Itaru Ebihara

Serum Levels of BAFF and APRIL in Myeloperoxidase Anti-Neutrophil Cytoplasmic Autoantibody-Associated Renal Vasculitis: Association with Disease Activity

Background: A proliferation-inducing ligand (APRIL) and the B cell activation factor belonging to the tumor necrosis factor family (BAFF) have proven to be key factors in the selection and survival of B cells, and a higher concentration of BAFF has been shown to contribute to autoreactive B cell survival and elevated autoantibody production. Here, serum BAFF and APRIL levels were investigated to analyze their association with disease activity in myeloperoxidase anti-neutrophil cytoplasmic autoantibody (MPO-ANCA)-associated renal vasculitis. Methods: APRIL and BAFF levels in serum obtained from 37 patients with MPO-ANCA-associated vasculitis were measured by ELISA. Samples were taken from active vasculitis patients, inactive vasculitis patients and inactive vasculitis patients with infectious complications. Results: Although there was no difference in serum APRIL among the active vasculitis, inactive vasculitis and infectious complication patients, serum BAFF was higher in active vasculitis patients than in inactive vasculitis, infectious complication and control patients (for all, p < 0.001). There was no significant correlation between serum APRIL and ANCA titers, but there was a significant correlation between serum BAFF and ANCA titers (r = 0.465, p < 0.001). Conclusion: Excessive BAFF production in MPO-ANCA-associated vasculitis may be one of the factors for autoimmune B cell tolerance, resulting in MPO-ANCA production.

Predominance of type-2 immune response in idiopathic membranous nephropathy. Cytoplasmic cytokine analysis.

Background: The Th1/Th2 paradigm is proving increasingly useful in the understanding of infectious diseases and many autoimmune diseases. Th1 cells predominantly produce interleukin-2 (IL-2) and interferon-γ (IFN-γ) and are instrumental in initiating delayed-type hypersensitivity and activating macrophages. Th2 cells secrete other cytokines, such as IL-4, IL-5, IL-10 and IL-13 that trigger B-cell activation and immunoglobulin synthesis. It has been shown that in patients with membranous nephropathy, there may be a predominance of Th2, because of the presence of IgG, particularly IgG4, which belongs to a subclass of the type-2 immune response, and complement deposits in glomeruli. In this study, we investigated the immunoresponse of helper T cells, i.e. Th predominance in patients with idiopathic membranous nephropathy. Methods: We used flow cytometry to assess the levels of circulating Th cells in patients with idiopathic membranous nephropathy (n = 8) and in normal individuals (n = 23) based on the expression of intracellular type-1 and type-2 cytokines. Because the production of each of these cytokines has a specific time course, we observed the cytokine synthesis at 3, 6, 9 and 12 h after stimulation. Results: The percentages of IL-2+/CD4+ cells from patients with idiopathic membranous nephropathy were significantly lower than those from normal individuals at 6, 9 and 12 h, with the difference becoming more significant over time. IFN-γ+/CD4+ cells and IL-4+/CD4+ cells were not significantly different between the two groups. In patients with idiopathic membranous nephropathy, the percentages of IL-10+/CD4+ cells were significantly higher than those in normal individuals at each point in time. Conclusion: Increased IL-10-producing Th cells may lead to suppression of delayed-type hypersensitivity and activate suppressor cells and IgG4 synthesis, resulting in idiopathic membranous nephropathy.

Tubulointerstitial nephritis and uveitis syndrome associated with hyperthyroidism

We report a 17-year-old male patient with tubulointerstitial nephritis and uveitis (TINU) associated with hyperthyroidism. He presented with a 2-month history of fatigue, loss of appetite, low-grade fever, and a 12-kg weight loss when he was admitted to our hospital. He had iritis, which was complicated by fibrin in the anterior chamber, diagnosed by slit-lamp examination. On laboratory examinations, deteriorated renal function (blood urea nitrogen level was 25.9 mg/dl and creatinine level was 2.82 mg/dl) and elevated urinary levels of N-acetyl-β-D-glucosaminidase (33.1 U/l) and β2-microglobulin (78 600 µg/l) were observed. Serum thyroid-stimulating hormone (TSH) was undetectable, at less than 0.01 µIU/ml, and free triiodothyronine and free thyroxine were elevated, up to 5.23 pg/ml and 2.85 ng/dl, respectively. The titers of antithyroglobulin and antithyroid microsomal and TSH-receptor antibodies were not elevated. Abdominal and thyroidal ultrasonography showed evident bilateral enlargement of the kidneys and diffuse enlargement of the thyroid gland. Iodine-123 scintigraphy showed low uptake in the thyroid gland. The biopsied renal specimen showed mild edema and severe diffuse infiltration of mononuclear cells and few eosinophils in the interstitium, without any glomerular or vascular abnormalities. Based on the clinical features and pathological findings, a diagnosis of TINU syndrome with associated hyperthyroidism was made. Treatment was started with 30 mg/day of prednisolone. The iritis disappeared, and the patients clinical status improved remarkably. This case suggests the possibility of thyroid dysfunction in some patients with TINU syndrome, and we believe thyroid function should be measured in all TINU patients. Moreover, histopathological diagnosis of the thyroid glands before treatment is necessary for TINU patients with thyroid dysfunction.

Vascular endothelial growth factor and soluble fms-like tyrosine kinase-1 in septic shock patients treated with direct hemoperfusion with a polymyxin B-immobilized fiber column.

Abstract:  Sepsis is characterized by a systemic inflammatory response to a microbial pathogen. In sepsis, capillary permeability is a tightly regulated feature of microcirculation in all organ beds and is fundamentally altered. We investigated the vascular endothelial growth factor (VEGF) level as a vascular permeability factor and the soluble fms‐like tyrosine kinase‐1 (Flt‐1) level as an antagonist of the VEGF receptors. Serum VEGF and soluble Flt‐1 levels in 21 patients with septic shock, who were treated with direct hemoperfusion with a polymyxin B‐immobilized fiber column (DHP‐PMX), were measured by enzyme‐linked immunoassay. The VEGF and the soluble Flt‐1 levels were more elevated in patients with septic shock than in controls. Between 14 survivors and 7 non‐survivors, there was no significant difference in VEGF level before the DHP‐PMX therapy, but the soluble Flt‐1 level of survivors was significantly lower than that of non‐survivors. Although there was no significant difference between starting and ending VEGF levels in survivors, in non‐survivors the VEGF level at the end of DHP‐PMX therapy was significantly lower than that at the start. In survivors, the soluble Flt‐1 level at the end of DHP‐PMX therapy was significantly lower than that at the start. On the other hand, in non‐survivors, there was no significant difference between the ending and starting soluble Flt‐1 levels. The soluble Flt‐1 level may be a suitable marker of disease severity and mortality.

Angiopoietin Balance in Septic Shock Patients With Acute Kidney Injury: Effects of Direct Hemoperfusion With Polymyxin B-Immobilized Fiber.

Acute lung injury (ALI) in sepsis is characterized by an increase in microvascular permeability, resulting in pulmonary edema. Several studies have suggested that angiopoietin‐1 and ‐2 play a contributory role in the pathogenesis of ALI. Polymyxin B‐immobilized fiber column hemoperfusion is effective for sepsis‐induced ALI. We investigated the angiopoietin levels before and after direct hemoperfusion with polymyxin B‐immobilized fiber column (PMX) therapy. Enzyme‐linked immunoassay was used to measure the serum angiopoietin‐1 and ‐2 levels in 25 patients with septic shock treated with PMX. Eleven of the 25 patients were diagnosed with ALI. There was a significant positive correlation between the angiopoietin‐1 level and the PaO2/FiO2 ratio, but there was a significant inverse correlation between the angiopoietin‐2 level and the PaO2/FiO2 ratio. The mean angiopoietin‐1 level before PMX therapy in the ALI group was significantly lower and the mean angiopoietin‐2 level was significantly higher than in the non‐ALI group. The mean angiopoietin‐1 level of the ALI patients in response to PMX therapy was increased during PMX therapy, but that of the non‐ALI patients with newly occurring ALI showed a decreased angiopoietin‐1 level. On the other hand, the mean angiopoietin‐2 level of the responders was decreased during PMX therapy, but that of patients with newly occurring ALI showed an increased angiopoietin‐2 level. This result suggested that each angiopoietin‐1 and ‐2 level may play a role in the pathogenesis of ALI and that PMX therapy ameliorates the angiopoietin balance in patients with ALI in sepsis.

Serum ratio of soluble triggering receptor expressed on myeloid cells-1 to creatinine is a useful marker of infectious complications in myeloperoxidase-antineutrophil cytoplasmic antibody-associated renal vasculitis

BACKGROUND The contribution of infections to the mortality of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis patients is important and should induce early and careful control of these events. However, the differentiation of infection from active vasculitis is often difficult. The usefulness of serum-soluble triggering receptor expressed on myeloid cells-1 (TREM-1) for detecting the presence of infectious complications regardless of disease activity was investigated. METHODS Soluble TREM-1 in serum obtained from 41 patients with myeloperoxidase (MPO)-ANCA-associated vasculitis was measured by an enzyme-linked immunosorbent assay. Twenty-nine samples were from active vasculitis patients, 27 samples from inactive vasculitis patients without infection and 17 samples from inactive vasculitis patients with infectious complications. Serum-soluble TREM-1 was also measured in 10 patients with acute pyelonephritis and 30 patients with chronic kidney disease (CKD). RESULTS There was a significant correlation between serum levels of soluble TREM-1 and serum creatinine levels among all patients (r = 0.554, P < 0.0001). The serum-soluble TREM-1/creatinine ratio was higher in inactive vasculitis patients with infectious complications than in active vasculitis, inactive vasculitis without infection and CKD patients (P = 0.0005, P < 0.0001 and P < 0.0001, respectively), but not significantly different to that in acute pyelonephritis patients. On receiver-operating-characteristic curve analysis, a lower-limit value of 9.40 ng/mg for this ratio had a sensitivity of 84.6% and a specificity of 90.8% in differentiating patients with infection from those without infection. CONCLUSIONS The serum ratio of soluble TREM-1 to creatinine may be a useful marker for detection of infectious complications in MPO-ANCA-associated vasculitis.

Angiopoietin balance in septic shock patients treated by direct hemoperfusion with polymyxin b-immobilized fiber.

Capillary permeability is a tightly regulated feature of microcirculation in all organ beds; however, in sepsis this feature is fundamentally altered. We previously reported elevated levels of vascular endothelial growth factor and its receptor (fms‐like tyrosine kinase‐1) in patients with septic shock, then investigated two kinds of angiopoietins in those patients. An enzyme‐linked immunoassay was used to measure serum angiopoietin‐1 and ‐2 levels in 12 patients with septic shock who were treated by direct hemoperfusion with a polymyxin B‐immobilized fiber column (DHP‐PMX). The angiopoietin‐1 level was lower in patients with septic shock (7.01 ± 10.08 ng/mL) than in controls (28.24 ± 11.61 ng/mL, P < 0.001), but the angiopoietin‐2 level was higher in septic shock patients (40.83 ± 30.13 ng/mL vs. 2.47 ± 1.78 ng/mL, P < 0.001). Between seven survivors and five non‐survivors there was no significant difference in angiopoietin‐1 levels before DHP‐PMX therapy. During DHP‐PMX therapy, however, the angiopoietin‐2 level was significantly decreased in survivors (31.52 ± 26.15 ng/mL vs. 17.32 ± 22.46 ng/mL, P = 0.035). Moreover, at the end of the therapy, the angiopoietin‐1 level was significantly lower in non‐survivors (1.14 ± 1.30 ng/mL vs. 10.43 ± 13.56 ng/mL, P = 0.042), but the angiopoietin‐2 level in non‐survivors was significantly higher (70.79 ± 40.47 ng/mL vs. 17.32 ± 22.46 ng/mL, P = 0.019). The angiopoietin‐2 level may be associated with vascular permeability in septic patients, and angiopoietins may be suitable markers of disease severity and mortality.

Blood Flow Analysis of the Head and Lower Limbs by the Laser Doppler Blood Flowmeter During LDL Apheresis

Abstract:  The presence of peripheral arterial disease substantially increases the risk for both morbidity and mortality among end‐stage renal disease patients. Low‐density lipoprotein (LDL) apheresis has been also applied for the treatment of peripheral arterial disease to reduce LDL levels, resulting in the improvement of the blood flow to the ischemic limbs. In this study, we investigated the continuous changes of the tissue blood flows in the lower limbs and head during LDL‐apheresis treatment by a non‐invasive method (the non‐invasive continuous monitoring method (NICOMM) system). In this study, the tissue blood flow in both the head and lower limbs showed a significantly enhancement from before to after treatment. The tissue blood flow in the lower limbs showed a significantly larger improvement than that in the head. The short‐term effects of LDL apheresis were confirmed by using the NICOMM system; thus, this system will be useful for the determination of the appropriate schedule of LDL apheresis for long‐term effectiveness.

Serum TNF-Related and Weak Inducer of Apoptosis Levels in Septic Shock Patients

Capillary permeability is a tightly regulated feature of microcirculation in all organ beds. In sepsis, this feature is fundamentally altered. We have previously reported elevated levels of angiopoietin‐2 in patients with septic shock, and have investigated tumor necrosis factor (TNF)‐related and weak inducer of apoptosis (TWEAK), which mediates both angiogenesis and inflammation, in those patients. Enzyme‐linked immunoassay was used to measure serum TWEAK levels in 20 patients with septic shock, all of whom were treated by direct hemoperfusion with a polymyxin B‐immobilized fiber column (DHP‐PMX), and in 20 non‐septic controls. The TWEAK levels were higher in patients with septic shock (192.8 ± 230.5 pg/mL) than in controls (84.1 ± 28.7 pg/mL, P = 0.043). Between 11 survivors and 10 non‐survivors, there was no significant difference in the serum TWEAK levels before the DHP‐PMX therapy. During DHP‐PMX therapy, however, the serum TWEAK levels were significantly increased in non‐survivors (142.2 ± 88.1 pg/mL to 399.0 ± 307.1 pg/mL, P = 0.022). There was a significant correlation between the serum TWEAK levels and white blood cell counts (r = 0.393, P < 0.001), platelet counts (r = 0.418, P < 0.001), or serum CRP levels (r = 0.259, P = 0.029), but there was no correlation between the serum TWEAK levels and blood pressure. The serum TWEAK levels were also correlated with the ratio of angiopoietin‐2 to ‐1 (r = 0.464, P < 0.001). TWEAK may be a suitable marker of disease severity and mortality in septic patients, and TWEAK levels may be associated with vascular permeability via angiopoietin balance.

Soluble Vascular Endothelial‐Cadherin Levels in Patients With Sepsis Treated With Direct Hemoperfusion With a Polymyxin B‐immobilized Fiber Column

Capillary permeability is a tightly regulated feature of microcirculation in all organ beds; however, in sepsis this feature is fundamentally altered. Several molecules are investigated as associated factors with capillary permeability and vascular endothelial (VE)‐cadherin internalization by vascular endothelial growth factor (VEGF)‐induced signaling through VEGF receptors leads to increased vascular endothelial cell detachment and trans‐endothelial permeability. We investigated serum soluble VE‐cadherin levels in septic patients. An enzyme‐linked immunoassay was used to measure serum soluble VE‐cadherin levels in 47 septic patients treated by direct hemoperfusion with a polymyxin B‐immobilized fiber column (DHP‐PMX). The serum soluble VE‐cadherin level of septic patients before PMX‐DHP was 3424.1 ± 2033.0 ng/mL, which was significantly lower than that of the controls (5862.0 ± 1521.2 ng/mL; P < 0.0001). The time course of serum soluble VE‐cadherin levels remained unchanged during PMX‐DHP therapy. There was no significant difference in serum soluble VE‐cadherin levels before PMX‐DHP therapy between survivors and non‐survivors, and there was no significant difference in those levels between the groups at any time after the initiation of PMX‐DHP therapy. There was no correlation between soluble VE‐cadherin levels and clinical data, except white blood cell count (r = −0.277, P = 0.0009). There was no correlation between soluble VE‐cadherin levels and the levels of angiopoietin 1 and 2. In summary, the relationship between VE‐cadherin and capillary permeability in sepsis could not be demonstrated. Soluble VE‐cadherins are not reflected in the balance between intercellular junction plasticity and integrity, but VE‐cadherin stabilization by its phosphorylation or internalization may be associated with capillary permeability.