The onset risk of carcinoma in patients continuing tacrolimus topical treatment for oral lichen planus: a case report.

Oral lichen planus is a chronic inflammatory mucocutaneous disease. Topical use of steroids and other immuno-modulating therapies have been tried for this intractable condition. Nowadays, tacrolimus ointment is used more commonly as a choice for treatment. However, a number of discussions have taken place after tacrolimus was reported to be carcinogenic. This report describes a patient who applied tacrolimus ointment to the lower lip after being diagnosed with oral lichen planus in 2008, and whose lesion developed squamous cell carcinoma in 2010. Since the relationship between tacrolimus and cancer development has been reported in only a few cases, including this case report, the clinician must be careful selecting tacrolimus as a second-line treatment for oral lichen planus.

Antigen-independent development of Foxp3+ regulatory T cells suppressing autoantibody production in experimental pemphigus vulgaris.

The CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) play suppressive roles in various types of autoimmunity. It has been reported that Tregs develop in the thymus after high-affinity interaction of their TCR with self-peptide/MHC ligands mostly utilizing TCR-transgenic system. In this study, we examined whether the specific antigen is involved in the development of polyclonal Tregs in pemphigus vulgaris (PV), an autoimmune blistering disease caused by anti-desmoglein 3 (Dsg3) IgG antibodies, as a model system. Adoptive transfer of splenocytes of Dsg3(-)(/-) mice immunized with recombinant mouse Dsg3 to Rag2(-)(/-) recipient mice expressing Dsg3 resulted in the stable production of anti-Dsg3 IgG and the development of PV phenotypes. We show here that Tregs control anti-Dsg3 antibody production in PV model mice: the adoptive transfer of Tregs and the depletion of endogenous Tregs suppressed and augmented, respectively, the anti-Dsg3 antibody production. To examine whether the endogenous expression of Dsg3 is involved in the generation of these PV-relevant Tregs, we compared the potential of wild-type Tregs with that of Tregs from Dsg3(-)(/-) mice. Polyclonal Tregs from Dsg3(-)(/-) mice were more potent than that of wild-type mice, in both adoptive transfer and Treg-depletion experiments, while suppressive activities against IgG production against an irrelevant antigen were similar between Tregs from wild-type and Dsg3(-)(/-) mice. Our observation implies that Tregs capable of suppressing T(h) cells that drive autoantibody production can develop in the absence of the target antigen.

Novel system evaluating in vivo pathogenicity of desmoglein 3-reactive T cell clones using murine pemphigus vulgaris.

Autoreactive T cells are thought to be involved in the pathogenesis of autoimmune diseases, but evidence for their direct pathogenicity is almost lacking. Herein we established a unique system for evaluating the in vivo pathogenicity of desmoglein 3 (Dsg3)-reactive T cells at a clonal level in a mouse model for pemphigus vulgaris (PV), an autoimmune blistering disease induced by anti-Dsg3 autoantibodies. Dsg3-reactive CD4(+) T cell lines generated in vitro were adoptively transferred into Rag-2(-/-) mice with primed B cells derived from Dsg3-immunized Dsg3(-/-) mice. Seven of 20 T cell lines induced IgG anti-Dsg3 Ab production and acantholytic blister, a typical disease phenotype, in recipient mice. Comparison of the characteristics between pathogenic and nonpathogenic Dsg3-reactive T cell lines led to the identification of IL-4 and IL-10 as potential factors associated with pathogenicity. Further in vitro analysis showed that IL-4, but not IL-10, promoted IgG anti-Dsg3 Ab production by primed B cells. Additionally, adenoviral expression of soluble IL-4Ralpha in vivo suppressed IgG anti-Dsg3 Ab production and the PV phenotype, indicating a pathogenic role of IL-4. This strategy is useful for evaluating the effector function of autoreactive T cells involved in the pathogenesis of various autoimmune diseases.

G-protein-coupled receptor GPR49 is up-regulated in basal cell carcinoma and promotes cell proliferation and tumor formation.

The significance of Hedgehog (HH) signaling in the development of basal cell carcinoma (BCC) has been established. Although several target genes of HH signaling have been described previously, their precise role in tumorigenesis and cell proliferation is not yet known. To identify genes responsible for tumor formation in BCC, we screened a DNA microarray database of human BCC cases; the orphan G-protein-coupled receptor GPR49 was found to be up-regulated in all cases. GPR49 is a novel gene reported to be a marker of follicular and other tissue stem cells. Using real-time quantitative RT-PCR analysis, significant expression of GPR49 mRNA was observed in 19 of 20 BCC cases (95%) compared with controls. Up-regulation of GPR49 was confirmed by in situ hybridization. Moreover, knockdown of mouse Gpr49 showed suppression of cell proliferation in a mouse BCC cell line, and overexpression of GPR49 in human immortalized keratinocyte HaCaT cells induced proliferation. Furthermore, HaCaT cells overexpressing GPR49 showed tumor formation when transplanted into immunodeficient mice. In addition, inhibition of the HH signaling pathway in a mouse BCC cell line down-regulated endogenous Gpr49, whereas activation of HH signaling in mouse NIH3T3 cells up-regulated endogenous GPR49. These results suggest that GPR49 is expressed downstream of HH signaling and promotes cell proliferation and tumor formation in cases of BCC.

Pemphigus mouse model as a tool to evaluate various immunosuppressive therapies.

Pemphigus vulgaris (PV) is an autoimmune bullous disease caused by immunoglobulin G (IgG) autoantibodies against desmoglein 3 (Dsg3). We have generated an active disease mouse model for PV by adoptive transfer of Dsg3(-/-) lymphocytes. In this study, we investigated the benefits and limitations of this model as a tool to evaluate various immunosuppressive therapeutic strategies. We used the following three measurements to evaluate the effects of the drugs during the time course: Dsg3 enzyme-linked immunosorbent assay scores that represent the level of production of anti-Dsg3 IgG, body weight loss that reflects the severity of oral erosions and PV score that reflects the extent of skin lesions. We examined various immunosuppressive agents currently used to treat patients with PV model mice in preventive protocol. Cyclophosphamide almost completely suppressed the production of anti-Dsg3 IgG, development of body weight loss and the appearance of the PV phenotype in contrast with the control group without the drug. Azathioprine, cyclosporin A and tacrolimus hydrate also showed suppressive effects to various degrees. However, methylprednisolone and dexamethasone failed to show significant effects in contrast to the findings reported in humans. Knowing the advantages and limitations of this model will provide an important foundation for the future evaluation and development of novel therapeutic strategies.

Autoreactive B-cell elimination by pathogenic IgG specific for the same antigen: implications for peripheral tolerance.

Harmful pathogenic IgG auto-antibodies are produced against desmoglein 3 (Dsg3) in pemphigus vulgaris, an autoimmune blistering disease. Dsg3 is a cadherin-type cell adhesion molecule expressed in desmosomes of the skin and mucous membranes. In AK7-transgenic mice expressing non-pathogenic AK7 IgM against Dsg3, autoreactive transgenic B cells escape from the deletion or inactivation and exist in the periphery. However, when a pathogenic anti-Dsg3 IgG1 mAb (AK23) capable of inducing blisters was injected into AK7-transgenic mice, AK7 B cells were eliminated from the bone marrow (BM) and spleen only when Dsg3 was expressed in the periphery. In contrast, non-pathogenic IgG mAbs (AK7, AK9) failed to eliminate AK7 B cells. Interestingly, the AK23-mediated elimination of mature AK7 B cells in the spleen was significantly diminished in AK7-transgenic mice on a Rag2(-/-) background while BM B cells were still eliminated, suggesting the presence of T-cell-dependent and -independent mechanisms. T cell transfer studies into AK7-Rag2(-/-) mice revealed that autoreactive B-cell elimination in the periphery requires CD4(+) T cells from wild-type mice but not from gld (FasL mutant) mice. The B-cell elimination was impaired in both BM and periphery when Bcl2 was over-expressed in AK7 B cells. These findings suggest that autoreactive B cells exist unless they are harmful, but once harmful or dangerous events such as tissue destruction are sensed, the mature autoreactive B cells in the periphery are eliminated via a Fas-mediated process in a CD4(+) T cell-dependent manner.

A randomized double-blind trial of intravenous immunoglobulin for pemphigus.

BACKGROUND: Pemphigus is a rare life-threatening intractable autoimmune blistering disease caused by IgG autoantibodies to desmogleins. It has been difficult to conduct a double-blind clinical study for pemphigus partly because, in a placebo group, appropriate treatment often must be provided when the disease flares. OBJECTIVE: A multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of a single cycle of high-dose intravenous immunoglobulin (400, 200, or 0 mg/kg/d) administered over 5 consecutive days in patients relatively resistant to systemic steroids. METHODS: We evaluated efficacy with time to escape from the protocol as a novel primary end point, and pemphigus activity score, antidesmoglein enzyme-linked immunosorbent assay scores, and safety as secondary end points. RESULTS: We enrolled 61 patients with pemphigus vulgaris or pemphigus foliaceus who did not respond to prednisolone (> or =20 mg/d). Time to escape from the protocol was significantly prolonged in the 400-mg group compared with the placebo group (P < .001), and a dose-response relationship among the 3 treatment groups was observed (P < .001). Disease activity and enzyme-linked immunosorbent assay scores were significantly lower in the 400-mg group than in the other groups (P < .05 on day 43, P < .01 on day 85). There was no significant difference in the safety end point among the 3 treatment groups. LIMITATION: Prednisolone at 20 mg/d or more may not be high enough to define steroid resistance. CONCLUSION: Intravenous immunoglobulin (400 mg/kg/d for 5 d) in a single cycle is an effective and safe treatment for patients with pemphigus who are relatively resistant to systemic steroids. Time to escape from the protocol is a useful indicator for evaluation in randomized, placebo-controlled, double-blind studies of rare and serious diseases.

Abnormal keratin expression in circumscribed palmar hypokeratosis.

BACKGROUND: Circumscribed palmar or plantar hypokeratosis (CPH) is a rare skin disorder only recently described. OBJECTIVE: To determine the diagnostic features and to provide insight into the pathogenesis of CPH, with analysis of two new Japanese cases. METHODS: Dermoscopy, immunohistochemistry, electron microscopy, polymerase chain reaction amplification for human papillomavirus (HPV) DNA and 16S microbial rRNA gene profiling were conducted. RESULTS: Dermoscopy showed characteristic features using both dry and jelly immersion observation; step-like desquamation and a homogeneous erythema with regularly distributed whitish spots. Immunohistochemistry revealed strong staining with anti-pankeratin antibody (AE1+AE3) and anti-keratin 16 antibody, and decreased expression of keratin 2e. EM revealed a breakage of the corneocytes within their cytoplasm, but structures for cell attachment were intact. HPV and lesion-specific bacteria were not detected. LIMITATIONS: The number of cases analyzed was two. CONCLUSION: Hyperproliferative epidermal state along with enhanced corneocyte fragility may account for the unique features in CPH.

Additive contribution of multiple factors in the development of pneumatosis intestinalis: a case report and review of the literature.

We describe a 53-year-old patient with dermatomyositis, who developed pneumatosis intestinalis (PI) accompanied by pneumoperitoneum, pneumoretroperitoneum, pneumomediastinum, and subcutaneous emphysema of the neck. The development of PI in our patient was possibly attributed to the effect of factors such as dermatomyositis, corticosteroids, methotrexate, and alpha-glucosidase inhibitor (AGI). The coexistence of multiple factors associated with PI might enhance the risk of developing PI, even though each of them alone is not sufficient to induce it. In particular, the use of AGIs for patients treated with immunosuppressive agents such as corticosteroids requires evaluation.

Compound heterozygosity for novel splice site mutations of ITGA6 in lethal junctional epidermolysis bullosa with pyloric atresia.

Junctional epidermolysis bullosa with pyloric atresia (PA-JEB) is a rare congenital bullous disease with gastrointestinal disturbance that has been associated with mutations in ITGA6 or ITGB4 encoding the α6 or ß4 subunit of integrin, respectively. Only six ITGA6 mutations in PA-JEB have been reported while many ITGB4 mutations have been identified, and all the ITGA6 mutations were homozygous. Here, we report a case of lethal type PA-JEB, in which immunofluorescence showed the lack of both α6 and ß4 integrins resulting from compound heterozygous splice site mutation in ITGA6, c.387G>T and c.2506-1G>C. Maternal c.387G>T induced the skipping of the entire exon 3 and both exons 3 and 4, resulting in premature termination codon and in-frame deletion, respectively. Paternal c.2506-1G>C caused the skipping of the exon 20 and resulted in in-frame deletion. As a reason why the present case showed lethal phenotype despite the in-frame deletion mutation, rapid degradation of neo-synthesized α6 protein and/or impaired transport of integrin were suggested from previous reports, and the lack of localization of integrin α6ß4 to the epidermal basement membrane resulted in skin fragility. Our case expands the variety of integrin α6 mutations in PA-JEB.

Tolerance induction by the blockade of CD40/CD154 interaction in pemphigus vulgaris mouse model.

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by IgG autoantibodies against desmoglein 3 (Dsg3). We have recently developed an active disease mouse model for PV by adoptive transfer of splenocytes from Dsg3(-/-) mice. The purpose of this study was to determine the role of CD40/CD154 interaction in the pathogenic antibody production and development of the disease in PV model mice. When anti-CD154 monoclonal antibody (mAb) was administered to recipient mice prior to adoptive transfer, anti-CD154 mAb almost completely blocked the anti-Dsg3 IgG production and prevented blister formation. The blockade of CD40/CD154 interaction induced tolerance against Dsg3 as the suppression of antibody production was observed through day 70, and it was maintained even after challenge by immunization with recombinant mouse Dsg3 or by adoptive transfer of immunized Dsg3(-/-) splenocytes. Furthermore, the tolerance to Dsg3 was transferable because cotransfer of splenocytes from anti-CD154 mAb-treated mice and naïve Dsg3(-/-) splenocytes significantly suppressed anti-Dsg3 IgG production in recipient mice. In contrast, when anti-CD154 mAb was injected after the mice had developed the PV phenotype, no significant suppression of the production of anti-Dsg3 IgG was observed. These findings indicate that the CD40/CD154 interaction is essential for the induction of pathogenic anti-Dsg3 IgG antibodies and that antigen-specific immune-regulatory cells induced by anti-CD154 mAb would hold a therapeutic option for autoimmune diseases.

A history of Japanese dermatology: past, present and future.

On the occasion of the 14th Korea-Japan joint meeting of dermatology, the founding of the Japanese Dermatological Association, its activities and relationship to neighboring societies were presented to let both Korean and Japanese participants know the current status of Japanese dermatology. It is felt that one central meeting in Asia will be necessary to make a strong impact on not only Asian but also Western colleagues. We should make more of an effort to get used to our common international language, English, so that we can communicate with other Asian colleagues more closely and in more depth in this era of increasing globalization.

In vivo ultrastructural localization of the desmoglein 3 adhesive interface to the desmosome mid-line.

Desmoglein (Dsg) is a cadherin cell-cell adhesion molecule located in desmosomes and its precise mechanism for cell-cell adhesion still remains to be elucidated. Opposing cadherin molecules may adhere to the N-terminal EC1 domains, or the entire length of the extracellular (EC) domains may overlap. To solve this controversy, we performed immunoelectron microscopy to map the Dsg3 epitopes in desmosomes. Three different hybridoma cell lines producing anti-Dsg3 monoclonal antibodies (mAb) were intraperitoneally injected into immunodeficient mice and the precise ultrastructural location of bound IgG between the mucosal epithelial cells in vivo was statistically measured and analyzed. The binding site of the AK23 mAb that recognizes the N-terminal EC1 domain was localized to the electron-dense mid-line of desmosomes. The binding sites of AK7 and AK18, which recognize the C-terminal membrane proximal and middle portions of the EC domains, were localized to the desmosomal region proximal to the membrane and the region between the plasma membrane and the dense mid-line, respectively. These results indicate that the N-terminal regions of Dsg3 from opposing cells interact at the dense mid-line of desmosomes where EC1 overlaps.

Genetic identification and detection of human pathogenic Rhizopus species, a major mucormycosis agent, by multiplex PCR based on internal transcribed spacer region of rRNA gene.

BACKGROUND: Mucormycosis is an invasive opportunistic infection caused by fungi belonging to the order Mucorales. Due to the lack of laboratory tests, the diagnosis of mucormycosis is notoriously difficult. Added with its rapid progression as well as the debilitated state of the patients who contract the disease, mortality is extremely high. OBJECTIVE: The goal of this study was to genetically identify human pathogenic Rhizopus species, a major mucormycosis agent, by the internal transcribed spacer (ITS) region of rRNA gene. METHODS: Primers were designed to identify five Rhizopus species known to cause human disease by multiplex PCR. PCR was done not only with test strains and clinical isolates, but also with clinical samples from cutaneous mucormycosis patients. Sporangiospore morphology was observed by scanning electron microscopy to confirm the correlation of phenotypic and genotypic features. RESULTS: Multiplex PCR identified five Rhizopus species including Rhizopus oryzae, where R. azygosporus could only be distinguished from R. microsporus by certain polymorphisms that were present in its sequence. When this multiplex PCR was applied to clinical samples from three mucormycosis patients (paraffin sections from all and sera from one patient), Rhizopus DNA corresponding to the isolated pathogens were specifically detected. CONCLUSION: While fungal DNA detection from clinical samples is a rigorously studied area, this is the first report to genetically identify and detect Rhizopus species from human mucormycosis specimens. This may expand the possibility of this multiplex PCR system not only to identify isolated fungi, but also as a screening method for visceral mucormycosis.

Detection of potentially novel bacterial components of the human skin microbiota using culture-independent molecular profiling.

Although the micro-organisms forming the cutaneous microbiota are considered to play important roles in the modification and prevention of skin diseases, a comprehensive analysis of their composition has not yet been carried out because of difficulties in determining yet-to-be-cultured micro-organisms in the samples. Swab-scrubbed forehead skin samples of five healthy volunteers were analysed by profiling 16S rRNA genes, as well as by conventional culture methods, to provide a profile of the cutaneous microbiota that included yet-to-be-cultured bacteria from normal human skin. Cluster analyses of the 16S rRNA gene sequences indicated a marked increase in diversity compared with that derived from the culture methods. Nineteen previously recognized species and 13 novel phylotypes were obtained from the analysis of 416 clones. In addition to well-known bacteria such as Staphylococcus epidermidis and Propionibacterium acnes, phylotype A, the 16S rRNA gene of which is 97 % similar to that of Methylophilus methylotrophus, was detected in three of the five samples, in one of which it was the predominant clone. Culture-independent genetic profiling of 16S rRNA genes for detecting human cutaneous microbiota has allowed us to detect potentially novel components of the cutaneous microbiota in humans.

Usefulness of BP180 NC16a enzyme-linked immunosorbent assay in the serodiagnosis of pemphigoid gestationis and in differentiating between pemphigoid gestationis and pruritic urticarial papules and plaques of pregnancy.

BACKGROUND: Pemphigoid gestationis (PG) is a rare pregnancy-associated subepidermal immunobullous disease that targets hemidesmosomal proteins, particularly BP180. Clinically, PG can resemble the eruption known as polymorphic urticarial papules and plaques of pregnancy (PUPPP), and accurate differentiation between these 2 pruritic pregnancy dermatoses has important implications for fetal and maternal prognoses. Results of epitope mapping studies show that IgG autoantibodies in up to 90% of PG serum samples target the well-defined membrane-proximal NC16a domain of BP180. OBJECTIVE: To examine the usefulness of a commercially available NC16a domain enzyme-linked immunosorbent assay in the serodiagnosis of PG and in the differentiation of PG from PUPPP. PARTICIPANTS: A total of 412 women consisting of pretreatment patients with PG (n = 82), patients with PUPPP (n = 164), and age- and sex-matched controls (n = 166). METHODS: All serum samples were assayed in duplicate. Receiver operating characteristic analyses were performed to determine a cutoff value for the diagnosis of PG and for differentiation from PUPPP and controls. RESULTS: A cutoff value of 10 enzyme-linked immunosorbent assay units was associated with specificity and sensitivity of 96%. CONCLUSIONS: The NC16a enzyme-linked immunosorbent assay is highly sensitive and highly specific in differentiating PG from PUPPP, and it is potentially a valuable tool in the serodiagnosis of PG.

Cutaneous type pemphigus vulgaris: a rare clinical phenotype of pemphigus.

Pemphigus is an autoimmune blistering disease of the skin, mucous membranes, or both. There are two main categories of pemphigus: pemphigus foliaceus (PF) and pemphigus vulgaris (PV). PV is further subdivided into mucosal dominant and mucocutaneous types, according to the extent of cutaneous lesions. These classes of pemphigus have distinct histopathologic and serologic findings, with most cases falling into these subtypes. We report 4 cases that clinically showed blisters and erosions in the skin only, without mucosal involvement. Histologic examination of cutaneous lesions demonstrated suprabasilar acantholysis, a typical finding for PV. These patients had predominant anti-desmoglein 1 (Dsg1) IgG autoantibodies as well as anti-Dsg3 IgG autoantibodies, as determined by enzyme-linked immunosorbent assay. The desmoglein compensation theory posits that this rare phenotype can be produced by pathogenically weak anti-Dsg3 IgG in the presence of potent anti-Dsg1 IgG autoantibodies. Thus, cutaneous type PV without apparent mucosal involvement is observed as a rare clinical and histologic expression of pemphigus. This expression can be a transient phenotype that may develop from, or evolve into, other subtypes of pemphigus.

Identification of Trichophyton rubrum by nested PCR analysis from paraffin embedded specimen in trichophytia profunda acuta of the glabrous skin.

Trichophytia profunda acuta of the glabrous skin (TPAGS) arose in a 67-year-old Japanese man. The patient presented indurated erythematous plaques and nodules on his left forearm. Direct microscopic examination of the scale in KOH preparation was negative for fungal elements, and culture for dermatophytes was also negative. Although fungal infection could not be proven in hematoxillin-eosin stained sections, deep-cut sections of the biopsied skin lesion with PAS stain revealed the ectothrix presence of fungal elements. Nested PCR was done with Trichophyton specific primers directed to internal transcribed spacer gene 1 (ITS1), using template DNA obtained from formalin fixed, paraffin embedded skin sections. A single band corresponding to T. rubrum was obtained, and the etiological agent was thus identified. KOH tests and cultures may often turn out unsuccessful, perhaps reflecting the hair follicle dominant fungus growth in TPAGS. Although these tests are most important for diagnosis of TPAGS, nested PCR using paraffin embedded skin sections may be an alternative method to identify the etiological agent.

[Dermatomycoses and medically important fungi that are necessary subjects of study for dermatology specialists -a personal experience].

Among the numerous skin diseases, dermatomycosis is the one caused by fungus (parasite) infecting the skin (host) . Once diagnosis is made, dermatomycosis can be cured with the use of appropriate anti-fungal drugs. Therefore, it is a much more easily treatable disease compareds with intractable skin diseases. From his own experience, the author shows that dermatomycoses are good subspecialties to deal with because many of them are controllable. At the same time, the author points out that basic research on medically important fungi needs to be done as collaborative studies with basic scientists and dermatology specialists. This brief review covers several topics including diagnostics of medical mycoses, imported medical mycoses, tinea, and cutaneous deep mycoses.

IgG binds to desmoglein 3 in desmosomes and causes a desmosomal split without keratin retraction in a pemphigus mouse model.

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by IgG autoantibodies against desmoglein 3 (Dsg3). In this study, we characterized the ultrastructural localization of in vivo-bound IgG, Dsg3, and desmoplakin during the process of acantholysis in an active mouse PV model, using post-embedding immunoelectron microscopy. In non-acantholytic areas of keratinocyte contact, IgG labeling was restricted to the extracellular part of desmosomes, and was evenly distributed throughout the entire length of the desmosome. The distribution of in vivo IgG was similar to that of anti-Dsg3 labeling in the control mouse. Within the acantholytic areas, there were abundant split-desmosomes with keratin filaments inserted into the desmosomal attachment plaques. These split-desmosome extracellular regions were also decorated with anti-Dsg3 IgG and were associated with desmoplakin staining in their cytoplasmic attachment plaques. No apparent split-desmosomes, free of IgG-labeling were observed, suggesting that Dsg3 was not depleted from the desmosome before the start of acantholysis in vivo. Desmosome-like structures (without keratin insertion) were found only on the lateral surfaces of basal cells, but not on the apical surfaces at the site of acantholytic splits. These findings indicate that anti-Dsg3 IgG antibodies can directly access Dsg3 present in desmosomes in vivo and cause the subsequent desmosome separation that leads to blister formation in PV.