Toshioki Sawaki

Proposal for a new clinical entity, IgG4-positive multiorgan lymphoproliferative syndrome: analysis of 64 cases of IgG4-related disorders

Background: Mikulicz’s disease (MD) has been considered as one manifestation of Sjögren’s syndrome (SS). Recently, it has also been considered as an IgG4-related disorder. Objective: To determine the differences between IgG4-related disorders including MD and SS. Methods: A study was undertaken to investigate patients with MD and IgG4-related disorders registered in Japan and to set up provisional criteria for the new clinical entity IgG4-positive multiorgan lymphoproliferative syndrome (IgG4+MOLPS). The preliminary diagnostic criteria include raised serum levels of IgG4 (>135 mg/dl) and infiltration of IgG4+ plasma cells in the tissue (IgG4+/IgG+ plasma cells >50%) with fibrosis or sclerosis. The clinical features, laboratory data and pathologies of 64 patients with IgG4+MOLPS and 31 patients with typical SS were compared. Results: The incidence of xerostomia, xerophthalmia and arthralgia, rheumatoid factor and antinuclear, antiSS-A/Ro and antiSS-B/La antibodies was significantly lower in patients with IgG4+MOLPS than in those with typical SS. Allergic rhinitis and autoimmune pancreatitis were significantly more frequent and total IgG, IgG2, IgG4 and IgE levels were significantly increased in IgG4+MOLPS. Histological specimens from patients with IgG4+MOLPS revealed marked IgG4+ plasma cell infiltration. Many patients with IgG4+MOLPS had lymphocytic follicle formation, but lymphoepithelial lesions were rare. Few IgG4+ cells were seen in the tissue of patients with typical SS. Thirty-eight patients with IgG4+MOLPS treated with glucocorticoids showed marked clinical improvement. Conclusion: Despite similarities in the involved organs, there are considerable clinical and pathological differences between IgG4+MOLPS and SS. Based on the clinical features and good response to glucocorticoids, we propose a new clinical entity: IgG4+MOLPS.

Associations between salivary gland histopathologic diagnoses and phenotypic features of Sjogren's syndrome among 1,726 registry participants.

OBJECTIVE To examine associations between labial salivary gland (LSG) histopathology and other phenotypic features of Sjögrens syndrome (SS). METHODS The database of the Sjögrens International Collaborative Clinical Alliance (SICCA), a registry of patients with symptoms of possible SS as well as those with obvious disease, was used for the present study. LSG biopsy specimens from SICCA participants were subjected to protocol-directed histopathologic assessments. Among the 1,726 LSG specimens exhibiting any pattern of sialadenitis, we compared biopsy diagnoses against concurrent salivary, ocular, and serologic features. RESULTS LSG specimens included 61% with focal lymphocytic sialadenitis (FLS; 69% of which had focus scores of ≥1 per 4 mm²) and 37% with nonspecific or sclerosing chronic sialadenitis (NS/SCS). Focus scores of ≥1 were strongly associated with serum anti-SSA/SSB positivity, rheumatoid factor, and the ocular component of SS, but not with symptoms of dry mouth or dry eyes. Those with positive anti-SSA/SSB were 9 times (95% confidence interval [95% CI] 7.4-11.9) more likely to have a focus score of ≥1 than were those without anti-SSA/SSB, and those with an unstimulated whole salivary flow rate of <0.1 ml/minute were 2 times (95% CI 1.7-2.8) more likely to have a focus score of ≥1 than were those with a higher flow rate, after controlling for other phenotypic features of SS. CONCLUSION Distinguishing FLS from NS/SCS is essential in assessing LSG biopsies, before determining focus score. A diagnosis of FLS with a focus score of ≥1 per 4 mm², as compared to FLS with a focus score of <1 or NS/SCS, is strongly associated with the ocular and serologic components of SS and reflects SS autoimmunity.

Cutoff Values of Serum IgG4 and Histopathological IgG4+ Plasma Cells for Diagnosis of Patients with IgG4-Related Disease.

IgG4-related disease is a new disease classification established in Japan in the 21st century. Patients with IgG4-related disease display hyper-IgG4-gammaglobulinemia, massive infiltration of IgG4+ plasma cells into tissue, and good response to glucocorticoids. Since IgG4 overexpression is also observed in other disorders, it is necessary to diagnose IgG4-related disease carefully and correctly. We therefore sought to determine cutoff values for serum IgG4 and IgG4/IgG and for IgG4+/IgG+ plasma cells in tissue diagnostic of IgG4-related disease. Patients and Methods. We retrospectively analyzed serum IgG4 concentrations and IgG4/IgG ratio and IgG4+/IgG+ plasma cell ratio in tissues of 132 patients with IgG4-related disease and 48 patients with other disorders. Result. Serum IgG4 >135  mg/dl demonstrated a sensitivity of 97.0% and a specificity of 79.6% in diagnosing IgG4-related disease, and serum IgG4/IgG ratios >8% had a sensitivity and specificity of 95.5% and 87.5%, respectively. IgG4+cell/IgG+ cell ratio in tissues >40% had a sensitivity and specificity of 94.4% and 85.7%, respectively. However, the number of IgG4+ cells was reduced in severely fibrotic parts of tissues. Conclusion. Although a recent unanimous consensus of all relevant researchers in Japan recently established the diagnostic criteria for IgG4-related disease, findings such as ours indicate that further discussion is needed.

DIP2 disco-interacting protein 2 homolog A (Drosophila) is a candidate receptor for follistatin-related protein/follistatin-like 1--analysis of their binding with TGF-β superfamily proteins.

Follistatin‐related protein (FRP)/follistatin‐like 1 (FSTL1) is a member of the follistatin protein family, all of which share a characteristic structure unit found in follistatin, called the FS domain. Developmental studies have suggested that FRP regulates organ tissue formation in embryos. Immunological studies showed that FRP modifies joint inflammation in arthritic disease, and modulates allograft tolerance. However, the principle physiological function of FRP is currently unknown. To address this issue, we cloned four FRP‐associated proteins using a two‐hybrid cloning method: disco‐interacting protein 2 homolog A from Drosophila (DIP2A), CD14, glypican 1 and titin. Only DIP2A was expected to be a membrane receptor protein with intracellular regions. Over‐expression of FLAG epitope‐tagged DIP2A augmented the suppressive effect of FRP on FBJ murine osteosarcoma viral oncogene homolog (FOS) expression, and the Fab fragment of IgG to FLAG blocked this effect. Knockdown of Dip2a leaded to Fos gene up‐regulation, and this was not affected by exogenous FRP. These in vitro experiments confirmed that DIP2A could be a cell‐surface receptor protein and mediate a FOS down‐regulation signal of FRP. Moreover, molecular interaction analyses using Biacore demonstrated that FRP bound to DIP2A and CD14, and also with proteins of the TGF‐β superfamily, i.e. activin, TGF‐β, bone morphogenetic protein 2/4 (BMP‐2/4), their receptors and follistatin. FRP binding to DIP2A was blocked by CD14, follistatin, activin and BMP‐2. FRP blocked the ligand–receptor binding of activin and BMP‐2, but integrated itself with that of BMP‐4. This multi‐specific binding may reflect the broad physiological activity of FRP.

Impaired TCR signaling through dysfunction of lipid rafts in sphingomyelin synthase 1 (SMS1)-knockdown T cells

During T cell activation, TCRs cluster at the center of the T cell-antigen-presenting cell interface forming the central supramolecular activation cluster. Although it has been suggested that sphingolipid- and cholesterol-rich microdomains, termed lipid rafts, form platforms for the regulation and transduction of TCR signals, an actual role for membrane sphingomyelin (SM), a key component of lipid rafts, has not been reported. After cloning a gene responsible for SM synthesis, sphingomyelin synthase (SMS) 1, we established a SM-knockdown cell line (Jurkat-SMS1/kd) by transfection of SMS1-short-interfering RNA into Jurkat T cells, which is deficient in membrane expression of SM. Upon CD3 stimulation, expression of CD69 (the earliest leukocyte activation antigen), activation-induced cell adhesion and proliferation as well as TCR clustering was severely impaired in Jurkat-SMS1/kd cells. CD3-induced tyrosine phosphorylation and association of linker for activation of T cell with ZAP-70 and Grb2 and phosphorylation of protein kinase C (PKC) were also severely impaired in Jurkat-SMS1/kd cells. Finally, translocation of TCR, ZAP-70 and PKC into lipid rafts was markedly decreased in Jurkat-SMS1/kd cells. These findings indicate that membrane SM is crucial for TCR signal transduction, leading to full T cell activation through lipid raft function.

The SSB-positive/SSA-negative antibody profile is not associated with key phenotypic features of Sjögren's syndrome

Objective To determine whether the Sjögrens syndrome B (SSB)-positive/Sjögrens syndrome A (SSA)-negative antibody profile is associated with key phenotypic features of SS. Methods Among registrants in the Sjögrens International Collaborative Clinical Alliance (SICCA) with possible or established SS, we compared anti-SSA/anti-SSB reactivity profiles against concurrent phenotypic features. We fitted logistic regression models to explore the association between anti-SSA/anti-SSB reactivity profile and each key SS phenotypic feature, controlling for potential confounders. Results Among 3297 participants, 2061 (63%) had negative anti-SSA/anti-SSB, 1162 (35%) had anti-SSA with or without anti-SSB, and 74 (2%) anti-SSB alone. Key SS phenotypic features were more prevalent and had measures indicative of greater disease activity in those participants with anti-SSA, either alone or with anti-SSB, than in those with anti-SSB alone or negative SSA/SSB serology. These between-group differences were highly significant and not explained by confounding by age, race/ethnicity or gender. Participants with anti-SSB alone were comparable to those with negative SSA/SSB serology in their association with these key phenotypic features. Among SICCA participants classified with SS on the basis of the American-European Consensus Group or American College of Rheumatology criteria, only 2% required the anti-SSB-alone test result to meet these criteria. Conclusions The presence of anti-SSB, without anti-SSA antibodies, had no significant association with SS phenotypic features, relative to seronegative participants. The solitary presence of anti-SSB antibodies does not provide any more support than negative serology for the diagnosis of SS. This serological profile should thus be interpreted cautiously in clinical practice and potentially eliminated from future classification criteria.

Clonality analysis of lymphoproliferative disorders in patients with Sjögren's syndrome

The aim of this study was to clarify the nature of the clonal lymphocyte infiltration in Sjögrens syndrome (SS) patients associated with lymphoproliferative disorders. We examined B cell clonality in lymphoproliferative tissues from six primary SS patients associated with lymphoproliferative disorders or lymphoma by cloning and sequencing of the gene rearrangement of the immunoglobulin heavy chain complementarity determining region 3 (IgVH–CDR3). Three patients with sequential observation showed progressional clonal expansion with the presence of the same subclone in different tissues during the course of disease. Among them, one patient developed mucosa‐associated lymphoid tissue (MALT) lymphoma in glandular parotid. The other three SS patients concomitant with malignant B cells lymphomas showed different clonal expansion of B cells between nodal sites and salivary glands. The cloanality analysis indicated that monoclonal B cell population could spread from one glandular site to another site during the course of SS, suggesting that the malignant clone may arise from the general abnormal microenvironment, not restricted to the glandular tissue, in some SS patients.

CD4+ T-cell dysfunctions through the impaired lipid rafts ameliorate concanavalin A-induced hepatitis in sphingomyelin synthase 1-knockout mice

Membrane microdomains consisting of sphingomyelin (SM) and cholesterol appear to be important for signal transduction in T-cell activation. The present study was designed to elucidate the role of membrane SM in vivo and in vitro using sphingomyelin synthase 1 (SMS1) knock out (SMS1(-/-)) mice and Concanavalin A (ConA)-induced hepatitis. After establishing SMS1(-/-) mice, we investigated CD4+ T-cell functions including proliferation, cytokine production and signal transduction in vivo. We also examined severity of hepatitis, cytokine production in serum and liver after ConA injection at a dose of 20 mg kg(-1). CD4+ T cells from SMS1(-/-) mice showed severe deficiency of membrane SM and several profound defects compared with wild-type controls as follows: (i) cellular proliferation and production of IL-2 and IFN-γ by co-cross-linking of CD3 and CD4; (ii) tyrosine phosphorylation of LAT and its association with ZAP-70; (iii) clustering and co-localization of TCR with lipid rafts. Consistent with these impaired CD4+ T-cell functions in vitro, SMS1(-/-) mice showed decreased serum levels of IL-6 and IFN-γ by ConA injection, which renders SMS1(-/-) mice less sensitive to ConA-induced hepatitis. These results indicated that the deficiency of membrane SM caused the CD4+ T-cell dysfunction through impaired lipid raft function contributed to protection of ConA-induced liver injury, suggesting that the membrane SM is critical for full T-cell activation both in vitro and in vivo.

Successful treatment of amegakaryocytic thrombocytopenia with anti-CD20 antibody (rituximab) in a patient with systemic lupus erythematosus

Abstract Amegakaryocytic thrombocytopenia is an extremely rare disorder in systemic lupus erythematosus, and its mechanism and treatment are still largely unknown. We describe a 42-year-old woman with systemic lupus erythematosus who presented various clinical manifestations of life-threatening amegakaryocytic thrombocytopenia (10,000 platelets/mm3 with a marked decrease of megakaryocytes in the bone marrow), proteinuria, psychosis, refractory chylothorax, ascites, and type II diabetes caused by the anti-insulin receptor autoantibody. She was initially treated with prednisolone (25–50 mg/day) and cyclosporine A (200 mg/day) without any improvement in severe thrombocytopenia. However, her clinical symptoms, including platelet counts, dramatically improved, with a concurrent decrease in the anti-c-Mpl antibody, an autoantibody against the thrombopoietin receptor, after a subsequent treatment with rituximab (375 mg/m2 intravenously, weekly, for two consecutive weeks). Our case suggested that amegakaryocytic thrombocytopenia in patients with systemic lupus erythematosus might be mediated by the anti-c-Mpl antibody and could be treated with rituximab through elimination of pathogenic B cells producing autoimmune antibodies.

Association of Epstein-Barr virus with human immunodeficiency virus-negative peripheral T-cell lymphomas in Japan.

Abstract:  The association of Epstein–Barr virus (EBV) with human immunodeficiency virus‐negative T‐cell lymphoma was examined in 68 patients using the polymerase chain reaction (PCR) with DNA obtained from formalin‐fixed paraffin‐embedded tissues and an in situ hybridization technique. EBV‐encoded RNA (EBER) was detected in 43 of 68 cases (63%) of peripheral T‐cell lymphoma: in 100% (11 of 11 cases) of NK/T‐cell lymphomas, 70% (14 of 20 cases) of angioimmunoblastic T‐cell lymphomas (AILT) and 49% (18 of 37 cases) of other types of peripheral T‐cell lymphoma. A positive band was also detected at high incidence (36 of 65 cases; 55%) in a PCR analysis using primers to detect the Bam HI‐W fragment of EBV. In the immunohistochemical analysis using a monoclonal antibody to latent membrane protein 1 (LMP‐1) of EBV, one of the EBV‐encoded latent gene products, LMP‐1, was found to be expressed in 13 of 64 cases (20%), but EBNA‐2 was not expressed in all the cases examined (0 of 59 cases; 0%). The 5‐yr survival rate was 28% for peripheral T‐cell lymphomas overall, 0% for NK/T‐cell lymphomas, 38% for AILTs and 28% for other types of peripheral T‐cell lymphoma. The difference in the overall survival rate between NK/T‐cell lymphoma and non‐NK/T‐cell lymphoma was significant (P = 0.0498 by Log‐rank test). Among peripheral T‐cell lymphoma patients overall, the group severely infected with EBV (EBER‐ISH ++) had a lower 5‐yr survival rate (8%) than the group slightly (EBER‐ISH +) or not infected (38%; P = 0.0013).