Acquired susceptibility to autoimmune diseases in pediatric patients with Escherichia coli infection: A population-matched retrospective cohort study.

BACKGROUND: Escherichia coli (E.coli) infection has been proposed to play an important role as an initial trigger in the development of autoimmunity via molecular mimicry. However, there has been no preliminary cohort study to establish the association of E.coli infection with autoimmune diseases. Therefore, we conducted a large scale, population-matched cohort study to determine the risk of autoimmune disease among patients with exposure to E.coli. METHODS: Utilizing the National Health Insurance Service database, we retrospectively analyzed a total of 259,875 Korean children that consisted of 23,625 exposed and 236,250 unexposed persons from January 1, 2002 to December 31, 2017. The exposed cohort was defined as patients diagnosed with E.coli infection. Unexposed controls were matched by birth year and sex at a 1:10 ratio for each exposed patient, using incidence density sampling. The primary outcome was autoimmune disease development. We used the Cox model to estimate the risks of autoimmune diseases among patients diagnosed with E.coli infection. RESULTS: Over a mean follow-up of 10 years, there were 1455 autoimmune disease cases among exposed patients (incidence rate, 63.6 per 10,000 person-years) and 11,646 autoimmune disease cases among unexposed persons (incidence rate, 50.4 per 10,000 person-years), with an adjusted hazard ratio (HR) of 1.254 (95% CI 1.187-1.325). E.coli infection was associated with increased risks of autoimmune diseases; Reactive arthritis, HR 1.487, 95% CI 1.131-1.956; Henoch Schönlein purpura, HR 1.265, 95% CI 1.050-1.524; Systemic lupus erythematosus, HR 1.838, 95% CI 1.165-2.898; Sjögren's syndrome, HR 2.002, 95% CI 1.342-2.987; IgA nephropathy, HR 1.613, 95% CI 1.388-1.874. Kaplan-Meier cumulative incidence curves also showed a significant association between E.coli infection and incident autoimmune disease (p < 0.0001). This relationship was not only independent of demographic variables, but also remained consistent across various sensitivity analyses. On the other hand, patients with longer hospital stay for E.coli infection were at a higher risk of autoimmune disease (p = 0.0003), and the risk of autoimmune disease also tended to increase, as the frequency of E.coli infection was higher. Moreover, the relative risk of autoimmune disease seemed to be attenuated by use of antibiotics and a history of intestinal infectious disease, but elevated by coexistence of other autoimmune diseases. CONCLUSIONS: Our cohort study indicates that E.coli infection was significantly associated with increased susceptibility to autoimmune diseases, even after adjusting for different factors. Thus, among environmental factors, a previous history of E.coli infection could be a predisposing risk factor in the development of autoimmune diseases.

Bone erosion is associated with reduction of circulating endothelial progenitor cells and endothelial dysfunction in rheumatoid arthritis.

OBJECTIVE: To identify factors influencing endothelial progenitor cell (EPC) counts in patients with rheumatoid arthritis (RA). METHODS: The number of circulating CD34+/ vascular endothelial growth factor receptor 2-positive EPCs was measured in 126 RA patients and 46 non-RA control patients. Endothelial function was assessed by brachial flow-mediated dilation (FMD). Serum CXCL12 concentrations were determined using an enzyme-linked immunosorbent assay. EPCs and FMD were measured at baseline and after 24 weeks of anti-tumor necrosis factor (TNF) therapy in 29 patients with active RA. RESULTS: The numbers of circulating EPCs were significantly lower in the RA patients than in the non-RA controls. In multivariate analysis, older age, reduced levels of high-density lipoprotein cholesterol, and higher bone erosion scores were independent risk factors for reduced EPC counts in RA patients. Serum CXCL12 levels correlated negatively with EPC counts, but positively with bone erosion scores. FMD was impaired in RA patients, and a decreased FMD in RA was closely associated with a higher bone erosion score and a reduced EPC count. In addition, EPC counts were restored by anti-TNF therapy, and this increase was paralleled by improvement in FMD. Interestingly, restoration of EPC counts was attenuated in patients with higher bone erosion scores than in those with lower scores, despite similar levels of improvement in disease activity. CONCLUSION: The numbers of circulating EPCs in RA patients are reduced and are inversely correlated with serum levels of CXCL12. Reduced EPC counts are closely associated not only with bone erosion, but also with endothelial dysfunction.

Osteoprotegerin causes apoptosis of endothelial progenitor cells by induction of oxidative stress.

OBJECTIVE: Elevated serum osteoprotegerin (OPG) levels represent an independent risk factor for atherosclerotic disease, although the underlying mechanism is not clear. The aim of this study was to investigate the association of serum OPG levels and circulating endothelial progenitor cell (EPC) numbers, and to explore the effect of OPG on EPC apoptosis and its underlying mechanisms. METHODS: Flow cytometry was used to enumerate EPCs in the peripheral blood of 91 patients with systemic lupus erythematosus (SLE). Cultured EPCs, isolated from peripheral blood, were challenged with OPG, and apoptosis was evaluated by TUNEL staining. Expression of apoptosis-related proteins was measured by real-time quantitative polymerase chain reaction (qPCR) and Western blotting. Reactive oxygen species (ROS) were detected by flow cytometry, and the expression of NADPH oxidase (NOX) and MAP kinases (MAPK) was measured by qPCR and Western blotting. RESULTS: The serum OPG level was independently associated with reduced numbers of EPCs in patients with SLE. In vitro treatment with OPG significantly induced apoptosis of EPCs; this effect was mediated by syndecan 4. OPG-induced apoptosis was abolished by the ROS scavenger N-acetylcysteine and the NOX inhibitor diphenyleniodonium. OPG increased ROS production through activation of NOX-2 and NOX-4 and triggered phosphorylation of ERK-1/2 and p38 MAPK. Quenching of ROS by knockdown of NOX-2 or NOX-4 transcripts inhibited phosphorylation of ERK-1/2 and p38 MAPK. Moreover, inhibitors of ERK-1/2 and p38 MAPK decreased ROS production and subsequent EPC apoptosis, indicating a feed-forward loop between NOX and MAPK to amplify ROS production related to apoptosis. CONCLUSION: Elevated OPG levels increase apoptosis of EPCs by induction of oxidative stress.

The efficacy of tramadol/acetaminophen combination tablets (Ultracet®) as add-on and maintenance therapy in knee osteoarthritis pain inadequately controlled by nonsteroidal anti-inflammatory drug (NSAID).

The purpose of this study is to compare the efficacy of tramadol 37.5 mg/acetaminophen 325 mg combination tablets (tramadol/APAP) with that of nonsteroidal anti-inflammatory drugs (NSAIDs) as maintenance therapy following tramadol/APAP and NSAID combination therapy in knee osteoarthritis (OA) pain which was inadequately controlled by NSAIDs. Subjects with knee OA for over 1 year and moderate pain (numerical rating scale [NRS] ≥5) despite at least 4 weeks' NSAID therapy (meloxicam 7.5 mg or 15 mg qd or aceclofenac 100 mg bid) received tramadol/APAP add-on (combination with NSAID) for 4 weeks. Thereafter, subjects with significant pain improvement (NRS <4) were randomized to receive either tramadol/APAP or NSAID for 8 weeks. On days 29 and 57, Western Ontario and McMaster Universities (WOMAC) OA index score was measured. Secondary measures included pain intensity (NRS), pain relief score, and subjects' and investigators' overall medication assessments. Of 143 subjects enrolled, 112 completed the 4-week tramadol/APAP and NSAID combination phase and 97 (67.8%) experienced significant pain improvement. Of the 97 subjects randomized, 36 in tramadol/APAP group and 47 in NSAID group completed the 8-week comparator study. On days 29 and 57, WOMAC scores and pain intensities did not increase in both groups compared to measurements immediately after the combination therapy. At these two time points, there were no significant differences in WOMAC scores, pain intensities, and other secondary measures between the two groups. Overall adverse event rates were similar in both groups. Tramadol/APAP add-on significantly improved knee OA pain which had been inadequately controlled by NSAIDs. In those subjects who showed favorable response to tramadol/APAP and NSAID combination therapy, both tramadol/APAP and NSAIDs were effective at maintaining the pain-reduced state and there was no significant difference in efficacy between tramadol/APAP and NSAIDs.

Characterization of antiphospholipid antibodies in chronic hepatitis B infection.

BACKGROUND: Many infections are associated with antiphospholipid antibodies (aPLs). The purpose of this study was to investigate the prevalence, persistence, clinical significance, and characteristics of aPLs in hepatitis B virus (HBV)-infected patients. METHODS: This study included 143 patients with HBV infection and 32 healthy individuals as controls. The presence of anticardiolipin antibodies (aCL Ab), anti-ß(2)-glycoprotein I antibodies (ß(2)GPI Ab), and lupus anticoagulant (LA) was assessed. RESULTS: The total prevalence of aPLs in HBV-infected patients was 12.6% (18 of 143). Of these 18 patients, 15 had low to medium titers of aCL Ab (10 with IgM, 4 with IgG, and 1 with both isotypes). ß(2)GPI Ab and LA were detected in 3 (2.1%) and 2 (1.4%) patients with HBV infection, respectively. In follow-up specimens from 14 patients with elevated levels of aCL Ab or ß(2)GPI Ab, 10 (71.4%) showed the persistent presence of aPLs. No clinical manifestations related to aPLs were identified. CONCLUSION: In HBV-infected patients, the most frequently detected antiphospholipid antibodies were IgM aCL Ab, which have a weak association with the clinical manifestations of APS. Unlike the transient presence reported for other infection-associated aPLs, most aPLs were persistently detected over a 12-week period in patients with HBV infection.

Pararenal retroperitoneal Castleman's disease mimicking systemic lupus erythematosus.

A 41-year-old man diagnosed initially as probable systemic lupus erythematosus (SLE) visited our hospital complaining of a persistent painful oral ulcer and multiple spots like coffee beans on his trunk. Antibodies except for anti-dsDNA and anti-histone antibodies and other serologies were negative. Conventional cytotoxic and immunomodulatory agents did not have any effect on these lesions. Computed tomography for evaluating persistent dry cough incidentally showed a huge mass in the left mid-retroperitoneum. Surgical treatment was done and the final diagnosis was Castleman's disease (CD). CD is a relatively rare disorder characterized by a massive non-malignant tumor of lymphoid tissues, with unknown etiology. It commonly presents as a localized soft tissue mass within the mediastinum or neck, and rarely in the retroperitoneal space. Since some cases of CD may share systemic, immune and histopathologic features of autoimmune disease, exact diagnosis is difficult to make based on the clinical and laboratory clues alone. We report herein an unusual case with pararenal retroperitoneal CD mimicking SLE.

The role of macrophages in the in vitro generation of extracellular DNA from apoptotic and necrotic cells.

Cell death is a ubiquitous process that occurs by apoptosis or necrosis depending on the triggering event. While apoptotic and necrotic cells differ biochemically, both are cleared by macrophages for elimination. The process is very efficient, although DNA can appear in the blood in various clinical conditions associated with cell death. To define the role of macrophages in the generation of extracellular DNA, in vitro experiments were performed, assessing the release of DNA into the media of apoptotic or necrotic Jurkat cells cultured with RAW264.7 or J774 macrophage cell lines. DNA was measured by a fluorimetric assay using the dye PicoGreen. In these experiments, while necrotic cells alone did not release DNA, in the presence of macrophages, significant amounts of DNA appeared in the medium. This DNA contained sequences from the Jurkat cells and had reduced molecular weight in comparison to cellular DNA. Furthermore, coculture of macrophages with enucleated necrotic Jurkat cells did not release DNA, suggesting that the DNA came from the dead cell. In contrast, Jurkat cells made apoptotic by treatment with either staurosporine or etoposide spontaneously released DNA, while coculture with macrophages caused a decrease in the DNA released. With apoptotic cells, the DNA in the medium showed low molecular weight and laddering whether or not macrophages were present. Together, these results indicate that macrophages play an important role in the generation of extracellular DNA from dead and dying cells, with the effect dependent on how the cell died.

Elevated vascular endothelial growth factor in systemic sclerosis.

OBJECTIVE: To determine the serum levels of vascular endothelial growth factor (VEGF) in patients with systemic sclerosis (SSc) and to search for relationships between its serum levels and the clinical manifestations. METHODS: Serum levels of VEGF in patients with SSc and healthy controls were determined by ELISA. At the time of blood sampling, individual organ involvement was assessed, and a video microscope and PC based image processing were used to visualize nailfold capillaries and to quantify capillary density. RESULTS: Serum levels of VEGF in 48 patients with SSc were significantly higher than in 30 controls (432 +/- 356 vs 91 +/- 64 pg/ml; p < 0.001). Patients with diffuse cutaneous SSc (n = 21) had higher levels of serum VEGF than those with limited cutaneous SSc (n = 27) (432 +/- 356 vs 135 +/- 127 pg/ml; p < 0.001). Serum VEGF levels correlated well with the extent of skin sclerosis, as determined by modified Rodnan skin score (r = 0.656, p < 0.001) and serum TGF-beta levels (r = 0.530, p < 0.001). In particular, serum VEGF levels were inversely correlated with the capillary density of nailfold (r = -0.649, p < 0.001). However, no significant differences were found in the serum levels of VEGF between patients with systemic organ involvement and those without. CONCLUSION: The extent of skin sclerosis may contribute to the elevation of serum VEGF and high VEGF levels may serve as a surrogate indicator of capillary damage in SSc.