Yoshihiro Kuwano

Regulatory B cells (B10 cells) have a suppressive role in murine lupus: CD19 and B10 cell deficiency exacerbates systemic autoimmunity.

B cells play critical roles in the pathogenesis of lupus. To examine the influence of B cells on disease pathogenesis in a murine lupus model, New Zealand Black and New Zealand White F1 hybrid (NZB/W) mice were generated that were deficient for CD19 (CD19−/− NZB/W mice), a B cell-specific cell surface molecule that is essential for optimal B cell signal transduction. The emergence of anti-nuclear Abs was significantly delayed in CD19−/− NZB/W mice compared with wild type NZB/W mice. However, the pathologic manifestations of nephritis appeared significantly earlier, and survival was significantly reduced in CD19−/− NZB/W mice compared with wild type mice. These results demonstrate both disease-promoting and protective roles for B cells in lupus pathogenesis. Recent studies have identified a potent regulatory B cell subset (B10 cells) within the rare CD1dhiCD5+ B cell subset of the spleen that regulates acute inflammation and autoimmunity through the production of IL-10. In wild type NZB/W mice, the CD1dhiCD5+B220+ B cell subset that includes B10 cells was increased by 2.5-fold during the disease course, whereas CD19−/− NZB/W mice lacked this CD1dhiCD5+ regulatory B cell subset. However, the transfer of splenic CD1dhiCD5+ B cells from wild type NZB/W mice into CD19−/− NZB/W recipients significantly prolonged their survival. Furthermore, regulatory T cells were significantly decreased in CD19−/− NZB/W mice, but the transfer of wild type CD1dhiCD5+ B cells induced T regulatory cell expansion in CD19−/− NZB/W mice. These results demonstrate an important protective role for regulatory B10 cells in this systemic autoimmune disease.

/`Slings/' enable neutrophil rolling at high shear

Most leukocytes can roll along the walls of venules at low shear stress (1 dyn cm−2), but neutrophils have the ability to roll at tenfold higher shear stress in microvessels in vivo. The mechanisms involved in this shear-resistant rolling are known to involve cell flattening and pulling of long membrane tethers at the rear. Here we show that these long tethers do not retract as postulated, but instead persist and appear as ‘slings’ at the front of rolling cells. We demonstrate slings in a model of acute inflammation in vivo and on P-selectin in vitro, where P-selectin-glycoprotein-ligand-1 (PSGL-1) is found in discrete sticky patches whereas LFA-1 is expressed over the entire length on slings. As neutrophils roll forward, slings wrap around the rolling cells and undergo a step-wise peeling from the P-selectin substrate enabled by the failure of PSGL-1 patches under hydrodynamic forces. The ‘step-wise peeling of slings’ is distinct from the ‘pulling of tethers’ reported previously. Each sling effectively lays out a cell-autonomous adhesive substrate in front of neutrophils rolling at high shear stress during inflammation.

Efficacy of Diagnostic Ultrasonography of Lipomas, Epidermal Cysts, and Ganglions

OBJECTIVE To determine the efficacy of ultrasonography for the diagnosis of subcutaneous benign lesions. DESIGN Retrospective study. SETTING Tokyo Kousei-Nenkin Hospital, Tokyo, Japan. Patients The study included 183 patients with subcutaneous benign lesions who underwent ultrasonography and then received a pathologic diagnosis after surgery. MAIN OUTCOME MEASURES The study evaluated the number of cases in which the preoperative diagnosis after ultrasonography or just after palpation agreed with the pathologic diagnosis. RESULTS Ultrasonography significantly increased the preoperative diagnostic yield of subcutaneous benign lesions (after palpation, 29%; after ultrasonography, 46%; P < .001). The sensitivity for the diagnosis of lipoma (after palpation, 54.8%; after ultrasonography, 88.1%; P < .01) and the specificity for the diagnosis of epidermal cyst (after palpation, 93.5%; after ultrasonography, 99.3%; P < .05) significantly increased after ultrasonography. The sensitivity for the diagnosis of epidermal cyst and ganglion also tended to increase after ultrasonography. Conclusion The study results suggest that ultrasonography is useful for the preoperative examination of subcutaneous benign lesions.

CD22 Expression Mediates the Regulatory Functions of Peritoneal B-1a Cells during the Remission Phase of Contact Hypersensitivity Reactions

Although contact hypersensitivity (CHS) has been considered a prototype of T cell-mediated immune reactions, recently a significant contribution of regulatory B cell subsets in the suppression of CHS has been demonstrated. CD22, one of the sialic acid-binding immunoglobulin-like lectins, is a B cell-specific molecule that negatively regulates BCR signaling. To clarify the roles of B cells in CHS, CHS in CD22−/− mice was investigated. CD22−/− mice showed delayed recovery from CHS reactions compared with that of wild-type mice. Transfer of wild-type peritoneal B-1a cells reversed the prolonged CHS reaction seen in CD22−/− mice, and this was blocked by the simultaneous injection with IL-10 receptor Ab. Although CD22−/− peritoneal B-1a cells were capable of producing IL-10 at wild-type levels, i.p. injection of differentially labeled wild-type/CD22−/− B cells demonstrated that a smaller number of CD22−/− B cells resided in lymphoid organs 5 d after CHS elicitation, suggesting a defect in survival or retention in activated CD22−/− peritoneal B-1 cells. Thus, our study reveals a regulatory role for peritoneal B-1a cells in CHS. Two distinct regulatory B cell subsets cooperatively inhibit CHS responses. Although splenic CD1dhiCD5+ B cells have a crucial role in suppressing the acute exacerbating phase of CHS, peritoneal B-1a cells are likely to suppress the late remission phase as “regulatory B cells.” CD22 deficiency results in disturbed CHS remission by impaired retention or survival of peritoneal B-1a cells that migrate into lymphoid organs.

B Cell Antigen Receptor and CD40 Differentially Regulate CD22 Tyrosine Phosphorylation

Cell surface molecules on lymphocytes positively or negatively modulate the Ag receptor signaling, and thus regulate the fate of the cell. CD22 is a B cell-specific cell surface protein that contains multiple ITIMs in the cytoplasmic tail, and critically regulates B cell activation and survival. CD22 regulation on B cell signaling is complex because CD22 can have both positive and negative roles in various contexts. We generated phosphospecific polyclonal Abs reacting four major CD22 tyrosine motifs (Y762, Y807, Y822, and Y842) and analyzed the pattern and intensity of phosphorylation of these tyrosine residues. The tyrosine motifs, Y762, Y822, and Y842, are considered as ITIM, whereas the other, Y807, is suggested to be important for Grb2 recruitment. Approximately 10% of the four tyrosine residues were constitutively phosphorylated. Upon anti-IgM ligation, CD22 Y762 underwent most rapid phosphorylation, whereas all four tyrosine residues were eventually phosphorylated equally at ∼35% of all CD22 molecules in the cell. By contrast, anti-CD40 stimulation specifically up-regulated anti-IgM-induced phosphorylation of tyrosines within two ITIM motifs, Y762 and Y842, which was consistent with in vivo finding of the negative role of CD22 in CD40 signaling. Thus, CD22 phosphorylation is not only quantitatively but also qualitatively regulated by different stimulations, which may determine the outcome of B cell signaling.

Serum chemokine profile in patients with bullous pemphigoid

Background  Bullous pemphigoid (BP) is an autoimmune inflammatory disease causing blister formation at the dermoepidermal junction. Cutaneous infiltration of activated CD4+ T cells and eosinophils is an early event in blister formation during the disease process, suggesting that the trafficking of circulating leucocytes through the sites of inflammation is crucial in the pathogenesis of the disease. While the accumulated evidence suggests that some cytokines are involved in the pathogenesis, there have been few reports about serum chemokine profiles in patients with BP.

Serum chemokine profiles in patients with alopecia areata

Background  Although chemokines play an important role in various inflammatory diseases, there have been few studies about the role of chemokines in alopecia areata (AA).

Decreased cathepsin V expression due to Fli1 deficiency contributes to the development of dermal fibrosis and proliferative vasculopathy in systemic sclerosis

OBJECTIVES Cathepsin V (CTSV) is a proteolytic enzyme potentially modulating angiogenic processes, collagen degradation and keratinocyte differentiation. We aimed to investigate the clinical association of serum CTSV levels and the mechanism by which CTSV expression is altered in SSc. METHODS Serum CTSV levels were determined by ELISA in 51 SSc and 18 healthy subjects. CTSV expression was evaluated by immunostaining in SSc and normal skin and by RT-real-time PCR in normal and SSc dermal fibroblasts, normal dermal fibroblasts treated with TGF-β1 or Fli1 siRNA and human dermal microvascular endothelial cells (ECs) treated with Fli1 siRNA. RESULTS Serum CTSV levels were significantly lower in dcSSc and lcSSc patients than in healthy controls. In early-stage dcSSc, serum CTSV levels were remarkably and uniformly decreased compared with healthy controls. The decrease in serum CTSV levels in mid- and late-stage dcSSc and in lcSSc was linked to the development of proliferative vasculopathy. CTSV expression was decreased in microvascular ECs, pericytes/vascular smooth muscle cells and keratinocytes of dcSSc and lcSSc skin and in dermal fibroblasts of dcSSc skin compared with control skin. Consistently, CTSV expression was decreased in cultured dermal fibroblasts from early-stage dcSSc. Furthermore, mRNA levels of the CTSV gene were significantly decreased in normal fibroblasts treated with TGF-β1 or Fli1 siRNA and in human dermal microvascular ECs treated with Fli1 siRNA. CONCLUSION Loss of CTSV expression may contribute to the development of fibrosis, vasculopathy and the altered phenotype of keratinocytes in SSc.

Successful experience of rituximab therapy for systemic sclerosis-associated interstitial lung disease with concomitant systemic lupus erythematosus.

Previous studies have demonstrated that B cells play critical roles in autoimmune disorders including systemic sclerosis (SSc) and systemic lupus erythematosus (SLE). However, the effectiveness of rituximab (RTX), a chimeric anti‐CD20 antibody, for SSc‐associated interstitial lung disease (ILD) or SLE disease activity remains controversial. We herein report an SSc patient with severely progressed ILD and concomitant SLE treated by two cycles of RTX at baseline and half a year later. This treatment improved ILD and SLE activities, along with reduction of dermal sclerosis and serum anti‐topoisomerase I antibody levels. In addition, our detailed time‐course data indicate that half a year may be appropriate as an interval between each cycle of RTX therapy aimed at SSc‐associated ILD or SLE. Overall, the current report could pave the way to establish RTX as a disease‐modifying drug for patients with SSc and/or SLE showing resistance to other already approved medications.

Analysis of gene mutations in three cases of dermatofibrosarcoma protuberans (DFSP): ordinary DFSP, DFSP with fibrosarcomatous lesion (DFSP-FS) and lung metastasis of DFSP-FS

BACKGROUND Fusion of the collagen type I alpha 1 (COL1A1) gene with the platelet-derived growth factor B-chain (PDGFB) gene has been pointed out in dermatofibrosarcoma protuberans (DFSP). Various exons of the COL1A1 gene have been shown to be involved in the fusion with exon 2 of the PDGFB gene. OBJECTIVE We studied the breakpoints of the COL1A1 gene using the tumor specimens from three patients with DFSP. METHODS Reverse transcriptase-polymerase chain reaction (PCR) was performed using cultured DFSP tumor cells or frozen tissue. Nucleotide sequence analysis was carried out using the PCR products to identify the breakpoints. RESULTS Cases 1, 2 and 3 were diagnosed as ordinary DFSP, DFSP with fibrosarcomatous lesion (DFSP-FS) and lung metastasis of DFSP-FS, respectively. The COL1A1-PDGFB fusion transcripts were detected from the tumor specimens. Sequence analysis revealed that the ends of exons 42, 29 and 38 in the COL1A1 gene were fused with the start of exon 2 in the PDGFB gene in case 1, 2 and 3, respectively. CONCLUSION This study identified a novel COL1A1 breakpoint, namely, exon 42 of the COL1A1 gene. Detection of the aberrant fusion transcript seems to be useful at differential diagnosis both in primary and metastatic lesions.