Spontaneous Regression of Blastic Plasmacytoid Dendritic Cell Neoplasm Following Sepsis by Serratia marcescens: A Case Report and Literature Review.

Spontaneous regression is rare in patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN). An 85-year-old man presented with pancytopenia and skin lesions, and the bone marrow exhibited 79.6% CD4+, CD56+, CD123+, and TCL-1+ abnormal cells, with a normal karyotype; he was thus diagnosed with BPDCN. While being followed without chemotherapy, he was admitted due to sepsis induced by Serratia marcescens, which was successfully treated with antibiotics. Notably, his blood cell counts improved, and the skin lesions disappeared. To our knowledge, this is the first reported case of spontaneous regression of BPDCN with a decrease in tumor cells in the bone marrow following sepsis.

A case of TAFRO syndrome, a variant of multicentric Castleman's disease, successfully treated with corticosteroid and cyclosporine A.

We report a case of a 46-year-old woman with fever, pleural effusion, massive ascites, severe edema, hepatosplenomegaly, elevation of serum creatinine level, proteinuria, and severe thrombocytopenia. Her clinical features were compatible with TAFRO syndrome proposed as a variant of multicentric Castleman's disease, that is occasionally associated with poor prognosis. Treatment with corticosteroid improved her symptoms partially. However, thrombocytopenia, ascites, and edema persisted. The use of cyclosporine A successfully improved her condition, resulting in remission.

A novel autoantibody against fibronectin leucine-rich transmembrane protein 2 expressed on the endothelial cell surface identified by retroviral vector system in systemic lupus erythematosus.

INTRODUCTION: Anti-endothelial cell antibodies (AECAs) are thought to be critical for vasculitides in collagen diseases, but most were directed against molecules localized within the cell and not expressed on the cell surface. To clarify the pathogenic roles of AECAs, we constructed a retroviral vector system for identification of autoantigens expressed on the endothelial cell surface. METHODS: AECA activity in sera from patients with collagen diseases was measured with flow cytometry by using human umbilical vein endothelial cells (HUVECs). A cDNA library of HUVECs was retrovirally transfected into a rat myeloma cell line, from which AECA-positive clones were sorted with flow cytometry. cDNA of the cells was analyzed to identify an autoantigen, and then the clinical characteristics and the functional significance of the autoantibody were evaluated. RESULTS: Two distinct AECA-positive clones were isolated by using serum immunoglobulin G (IgG) from a patient with systemic lupus erythematosus (SLE). Both clones were identical to cDNA of fibronectin leucine-rich transmembrane protein 2 (FLRT2). HUVECs expressed FLRT2 and the prototype AECA IgG bound specifically to FLRT2-transfected cells. Anti-FLRT2 antibody activity accounted for 21.4% of AECAs in SLE. Furthermore, anti-FLRT2 antibody induced complement-dependent cytotoxicity against FLRT2-expressing cells. CONCLUSIONS: We identified the membrane protein FLRT2 as a novel autoantigen of AECAs in SLE patients by using the retroviral vector system. Anti-FLRT2 antibody has the potential to induce direct endothelial cell cytotoxicity in about 10% of SLE patients and could be a novel molecular target for intervention. Identification of such a cell-surface target for AECAs may reveal a comprehensive mechanism of vascular injury in collagen diseases.

Thrombotic microangiopathy presenting with a considerable accumulation of ascites: a case report.

A 46-year-old man presented with fever, thrombocytopenia, and a considerable accumulation of ascites. Although prednisolone and intravenous cyclophosphamide pulse (IVCY) were effective, he experienced recurrence. Renal insufficiency and hemolytic anemia developed subsequently. Schistocytes, negative Coombs' test, and elevated lactate dehydrogenase levels indicated thrombotic microangiopathy (TMA). He recovered well after receiving plasma infusion, IVCY, and prednisolone. Renal biopsy revealed subendothelial widening, thereby confirming TMA. This is a very rare case of TMA that presented with a considerable volume of ascites.

Pregnancy-associated thrombotic thrombocytopenic purpura with anti-centromere antibody-positive Raynaud's syndrome.

Thrombotic thrombocytopenic purpura (TTP), scleroderma renal crisis (SRC), and hemolysis, elevated liver enzyme levels, and a low platelet count (HELLP) syndrome display common symptoms that include microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. Therefore, it is important to distinguish between them because their treatments vary: however, the differential diagnosis is sometimes difficult. We report a 32-year-old woman who was referred to our department for further examination of microangiopathic hemolytic anemia, thrombocytopenia, and a slightly elevated serum creatinine level with anti-centromere antibody-positive Raynaud's syndrome in the early puerperal period. TTP, SRC, and HELLP syndrome were considered in the differential diagnosis, but the measurement of a disintegrin-like metalloprotease with thrombospondin type 1 motifs 13 (ADAMTS 13) activity and its inhibitor level led to the diagnosis of TTP. She was successfully treated by plasma exchange and high-dose prednisolone and angiotensin-converting enzyme inhibitor. If microangiopathic hemolytic anemia and thrombocytopenia are observed in perinatal women or patients with signs of systemic sclerosis, the measurement of ADAMTS13 activity and its inhibitor level are essential for diagnosis and therapeutic choice.

The use of tacrolimus for recurrent lupus enteritis: a case report.

INTRODUCTION: Patients with lupus enteritis sometimes experience recurrence. In such cases, the addition of cyclophosphamide to the treatment regimen is recommended. However, an appropriate treatment has not been established in cases where cyclophosphamide failed to prevent the disease. CASE PRESENTATION: An 18-year-old Japanese woman was admitted for a recurrence of lupus enteritis. One year before admission she was treated for lupus enteritis with high-dose corticosteroid together with intravenous cyclophosphamide pulse therapy. Upon admission, she was administered again with high-dose corticosteroid and her abdominal pain rapidly subsided. Tacrolimus was later used as an immunosuppressive agent and a complete remission has been maintained. CONCLUSION: Tacrolimus can be a useful agent for recurrent lupus enteritis that is resistant to conventional therapy.

Peripheral T cell lymphoma with a high titer of proteinase-3-antineutrophil cytoplasmic antibodies that resembled Wegener's granulomatosis.

Here, we present a 54-year-old man with proptosis and swelling below the left eyelid. Laboratory findings showed high levels of PR3-ANCA and histological examination of the first biopsy revealed acute inflammation. Together with the findings of MRI, a diagnosis of WG was made. However, the disease progressed rapidly and histological examination of the second biopsy revealed infiltration of neoplastic T lymphocytes with aberrant loss of CD7. A final diagnosis of peripheral T cell lymphoma, not otherwise specified (WHO) was made, and complete remission was achieved by chemotherapy. This is a very rare case of T cell lymphoma with a high titer of PR3-ANCA.

Human parvovirus B19 transgenic mice become susceptible to polyarthritis.

Human parvovirus B19 (B19) often causes acute polyarthritis in adults. In this paper, we analyzed nucleotide sequences of the B19 genome of patients with rheumatoid arthritis (RA), and then introduced the nonstructural protein 1 (NS1) gene of B19 into C57BL/6 mice that had a genetic origin not susceptible to arthritis. The transgenic mice developed no lesions spontaneously, but were susceptible to type II collagen (CII)-induced arthritis. B19 NS1 was expressed in synovial cells on the articular lesions that were histologically characteristic of granulomatous synovitis and pannus formation in cartilage and bone. Serum levels of anti-CII Abs and TNF-alpha increased in NS1 transgenic mice to the same levels as those of DBA/1 mice, which were susceptible to polyarthritis. Stimulation with CII increased secretion of Th1-type- and Th2-type cytokines in NS1 transgenic mice, indicating that a nonpermissive H-2(b) haplotype in the wild type of C57BL/6 mice can be made susceptible to polyarthritis through the expression of NS1. This study is the first to show that a viral agent from the joints in humans can cause CII-induced arthritis resembling RA.

SS-A/Ro52, an autoantigen involved in CD28-mediated IL-2 production.

An autoantibody against SS-A/Ro52 (Ro52) is most frequently found in the sera of patients with Sjögren's syndrome, systemic lupus erythematosus, and congenital heart block from anti-Ro52 Ab-positive mother. However, the physiological function of the autoantigen SS-A/Ro52 has not yet been elucidated. In this study, we describe the role of Ro52 protein in T cell activation. Overexpression of SS-A/Ro52 in Jurkat T cell resulted in enhanced IL-2 production following CD28 stimulation. Furthermore, transfection of anti-Ro52-specific small RNA duplexes partially blocked the expression of native and overexpressed Ro52 in Jurkat T cell, resulting in decreased IL-2 production via CD28 pathway in these cells. Finally, intracellular localization of Ro52 dramatically changed following CD28 stimulation. Our data reveal a novel function of Ro52 in CD28-mediated pathway, which eventually contributes to cytokine production and expression of the T cell biological programs.