Shigaku Ikeda

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.

Cathelicidin LL-37 induces the generation of reactive oxygen species and release of human α-defensins from neutrophils

Background  Psoriasis is characterized by epidermal infiltration of neutrophils that destroy invading microorganisms via a potent antimicrobial arsenal of oxidants and antimicrobial agents. In contrast to atopic dermatitis, psoriasis exhibits low levels of skin infections due to the presence of antimicrobial agents, including cathelicidin LL‐37. LL‐37 kills a broad spectrum of microbes, and activates neutrophil chemotaxis.

Clinical trial of a laser device called fractional photothermolysis system for acne scars

Ablative laser resurfacing is an effective treatment for acne scars. However, edema and prolonged erythema are common. Additionally, scarring and hyperpigmentation are often induced. A new concept of laser called fractional photothermolysis has been designed to create microscopic thermal wounds to achieve skin rejuvenation without significant side‐effects. We treated 10 patients with acne scars using this laser system (Reliant Fraxel SR Laser). All the patients were successfully treated with minimal adverse effects. The fractional photothermolysis system represents an optional method for the treatment of acne scars.

Antimicrobial peptides human β-defensin (hBD)-3 and hBD-4 activate mast cells and increase skin vascular permeability

Antimicrobial peptides human β‐defensins (hBD) are mainly produced by epithelia of several organs including skin, and participate in innate immunity by killing invading pathogens. Besides their microbicidal activities, hBD activate several inflammatory and immune cells. Since hBD are generated by tissues where mast cells are present, we hypothesized that these peptides could activate mast cells. In this study, we demonstrated that both hBD‐3 and hBD‐4 induced mast cell degranulation, prostaglandin D2 production, intracellular Ca2+ mobilization and chemotaxis. Furthermore, hBD‐3‐ and hBD‐4‐induced activation of mast cells was suppressed by pertussis toxin and U‐73122, inhibitors for G protein and phospholipase C, respectively. We further revealed that hBD‐3 and hBD‐4 increased vascular permeability in the skin, which was dependent on the presence of mast cells, because hBD‐3 and hBD‐4 failed to enhance vascular permeability in mast cell‐deficient Ws/Ws rats. We also demonstrated that hBD‐3 and hBD‐4 induced phosphorylation of MAPK p38 and ERK1/2, which were further required for hBD‐mediated mast cell activation, as evidenced by the inhibitory effects of p38 and ERK1/2 inhibitors on mast cell degranulation. Together, these findings suggest the key role of hBD in inflammatory responses by recruiting and activating mast cells, and increasing vascular permeability.

Crucial Commitment of Proteolytic Activity of a Purified Recombinant Major House Dust Mite Allergen Der p1 to Sensitization toward IgE and IgG Responses

The major proteolytic allergen derived from the house dust mite Dermatophagoides pteronyssinus, Der p1, is one of the most clinically relevant allergens worldwide. In the present study, we evaluate the contribution of the proteolytic activity and structure of a highly purified rDer p 1 to immune responses. Mice were i.p. immunized with three forms of rDer p 1 adsorbed to Alum: one enzymatically active, one treated with an irreversible cysteine protease-specific inhibitor, E-64, and one heat denatured. Immunization with E-64-treated or heat-denatured rDer p 1 elicited much less production of serum total IgE and not only rDer p 1-specific IgE but also IgGs compared with immunization with active rDer p 1. Assays for Ab-binding and its inhibition and structural analyses indicated that E-64-treated rDer p 1 retained its global structure and conformational B cell epitopes. A proliferative response and production of IL-5 by spleen cells restimulated with rDer p 1 were observed on immunization with the active rDer p 1 but not E-64-treated rDer p 1. The cells from mice immunized with heat-denatured rDer p 1 exhibited the highest levels of proliferation and production of IL-5 and IFN-γ. The results indicate that the proteolytic activity of the highly purified rDer p 1 crucially commits to the sensitization process, including both IgE and IgG responses. Additionally, we demonstrated immunogenic differences by functional or structural manipulations of the rDer p 1. The findings have implications for sensitization to this relevant allergen in humans and for the design of modified allergen-vaccines for future allergen-specific immunotherapy.

Mite serine protease activates protease-activated receptor-2 and induces cytokine release in human keratinocytes

Background:  House dust mites produce serine and cysteine proteases. Mite‐derived proteases have been suggested to be involved in the pathogenesis of allergies; however, whether mite‐derived serine protease activity can stimulate keratinocytes remains unknown.

Therapeutic guidelines for the treatment of generalized pustular psoriasis (GPP) based on a proposed classification of disease severity.

Generalized pustular psoriasis (GPP) is a rare but notoriously recalcitrant cutaneous diseases. Therefore, there have been few reports of more than ten patients with GPP who were treated at the same institution. The severity of this disease and its response to each therapeutic modality vary among patients. In some GPP is life-threatening, but in others it may show a benign, chronic course for a long period of time. Before starting treatment, a knowledge of the therapeutic efficacy and side effects of each drug used in the treatment of GPP is necessary. In our multicenter study, we compared the effectiveness of and adverse reactions to several systemically administered drugs. Following the development of a unique classification of the disease severity based on scoring the clinical symptoms and the laboratory findings, we propose here therapeutic guidelines for the treatment of GPP.

History of the establishment and revision of diagnostic criteria, severity index and therapeutic guidelines for pemphigus in Japan.

We summarize the process of establishing and revising the diagnostic criteria, severity index and therapeutic guidelines for pemphigus in Japan (including the results of a nationwide survey regarding these guidelines). We also summarize the content and present an evaluation of the utility of these guidelines. Due to the publication of these documents throughout the Japanese medical community, it appears that patients with pemphigus have recently begun to receive appropriate treatment, dramatically improving their quality of life and prognosis. Continuous examination of these criteria by means of follow-up studies of patients treated according to the guidelines is necessary to determine the long-term efficacy of treatment. To this end, it is hoped that these guidelines will be more extensively disseminated among the medical community.

Identification of poly-reactive natural IgM antibody that recognizes late apoptotic cells and promotes phagocytosis of the cells

AbstractNatural IgM can recognize apoptotic cells, but the molecular structure and the role in macrophage phagocytosis of apoptotic cells remain unclear. Objectives(1) To examine the binding of previously isolated natural IgM (3B4) to apoptotic cells and its effects on phagocytosis of apoptotic cells. (2) To characterize the molecular structure of 3B4. Methods:3B4 binding to apoptotic thymocytes was examined by flow cytometry. Polyreactivity of 3B4 was assayed by ELISA. PKH26-labeled Macrophages were incubated with PKH67-stained apoptotic cells in the presence of 3B4. Macrophages phagocytosis of apoptotic cell was evaluated by flow cytometry. The DNA segments of 3B VH and VK were sequenced and analyzed. Results:3B4 IgM recognized late apoptotic cells. Polyreactive-recognitions of lysophosphatidylcholine (LPC) as well as some autoantigens were observed in 3B4. Phagocytosis of late apoptotic cells was increased in the presence of 3B4. The VH and VK genes of 3B4 showed a germline gene context, while N-sequences and nucleotide loss were observed in CDR3. Conclusion: 3B4 promotes macrophage phagocytosis of late apoptotic cells in a complement-independent process. 3B4 has a germline configuration and is possibly ligand-selected. Out experiments suggest an independent role of natural IgM as opsonin in clearance of late apoptotic cells.

A case of chromomycosis caused by Fonsecaea pedrosoi and a review of reported cases of dematiaceous fungal infection in Japan

We report a case of chromomycosis caused by Fonsecaea pedrosoi that developed in the left buttock of a 63‐year‐old female farmer. About 4 years ago, the patient developed erythema in the left buttock, which gradually spread. At the first consultation, we noted a well‐defined, red‐brown, infiltrated erythematous plaque (8 × 6 cm). Histopathological examination revealed a granulomatous lesion, containing sclerotic cells, associated with giant cells in the upper dermis. The causative fungus was difficult to identify due to low conidiogenesis, but was eventually identified by slide culture as F. pedrosoi. Excision and skin graft were performed, and no recurrence has been observed after 2 years. In Japan, 212 cases of dematiaceous fungal infection were reported in the period from 1982 to 2001. The causative fungus was F. pedrosoi in the majority of cases (126/212; 66%), followed by Exophiala jeanselmei (36/212; 19%). Similar incidence of dematiaceous fungal infection was reported in male and female patients. The upper limbs were affected most frequently in both male and female patients. Ten cases were associated with visceral lesions.