBJECTIVE

Our objective was to demonstrate that sulfasalazine is effective in the treatment of LP.

METHODS

Twenty patients were diagnosed in our department with LP of the skin and/or mucosa between 1985 and 2001 on the basis of clinical and histologic findings.

RESULTS

All patients were treated with sulfasalzine at initial doses of 1.5 g/day, increasing by 0.5 g/week to 3 g/day for 4-16 weeks. Some patients also received descendent doses for 2-12 months. Complete responses were observed in 13 patients and partial responses in seven patients. All patients reported an early resolution of the pruritus. No changes were detected in mucosal LP. Most of the patients tolerated the treatment well and only eight patients presented some minor side-effects.

CONCLUSION

Sulfasalazine is a successful therapeutic option for cutaneous LP, constituting an alternative to corticosteroids and retinoids.

In vivo blockade of pemphigus vulgaris acantholysis by inhibition of intracellular signal transduction cascades

BACKGROUND

Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. The mechanism of blister formation in pemphigus has not been defined; however, in vitro data suggest a role for activation of intracellular signalling cascades.

OBJECTIVES

To investigate the contribution of these signalling pathways to the mechanism of PV IgG-induced acantholysis in vivo.

METHODS

We used the passive transfer mouse model. Mice were injected with IgG fractions of sera from a patient with PV, with or without pretreatment with inhibitors of proteins that mediate intracellular signalling cascades.

RESULTS

Inhibitors of tyrosine kinases, phospholipase C, calmodulin and the serine/threonine kinase protein kinase C prevented PV IgG-induced acantholysis in vivo.

CONCLUSIONS

These observations strongly support the role of intracellular signalling cascades in the molecular mechanism of PV IgG-induced acantholysis.

Pemphigus vulgaris autoantibodies induce apoptosis in HaCaT keratinocytes

Pemphigus vulgaris (PV) is an autoimmune disease characterized by binding of IgG autoantibodies to epidermal keratinocyte desmosomes. IgG autoantibodies obtained from a patient with mucocutaneous PV reacted with plakoglobin (Plkg) in addition to desmoglein-3 (Dsg3) and Dsg1. Immunofluorescence analysis confirmed that IgG autoantibodies, unlike antibodies from a healthy volunteer, caused disruption of cell-cell contacts in HaCaT keratinocytes. Moreover, apoptosis was enhanced in cells treated with autoantibodies compared to those treated with normal antibodies. The apoptotic process induced by IgG autoantibodies was characterized by caspase-3 activation, Bcl-2 depletion and Bax expression. The present report demonstrates that PV IgG autoantibodies promote apoptosis in HaCaT keratinocytes.

Acneiform lesions secondary to ZD1839, an inhibitor of the epidermal growth factor receptor

Drugs that inhibit the epidermal growth factor receptor, such as ZD1839 or C225, are being used increasingly in the treatment of solid tumours. This has led to the appearance of new secondary effects. We describe the case of a patient who presented with an acneiform eruption secondary to the administration of ZD1839. These lesions healed in a few days after stopping the drug.

Porphyria cutanea tarda, dermatomyositis and non-Hodgkin lymphoma in virus C infection

Virus C infection has been associated with a broad spectrum of extrahepatic diseases such as essential mixed cryoglobulinemia, membranous glomerulonephritis, vasculitis, rheumatoid arthritis and lupus erythematosus. The etiologic role of virus C has also been observed in some neoplasms such as non-Hodgkin's lymphoma and the monoclonal gammapathies. Many studies also support the link between this virus and porphyria cutanea tarda (PCT). Isolated cases suggest a relationship with dermatomyositis. Herein, we report the coexistence of PCT, non-Hodgkin's lymphoma and dermatomyositis in the same patient affected with virus C infection which has never previously been described.

Systemic lupus erythematosus-associated anetoderma and anti-phospholipid antibodies

Anetoderma is characterized by a loss of normal elastic tissue that presents clinically as localized areas of wrinkled or flaccid skin. We describe the case of a 30-year-old woman with systemic lupus erythematosus-associated anetoderma and positive anti-phospholipid antibodies. We discuss the possible role of these antibodies in the pathogenesis of anetoderma, and, when detected, the need to check for an associated anti-phospholipid syndrome in such patients.

Bleomycin in the treatment of keloids and hypertrophic scars by multiple needle punctures

BACKGROUND

The treatment of keloids and hypertrophic scars has been difficult and a recent French study showed that bleomycin has been useful in the treatment of these lesions.

OBJECTIVE

To determine the effectiveness and safety of bleomycin in the treatment of hypertrophic scars and keloids when this drug is administered through multiple superficial punctures.

METHODS

We applied bleomycin to keloids and hypertrophic scars in 13 patients using a multiple-puncture method on the surface of the skin. All patients were given bleomycin at a concentration of 1.5 IU/ml. Clinical response after treatment was classified according to the following scale: complete flattening (100%), highly significant flattening (>90%), or significant flattening (75-90%).

RESULTS

The clinical response was very positive in all cases: complete flattening in six cases, highly significant flattening in six cases, and significant flattening in one case. Two patients presented a recurrence as a small nodule 10 and 12 months after the last infiltration.

CONCLUSIONS

These clinical findings show that administration of bleomycin in keloids and hypertrophic scars shows promise and needs further investigation.

Correlation between profile of circulating mononuclear cells and clinical manifestations in patients with pemphigus vulgaris

Phenotypes of 38 samples of mononuclear (PBMC) cells from 11 different patients with pemphigus vulgaris (PV) at different stages of the disease were explored looking for a possible relationship between cell immunity, mucocutaneous or mucosal lesion intensity and capacity of serum autoantibodies to elicit the disease in mice. PBMC from 5 patients with mucocutaneous lesions and sera with IgG capable of inducing the disease in neonatal mice had a high proportion of mature monocytes with CD14low DRhigh, and co-expressing CD16 and CD11b. In addition, a high proportion of CD19+CD5+ activated B cells and a very low proportion of naive CD4+CD45RA+ and CD8+CD11b+ T lymphocytes was observed. Monocytes from these patients expressed inducible nitric oxide synthase (iNOS). In contrast, PBMC from 6 patients, with lesions restricted to mucosal membranes and IgG lacking the capacity to induce the disease in mice, contained a high proportion of CD14high DRlow co-expressing CD16 circulating macrophages, CD8+CD11b+ T cells, and a low proportion of activated B lymphocytes. The results suggest a possible association between proportion of different antigen presenting cells (monocytes with high HLA-DR and low CD14 expression and activated B lymphocytes, or differentiated monocytes/macrophages), type of PV and capacity of serum autoantibodies to elicit the disease in mice.

Langerhans' cell histiocytosis on the vulva

BACKGROUND

Langerhans' cell histiocytosis (LCH) affecting the vulva alone is rare. At present, there are 51 published cases of LCH affecting the genital area. Of these, only 7 had LCH located in the genital area alone; in these cases, there was no subsequent systemic spread of the disease. A report of the 8th such case is presented with a review of the previous 7 cases.

CASE

A 40-year-old white woman presented with a several-month history of pruritic and ulcerous lesions on the vagina which had then spread to the vulva. No tiredness, general malaise, or associated temperature was observed. Physical examination disclosed an erythematous plaque on the labia minora, which was bilateral and slightly infiltrated. The rest of the physical examination brought no other disorders of interest to light. Histological findings were characteristic of LCH. Four cycles of iv vincristine (2 mg/m cycle) 15 days apart did not obtain objective or symptomatic improvement in the vulvar lesions. Therefore, a local and partial extirpation of both labia minora was performed. Eighteen months after surgery, the patient has no symptoms or signs of local recurrence or systemic spread.

CONCLUSIONS

Although the occurrence of LCH on the vulva is very unusual, we must bear this possibility in mind when a woman presents atypical chronic lesions on the genital mucosa. In such cases, it is necessary to perform a biopsy on the mucosa, rule out the possibility of systemic disease, and review the patient periodically in order to forestall a possible spread of the disease at any time.

Congenital infiltrating lipoma of the upper limb in a patient with von Willebrand disease

Infiltrating lipoma is a rare variety of lipoma, characterized by an infiltration of the adipose tissue of the muscles. Infiltrating lipomas are usually classified in two groups: intermuscular infiltrating lipoma and intramuscular infiltrating lipoma. Most are acquired, and they usually appear in middle-aged individuals. Exceptionally, they are congenital. In such cases they are not related to other diseases. We report an 8-year-old boy with a congenital infiltrating lipoma of the upper limb and von Willebrand disease. Both diseases are linked to an alteration in chromosome 12, but this clinical association seems to be random rather than causal.

Disseminated epidermolytic acanthoma probably related to trauma

Epidermolytic acanthoma is a rare benign tumour, which may occur in both isolated and disseminated forms. Only seven cases of disseminated epidermolytic acanthoma (DEA) have been described. This entity should be distinguished from other hereditary or acquired conditions which involve epidermolytic hyperkeratosis and other benign acanthomas. On the basis of the clinical history and the histological findings, we diagnosed a case of DEA which was probably secondary to repeated trauma.

Wells' syndrome (eosinophilic cellulitis): correlation between clinical activity, eosinophil levels, eosinophil cation protein and interleukin-5

Wells' syndrome (WS) (eosinophilic cellulitis) is characterized by the presence of oedematous skin lesions associated with eosinophilia of the tissues. It has recently been observed that in patients with this disease, increased eosinophil cation protein (ECP) and interleukin (IL) -5 can be detected in peripheral blood, with T lymphocytes that have mRNA for this lymphokine. We present a patient with WS in whom we found a close correlation between clinical activity, eosinophils in blood and bone marrow, and ECP and IL-5 levels in peripheral blood and tissues. We underline the major part played by IL-5 in this disease.

Mechanisms of acantholysis in pemphigus vulgaris: role of IgG valence

Pemphigus vulgaris (PV) is a dermatosis mediated by autoantibodies against desmoglein 3 (Dsg3). It was known that intraperitoneal (i.p.) injections of PV IgG and PV F(ab')2, but not of PV Fab, into neonatal mice reproduced the key features of the disease in these animals. It was proposed that crosslinking of antigen by bivalent PV autoantibodies may trigger acantholysis in PV. In the present study, we have used subcutaneous (s.c.) injections of PV IgG and its proteolytic fragments into neonatal mice to test equimolar amounts of these autoantibody fractions. Mice developed clinical and histological features of PV in a dose-dependent manner following a similar time course. PV IgG and Fab fractions induced acantholysis as early as 2 hr after the injection. It was also demonstrated that sc injections of PV Fab were more effective in inducing disease than ip injections. PV autoantibodies may bind an "adhesive site" of Dsg3 and impair its function, thus triggering acantholysis.