Yoshinori Katada

Delayed onset and reduced severity of collagen-induced arthritis in interleukin-6-deficient mice

OBJECTIVE To investigate the roles of interleukin-6 (IL-6) in the pathogenesis of rheumatoid arthritis (RA) by studying its effect on murine collagen-induced arthritis (CIA). METHODS IL-6-deficient (IL-6-/-) mice with a genetic background of susceptibility to CIA were generated by backcrossing them with DBA/1J mice for 8 generations. Clinical and immunologic features were compared between these mice and IL-6 wild-type (IL-6+/+) littermates with CIA. RESULTS Serum IL-6 levels increased during the development of CIA in IL-6+/+ mice. Two prominent peaks were observed. The first was coincident with the onset of arthritis, and the second one was observed during exacerbation of the disease. The onset of arthritis in IL-6-/- mice was delayed for 2 weeks compared with that in IL-6+/+ mice, and the severity of arthritis, as indicated by the arthritis score, remained significantly lower in IL-6-/- mice during the entire followup period (14 weeks), although all IL-6-/- mice developed definite arthritis as did the IL-6+/+ mice. Histologic severity was also reduced in IL-6-/- mice. In addition, radiologic changes such as osteopenia and bone erosion were reduced significantly in these animals. Both humoral and cellular responses to type II collagen (CII) in IL-6-/- mice were reduced to about half those in IL-6+/+ mice. In addition, enhanced production of IL-4 and IL-10 in response to concanavalin A stimulation was observed in IL-6-/- mice. CONCLUSION IL-6 plays an important role in the development of CIA, and both suppression of specific immune responses to CII and a tendency to a shift toward a Th2 cytokine profile might contribute in part to the attenuation of CIA in IL-6-/- mice. These findings suggest that blockade of IL-6 might be beneficial in the treatment of RA.

RANKL‐Induced Expression of Tetraspanin CD9 in Lipid Raft Membrane Microdomain Is Essential for Cell Fusion During Osteoclastogenesis

We showed that CD9, a member of tetraspanin superfamily proteins, is expressed in a specific membrane microdomain, called “lipid raft,” and is crucial for cell fusion during osteoclastogenesis after activation of the RANK/RANKL system.

Enhanced production of osteopontin in multiple myeloma: clinical and pathogenic implications

Summary. In this study, we examined osteopontin (OPN) production in myeloma cells and plasma OPN levels in multiple myeloma (MM) patients. We assessed OPN production in bone marrow cells (BMCs) by immunocytochemistry and enzyme‐linked immunosorbent assay (ELISA). We also assessed OPN production in various B‐cell malignant cell lines, including three myeloma cell lines by reverse transcription polymerase chain reaction (RT‐PCR) and Western blotting. In addition, we measured plasma OPN concentrations by ELISA in 30 MM patients, 21 monoclonal gammopathy of undetermined significance (MGUS) patients and 30 healthy volunteers. As a result, in an immunocytochemical study, abundant OPN was detected in BMCs from overt MM patients, whereas no OPN was detected in BMCs from patients with other haematological diseases, including MGUS. Cultured BMCs from overt MM patients produced more OPN than those from patients with either smouldering MM or MGUS. Myeloma cell lines spontaneously produced OPN. Plasma OPN levels of MM patients were significantly higher than those of MGUS patients and healthy volunteers (P < 0·05). Moreover, they correlated with both progression and bone destruction of the disease (P < 0·05). These suggest that myeloma cells actively produce OPN, which possibly contributes to osteoclastic bone resorption in MM. Plasma OPN levels may be a useful biomarker for assessing bone destruction in MM and distinguishing MM from MGUS or smouldering MM.

A case of Mikulicz’s disease with Th2-biased cytokine profile: possible feature discriminable from Sjögren’s syndrome

This article concerns a male patient with Mikulicz’s disease (MD) accompanied with marked elevation of serum immunoglobulin (Ig)G4 and IgE levels. His peripheral blood mononuclear cells (PBMC) showed markedly enhanced in vitro production of interleukin (IL)-4, IL-5, IL-13, but not interferon gamma (IFN-γ) compared with patients with Sjögren’s syndrome (SS) and healthy donors, suggesting distinct Th2 bias in this MD patient. Besides the prominent infiltration of IgG4-producing plasma cells, the enhanced expression of both CD40 and CD40 ligand (CD40L) were observed in the swollen salivary gland of the MD patient, suggesting enhanced signaling pathways for the induction of IgG4 and IgE switching. Possible differences between MD and SS in light of their underlying pathogenesis are discussed.

Peripheral blood T lymphocytes and basophils, freshly isolated from house-dust-mite-sensitive patients, produce interleukin-4 in response to allergen-specific stimulation.

We examined the capacity of interleukin-4 (IL) production from lymphocytes and basophils, isolated from the peripheral blood of allergic patients sensitive to house dust mite, after stimulation with mite extract. IL-4 production was measured by a sensitive bioassay based on coculture with CT.h4S (a human IL-4-responsive cell line). Lymphocytes and basophils from patients with elevated serum IgE specific to mite allergen [radioallergosorbent test (RAST) score > 3] could produce detectable levels of IL-4 in response to mite extract, whereas those from patients with a RAST score of less than 2 or normal volunteers could not. The sensitivity of basophils to mite extract was high, so that a lower concentration of mite extract (1-10 ng/ml) could induce maximal IL-4 production. On the other hand, a higher concentration (10 micrograms/ml) was required for maximal IL-4 production from the lymphocytes. These findings demonstrate that allergen-specific IL-4-producing cells, lymphocytes and basophils, are generated in vivo in allergic patients and also that there exist characteristic differences between lymphocytes and basophils related to the in vivo source of IL-4.

Correlation between salivary epidermal growth factor levels and refractory intraoral manifestations in patients with Sjögren's syndrome

Abstract Objective. To assess changes in salivary epidermal growth factor (EGF) levels and the correlation between these levels and the severity of intraoral manifestations in Sjögrens syndrome (SS). Methods. Forty SS patients and 23 controls were enrolled. Salivary EGF concentration was measured using an enzyme-linked immunosorbent assay, and intraoral manifestations were evaluated using a short version of the Oral Health Impact Profile (OHIP-14). The associations among salivary flow rate, EGF levels and the severity of intraoral manifestations were analyzed. Results. The total salivary EGF output was significantly decreased in the SS patients compared with the controls (9237.6 ± 8447.0 vs. 13296.9 ± 7907.1 pg/10 min, respectively, p = 0.033). In the SS patients, total EGF output and salivary flow rate showed a strong positive correlation (rs = 0.824, p = 0.0005), while total EGF output and disease duration showed a negative correlation (rs = −0.484, p = 0.008). Further, total EGF output was significantly correlated with the OHIP-14 score (rs = −0.721, p = 0.012). Conclusions. The salivary flow rate and EGF levels are decreased in SS, and this deterioration in saliva quality causes refractory intraoral manifestations. Our findings have provided new therapeutic targets for SS.

Idiopathic portal hypertension in a systemic sclerosis patient heterozygous for factor V Leiden mutation

Abstract. Here we present a rare case of systemic sclerosis (SSc) with idiopathic portal hypertension (IPH) having factor V Leiden mutation, a well-known genetic risk factor for various venous thromboses. A 53-year-old SSc patient showing huge esophageal varices and splenomegaly without liver cirrhosis was diagnosed with IPH. As heterozygous Leiden mutation was detected, some coagulation abnormality and resultant formation of microthrombi in the branches of portal vein were suggested as a cause of IPH in this case. This is the first report showing the possible association between Leiden mutation and one of the complications of SSc.

Expansion of a CD28-intermediate subset among CD8 T cells in patients with infectious mononucleosis.

ABSTRACT Infectious mononucleosis (IM) is an acute sporadic infection that usually affects young adults, and during infection a massive expansion of CD8 T cells is generally considered to occur. However, CD28 expression of the expanded cells has not been characterized. When peripheral blood mononuclear cells of acute IM (AIM) patients were analyzed by flow cytometry, a continuous spectrum of CD28 intensity ranging from negative to high, which could be separated into CD28 negative, intermediate (int), and positive, was seen for CD8 T cells. We studied 26 IM patients who were diagnosed on the basis of standard methods and found that all patients had the continuous CD28 spectrum. CD28 is a costimulatory molecule on T cells, and its expression is associated with the subdivision of CD8 cells into cytotoxic (CD28-positive) and suppressor (CD28-negative) T cells. After 24 h of ex vivo culturing, however, the continuous spectrum was found to consist of only CD28-positive and CD28-negative CD8 T cells, because the CD28-int cells had disappeared due to apoptosis. The CD28-int T cells have several cytotoxic functions, suggesting that CD28-int T cells are effectors. Examination of other costimulatory markers in AIM patients showed that CD80 and CD152 were not affected. In patients with other viral infections, such as measles or rubella, however, the continuous spectrum was not detected. These results suggest that there is an unusual CD28 expression pattern in patients with AIM, namely, the presence of a functional CD28-int subset among CD8 T cells. These findings are of special importance for clarifying the defense mechanism against Epstein-Barr virus infection, and the role of CD28 molecules in humans and should also be helpful for the diagnosis of AIM.

A case of granuloma in the occipital lobe of a patient with Wegener’s granulomatosis

We report a case of Wegener’s granulomatosis (WG) with central nervous system (CNS) involvement in a woman who complained of bilateral visual disturbance. The intracranial necrotizing granulomatous lesion was confirmed by MR imaging and brain biopsy. After high-dose oral corticosteroid treatment, not only clinical manifestations but also laboratory tests improved. Moreover, the CNS lesion completely regressed. This suggests that high-dose corticosteroid alone might be effective in treating WG with CNS involvement.

Rapid decrease in salivary epidermal growth factor levels in patients with Sjögren's syndrome: A 3-year follow-up study

Objectives. To assess changes in salivary epidermal growth factor (EGF) levels within three years and investigate the correlation between these changes and the severity of intraoral manifestations in patients with Sjögrens syndrome (SS). Methods. Twenty-three SS patients (14 primary SS and 9 secondary SS) and 14 controls were followed up for three years. Salivary EGF concentration was measured using an enzyme-linked immunosorbent assay, and intraoral manifestations were evaluated using a short version of the Oral Health Impact Profile (OHIP-14). Changes in salivary flow rate, EGF level, and severity of intraoral manifestations were analyzed, along with associations among them. Results. The OHIP-14 score significantly increased and the total salivary EGF output significantly decreased after three years in the SS group (10.2 ± 8.8 vs. 12.6 ± 9.2, p = 0.040; 10158.4 ± 9820.9 vs. 8352.8 ± 7813.3 pg/10 min, p = 0.032), though the salivary flow rate did not change. The decrease in total EGF output was especially high in patients with long disease duration and poor oral health-related quality of life (OHRQoL). In patients with poor OHRQoL, the change in total EGF output significantly correlated with the OHIP-14 score (r = − 0.847, p = 0.008). However, there was no correlation between the change in salivary flow rate and the OHIP-14 score. Conclusions. The rapid decrease in salivary EGF level contributes to the progression of intraoral manifestations of SS.