Human Mast Cell Chymase Cleaves Pro-IL-18 and Generates a Novel and Biologically Active IL-18 Fragment

Increased release of IL-18 in the skin causes atopic dermatitis (AD)-like skin lesions, suggesting a role of IL-18 in the pathogenesis of AD. Caspase-1 is a well-known activator of IL-18, but caspase-1 knockout mice still have biologically active IL-18. Normal human keratinocyte constitutively produces pro-IL-18, but it is unable to activate it, suggesting the existence of an alternative pathway for IL-18 in the skin. Dermal accumulation of mast cells is commonly observed in AD patients and in experimental mouse models of AD. Connective tissue mast cells contain high amounts of chymase and tryptase in their cytoplasmic granules. In the present study, we demonstrated that activation of IL-18 is a novel function of human mast cell chymase. Human mast cell chymase rapidly cleaves recombinant pro-IL-18 at 56-phenylalanine and produces a biologically active IL-18 fragment that is smaller than any other reported IL-18-derived species. The human mast cell chymase and the novel IL-18-derived active peptide may be novel therapeutic targets in AD- and IL-18-associated diseases.

Reduced heterochromatin protein 1-beta (HP1beta) expression is correlated with increased invasive activity in human melanoma cells

Heterochromatin protein 1 (HP1) is associated with heterochromatin formation and the regulation of gene expression. In this study, we demonstrated that decreased HP1beta, but not HPla, mRNA and protein expression, correlates with invasive potential in five human melanoma cell lines, and we used immunohistochemistry to confirm that HP1beta expression is suppressed during melanoma progression. HPIP levels are decreased in (V600E)B-RAF-transformed mouse melanocytes, suggesting that HP1beta-mediated suppressive mechanisms correlate with melanoma oncogenesis. Expression of microphthalmia associated-transcription factor (MITF), an important melanocyte differentiation factor, is reduced in melanoma, which is correlated with poor prognosis. In CRL1579, SK-MEL-28 and HMV-II human melanoma cells in which HP1beta expression is reduced by RNAi, MITF RNA levels and invasiveness activities are differentially altered and are not correlated with each other. Our findings indicate that the (V600E)B-RAF mutation induces HPIbeta down-regulation, which causes epigenetic gene regulation associated with melanoma progression.

Keratin profiles may differ between intraepidermal and intradermal invasive eccrine porocarcinoma

We report two cases of eccrine porocarcinoma (EPC), one of intrepidermal EPC (IEEPC) and one of intradermal invasive EPC (IDEPC) in an immunohistochemical study of cytokeratins (CK) using nine different anti-keratin antibodies against CK1, 7, 8, 10, 14, 16, 17, 18 and 19. IEEPC expressed terminal differentiated CK1 and CK10. In contrast, IDEPC expressed simple-epithelial keratins such as CK7, 8, 18 and 19. Keratin expression of IEEPC preserves the immunophenotypes of normal epidermis. IDEPC, however, expresses poorly differentiated keratin. These results suggest that the keratin profiles of EPC are correlated with the invasive degree and reflect the clinical prognosis of EPC.

Cytokeratin expression in trichilemmal carcinoma suggests differentiation towards follicular infundibulum

An immunohistochemical study of cytokeratins (CK) in a case of trichilemmal carcinoma (TLC). CK expression showed the presence of CK 1, 10, 14 and 17, suggesting that TLC differentiates toward follicular infundibulum. In a comparison of CK expression between TLC and trichilemmoma, the absence of CK 15 and 16 in TLC may be related to transformation from trichilemmoma to TLC. Trichilemmal carcinoma (TLC) is a rare cutaneous tumor, and is considered as a malignant counterpart of trichilemmoma. The histogenesis of TLC remains unclear. The features of TLC resemble the outer root sheath. Monoclonal antibodies against cytokeratin (CK) are crucial markers for evaluating the origin of epithelial tumors and the stage of differentiation. To elucidate the origin and the stage of differentiation of TLC, an immunohistochemical study of CK was performed using nine different anti-keratin antibodies against CK1, 7, 8, 10,14,16,17, 18 and 19.

Cytokeratin, filaggrin, and p63 expression in reepithelialization during human cutaneous wound healing

Cytokeratin (CK), filaggrin (filament aggregating protein), and p63 expression and cellular distribution during reepithelialization has not been systemically studied in the healing stage of human cutaneous wounds. We examined these proteins by immunohistochemical methods in 12 cases of skin ulcer, using seven anti-keratin antibodies, anti-filaggrin, and anti-p63 antibody. At the edge of the wound in skin ulcers, CK1 and 10 expression was reduced, while CK14, 16, and 17 expression was raised. Beneath the wound bed, all layers of the epidermal tongue, deriving from sweat ducts, were positive for CK14 and 17. Both cytokeratins were also found in basal and luminal cells of the dermal duct. CK expression by epithelia continuous with hair follicles showed that, CK14, 16, and 17 were present, and CK1 and 10 were absent. Filaggrin expression was elevated in reepithelialized epithelium. Expression of p63 expression was verified in the suprabasal layer in reepithelialized epithelia. CK, filaggrin, and p63 expression in the reepithelialization stage at the wound edge and at epidermal appendages remaining in the wound bed is undifferentiated and hyperproliferative. The presence of CK14 and 17 in the remaining epidermal appendages in the pathological wound may be important in epidermal replacement.

Cutaneous dermoid cyst: cytokeratin and filaggrin expression suggesting differentiation towards follicular infundibulum and mature sebaceous gland

We experienced two cases of cutaneous dermoid cysts (DC). To elucidate the histogenesis of DC, we have studied cytokeratin (CK) expression in DC using ten different anti-keratin antibodies against CK1, 7, 8, 10, 14, 15, 16, 17, 18 and 19, and anti-filaggrin (filament aggregating protein) antibody. In the cyst wall of DC, CK1 and 10 were expressed in suprabasal layer, and CK14 was limited to the basal layer. In sebaceous gland-like structures, CK14 was detected in sebaceous acinus, and CK17 was detected in sebaceous duct. The other CKs were not detected. Filaggrin was intensely detected in the granular layer in the cyst wall of DC. CK expression profile of DC was similar to follicular infundibulum and sebaceous gland. These results suggested that DC differentiates towards follicular infundibulum and mature sebaceous gland.

A novel acoustic evaluation system of scratching in mouse dermatitis: rapid and specific detection of invisibly rapid scratch in an atopic dermatitis model mouse

Scratching is an essential and a skin specific behavior induced by itching, which is a common symptom of atopic dermatitis (AD) and other types of dermatitis. Itching sensation and scratching are closely associated and thus scratching times are currently used for evaluating itching in animal models. However, objective measuring systems of scratching to assess the grade of dermatitis and the effectiveness of anti-pruritic drugs in animal dermatitis models are lacking. To investigate a quantitative evaluation system for itching, we have developed a novel acoustic scratching counting system and compared its accuracy with time-consuming slow-motion video recording system. We have also objectively evaluated the efficacy of an antihistamine using this novel system. Scratching behavior of an AD model mouse (K14 driven IL-18 transgenic mouse) was recorded visually and acoustically. Specific scratching sound produced by mice was recorded and counted using a software we have developed, and the results obtained using our acoustic system were not statistically different from data obtained using slow motion video system. Surprisingly, mice scratched more than 10 times/second, which was invisibly rapid motion and revealed inaccuracy of conventional hand counting system. Results were identical to that of measured by 10 times time costing slow-motion video analysis. The antihistamine is clearly effective for suppression of scratching as demonstrated using this objective and accurate method. This novel motion analysis system will open a window for physiological and pathological analysis for animal models and development of anti-pruritic drugs.

Contribution of IL-18 to atopic-dermatitis-like skin inflammation induced by Staphylococcus aureus product in mice

Atopic dermatitis (AD) is a common inflammatory skin disease of unknown etiology. Cutaneous infection with microbes such as Staphylococcus aureus and/or skin cleansing with detergent exacerbates clinical AD. Here, we generated an AD animal model by destroying skin barrier function with detergent and subsequent topical application of protein A from S. aureus (SpA). NC/Nga mice, which genetically have reduced skin barrier function, and BALB/c mice having intact skin barrier function, were susceptible to this combination and developed severe and moderate AD, respectively, associated with dermal accumulation of eosinophils and mast cells. Both types of mice showed an increase in serum levels of IL-18, but not IgE. The epidermis of the NC/Nga mice rapidly expressed T helper type 1 (Th1)-associated chemokines, including ligands for CXCR3 and CCR5, after application of both SpA and detergent, but not after application of detergent alone. Although treatment with detergent induced moderate Th1 cell response, additional SpA treatment was a prerequisite for induction of the differentiation of naive T cells toward unique Th1 cells, termed "super Th1 cells," capable of producing both Th1 (IFN-gamma) and T helper type 2 cytokine (IL-13), as well as IL-3, and expressing CXCR3 and CCR5. Induction of super Th1 cells required IL-18 stimulation. Blockade of IL-18 prevented AD development, whereas blockade of IL-3 partially prevented AD development, suggesting a contribution of IL-18-dependent IL-3 production to AD with cutaneous mastocytosis. il18-/-BALB/c mice similarly evaded SDS/SpA-induced AD. Thus, IL-18 might be important for the development of infection-associated AD by induction of IL-3 from super Th1 cells.

Topical suplatast tosilate (IPD) ameliorates Th2 cytokine-mediated dermatitis in caspase-1 transgenic mice by downregulating interleukin-4 and interleukin-5

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by elevated serum levels of IgE. AD is associated with Th2 cytokines including interleukin (IL)-4, IL-5, IL-13 and IL-10. Systemic administration of suplatast tosilate (IPD) is currently used to treat Th2 cytokine-mediated AD.

OBJECTIVES

To evaluate the effect of topical IPD on skin lesions of AD using a genetically engineered AD mouse model (K14/caspase-1 transgenic mouse: KCASP1Tg).

METHODS

IPD ointment (3%) and white petrolatum (WP) were applied to KCASP1Tg mice every other day from 6 to 14 weeks after birth. Histopathological analysis of skin lesions and measurement of mRNA expression of cytokines in skin lesions and spleen cells were carried out. We also compared changes in serum parameters between IPD-treated and WP-treated KCASP1Tg mice.

RESULTS

WP-treated mice developed dermatitis at 8 weeks after birth. However, skin lesions in IPD-treated mice were limited. Histopathologically, skin lesions in WP-treated KCASP1Tg mice showed marked inflammatory changes with increased mast cell infiltration. However, mice treated with IPD showed minimum skin lesions with scarce mast cell infiltration. WP-treated KCASP1Tg mice had significant elevation in the serum levels of histamine, IgE and IL-18 as compared with IPD-treated KCASP1Tg mice. mRNA expression of IL-4 and IL-5 in the skin lesions from WP-treated KCASP1Tg mice was significantly higher than in those from IPD-treated mice. In the spleen, the expression of IL-4, IL-5 and interferon-gamma was significantly increased in WP-treated KCASP1Tg mice as compared with their IPD-treated counterparts.

CONCLUSIONS

This study shows that topical therapy with IPD inhibits the expression of IL-4 and IL-5 and ameliorates skin manifestations in an AD mouse model, suggesting the potential usefulness of topical IPD for the treatment of AD.

Expression of Interleukin-18 and Caspase-1 in Cutaneous T-Cell Lymphoma

PURPOSE

Cutaneous T-cell lymphoma (CTCL) is a malignancy of skin-homing Th2 T cells. Clonal T cells and CTCL skin lesions typically express Th2 cytokines, including interleukin (IL)-4, IL-5, and IL-10, but fail to produce Th1 cytokines. However, the reason for Th2 bias is unknown. IL-18 is a pleiotropic proinflammatory cytokine produced by monocytes/macrophages lineage as well as epithelial cells, such as human keratinocytes. In the absence of IL-12, IL-18 leads to increased immunoglobulin E production from B cells and enhanced production of IL-4 and IL-13 by basophils, mast cells, and CD4(+) T cells. We have analyzed cytokines in CTCL patients, which may bias the immune response around the Th1/Th2 axis.

EXPERIMENTAL DESIGN

We examined plasma of 95 CTCL patients and skin of 20 CTCL patients for IL-18, caspase-1, IL-12, and other cytokines. To identify the presence or absence of these cytokine proteins in CTCL and normal skin, we cultured explants from skin biopsies on three-dimensional matrices.

RESULTS

Plasma levels of IL-18 and its converting enzyme, caspase-1, were significantly elevated in CTCL. mRNA levels for these factors were also elevated in CTCL skin lesions. Matrices populated with CTCL lesional skin produced significant amounts of IL-18 and caspase-1; however, production of IL-12 protein was barely detectable.

CONCLUSIONS

We propose that the high levels of IL-18 expression in lesional CTCL skin contribute to increased plasma levels of IL-18 and that this, in the face of significantly lower levels of IL-12, may contribute to the Th2 bias seen in this disease.

Comparison of Activities of Enzymes Related to Energy Metabolism in Peripheral Leukocytes and Livers between Holstein Dairy Cows and ICR Mice

Activities of enzymes related to energy metabolism and isoenzyme patterns of lactate dehydrogenase (LDH) were determined in peripheral leukocytes and livers of Holstein dairy cows and Institute of Cancer Research (ICR) mice. In dairy cow liver, activities of enzymes in glycolysis, malate-aspartate shuttle and lipogenesis were lower, but activities of glucose-6-phosphatase in gluconeogenesis were higher than those in mouse liver. Glucokinase activities were below detection limit in leukocytes and liver of the cows. Dairy cow leukocytes and liver showed the isoenzyme patterns with dominance of LDH-1, -2 and-3, whereas mouse leukocytes and liver showed that LDH-5 was dominant. The LDH isoenzyme patterns were very similar between leukocytes and liver in each animal species. Some enzymes in leukocytes may reflect those enzymes activities in liver and be a useful indicator for energy metabolism in animals.

Basic fibroblast growth factor treatment for skin ulcerations in scleroderma

We report the use of topical application of recombinant human basic fibroblast growth factor (rhbFGF) to successfully treat therapy-resistant, chronic leg ulcers in scleroderma. Endothelial cell FGF receptors are directly stimulated by bFGF; also, bFGF promotes the regeneration of capillary-rich granulation tissue. We conclude that topical bFGF may be a powerful new pharmacologic tool for treating severe skin ulcers.

Skin-derived interleukin-7 contributes to the proliferation of lymphocytes in cutaneous T-cell lymphoma

Cutaneous T-cell lymphomas (CTCLs) are malignancies of T cells that have a special affinity for the skin. We have previously reported that much of the T-cell receptor repertoire is altered in CTCL, and both malignant and nonmalignant clones are numerically expanded, presumably in response to T-cell trophic cytokines. We therefore examined levels of the T-cell trophic cytokines IL-2, IL-4, IL-7, IL-12, IL-13, and IL-15 in plasma in 93 CTCL patients and healthy controls. Only IL-7 levels were elevated in CTCL. We next looked at lesional skin from patients with CTCL and found elevated levels of IL-7 mRNA. Explant cultures of normal and lesional CTCL skin biopsies revealed significantly more IL-7 protein production in CTCL skin. Additionally, cultures of CTCL skin released greater numbers of T cells than normal skin; this was blocked by the addition of an IL-7 neutralizing antibody. Finally, these cultures induced proliferation of normal peripheral skin-homing T cells that were added to the cultures. These observations led us to postulate that IL-7 produced by skin cells contributes to the survival and proliferation of T cells within skin lesions and is likely the source of elevated circulating IL-7 in CTCL.

Aurora-B and Rho-kinase/ROCK, the two cleavage furrow kinases, independently regulate the progression of cytokinesis: possible existence of a novel cleavage furrow kinase phosphorylates ezrin/radixin/moesin (ERM)

Cytokinesis is regulated by several protein kinases, such as Aurora-B and Rho-kinase/ROCK. We have indicated that these two kinases are the cleavage furrow (CF) kinases that accumulate at the cleavage furrow and phosphorylate several intermediate filament (IF) proteins into two daughter cells. It has been reported that Aurora-B phosphorylates MgcRacGAP to functionally convert to a RhoGAP during cytokinesis. Therefore, we investigated here the relationship between Aurora-B and Rho-kinase/ROCK in cytokinesis, by using small interfering RNA (siRNA) technique. Aurora-B depletion did not alter the cleavage furrow-specific localization of Rho-kinase/ROCK and vice versa. Treatment of Aurora-B or Rho-kinase/ROCK siRNA increased multinucleate cells, and the effect of double depletion was additive. Aurora-B depletion induced the reduction of cleavage furrow-specific phosphorylation of vimentin at Ser72 but not vimentin at Ser71, myosin light chain (MLC) at Ser19, and myosin binding subunit of myosin phosphatase (MBS) at Ser852. In contrast, Rho-kinase/ROCK depletion led to the reduction of cleavage furrow-specific phosphorylation of MLC at Ser19, MBS at Ser852, and vimentin at Ser71 but not vimentin at Ser72. Cleavage furrow-specific ezrin/radixin/moesin (ERM) phosphorylation was not altered in the Aurora-B- and/or Rho-kinase/ROCK-depleted cells. In addition, C3 or toxin B treatment did not abolish ERM phosphorylation at the cleavage furrow in cells attaining cytokinesis. These results suggest that Aurora-B and Rho-kinase/ROCK regulate the progression of cytokinesis without communicating to each other, and there may exist a novel protein kinase which phosphorylates ERM at the cleavage furrow.

Induction of allergic inflammation by interleukin-18 in experimental animal models

Interleukin-18 (IL-18) has been regarded as a proinflammatory cytokine because of its potent interferon-gamma-inducing activity. However, mutant mice that release excess amounts of IL-18 spontaneously develop pruritic chronic dermatitis-like atopic dermatitis (AD), suggesting the importance of IL-18 for the development of AD. Intriguingly, depletion of il-18 but not stat6, an essential transcriptional factor for IL-4 signaling, rescues the mice from AD, indicating IL-18-dependent, T-helper 2 (Th2) cell-independent AD. This type of AD is classified as innate-type allergy in contrast to Th2 cell-dependent ordinary allergy. Consistent with the previous studies, mice transferred with antigen-specific Th1 cells exhibit no airway hyperresponsiveness and respiratory eosinophilic inflammation after challenge with antigen alone. However, they suffer from asthma upon challenge with antigen plus IL-18, with comparable levels of both the alterations as in those transferred with Th2 cells following challenge with antigen. The former type of asthma is categorized as Th1-associated allergy. Therefore, it is definitely necessary to evaluate whether individual allergic disorders involve either of these IL-18-mediated pathways or a Th2-mediated one.

Apoptosis in the epidermis

Keratinization is a specialized form of apoptosis that produces the stratum corneum concomitant with keratinocyte cell death. Apoptosis of keratinocytes occurs not only during normal keratinization but also in response to various intracellular or extracellular death stimuli, such as genetic defects or UVB. In general, apoptosis is characterized by chromatin condensation, membrane blebbing, cell shrinkage, formation of apoptotic bodies, and deoxyribonucleic acid fragmentation. The nick-end labeling technique is a method to detect DNA fragmentation and is useful to assess the presence of apoptotic cells in tissues or cells. In this chapter, a practical procedure for nick-end labeling using paraffin-embedded sections of skin specimens is described.

Malate dehydrogenase activities are lower in some types of peripheral leucocytes of dogs and cats with type 1 diabetes mellitus

The activities of the enzymes in the malate-aspartate shuttle were measured in peripheral leucocytes of spontaneous type 1 diabetic dogs and cats treated with insulin injections. In the diabetic dogs and cats, fasting plasma glucose concentrations were three- or fourfold greater than the control levels in spite of insulin injections and the activities of cytosolic malate dehydrogenase (MDH), one of pivotal enzymes in the malate-aspartate shuttle, were remarkably lower than the controls. Depressed expression of cytosolic MDH mRNA was confirmed by RT-PCR analysis in the diabetic animals. The cytosolic ratio of MDH/lactate dehydrogenase (LDH) activity (M / L ratio) in leucocytes of the diabetic animals was significantly lower than that of normal control animals. The smaller M / L ratio appeared to reflect depression of energy metabolism in the diabetic animals. Intrinsically lower and further decreased MDH activities may be factors that induce insulin resistance observed in diabetic cats.

Drug eruption caused by azathioprine: value of using the drug-induced lymphocytes stimulation test for diagnosis

Azathioprine (AZA) is an immunosuppressant commonly used for organ transplantation and autoimmune diseases. Allergic side effects of AZA are rare, and reported allergic skin eruptions from AZA are very limited in Japan. We report AZA-induced drug eruption that developed in two cases of systemic scleroderma with polymyositis. One case presented with Stevens-Johnson syndrome, and the other had systemic papular erythema. The stimulation indices of the drug-induced lymphocyte stimulation test (DLST) for AZA in these two patients were as high as 2,180% and 430%, respectively, but those of healthy volunteers were under 120% without nonspecific suppression of lymphocyte proliferation. Other drugs used simultaneously were ruled out by patch and challenge tests. The challenge test for Stevens-Johnson syndrome type drug allergy is very risky. DLST is a good diagnostic tool for AZA allergy, especially for severe drug allergy cases.

Operative morbidity associated with groin dissections

PURPOSE

Groin dissection remains the treatment of choice for malignant neoplasms of the skin in the lower extremities and perineum. We sought to quantify the hospital complications after groin dissection, and to identify the patient- and procedure-related factors affecting these complications.

METHODS

We reviewed 20 consecutive patients who underwent a collective 25 groin dissections for malignant neoplasms of the skin between 1996 and 2002 to determine the incidence and degree of morbidity, and to analyze the clinical factors associated with morbidity. An S-shaped incision was used for the first 8 procedures, whereas a straight incision was used for the next 17.

RESULTS

The overall incidences of complications were 24% for wound infection, 52% for skin flap problems, 32% for seromas, 40% for edema, and 4% for hemorrhage, whereas the incidences of moderate to severe complications were 16% for wound infection, 16% for skin flap problems, 12% for seromas, 4% for edema, and 4% for hemorrhage. The incidence of wound infection tended to be higher after S-shaped incisions than after straight incisions ( P = 0.059), and the incidence of leg edema was significantly higher after S-shaped incisions than after straight incisions ( P = 0.028).

CONCLUSION

S-shaped incisions more often resulted in lymphatic collection and stagnation, with a higher incidence of wound infections and leg edema than straight incisions. Therefore, we now perform straight incisions to minimize the risk of wound infections and leg edema.

A case of a large dermatofibrosarcoma protuberans successfully treated with radiofrequency ablation and transcatheter arterial embolization

We present a large dermatofibrosarcoma protuberans on a 52 years-old woman's back that was successfully treated with transcatheter arterial embolization and radiofrequency ablation. The tumor developed on her back at the age of 14. Surgical treatment was not complete, and it relapsed at age 17 and again at age 24. The tumor enlarged to over 20x20x10 cm and flooded intermittently. The tumor cells with atypical nuclei were CD34 positive and proliferated in a storiform pattern. These findings were compatible with dermatofibrosarcoma protuberans. She was treated with blood transfusion for severe anemia. Two large feeding arteries were embolized, and the bottom of the tumor was treated with radiofrequency ablation. The tumor reduced in volume by more than 50%. It was then surgically removed and reconstructed with a free mesh skin graft. The combination pretreatment enabled radical resections of a large DFSP without severe complications.

The intravenous xylitol tolerance test in non-lactating cattle

Xylitol is a five-carbon sugar alcohol that is often used for treatment of ketosis in dairy cattle in Japan. An intravenous xylitol tolerance test (IVXTT, 0.1 g/kg, bolus injection through the jugular vein) was performed in 4 non-lactating cows (n = 4) and the results were compared with those of an intravenous glucose tolerance test (IVGTT) performed under equivalent conditions. The serum xylitol concentration reached a peak value (41.4+/-9.0 mg/dl) at 5 min, and then rapidly decreased and almost disappeared within 2 h. The C0 for xylitol was 56.9+/-16.6 mg/dl and the t(1/2) was 8.5+/-0.9 min. The administration of xylitol appeared to cause similar secretion of insulin to that caused by glucose. There was also a reduction in the concentration of free fatty acids. It seems that xylitol has value for the treatment of ketosis. However, rapid administration of xylitol appeared to have an osmotic diuretic action and might be a cause of dehydration.

Persistent secretion of IL-18 in the skin contributes to IgE response in mice

After exposure of the skin to microbes, the host develops skin-specific inflammation and an acquired immune response, in which keratinocytes (KC) and Langerhans cells play critical roles respectively. We established two animal models. (i) We examined the importance of KC-derived IL-18 for the systemic IgE response by using a skin transplantation model. As previously reported, transgenic mice (KCASP1Tg), that over-express caspase-1 in their KC, display high serum levels of IgE, and spontaneously develop chronic dermatitis by production of IL-18 and IL-1beta. We examined the capacity of transplantation of cutaneous lesions from KCASP1Tg to induce IgE production in wild-type or mutant mice with a syngeneic background. Transplantation of active cutaneous lesions, that expressed high levels of IL-18 and IL-1beta, induced long-lasting IgE production in wild-type mice without elevation of circulating IL-18 and IL-1beta. Furthermore, IL-18R-, CD4- or stat6-deficient mice transplanted with the lesions did not produce IgE, indicating that this IgE response is initiated by IL-18, and dependent on host-derived CD4(+) T cells and stat6. (ii) We investigated IL-18 secretion from KC upon stimulation with microbe products. Freshly isolated KC from wild-type mice secreted IL-18 in response to Protein A purified from Cowan 1 strain of Staphylococcus aureus (SpA), which often exacerbates human skin diseases, including atopic dermatitis. Cutaneous application of SpA increased serum levels of IL-18 and IgE. These results indicate that local accumulation of IL-18 triggers systemic IgE responses without exposure to antigen.

Animal models of psoriasis and pustular psoriasis

Investigation of psoriasis and pustular psoriasis is presently hampered by the lack of appropriate animal models. So far, more than ten models have been developed in mice by spontaneous gene mutations and by gene manipulation. However, none of them has satisfactorily reproduced the clinicopathological and immunopathological phenotypes of these diseases. Xenotransplantation techniques have been used for designing models of psoriasis vulgaris, in which CD4(+) T cells have been shown to play an important role. An ideal model for pustular psoriasis should have an immunological background and fulfill the diagnostic criteria of psoriasis.

Bilateral scalp necrosis with giant cell arteritis

We present a patient with bilateral scalp necrosis caused by giant cell arteritis (temporal arteritis). A 67-year-old woman, who had been treated with 5 mg of oral prednisolone every other day for polymyalgia rheumatica, developed painful egg-sized regions of necrosis on both of her temples. Doppler pulsemetory revealed bilateral obstruction of the temporal arteries. Biopsy revealed ischemic necrosis of the skin and necrotic angiitis of the temporal arteries with giant cell infiltration. Bilateral stenosis of the internal carotid arteries and moderate retinal bleeding were revealed by angiography. Daily administration of prednisolone (20 mg/day) with intravenous and topical limaprost alphadex markedly improved her condition. The ulcers reepithelized without surgical treatment. There are few reports of bilateral scalp necrosis. Rapid and complete obstruction of the temporal artery may result in this condition. Simultaneous development of two ulcerative lesions in the ventro-parietal cranial regions is thought to correspond to systemic arterial involvement, including involvement of the internal carotid arteries.

Changes in activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic dogs with glycemic control by intensive insulin treatment

Changes in plasma glucose, immunoreactive insulin (IRI), and free fatty acids (FFA) concentrations and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in type 1 diabetic dogs induced by streptozotocin administration before and after intensive insulin treatments. Before the insulin treatment, the plasma glucose concentrations were over 16.7 mmol/L and the activities of enzymes remarkably decreased in leukocytes of the diabetic dogs. In particular, malate dehydrogenase (MDH) activities decreased significantly. After glycemic control was achieved by insulin treatment, the plasma glucose concentrations were maintained between 6.8 and 7.7 mmol/L and the activities of enzymes restored to those in the control dogs. The changes in ML ratio (cytosolic MDH/lactate dehydrogenase specific activity ratio) reflected faithfully to metabolic conditions of animals and were considered to be a useful parameter to evaluate glycemic control and the effect of injected insulin in the diabetic dogs.

IL-18 contributes to the spontaneous development of atopic dermatitis-like inflammatory skin lesion independently of IgE/stat6 under specific pathogen-free conditions

Atopic dermatitis (AD) is a pruritic inflammatory skin disease. Because IL-18 directly stimulates T cells and mast cells to release AD-associated molecules, Th2 cytokines, and histamine, we investigated the capacity of IL-18 to induce AD-like inflammatory skin disease by analyzing KIL-18Tg and KCASP1Tg, which skin-specifically overexpress IL-18 and caspase-1, respectively. They spontaneously developed relapsing dermatitis with mastocytosis and Th2 cytokine accumulation accompanied by systemic elevation of IgE and histamine. Stat6-deficient KCASP1Tg displayed undetectable levels of IgE but manifested the same degree of cutaneous changes, whereas IL-18-deficient KCASP1Tg evaded the dermatitis, suggesting that IL-18 causes the skin changes in the absence of IgE/stat6. KIL-18Tg and IL-1-deficient KCASP1Tg took longer to display the lesion than KCASP1Tg. Thus, AD-like inflammation is initiated by overrelease of IL-18 and accelerated by IL-1. Our present study might provide insight into understanding the pathogenesis of and establishing therapeutics for chronic inflammatory skin diseases including AD.

Case report. Phaeohyphomycosis caused by Phialophora verrucosa developed in a patient with non-HIV acquired immunodeficiency syndrome

A 53-year-old woman had asymptomatic multiple nodules on her gluteal region for 6 months. She had a history of systemic corticosteroid treatment for Evans' syndrome. Recently she had developed an immunodeficiency condition with CD4+ cell depletion without an HIV infection and a normal serum gamma globulin level. A smear from the purulent exudate of the nodules revealed many brown-coloured hyphae, spores and few large dark-brown cells. A short, hairy, dark-brown coloured colony was cultivated on Sabouraud glucose agar. Slide culturing revealed only a Phialophora-type conidia formation, and the fungus was diagnosed as Phialophora verrucosa. Severe immunosuppressive condition (non-HIV acquired immunodeficiency syndrome) of this patients after systemic corticosteroid treatment for Evans' syndrome predisposed an opportunistic cutaneous fungal infection due to P. verrucosa. Cases with cutaneous infection due to P. verrucosa reported in Japan are summarized and discussed.

Pyoderma gangrenosum associated with paroxysmal nocturnal hemoglobulinuria and monoclonal gammopathy

Pyoderma gangrenosum developed in a man with a five-year history of paroxysmal nocturnal hemoglobinuria and monoclonal gammopathy. He had multiple walnut sized ulcers on his back and extremities, plasma IgM-k type M-protein and low erythrocytic CD55 expression. This is an extremely rare association. However, clonal expansion of plasma cells and chimeric expression of hematopoietic cell glycosylphosphatidylinositol (GPI)-anchored proteins may represent somatic mutations of hematopoietic stem cells in PG as well as PNH. PNH is based on abnormalities in the GPI-anchor formation on various hematopoietic and non-hematopoietic cells. Since the GPI-anchored proteins have pleiotropic functions in complement mediated cell lysis, leukocyte motility, and coagulation systems, the present case may indicate the possible involvement of a GPI-anchored protein abnormality in the pathogenesis of PG.

Effect of short-term low-intensity exercise on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in non-obese Japanese type 2 diabetic patients

The aim of the present study was to investigate the effects of short-term physical exercise that did not change body mass on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in 39 non-obese Japanese type 2 diabetic patients. Insulin sensitivity and insulin secretion were estimated with homeostasis model assessment insulin resistance (HOMA-IR) and HOMA-B-cell function proposed by Matthews et al., respectively. All patients were hospitalized and were engaged in low-intensity exercise that consisted of walking and dumbbell exercise for successive 7 days. There were no changes in hospital diet and the dose of any medications used throughout the study. Fasting glucose, insulin, and lipids were measured before and after exercise. After exercise, serum triglyceride levels significantly decreased, but no significant changes were observed in total and HDL cholesterol concentrations. Fasting glucose, insulin, and HOMA-IR levels significantly decreased after exercise, but HOMA-B-cell function did not change during the study. There was no significant difference between BMI levels before and after exercise. From these results, it can be concluded that short-term (7 days) low-intensity physical exercise combined with hospital diet reduces serum triglycerides, insulin resistance, and fasting glucose levels without affecting BMI in non-obese Japanese type 2 diabetic patients.

[A case of pulmonary eosinophilic granuloma arising rapidly 30 years after the start of smoking and remitting spontaneously without smoking cessation]

A case of pulmonary eosinophilic granuloma which arose rapidly after 30 years of smoking and remitted spontaneously without smoking cessation is reported. The patient was a 54-year-old man complaining of a dry cough who had been smoking 30 cigarettes a day for 30 years. Chest roentgenography showed multiple nodular shadows and cystic lesions in the upper and middle fields of both lungs. Chest computed tomography revealed multiple small cysts and small nodular lesions, mainly in both upper lung fields. CT findings strongly suggested pulmonary eosinophilic granuloma. A transbronchial lung biopsy (TBLB) was performed and 4 specimens were obtained, of which 3 showed granulomatous lesions with eosinophils and histiocytes. Furthermore, the granulomatous lesions were positive for S-100 protein staining. The symptoms and radiographic findings improved markedly within about 6 months after the onset of symptoms without treatment. Many cases of this disease were diagnosed in the past by open lung biopsy, but the number of cases diagnosed by TBLB is now increasing. The effectiveness of open lung biopsy has been emphasized in the diagnosis of pulmonary eosinophilic granuloma, but TBLB is also useful for diagnosis, especially in the active or early stage of the disease.

[A comparison between midline and paramedian approaches for combined spinal-epidural anesthesia]

We compared midline approach with paramedian approach for combined spinal-epidural anesthesia (CSEA) by needle through needle technique. Seventy patients undergoing elective gynecological surgery received CSEA with a 27 G Whitacre spinal needle, which protrudes 12 mm beyond the tip of the Tuohy needle. The successful subarachnoid puncture with first attempt was noted in 33 patients (94%) of midline group (M group), in 31 patients (89%) of paramedian group (P group). At the subarachnoid puncture, skin to epidural space distance (43.2 mm vs 53.4 mm) and protrusion length of spinal needle (5.5 mm vs 8 mm) were significantly longer in the P group than in the M group. Abdominal radiography revealed the flexion of epidural catheter in 19 patients (54%) of M group and in 2 patients (6%) of P group. The choice of midline or paramedian approach for CSEA did not affect the success rate of the subarachnoid puncture, but paramedian approach required longer protrusion length of the spinal needle than midline approach. To raise the success rate of subarachnoid puncture by paramedian approach, a long protruded spinal needle is recommended.

[Two cases of multi-drug-resistant pulmonary tuberculosis with para-aminosalicylic acid (PAS)-induced hypothyroidism]

Two cases of multi-drug-resistant pulmonary tuberculosis with para-aminosalicylic acid (PAS)-induced hypothyroidism were reported. Case 1; a 73-year-old male, complaining of edema, was admitted to our hospital. He had been treated for his multi-drug-resistant pulmonary tuberculosis during the past 1 year with an antituberculous regimen consisting of ethambutol (EB), ethionamide (ETH) and PAS. A thyroid profile performed when he was admitted to our hospital showed several marked abnormalities: serum thyroid stimulating hormone (TSH) was elevated (69.4 microIU/ml: normal, 0.4-4.2 mIU/ml), free thyroxine level (T4) (0.01 ng/dl; normal, 0.70-1.60 ng/dl) and free triiodothyronine level (Ts) (0.60 pg/ml; normal, 2.3-4.1 pg/ml) were low. PAS was discontinued after he was admitted to our hospital, since PAS was believed to be the cause of the hypothyroidism. A thyroid profile that was repeated after the exclusion of PAS from treatment showed the following results: the TSH level was decreased (13.4 mIU/ml), the free T4 (0.93 ng/dl) were normal. During treatment with PAS, he had never received thyroid replacement therapy. Case 2; A 22-year-old female, complaining of hemosputum. She had been treated for her multi-drug-resistant pulmonary tuberculosis during the past 11 months with an antituberculous regimen consisting of EB, ETH and PAS. A thryoid profile performed when she was admitted to our hospital showed several marked abnormalities: elevated serum TSH (112.7 mIU/ml), and low T4 (2.0 micrograms/dl) and T3 (1.1 ng/ml). A thyroid profile that was repeated after the exclusion of PAS from treatment showed the following results: the TSH level was decreased (5.1 mIU/ml). Drug-induced hypothyroidism is an infrequent side effect of therapy with PAS, and only a few cases of PAS-induced hypothyroidism have been reported so far. In this report, we describe patients with hypothyroidism who were receiving therapy for multi-drug-resistant tuberculosis, tuberculosis namely, resistant to at least isoniazid (INH) and rifampicin (RFP), with a regimen that contained PAS.

Postoperative complications after simultaneous vitrectomy and cataract surgery

OBJECTIVE

We reviewed postoperative complications after simultaneous vitrectomy, phacoemulsification, aspiration, and acryl lens insertion.

PATIENTS AND METHODS

Combined surgery was performed in 316 eyes of 279 patients between 1995 and 1997. Postoperative observation was continued in all of them for more than 6 months. The diagnoses that led to vitrectomy included diabetic retinopathy in 155 eyes, rhegmatogenous retinal detachment in 64 eyes, macular hole in 43 eyes, and other diseases in 93 eyes. The rate of postoperative complications that needed any reoperation was investigated.

RESULTS

Reoperations were needed for intravitreal hemorrhage in 23 eyes (7.3%), retinal detachment in 15 eyes (4.7%), rubeotic glaucoma in 6 eyes (1.9%), and other conditions in 4 eyes (1.3%). Among them, reoperations were performed on 13 eyes (4.1%) twice and more. A removal of an intraocular lens was needed in 16 eyes (5.1%) for treatment of vitreoretinal disease. In patients with diabetic retinopathy, reoperations were needed for intravitreal hemorrhage in 21 eyes (13.5%), rubeotic glaucoma in 6 eyes (3.9%), other diseases in 4 eyes (2.6%), and a removal of an intraocular lens was needed in 10 eyes (6.5%) at a higher rate than the other disease.

CONCLUSION

This combined surgery is considered advantageous for removing peripheral vitreous, while preventing these complications is important for preserving visual function.

Limited urinary concentration and damaged tubules in rats with a syngeneic kidney graft

BACKGROUND

The underlying mechanisms of renal transplant dysfunction are poorly understood. There is little information on tubular function in kidney grafts. The cDNAs encoding kidney-specific cell surface proteins required for renal reabsorption of sodium (sodium cotransporter in thick ascending limb of Henle, rBSC1) and water (apical water channel in collecting duct, AQP2) have been recently identified. Since transcripts of these proteins are up-regulated in dehydration in association with maximal concentration of urine, we examined urinary concentrating ability and expression levels of mRNA of these proteins in kidney isografts.

METHODS

Male Sprague-Dawley rats underwent syngeneic renal transplantation or unilateral nephrectomy (UNX) and were deprived of water for 24 hours at six weeks after the operation when histological and functional compensation of the intact kidney was complete. Blood and urinary samples were collected before and after dehydration. The amount of rBSC1 or AQP2 mRNA was measured using competitive polymerase chain reaction (PCR) by inducing a point mutation at the middle of PCR product for rBSC1 or by deleting 180 bp from 780 bp PCR product for AQP2, respectively. The protein expression was examined by Western blot analysis.

RESULTS

Both groups of rats demonstrated the same levels of compensatory renal hypertrophy (approximately 60% weight increase) and plasma creatinine values. Histological examination revealed enlarged glomeruli and tubules, but no findings of ischemic damage, such as tubular atrophy or interstitial changes. Urinary concentration was noted in the UNX rats but not in rats with kidney grafts. Competitive PCR demonstrated that dehydration did not increase rBSC1 and AQP2 transcripts in rats with kidney transplantation. Immunoblot analysis confirmed that the marked increase of both rBSC1 and AQP2 proteins was noted only in the remnant kidney of dehydrated rats.

CONCLUSIONS

Rats with kidney isografts have a limited capacity to concentrate urine and, at the same time, fail to increase rBSC1 and AQP2 transcripts. This suggests that there is a prolonged damage of renal tubules by ischemia or denervation of the donor kidney, both of which are inevitable in the transplantation procedure.

[A case of tuberculous peritonitis diagnosed by a direct smear of ascitic fluid complicated with an active pulmonary tuberculosis and intestinal tuberculosis]

We sometimes encounter difficulties in differentiating tuberculous peritonitis from other inflammatory disorders or ascites due to carcinomatous peritonitis. Acid-fast bacilli are very rarely detected in ascites. In this study, we reported a case of tuberculous peritonitis accompanied with active pulmonary tuberculosis in which acid-fast bacilli were detected in ascites. The patient was a 37-year-old single man who had been admitted to our hospital on February 28, 2000, because acid-fast bacilli were detected in sputum, faces and ascites by a direct smear. He had a lower abdominal distention and pain. His serum CA 125 level was high, 121 U/ml. Abdominal ultrasonography showed marked ascites in Douglas pouch. However adenosine deaminase level was not high in his ascites. During treatment by the combination chemotherapy with INH, RFP, EB, and PZA, serum CA 125 level was decreased.

Alpha-synuclein protein is not scavenged in neuronal loss induced by kainic acid or focal ischemia

Alpha-synuclein, a presynaptic protein, is markedly included in Lewy bodies (LB) in Parkinson's and LB diseases. In this study, neuronal loss and the activation of glial cells such as microglia and astrocytes were induced by neurodegenerative insults such as the injection of kainic acid and occlusion of the middle cerebral artery. In contrast, immunoreactivity for alpha-synuclein did not change even at 7 days after these insults. These results suggest that alpha-synuclein protein may be so scarcely scavenged by glial cells that it readily condenses in neurodegenerative regions.

Nitric oxide synthase inhibitors cause motor deficits in mice

We investigated possible motor effects of 7-nitroindazole (7-NI), an neuronal nitric oxide synthase (nNOS) inhibitor, and N(G)-nitro-L-arginine methyl ester (L-NAME), an non-selective NOS inhibitor in mice using catalepsy and pole tests in comparison with dopamine D(2) receptor antagonist, haloperidol. We also studied the change in dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) contents of these compounds. The administration of 7-NI and L-NAME (40-160 mg/kg, s.c.) dose-dependently induced motor deficit in both catalepsy and pole tests. The motor deficit induced by 7-NI was more pronounced than the one produced by L-NAME. In contrast, haloperidol showed a marked motor deficit in mice. Haloperidol showed a marked motor deficit as compared with 7-NI and L-NAME. For dopamine, DOPAC and HVA contents, haloperidol exhibited a significant decrease in dopamine content and a significant increase in DOPAC and HVA content in the striatum. In contrast, 7-NI showed a significant increase in the striatal dopamine content. However, 7-NI had no significant change in the striatal DOPAC and HVA contents. On the other hand, no significant change in the striatal dopamine, DOPAC and HVA contents was observed in L-NAME-treated mice. The present study also showed that the motor deficit induced by 7-NI or L-NAME was significantly attenuated by the treatment with L-arginine. These results demonstrate that NOS inhibitors as well as dopamine D(2) receptor antagonist haloperidol can induce motor deficit in mice. The present study also suggests that the mechanism in the motor deficit caused by NOS inhibitors may be different from that in the motor deficit induced by haloperidol. Furthermore, our findings suggest that nNOS may play some role in control of motor behavior.

Prevention of coronary vascular disease by transplantation of T-cell-depleted bone marrow and hematopoietic stem cell preparation in autoimmune-prone w/BF(1) mice

This project was designed to investigate the application of bone marrow transplantation to a progressive and ultimately fatal systemic autoimmune disease. Male (NZW x BXSB)F1 (W/BF1) mice develop acute systemic autoimmune disease characterized by degenerative coronary vascular disease (CVD) with myocardial infarctions, hypertension, thrombocytopenia, glomerulonephritis, and persistently elevated levels of circulating immune complexes. After preliminary studies established the onset of disease between 10 and 12 weeks of age, 6- to 8-week-old male W/BF1 mice were targeted for transplantation with either T-cell-depleted bone marrow or purified hematopoietic stem cells from haploidentical B6C3/F1 mice. Posttransplantation flow cytometric analysis of splenocytes demonstrated donor phenotypes in W/BF1 recipient mice that had received T-cell-depleted marrow or hematopoietic stem cell preparations (lineage negative, CD71 negative) from B6C3/F1 donors. Survival of W/BF1 mice transplanted with bone marrow from normal B6C3/F1 donors was very high, and assessment at 100 days after transplantation revealed reduction in onset and severity of disease. Autoantibodies to cardiolipin and double-stranded DNA were markedly reduced to levels present in normal mice. Immunohistochemistry of heart and kidney tissue revealed significant amelioration of degenerative CVD and glomerulonephritis in the majority of W/BF1 recipients of marrow transplants from B6C3/F1 donors. All engrafted W/BF1 mice displayed normal immunologic competence 100 days posttransplantation.

[Bronchiolo-alveolar cell carcinoma arising after active pulmonary tuberculosis' report of two cases]

We report on two patients diagnosed as having active pulmonary tuberculosis who later developed lung cancer. In both cases, the lung cancer was detected during the treatment of pulmonary tuberculosis. Both patients were initially considered to be experiencing exacerbation of pulmonary tuberculosis. Case 1 was seen in a 74-year-old man. His chest roentgenogram revealed microscopic cavitary lesions with infiltration into both lung fields. His sputum tested positive for acid-fast bacilli. Although he was treated with isoniazid (INH), rifampicin (RFP), ethambutol (EB) and pyrazinamide (PZA), his general condition deteriorated, and the infiltrative shadows in the lung fields had expanded on subsequent chest radiography. Transbronchial lung biopsy (TBLB) yielded findings compatible with a diagnosis of bronchiolo-alveolar cell carcinoma. Case 2 occurred in a 52-year-old man. His chest radiograph revealed cavitary lesions with infiltration into both lung fields. His sputum also tested positive for acidfast bacilli. Despite medication with INH, RFP, EB and PZA, the infiltrative shadow in his chest radiograph increased in size. Bronchiolo-alveolar cell carcinoma was confirmed after examination of the sputum cytology. Case 1 was diagnosed as lung cancer 10 months after being admission to the hospital, and Case 2, seven months after hospitalization. Recent discussion concerning the simultaneous occurrence of pulmonary tuberculosis and bronchogenic carcinoma suggests a high frequency of coexistence of the two diseases. However, the coexistence of active tuberculosis with bronchiolo-alveolar cell carcinoma, as in our cases, is rare.

[A case of tuberculous pericarditis developing constrictive pericarditis]

A case of constrictive pericarditis which developed after the onset of clinical manifestation of tuberculous pericarditis was reported. A 75-year-old male, complaining of anorexia, was admitted to our hospital. Adenosinedeaminase (ADA) level in pericardial effusion was found to be increased, and the culture of pericardial effusion was positive for tubercle bacilli. Diagnosed as having tuberculous pleuritis and pericarditis, he underwent chemotherapy for tuberculosis. However, massive pleural effusion developed later and pleural effusion drainage was carried out. Despite repeated drainage, pleural effusion continued to recur. Chest CT revealed apparent pericardial thickening, in addition, cardiac catheterization revealed elevation of mean right atrial pressure and marked deterioration of cardiac functions including decrease of cardiac output. These findings were compatible with constrictive pericarditis. After these investigations a diagnosis of constrictive pericarditis was established, and the patient underwent a pericardiectomy. Pathological examination of resected specimens revealed tuberculous inflammation.

Arrangement of D-periodic collagen fibrils and association of proteoglycans with fibrils in the synovium of the mouse temporomandibular joint

The present study was performed to examine changes in the arrangement of D-periodic collagen fibrils in the synovium of the growing temporomandibular joint in mice. At 1 week of age, the mandibular condyle was undeveloped, and only a few collagen fibrils were recognizable in the subintimal layer of the synovium. At 8 weeks, the mandibular condyle was structurally developed with an increase of collagen fibrils in the synovium; a fully mature condyle was observed at 6 months of age. The close association of proteoglycans with collagen fibrils in the synovium of the growing joint was examined by both conventional and energy-filtering transmission electron microscopy of cupromeronic blue-stained specimens. Proteoglycans were associated with D-periodic collagen fibrils in the short filamentous form in random fashion at 1 week of age, but in a regular pattern with D-periodicity at 6 months. These associations in the synovium could be correlated with the mechanical character of the temporomandibular joint.

IL-18 induction of IgE: dependence on CD4+ T cells, IL-4 and STAT6

Overproduction of immunoglobulin E (IgE) and T helper cell type 2 (TH2) cytokines, including interleukin 4 (IL-4), IL-5 and IL-13, can result in allergic disorders. Although it is known that IL-4 is critical to the polarization of naïve CD4+ T cells to a TH2 phenotype, both in vitro and in many in vivo systems, other factors that regulate in vivo IL-4 production and TH2 commitment are poorly understood. IL-18, an IL-1-like cytokine that requires cleavage with caspase-1 to become active, was found to increase IgE production in a CD4+ T cells-, IL-4- and STAT6-dependent fashion. IL-18 and T cell receptor-mediated stimulation could induce naïve CD4+ T cells to develop into IL-4-producing cells in vitro. Thus, caspase-1 and IL-18 may be critical in regulation of IgE production in vivo, providing a potential therapeutic target for allergic disorders.

Skin-specific caspase-1-transgenic mice show cutaneous apoptosis and pre-endotoxin shock condition with a high serum level of IL-18

To study the pathophysiological roles of overexpressed caspase-1 (CASP1), originally designated as IL-1 beta-converting enzyme, we generated transgenic mice in which human CASP1 is overexpressed in their keratinocytes. The transgenic mice spontaneously developed recalcitrant dermatitis and skin ulcers, characterized by the presence of massive keratinocyte apoptosis. The skin of the mice contained the active form of human CASP1 and expressed mRNA for caspase-activated DNase, an effector endonuclease responsible for DNA fragmentation. Their skin and sera showed elevated levels of mature IL-18 and IL-1 beta, but not of IFN-gamma. The plasma from these animals induced IFN-gamma production by IL-18-responsive NK cells. Administration of heat-killed Propionibacterium acnes, a potent in vivo type 1 cell inducer, caused IFN-gamma-mediated lethal liver injury in the transgenic mice, which was completely inhibited by treatment with neutralizing anti-IL-18 Ab. These results indicated that in vivo overexpression of CASP1 caused spontaneous apoptotic tissue injury and rendered mice highly susceptible to exogenous type 1 cell-inducing condition in collaboration with endogenously accumulated proinflammatory cytokines.