The systemic autoimmune disease such as systemic lupus erythematosus (SLE) is characterized by the deposition of immune complexes in multiple organs. Fcγ receptors (FcγR) recognize the Fc portion of IgG and are important in determining the response of leukocytes to deposited immune complexes. FcγR also provide positive and negative regulation of immune cell responses. The activatory FcγR including the FcR common γ chain take balance with Fcγ RIIB, the only inhibitory FcγR. Development of lupus-like autoimmune disease as well as monocytosis in BXSB mice is dependent on the activatory and inhibitory FcγR. In human SLE, dysregulated expression of FcγRIIB on memory B cells is reported and numbers of associations with genetic polymorphism are also reported. The cell-specific modulation of these activatory or inhibitory FcγRs are expected for the new therapeutic strategy in autoimmune diseases.

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  Photoallergy is an entity of allergy in the dermatological field. Sunlight is involved in the pathophysiology of photoallergy. Photoallergy is classified into intrinsic and extrinsic diseases. As extrinsic diseases, photosensitivity due to drugs and photocontact dermatitis are important for physicians as well as dermatologists. Physicians should have accurate understanding of these disorders.

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  IL-23 is produced by dendritic cells, and other antigen presenting cells. IL-23 is required for the induction, expansion, maintenance and downstream effector functions of Th17 cells. Th17 cells upregulate neutrophil chemokines, antimicrobial peptides, and other pro-inflammatory cytokines. The lack of Th17 cells results in susceptibility to Candida, Streptococcal and Staphylococcal infections. On the contrary, the excess of Th17 cells induce various autoimmune diseases such as psoriasis. Several studies revealed that infections were more common in psoriatics than in healthy individuals. Superantigens released by microorganisms have been suggested as exogenous triggers that stimulate T cells to initiate psoriasis. Understanding the Th17 responses and their interactions with the immune system will likely provide crucial insights in the host defense and autoimmune diseases like psoriasis, and this will provide new tools for the development of effective immunomodulatory treatment strategies for infectious diseases and autoimmune diseases.

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  Although inflammation is important for host defense, excessive inflammation sometimes causes serious consequences. IL-1β is one of major proinflammatory cytokines. Dysregulation of IL-1β promotes development of several diseases. Mature IL-1β is produced by cleavage of its proform by a protein complex named inflammasome. Inflammasome consists of NOD-LRRs containing family (NLR proteins), an adaptor protein, and a cysteine protease caspase-1. Several NLRs can be assembled into inflammasome in response to various stimulatory signals.
  Genetic disorder of inflammasome-IL-1 system cause autoinflammatory diseases such as cryopyrin-associated autoinflammatory disease, familial Mediterranean fever, deficiency of IL-1 receptor antagonist, and PAPA syndrome. This article reviews recent advances in the study of inflammasome and related diseases.

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  Gangliosides, N-acetylneuraminic acid (sialic acid)-bearing glycosphingolipids, are believed to reside in clusters within membrane microdomains, called lipid rafts or glycosynapse. Recent studies demonstrated that antiganglioside antibodies play an important role in the pathogenesis of Guillain-Barré syndrome (GBS) and Fisher syndrome (FS). The anti-GM1 antibodies are likely to damage peripheral nerves through complement activation with dysfunction of voltage-gated sodium channels. Some antiganglioside antibodies may cause dysfunction of voltage-gated calcium channels without complement activation. Clustered epitopes of ganglioside complexes (GSCs) consisting of two gangliosides can be targeted by serum antibodies in GBS and FS. Anti-GD1a/GD1b complex antibodies are associated with severe GBS. Approximately 50% of FS patients have antibodies to GSCs containing GQ1b or GT1a. Various glycolipids including GSCs may form complex glycolipid environment in the cell membrane, regulating the accessibility and the avidity of antiganglioside antibodies. In addition to antibody specificity, the glycolipid environment or specific distribution of target gangliosides in peripheral nervous system can influence pathogenic effects of antiganglioside antibodies in GBS and FS. Conformational and functional analyses of glycoepitopes of GSCs in the biological membrane will provide new vistas to research on antibody-antigen interaction in GBS, and shed light on microdomain function mediated by carbohydrate-to-carbohydrate interaction.

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  Podocytes are glomerular visceral epithelial cells, which function as molecular sieve with foot process (FT) and slit diaphragm (SD) spanning FT, not to allow high molecular weight protein to be filtrated through glomerular capillary loop. Pathological proteinuria is caused by discoordinated tertiary podocyte structure such as disappearance of FT and/or SD, and irreversible glomeular sclerosis is caused by podocyte loss due to cell death and/or detachment from capillary wall. With recent advance of nephrological research technology such as podocyte cell culture system, genetically engineered transgenic mice with podocyte-specific regulation of gene expression, podocyte-associated biomarkers, the new isolation method of glomeruli, laser capture microdissection, multiphoton imaging and extracellular flux analyzer, new findings of pathogenesis of glomerular lesions will be expected, not only in primary glomerulonephritis, but also in secondary glomerulonephritis or glomerulopathy due to rheumatic diseases.

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  Weber-Christian disease (WCD) is a syndrome characterized by recurrent subcutaneous nodules, fever, occasional lipoatrophy, fatigue, arthralgia, and myalgia. We report a case of WCD associated with rheumatoid arthritis. A 65-year-old woman consulted our outpatient clinic because of bilateral hand swelling. The patient had presented with fever and subcutaneous nodules in her trunk and upper and lower extremities in 1983. At that time, the dermatology department diagnosed this patient as having WCD after biopsy of the nodules demonstrated lobular panniculitis. She has been treated with corticosteroid (5-15 mg/day) since then. The patient continued to have recurrent episodes of transient inflammatory arthritis in the small joints of the fingers and fever, and was initially assessed at our institution in October 2007. Finally, in November 2007, she was diagnosed as having both WCD and rheumatoid arthritis (RA) and treated with corticosteroid (5 mg/day) and methotrexate (MTX) (7.5 mg/week). Thereafter, her clinical symptoms gradually improved. This is the second case of WCD showing the subsequent development of RA, successfully treated with MTX, in the English literature. This case may provide clinical insight into WCD and RA.

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  In May 2009, a 57-year-old woman who had rheumatoid arthritis since 9 years was admitted to our hospital for dyspnea due to interstitial pneumonia (IP). On admission, she exhibited proximal scleroderma, finger edema, Raynaud's phenomenon, digital pitting scars, ankyloglossia, and esophageal dysmotility. The patient was diagnosed as having systemic sclerosis (SSc), according to the American College of Rheumatology criteria. After initiation of high-dose corticosteroid therapy, gradual amelioration of IP was observed. However, the patient complained of abdominal fullness. Computed tomography and intestine series findings revealed significant dilatation of the small intestine due to intra-abdominal free air and pneumatosis cystoides intestinalis but no mechanical obstruction, leading to a diagnosis of SSc with pseudo-obstruction. The patient underwent decompression with a long intestinal tube, which led to improvement in her symptoms. Although erythromycin (EM) and some prokinetic agents were administered, abdominal involvement recurred several days after resumption of oral ingestion. Therefore, we changed the antibiotic from EM to metronidazole (750 mg/day). Her manifestations were promptly ameliorated by metronidazole therapy in 4 days and did not recur. Metronidazole is an antibiotic used to treat intra-abdominal anaerobic bacterial infections and is also commonly used in preoperative treatment for colorectal surgery. In conclusion, we report a case where SSc-associated pseudo-obstruction was successfully managed by metronidazole therapy.

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