Samvisterin, a new natural antiplasmodial betulin derivative from Uapaca paludosa (Euphorbiaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Uapaca paludosa is used in African traditional medicine for the treatment of malaria. MATERIALS AND METHODS: A bioguided fractionation of U. paludosa trunk bark extracts was performed on the basis of their antiplasmodial activity against Plasmodium falciparum. RESULTS: A new natural betulin derivative named samvisterin (2) was isolated. In addition, 12 already known compounds were isolated from U. paludosa and tested against P. falciparum: squalene (1); lupeol (3), betulonic acid methyl ester (4), ß-sitosterol (5), stigmasterol (6), betulin (7), betulinic acid (8), pentadecanoic acid (9), palmitic acid (10), margaric acid (11), stearic acid (12), methyl palmitate (13). With the exception of betulinic acid, all were isolated for the first time from U. paludosa. Their chemical structures were established on the basis of spectroscopic analysis. The antiplasmodial activity of compounds 1-8 was confirmed on the chloroquine-resistant strain of P. falciparum, FcM29-Cameroon, with IC50 values ranging from 0.7µg/ml (for 1) to 30µg/mL (for 3). The cytotoxicity of the fractions and isolated compounds was also determined on KB and Vero cell lines in order to determine the cytotoxicity/activity ratio of each one. CONCLUSIONS: The results obtained with samvisterin (2) show that this new compound is the most promising of the series, with a weak cytotoxicity leading to the best selectivity index values.

Tannic acid induces in vitro acantholysis of keratinocytes via IL-1alpha and TNF-alpha.

The mechanism of acantholysis in pemphigus vulgaris (PV) is an intriguing argument since several chemical mediators are implicated. We previously reported a central role for IL-1alpha and TNF- alpha, both able to regulate complement activation and plasminogen activators. Very little is known about what triggers the disease (drugs, viruses or food). In this study, we evaluate the molecular role of tannins in acantholysis. By HPLC chromatography we measured tannic acid (TA) and gallic acid (GA) in blister fluid of 4 groups of patients divided according to their dietary habits, including a regular diet, a diet rich in tannins, a diet free of tannins, and a group of pemphigus patients. Blister fluid was obtained from patients using a suction blister apparatus. We show that people with a diet rich in tannins have increased tannin metabolites (TA and GA) in the skin in respect to controls (tannin-rich diet: GA = 194.52+/-2.39 nmol/ml; TA = 348.28+/-1.4 nmol/ml versus tannin-Mediterranean diet: GA = 15.28+/-1.63 nmol/ml; TA = 22.81+/-1.68 nmol/ml). PV patients showed similar values to the Mediterranean diet population (PV patients: GA = 95.8+/-1.97 nmol/ml; TA = 199.09+/-4.15 nmol/ml versus Mediterranean diet: GA = 83.53+/-2.35 nmol/ml; TA = 195.1+/-2.50 nmol/ml). In an in vitro acantholysis system using TA and PV-IgG we show that TA 0.1 mM in NHEK culture is able to induce acantholysis. This effect was able to amplify the acantholytic action of PV-IgG in vitro. A blocking study using anti IL-1 alpha and anti TNF-alpha antibodies showed a reduction in TA-induced acantholysis. Taken together, these results suggest that a diet rich in tannins could be a trigger in genetically predisposed patients. If these data are confirmed, a complementary diet poor in tannins may be useful in patients affected by PV.

Elevated 8-isoprostane levels in basal cell carcinoma and in UVA irradiated skin.

Isoprostanes are prostaglandin isomers produced from the peroxidation of polyunsaturated fatty acids from the cellular membrane. They have been used as a specific index of cellular lipoperoxidation and as an indirect measure of oxidative stress. However, these molecules also present several biological activities. An oxidative environment measured as the presence of other indirect measurements of reactive oxygen species lipoperoxidation has recently been described in basal cell carcinoma, the most frequent type of non-melanoma skin cancer. This study aims to measure the levels of 8-isoprostaglandin F2alpha, an isoprostane widely studied in other models as a by-product of ROS-induced lipid peroxidation, in basal cell carcinoma and in UVA irradiated healthy skin. We found that 8-iso-PGF2 alpha is present in higher levels in BCC specimens compared to healthy non sun-exposed skin, confirming previous studies on the production of lipoperoxidation in this tumor. Moreover, we demonstrated that topical pre-treatment with a compound containing vitamin E is capable of reducing 8-iso-PGF2 alpha formation in UV irradiated skin suggesting a role for isoprostanes in UV induced inflammation and eventually carcinogenesis and confirming the function of vitamin E as an antioxidant in this model.

A note on endoparasites of wild ostriches (Struthio camelus) in the Mokolodi Nature Reserve, Gaborone, Botswana.

A study was undertaken to investigate the prevalence of endoparasites of wild ostriches at Mokolodi Nature Reserve, Gaborone, over a 7-month period. Large numbers of strongyle eggs were recovered from faecal material in April and September and a decline in the strongyle egg counts was evident during June and July. Noteworthy was the absence of helminth eggs in faecal samples collected from chicks and coccidia oocysts from any of the ostriches.

Lupus vulgaris developing at the site of misdiagnosed scrofuloderma.

Cutaneous tuberculosis is a rare form of extrapulmonary tuberculosis primarily occurring in developing countries. The recent increase in the incidence of tuberculosis, especially due to human immunodeficiency virus (HIV) infections, has led to a resurgence of extrapulmonary forms of this disease. We describe a case of lupus vulgaris in a 33-year-old woman who had a 5-year history of a slowly growing plaque on her neck. The lesion was located at the site of surgery repairing the scar resulting from the incision of a subcutaneous abscess during childhood. This lesion was misdiagnosed as bacterial abscess. Histopathologic examination of the plaque revealed non-caseating tuberculoid granulomas consisting of lymphocytes, epithelioid and giant cells. Staining for acid-fast bacilli and culture from biopsied tissue was negative. Polymerase chain reaction (PCR) for detection of Mycobacterium tuberculosis DNA, performed on a skin biopsy specimen, was positive. A diagnosis of lupus vulgaris developing at the site of a previous misdiagnosed scrofuloderma was made. Conventional antitubercular therapy with rifampicin, isoniazid and ethambutol was administered for 6 months, resulting in resolution of the lesion.

Skin reactions due to anti-epileptic drugs: several case-reports with long-term follow-up.

In this study, the clinical findings and management of allergic skin reactions induced by the most used antiepileptic drugs, Lamotrigine (LMT) and Carbamazepine (CBZ), were evaluated. Lamotrigine is an antiepileptic drug recently released in several countries; it is effective for a variety of seizure types in adults and children, both as an add-on agent and in monotherapy, and it is generally well tolerated. Clinical and epidemiologic evidence suggest serious cutaneous reactions to antiepileptic drugs are more likely to occur during the first 8 weeks and they appear to increase when drugs are administered with other anticonvulsants, such as Valproate (VPA). We selected 10 patients who presented an idiosyncratic skin rash when treated with carbamazepine (8 patients) and lamotrigine (2 patients) administered as monotherapy, and we followed up on these patients for several years. Seven reactions were mild/severe cutaneous eruptions; one Toxic Epidermal Necrolysis, a case of Stevens-Johnson and a case of Hypersensitivity Syndrome. All severe skin drug reactions were induced by Carbamazepine. In five patients the AEDs were ceased abruptly (sometimes with the administration of a different molecule), tapered in four and continued unchanged in one. We conclude that the discontinuation of the drug with substitution with another is the most effective treatment and that corticosteroids are helpful in mild cutaneous reactions, while in severe skin reactions, such as Toxic Epidermal Necrolysis, corticosteroids are only a complementary therapy since intravenous immunoglobulins are the first choice treatment.

Impaired ultraviolet-B-induced cytokine induction in xeroderma pigmentosum fibroblasts.

Xeroderma pigmentosum is a rare, autosomal recessive disease in which patients develop excessive solar damage at an early age and have a 1000-fold increased risk of developing cutaneous neoplasms. Xeroderma pigmentosum can be classified into seven complementation groups (A-G) with defects in different DNA nucleotide excision repair genes. Xeroderma pigmentosum patients also have impaired immune function including reduced natural killer cell activity and impaired induction of interferon-gamma. We hypothesized that altered cytokine induction may contribute to the immune defect in xeroderma pigmentosum patients. We examined cytokine mRNA expression after ultraviolet B irradiation using reverse transcriptase polymerase chain reaction in fibroblasts derived from five xeroderma pigmentosum patients in complementation groups A, C, and D and in complemented XP-A and XP-D cells. Cytokines interleukin-1beta and interleukin-6 displayed impaired ultraviolet B induction whereas interleukin-8 had normal induction in the xeroderma pigmentosum fibroblasts. Stable complementation of XP-A and XP-D cell lines increased ultraviolet-B-induced interleukin-1beta and interleukin-6 expression. These results demonstrate a deficient response of xeroderma pigmentosum fibroblasts to ultraviolet B in terms of cytokine interleukin-1beta and interleukin-6 induction but normal interleukin-8 induction and exhibit a role for DNA repair in cytokine induction.

Role of Th2 cytokines, RANTES and eotaxin in AIDS-associated eosinophilic folliculitis.

The pathogenesis of AIDS-associated eosinophilic folliculitis is still unknown. The expression of chemokines and Th2-type cytokines is increased in other conditions associated with tissue eosinophilia and in allergic reactions. We evaluated the mRNA expression by reverse transcriptase polymerase chain reaction of two Th2 cytokines (interleukin-4 and interleukin-5) and of two chemokines (RANTES and eotaxin) in the skin of 6 patients with AIDS-associated eosinophilic folliculitis; the tissue localization of eotaxin was shown by immunohistochemistry. We demonstrated the increased expression of interleukin-4, interleukin-5, RANTES and eotaxin in lesional skin of the patients compared to normal skin of HIV+ individuals. We concluded that a Th2 pattern is present in AIDS-associated eosinophilic folliculitis. The cytokine milieu in this disease may favour a Th2 immune response to an unknown antigen, whereby RANTES and eotaxin act in synergy with interleukin-4 and interleukin-5 to mediate tissue inflammation.

Rethinking the role of tumour necrosis factor-alpha in ultraviolet (UV) B-induced immunosuppression: altered immune response in UV-irradiated TNFR1R2 gene-targeted mutant mice.

BACKGROUND: Ultraviolet (UV) B-induced immunosuppression, implicated in the pathogenesis of skin cancers, is postulated to be mediated in part by cis-urocanic acid (cis-UCA) via tumour necrosis factor (TNF)-alpha. TNF-alpha produces morphological changes in Langerhans cells indistinguishable from those induced by UVB exposure and antibodies against TNF-alpha have been demonstrated to inhibit UVB-induced immunosuppression in vivo. OBJECTIVES: To clarify further the role of TNF-alpha in UVB-induced immunosuppression and in cis-UCA immunosuppression. METHODS: We performed a contact hypersensitivity (CHS) assay on gene-targeted mutant mice (TNFR1R2-/-) lacking genes for both receptors (p55 and p75) for TNF-alpha. Mice were either irradiated with UVB or injected intradermally with cis-UCA, sensitized with 2,4-dinitrofluorobenzene, challenged on the ears and the response was measured. RESULTS: The TNFR1R2-/- mice showed hyporesponsiveness in the CHS response compared with wild-type (P < 0.001), confirming the proinflammatory role of TNF-alpha. However, significant suppression of CHS was seen after irradiation and after cis-UCA injection in both locally (sensitization on irradiated site; P < 0.05) and systemically (sensitization on non-irradiated site; P < 0.05) sensitized wild-type and gene-targeted mice. CONCLUSIONS: These results demonstrate that TNF-alpha signalling is only partially involved in UVB-induced immunosuppression and does not play a major part in the cis-UCA immunosuppression mechanism.

Further support for a role for Th2-like cytokines in blister formation of pemphigus.

Pemphigus vulgaris and pemphigus foliaceus are commonly known as antibody-mediated bullous diseases. However, recently a role for infiltrating cells as contributors to the pathogenesis of these diseases has been suggested. The aims of our study were to characterize the immunophenotype of the cellular infiltrate of pemphigus lesional skin and to study the cytokines secreted. We have therefore performed an immunohistochemical study with a large panel of monoclonal antibodies (to CD3, CD4, CD8, CD25, CD30, myeloperoxidase, eosinophil cationic protein EG2, tryptase, human interleukin (IL)-2, human IL-4, human IL-5, human IL-6, human IL-8, and interferon (IFN)-gamma using the alkaline phosphatase-antialkaline phosphatase procedure on lesional and uninvolved skin of six patients with clinical, histological, and immunofluorescent proven pemphigus. We also performed RT-PCR in order to demonstrate mRNA expression of the cytokines of interest. Our results suggest the presence of a T cell population with a prevalent Th2-like cytokine pattern in lesional skin. In addition, we demonstrate a consistent number of granulocytes and mast cells that show clear signs of activation. These data suggest the involvement of an inflammatory infiltrate in the production of pemphigus lesions. In particular, we assume that Th2 cells may be implicated in the very early stages of autoimmune response, concluding that they exert broad activity in blister formation.

In vitro and in vivo expression of interleukin-1alpha and tumor necrosis factor-alpha mRNA in pemphigus vulgaris: interleukin-1alpha and tumor necrosis factor-alpha are involved in acantholysis.

Keratinocyte-derived cytokines have been implicated in the pathogenesis of a number of skin diseases. In this study we examined the possible role of keratinocyte-derived cytokines in the development of acantholysis in pemphigus vulgaris. Nineteen patients with pemphigus vulgaris, demonstrating the characteristic clinical, pathologic, and immunopathologic findings were studied. In situ immunolabeling demonstrated the presence of two cytokines interleukin-1alpha and tumor necrosis factor-alpha, in lesional and perilesional areas. Results were confirmed by reverse transcriptase-polymerase chain reaction, demonstrating overexpression of both cytokines in vivo. To study the role of these cytokines in the pathogenesis of pemphigus vulgaris both in vitro and in vivo studies were performed. The results of the in vitro study demonstrated that pemphigus vulgaris IgG induced interleukin-1alpha and tumor necrosis factor-alpha mRNA in the skin. The potential pathogenic role of these mediators was demonstrated by a blocking study using antibodies against human interleukin-1alpha and tumor necrosis factor-alpha in keratinocytes cultures. A combination of anti-interleukin-1alpha and anti-tumor necrosis factor-alpha antibodies inhibited in vitro pemphigus vulgaris IgG induced acantholysis. To confirm the role of interleukin-1 and tumor necrosis factor-alpha in pemphigus, we utilized passive transfer studies using interleukin-1 deficient mice (ICE-/-, interleukin-1beta-/-) and tumor necrosis factor-alpha receptor deficient mice (TNFR1R2-/-). Both groups demonstrated a decreased susceptibility to the passive transfer of pemphigus. Our data support the role of cytokines interleukin-1 and tumor necrosis factor-alpha in the pathogenesis of pemphigus vulgaris.

Imiquimod, a topical immune response modifier, induces migration of Langerhans cells.

Langerhans cells are bone marrow derived dendritic cells that represent the major antigen-presenting cells in the skin. Langerhans cells take up and process antigen within the epidermis and present processed antigen to T lymphocyte in the regional lymph nodes and thus form an integral part of the cutaneous immune response. The cutaneous immune response can be modified by a number of pharmacologic agents, including corticosteroids, cyclosporine, and retinoids as well as physical agents, such as ultraviolet light. For the most part these agents act by suppressing immune function. A topical immune response modifier, imiquimod has been shown to enhance the cutaneous immune response. Imiquimod has anti-viral and anti-tumor effects in animal models and has been approved for the topical treatment of external genital and perianal warts in humans. The biologic activity of imiquimod in part is due to its effect as a cytokine inducer. Preliminary data suggested that imiquimod could have an effect on Langerhans cells. In order to clarify this effect on Langerhans cells, we examined Langerhans cell morphology and migration in imiquimod-treated skin. The density of Ia + cells decreased 2 d after treatment, falling to approximately 43% by day 10. The Ia positive in cells remaining in the skin appeared larger and more dendritic suggesting an activated state. ATPase staining of epidermal sheet confirmed the decreased number of Langerhans cells. To clarify status of Langerhans cells, the activation of B7 was examined. Activation of B7-1 or B7-2 was not detected. Imiquimod, however, did enhance Langerhans cell migration from skin to draining lymph nodes. This enhanced Langerhans cell migration was also associated with an enhanced allergic contact hypersensitivity. These results suggest that the mechanism of modulation of immune response by imiquimod is in part due to effects on Langerhans cells.

Immune modulation in pemphigus vulgaris: role of CD28 and IL-10.

Pemphigus vulgaris (PV) is an autoimmune bullous skin disease characterized by Abs to the desmosomal cadherin desmoglein-3. Although the autoantibodies have been shown to be pathogenic, the role of the cellular immune system in the pathology of pemphigus-induced acantholysis is unclear. To further delineate the potential role of T cell-signaling pathways in the pathogenesis of PV, we performed passive transfer experiments with PV IgG in gene-targeted mutant mice. Our results demonstrated that CD28-deficient mice (lacking a costimulatory signal for T cell activation) are 5-fold more sensitive to the development of PV than wild-type mice. To evaluate whether the higher incidence of disease was due to an impairment in intercellular adhesion of keratinocytes, we performed an in vitro acantholysis, using CD28-/- mice keratinocytes. No alteration in in vitro adhesion was detected in CD28-/--type keratinocytes. Because the CD28 molecule plays a pivotal role in the induction of Th2 cytokines, we examined the levels of a prototypic Th2 cytokine (IL-10) in CD28-/- mice. Lower levels of IL-10 mRNA were found in lesions from CD28-/- mice. To determine whether pemphigus susceptibility in CD28-/- was related to IL-10 deficiency, we performed passive transfer experiments in IL-10-/- mice that demonstrated increased blisters compared with controls. To confirm that IL-10 is involved in the pathogenesis, rIL-10 was given with PV IgG. IL-10 significantly suppressed the disease activity. These data suggest a potential role of IL-10 in PV.

Carbamazepine-induced hypersensitivity syndrome in a child with epilepsy.

Carbamazepine is an effective anticonvulsant and is considered the drug of first choice for the treatment of partial and secondarily generalized seizures. Although carbamazepine is well tolerated, many side effects have been reported in the literature. The majority of these adverse effects are transient and do not lead to the discontinuation of the therapy. We present a case of a female child, aged 11 years and 6 months, who showed an anticonvulsant hypersensitivity syndrome induced by carbamazepine. This syndrome is a rare, potentially life-threatening adverse drug reaction. The patient developed a cutaneous nonpruritic rash, associated with high fever, diffuse lymphadenopathy, and arthralgias on the knees and the ankles with local signs of arthritis. Laboratory examination showed a lymphocytosis, mild thrombocytopenia, marked eosinophilia, and high transaminases. Corticosteroid therapy (betametasone 0,5 mg x 3 day) was started and carbamazepine was gradually withdrawn changing to valproic acid, with complete control of the seizures. The fever and the rash reduced gradually, beginning from the face and then disappearing completely after 10 days. Laboratory results showed a clear improvement: after 7 days the patient showed a complete normalization of the above parameters, except for transaminases. The complete normalization of these enzymes was observed after 2 weeks from the disappearance of the skin rash.

In vitro C3 mRNA expression in Pemphigus vulgaris: complement activation is increased by IL-1alpha and TNF-alpha.

BACKGROUND: Pemphigus vulgaris (PV) is a potentially life-threatening disease, characterized immunohistologically by IgG deposits and complement activation on the surface of keratinocytes. Complement activation has been implicated in the pathogenesis with C3 deposits in about 90% of patients. OBJECTIVE: In order to further elucidate the role of complement in PV and to define which cytokines play a role in C3 mRNA expression, we performed an in vitro study in human keratinocytes. METHODS: Normal human epidermal keratinocytes (NHuK) were incubated with PV serum and C3 mRNA was measured. We previously had shown that IL-1alpha and TNF-alpha are expressed in PV in vivo and in vitro. Since cytokines are able to modulate complement activation, mRNA expression was evaluated in a similar experiment after pretreatment using antibodies against IL-1alpha and TNF-alpha. RESULTS: Incubation of NHuK with PV sera caused their detachment from the plates after 20-30 minutes with a complete acantholysis within 12 hours. An early C3 mRNA expression was seen after 30 minutes with a peak level after 1 hour. Blocking studies, using antibodies against human IL-1alpha and TNF-alpha in NHuK together with PV-IgG, showed reduction of in vitro induced acantholysis and inhibition of C3 mRNA expression. CONCLUSION: This study supports the hypothesis that complement C3 is important in PV acantholysis and that complement activation is increased by IL-1alpha and TNF-alpha.

Enhanced epidermal Langerhans cell migration in IL-10 knockout mice.

The migration of epidermal Langerhans cells (LC) to lymph nodes (LN) is critical in the initiation of contact hypersensitivity (CHS) responses. Studies suggest that contact allergen-induced epidermal proinflammatory cytokines, including IL-1 and TNF-alpha, play important roles in promoting LC migration. Contact allergens also induce epidermal anti-inflammatory cytokines such as IL-10. Since IL-10 down-regulates proinflammatory cytokine production and inhibits CHS, we hypothesized that IL-10 might inhibit LC migration. To test this hypothesis, IL-10 knockout (KO) mice were epicutaneously sensitized with the hapten, FITC, and 24 h later hapten-bearing cells in the draining LN were examined. The number of hapten-bearing cells in the LN was significantly greater in IL-10 KO mice than in wild-type mice. The mutant mice also had an exaggerated CHS to FITC. Pretreatment with anti-TNF-alpha Ab or IL-1R antagonist significantly reduced the number of hapten-bearing cells in the LN, suggesting that IL-10 modulation of LC migration involves IL-1 and TNF-alpha. Moreover, IL-10 KO mice demonstrated a greater increase in TNF-alpha, IL-1alpha, and IL-1beta mRNAs in the allergen-exposed epidermis, and keratinocytes derived from the mutant mice were able to produce higher amounts of TNF-alpha and IL-1alpha protein. These data suggest that IL-10 plays an inhibitory role in LC migration and that this effect may occur via the down-regulation of TNF-alpha and IL-1 production.

A Th2-like cytokine response is involved in bullous pemphigoid. the role of IL-4 and IL-5 in the pathogenesis of the disease.

Bullous Pemphigoid is an autoimmune bullous disorder characterized by production of IgG against an hemidesmosomal antigen (230 kDa, 180 kDa) responsible for blistering of the skin. In the past several mediators have been implicated in the pathogenesis of the disease such as proteases and collagenases secreted by local inflammatory cells. In order to investigate the role of cytokines in BP, the cytokine pattern was evaluated by an immunohistochemical analysis and by reverse transcriptase polymerase chain reaction procedure in 13 BP patients. Cytokines examined were interleukin (IL)-2, IL-4, IL-5, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha. The T cell inflammatory infiltrate was also characterized by monoclonal antibodies showing CD3+, CD4+ T cells with a perivascular and scattered distribution in lesional skin. IL-4 and IL-5 were detected in a similar distribution to the inflammatory infiltrate. IL-4 and IL-5 mRNA levels were also revealed by RT-PCR. Proinflammatory cytokines such as TNF-alpha, IL-6 and Th1-like cytokines (IL-2 and INF-gamma) were not detected neither as proteins nor as mRNA. Since IL-4 and IL-5 are important in eosinophil chemoattraction, maturation and functional activity, the presence of IL-4 and IL-5 in BP suggest that these cytokines could be important in the pathogenesis of the disease.

'Suction split' as a routine method to differentiate epidermolysis bullosa acquisita from bullous pemphigoid.

BACKGROUND AND DESIGN: Epidermolysis bullosa acquisita (EBA) and bullous pemphigoid (BP) are diseases with similar clinical, histological, and immunofluorescent findings. Diagnosis requires the use of immunoelectron microscopy, immunoprecipitation or immunoblotting, but in recent years the differential diagnosis has been based on a cheaper technique named salt split skin. This study demonstrates that with a suction blister the fracture is at the same level as that obtained with the sodium split method and that it is also faster and cheaper. Suction blisters on normal skin and autoimmune perilesional bullous lesions, obtained with a hand vacuum pump, were studied by direct immunofluorescence and electron microscopy to evaluate the level of the split on normal suction split skin. Normal human split skin was also used as a substrate for an indirect immunofluorescent study using sera of patients with BP (68 sera), EBA (10 sera) and cicatricial pemphigoid (CP) (16 sera). Direct immunofluorescent examination was also done on perilesional skin after artificial separation obtained with a hand-vacuum pump in patients with the same diseases listed above (32 BP, 11 CP, 6 EBA). RESULTS: On normal human skin split by suction or sodium chloride (NaCl; 1 mol/l) direct immunofluorescence and electron microscopy demonstrated that the split is at the lamina lucida level. Indirect immunofluorescent study of both normal human skin and perilesional skin split using suction as a substrate showed IgG deposits localized on the floor of the suction blister in all cases of EBA, whereas in over 88% of cases of BP and in over 62% of CP the IgG were localized on the roof. Similar results were obtained with direct immunofluorescence in perilesional skin. CONCLUSIONS: 'Suction split' represents a simple technique to differentiate EBA from BP. This method provides final response in a few hours compared to at least 1-2 days with the sodium split method. Furthermore, the suction split method is cheaper and the tissue can be re-utilized for molecular biology and immunohistochemical studies.