Number needed to treat and cost per responder of Janus kinase inhibitors approved for the treatment of moderate-to-severe rheumatoid arthritis in Japan.

OBJECTIVE: This study evaluated the effectiveness and cost-effectiveness of baricitinib, tofacitinib, and upadacitinib regimens, compared to conventional synthetic disease-modifying antirheumatic drug (csDMARD) alone, among Japanese patients with moderate-to-severe rheumatoid arthritis (RA) inadequately responsive to csDMARD, measured in terms of number needed to treat (NNT) and cost per responder (CPR). METHODS: Efficacy data were derived from two recent network meta-analyses among global and Japanese population. The cost perspective was that of the Japanese Health Service. Both NNT and CPR were based on disease activity score for 28 joints with C-reactive protein (DAS28-CRP) remission and American College of Rheumatology (ACR) 20/50/70 at 12 and 24 weeks. RESULTS: Over 12 weeks, the median NNT and the median CPR to achieve DAS28-CRP remission were 4.3 and JPY 1,799,696 [USD 16,361], respectively, for upadacitinib 15 mg + csDMARD. The equivalent results were 6.0 and JPY 2,691,684 [USD 24,470] for baricitinib 4 mg + csDMARD and 5.6 and JPY 2,507,152 [USD 22,792] for tofacitinib 5 mg + csDMARD. Similar rankings were observed at 24 weeks and for other outcomes. CONCLUSIONS: Upadacitinib 15 mg was associated with the lowest NNT and CPR among the three Janus kinase inhibitors used in treatment regimens for Japanese patients with moderate-to-severe RA inadequately responsive to csDMARD.

The Safety Profile of Upadacitinib in Patients with Rheumatoid Arthritis in Japan.

INTRODUCTION: Upadacitinib is a Janus kinase inhibitor with demonstrated efficacy in patients with rheumatoid arthritis (RA). OBJECTIVE: The aim of this study was to assess the long-term safety of upadacitinib in patients with active RA from Japan compared with global clinical trial populations. METHODS: Pooled data in patients enrolled from Japan (the 'Japanese population'; SELECT-SUNRISE, SELECT-EARLY, and SELECT-MONOTHERAPY) were compared with that from global (Japan and ex-Japan) upadacitinib clinical trial populations and summarized descriptively. RESULTS: The Japanese population (mean age 57.0 years; mean RA duration 6.1 years) received upadacitinib 7.5 mg (n = 121), 15 mg (n = 126), and 30 mg (n = 124) once daily, while the global population (mean age 54.8 years; mean RA duration 9.1 years) received upadacitinib 6 mg twice daily/15 mg once daily (n = 2883) and 12 mg twice daily/30 mg once daily (n = 1375). Most patients were female (79.3%). The exposure-adjusted incidence rates (EAIRs) of serious adverse events in the Japanese population were 11.5, 12.2, and 21.2 per 100 patient-years (PY) with upadacitinib 7.5, 15, and 30 mg, respectively. Herpes zoster rates were higher in the Japanese population (7.8, 12.4, and 16.7 per 100 PY with 7.5, 15, and 30 mg, respectively) versus global populations (3.7 and 7.0 per 100 PY with 15 and 30 mg, respectively). Prior herpes zoster was a significant risk factor for herpes zoster. CONCLUSIONS: The safety profile of upadacitinib was generally similar between Japanese and global RA populations, except for higher EAIRs for serious adverse events and infections, including herpes zoster, in the Japanese population. TRIAL REGISTRATION NUMBERS: SELECT-EARLY: NCT02706873; SELECT-NEXT: NCT02675426; SELECT-COMPARE: NCT02629159; SELECT-MONOTHERAPY: NCT02706951; SELECT-BEYOND: NCT02706847; SELECT-SUNRISE: NCT02720523; BALANCE I: NCT01960855; BALANCE II: NCT02066389.

Impact of the genetic variants of GLCCI1 on clinical features of asthmatic patients.

BACKGROUND: Several gene variants are associated with a response to an inhaled corticosteroids (ICSs) treatment in patients with bronchial asthma. A variant of the glucocorticoid-induced transcript 1 (GLCCI1) genes has previously been associated with decreased lung function improvement upon treatment with ICSs in patients with bronchial asthma. Another report has also demonstrated that this genetic biomarker did not influence the change in flow volume in 1 second. However, no studies have considered the treatment content and the GLCCI1 variants. We were able to determine the relationship between the pulmonary function and clinical features and the variant of the GLCCI1 in Japanese asthmatic patients receiving long-term ICS treatment. MATERIALS AND METHODS: In this study, 405 patients with bronchial asthma, who were receiving ICS and living in Japan, were recruited, genotyped and underwent pulmonary function tests. To identify the GLCCI1 protein expression cells, endobronchial biopsy specimens were examined. RESULTS: We found that the pulmonary function was not significantly different in the homozygotes compared to the wild types. Also, the homozygotes increased the risk of a sustained step-up of the asthma treatment when compared to the wild type and heterozygotes. GLCCI1-positive cells were localized to the bronchial epithelial cells. The amount of GLCCI1 protein that cultured epithelial cells harboring GLCCI1 variants produced was less than the GLCCI1 wild type in the presence of a corticosteroid. CONCLUSIONS: A worsening of pulmonary function caused by GLCCI1 variants could be prevented due to recently used medications based on new action mechanisms.

A phosphatidylinositol 3-kinase inhibitor strongly suppressed pulmonary vascular remodeling of allergic vasculitis in a murine model.

OBJECTIVES: We investigated the effects of pan-class I PI3K inhibitor, ZSTK474 on vascular remodeling using a murine model of allergic vasculitis with eosinophil infiltration. METHODS: C57BL/6 mice were sensitized with OVA. The positive controls were exposed to aerosolized OVA daily for 7 days. The other group of mice were administered ZSTK474 (30 mg/kg, p.o. daily) in parallel with daily exposure to aerosolized OVA for 7 days. On the 3rd and 7th day, bronchoalveolar lavage (BAL) was performed and the lungs were excised for pathological analysis. Cell differentials were determined and the concentrations of IL-4, IL-5, IL-13 and TGF-ßin BAL fluid were measured. RESULTS: The total cell numbers and eosinophil numbers in BALF were greatly reduced in the ZSTK474-treated group on the 3rd and 7th day after exposure to OVA. The numbers of total white blood cells and eosinophils in the peripheral blood were significantly reduced in the ZSTK474-treated group on the 3rd and 7th day after exposure to OVA. The concentrations of IL-4, IL-5, and IL-13 in BAL fluids were also reduced significantly on the 3rd day in the ZSTK474-treated group. The concentrations of TGF-ß in BAL fluids were also reduced significantly on the 3rd and 7th day in the ZSTK474-treated group. The pathological scores reduced significantly in the ZSTK474-treated group compared to the control group. CONCLUSION: The PI3K inhibitor, ZSTK474 suppressed pulmonary vascular remodeling in the murine model of allergic vasculitis with eosinophil infiltration. PI3K signal transduction may have a critical role in the immunological process that induces allergic vasculitis.

Detection of cerebral microvascular lesions using 7 T MRI in patients with neuropsychiatric systemic lupus erythematosus.

Neuropsychiatric systemic lupus erythematosus (NPSLE) is speculated to be caused by disturbed microcirculation of the central nervous system. However, characteristic imaging findings of NPSLE have not been established. Hence, we investigated whether high-resolution images obtained using ultrahigh field MRI at 7 T can detect microcerebrovascular lesions in patients with NPSLE that have never been detected by conventional MRI. We prospectively examined 20 patients with SLE, including five with NPSLE, using a 7 T MRI scanner. High-resolution two-dimensional T2-weighted images and high-resolution three-dimensional T1-weighted images (T1WIs) before and after the administration of contrast agents were obtained. On the high-resolution T1WIs obtained at 7 T, minute punctate/linear hyperintense lesions in subcortical and/or cortical areas were found in four (80%) NPSLE patients and one (7%) non-NPSLE patient. Further, the minute punctate enhanced lesions in these areas were found on contrast-enhanced T1WIs in only three (60%) NPSLE patients. These findings suggesting microvascular thrombi or inflammation were significantly more frequent in NPSLE than in non-NPSLE patients (P=0.001). In contrast, other imaging findings, laboratory findings, and clinical characteristics were not different between the two groups. High-resolution T1WIs obtained at 7 T can detect minute lesions, indicating intracerebral microvascular lesions in patients with NPSLE.

Rapamycin attenuates pulmonary allergic vasculitis in murine model by reducing TGF-ß production in the lung.

BACKGROUND: Rapamycin has been reported to inhibit mesenchymal cell proliferation in a murine model of pulmonary fibrosis. In the present study, we examined the effects of rapamycin on vascular remodeling including intraluminal myofibroblast proliferation in a murine model of allergic vasculitis with eosinophil infiltration. METHODS: C57BL/6 mice were sensitized with ovalbumin (OVA) and alum. The positive controls were exposed to aerosolized OVA daily for 7 days. The other group of mice was administered with rapamycin (1mg/kg) intraperitoneally, in parallel with daily exposure to aerosolized OVA for 7 days. On the 3rd and 7th day, bronchoalveolar lavage (BAL) was performed and the lungs were excised for pathological analysis. Cell differentials were determined and concentrations of IL-4, IL-5, IL-13 and TGF-ß in the BAL fluid (BALF) were measured. Semi-quantitative analysis of pathological changes in the pulmonary arteries was evaluated according to the severity of vasculitis. RESULTS: The number of eosinophils in BALF was reduced significantly in the mice treated with rapamycin compared to the positive control. There was a significant decrease in the TGF-ß concentration of the BALF in the rapamycin-treated group compared to that of the positive control. The pathological scores were reduced significantly in the rapamycin-treated group compared to the positive control group. Intraluminal myofibroblasts in pulmonary arteries were reduced dramatically in the rapamycin-treated group compared to the positive control group. CONCLUSIONS: Rapamycin suppressed pulmonary vascular remodeling in a murine model of allergic vasculitis with eosinophil infiltration through reducing eosinophil infiltration and TGF-ß production in the lung and inhibition against biological action of TGF-ß.

Scedosporium aurantiacum brain abscess after near-drowning in a survivor of a tsunami in Japan.

Many victims of the tsunami that occurred following the Great East Japan Earthquake on March 11, 2011 developed systemic disorders owing to aspiration pneumonia. Herein, we report a case of tsunami lung wherein Scedosporium aurantiacum was detected in the respiratory tract. A magnetic resonance image of the patient's head confirmed multiple brain abscesses and lateral right ventricle enlargement. In this case report, we describe a potential refractory multidrug-resistant infection following a tsunami disaster.

Effects of imatinib mesylate on pulmonary allergic vasculitis in a murine model.

OBJECTIVES: Imatinib mesylate (IM) is a potent and specific tyrosine inhibitor and has been reported to inhibit mesenchymal cell proliferation in pulmonary fibrosis. In the present study, we examine the effects of IM on vascular remodeling in a murine model of allergic vasculitis with eosinophil infiltration. METHODS: C57BL/6 mice were sensitized with ovalbumin (OVA) and alum. The positive controls were exposed to aerosolized OVA daily for 7 days. IM treated mice with exposure to OVA were administered IM in parallel with daily exposure to aerosolized OVA for 7 days. On the 7th day, bronchoalveolar lavage (BAL) was performed and the lungs were excised for pathological analysis. Cell differentials were determined and the concentrations of cytokines in the BAL fluid (BALF) were measured. Semi-quantitative analysis of pathological changes in the pulmonary arteries was evaluated according to the criteria of severity of vasculitis. Immunohistochemistry for Ki-67 to detect proliferating cells was performed. RESULTS: The number of eosinophils in BALF was reduced significantly in the IM-treated group compared to the positive control. There was no significant difference in the concentrations of interleukin (IL)-2, IL-4, IL-5, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, tumor growth factor (TGF)-ß or platelet-derived growth factor in the BAL fluid between the positive control and the IM-treated group. The pathological scores of vasculitis and the ratio of Ki-67-positive intra-luminal cells were reduced significantly in the IM-treated group compared to the control group after OVA exposure. CONCLUSION: IM-suppressed pulmonary vascular remodeling in a murine model of allergic vasculitis with eosinophil infiltration.

Association of IL-13 gene polymorphisms with airway hyperresponsiveness in a Japanese adult asthmatic population.

BACKGROUND: A single nucleotide polymorphism (SNP; rs20541) in the IL-13 gene has been recognized as a risk factor for asthma. This SNP causes Arg to Gln (Q) substitution at position 110 in the mature IL-13 protein. We have recently showed that FEV1 in asthmatics with the Q110 variant of IL-13 declined faster, and progressive airway remodeling was observed in these subjects (Wynn, 2003 [1]). However, the effects of the IL-13 variant on airway hyperresponsiveness (AHR) remain to be elucidated. We analyzed the relationship between SNP rs20541 in IL-13 and AHR in asthmatics. METHODS: We recruited 182 asthmatics who visited the asthma outpatient clinic at Iwate Medical University Hospital from 2006 to 2011. Subjects were genotyped for rs20541. Asthma severity, atopic status, age of asthma onset, serum IgE concentration, AHR, and pulmonary function were studied in these subjects. AHR was measured using the continuous methacholine inhalation method (Astograph; Chest; Tokyo, Japan). RESULTS: Genotyping of rs20541 revealed 26 A/A, 77 A/G, and 79 G/G patient genotypes. The D min (U) of the 3 genotypes was 1.17±0.300 in A/A, 1.99±0.35 in A/G, and 2.85±0.39 in G/G. The D min in the 3 genotypes was significantly different. Spirometric data revealed that % FEV1 and % FEF75 were significantly different among the 3 groups of IL-13 genotypes, whereas no significant differences were observed in therapeutic steps, atopic status, house dust mite sensitization, or serum IgE concentration. CONCLUSION: The SNP rs20541 in IL-13 was associated with AHR in Japanese adult asthmatics.

Multiple Scedosporium apiospermum abscesses in a woman survivor of a tsunami in northeastern Japan: a case report.

INTRODUCTION: Scedosporium apiospermum is increasingly recognized as a cause of localized and disseminated mycotic infections in near-drowning victims. CASE PRESENTATION: We report the case of a 59-year-old Japanese woman who was a survivor of a tsunami in northeastern Japan and who had lung and brain abscesses caused by S. apiospermum. Initially, an aspergillus infection was suspected, so she was treated with micafungin. However, computed tomography scans of her chest revealed lung abscesses, and magnetic resonance images demonstrated multiple abscesses in her brain. S. apiospermum was cultured from her bronchoalveolar lavage fluid, and antimycotic therapy with voriconazole was initiated. Since she developed an increase in the frequency of premature ventricular contractions, an adverse drug reaction to the voriconazole was suspected. She was started on a treatment of a combination of low-dose voriconazole and liposomal amphotericin B. After combination therapy, further computed tomography scans of the chest and magnetic resonance images of her brain showed a demarcation of abscesses. CONCLUSIONS: Voriconazole appeared to have a successful record in treating scedosporiosis after a near drowning but, owing to several adverse effects, may possibly not be recommended. Thus, a combination treatment of low-dose voriconazole and liposomal amphotericin B may be a safe and effective treatment for an S. apiospermum infection. Even though a diagnosis of scedosporiosis may be difficult, a fast and correct etiological diagnosis could improve the patient's chance of recovery in any case.

A histopathological study of pulmonary hypertension in connective tissue disease.

Connective tissue diseases (CTD), such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD), develop pulmonary hypertension (PH). Generally all PH cases associated with any CTD are classified into the same PH group. However, histological examination shows both common and specific lesions for each disease. In patients with SLE, fibrosis is generally rare and mild. The findings of PH in SLE are similar to those in primary pulmonary hypertension. Many cases of SSc are accompanied by fibrosis. MCTD is rather close to SSc. Arterial and arteriolar lesions of MCTD are characterized by fibrous intimal thickening. In this review, we describe the pathological features of PH associated with each CTD.

Histological analysis of esophageal muscular layers from 27 autopsy cases with mixed connective tissue disease (MCTD).

Esophageal symptoms in mixed connective tissue disease (MCTD) have been investigated radiologically. We investigated the esophageal lesions in MCTD histopathologically, and analyzed relationships between these lesions and autoantibodies extracted from the serum of MCTD patients. Esophageal tissues from 27 MCTD patients submitted to autopsy were examined. We compared histopathological features of the esophagus in different wall layers from the mucosa, submucosa, and muscular layer to the adventitia, and in the upper, middle, and lower portions of esophagus. The most striking change observed was severe atrophy and occasional loss of smooth muscle cells in the muscular layer, followed by fibrosis. These muscular changes were particularly prominent in the inner layer of the lower esophagus. Immunohistochemically, degenerated muscular tissues of the esophagus were positive for anti-IgG and anti-C3 antibodies, but not for anti-IgM antibodies. IgG fractions extracted from three MCTD patients were immunohistochemically used to examine whether some antibodies in MCTD patients showed reactivity for esophageal components. The IgG fractions isolated from MCTD patients reacted with smooth muscle from non-connective tissue disease cases, suggesting that some serum antibodies may trigger esophageal changes. These findings suggest that esophageal lesions associated with clinical dysphagia in MCTD may be related to autoantibodies.

Novel ribbon-type nuclear factor of activated T cells decoy oligodeoxynucleotides preclude airways hyperreactivity and Th2 cytokine expression in experimental asthma.

BACKGROUND: Nuclear factor of activated T cells (NFAT) is required for the differentiation of Th2 responses, so we examined its role in mouse experimental asthma and tested the hypothesis that an NFAT blockade with a decoy against NFAT can prevent asthma progression. OBJECTIVE: To determine the effects of the NFAT decoy oligodeoxynucleotides (ODNs) on the development of airway inflammation, we designed a novel ribbon-type ODN containing two binding sites for NFAT in a single decoy molecule without an open end, which is more stable than a conventional decoy, and largely preserved its structural integrity in the presence of nucleases. METHODS: Ribbon-type NFAT decoy ODNs were transfected into ovalbumin (OVA)-sensitized CD3+ T cells in vitro. OVA-immunized mice received these cells by intraperitoneal injection. Airway hyperreactivity (AHR) was measured and the transfected CD3+ T cells' responses to the airways were characterized. RESULTS: Development of AHR after OVA challenge was effectively abolished after adoptive transfer of ribbon-type NFAT decoy ODN transfected CD3+ T cells. Transfer of ribbon-type decoy significantly reduced the number of inflammatory cells and the concentrations of IL-4, IL-5 and IL-13, but not IFN-γ, in the bronchoalveolar lavage of the recipient mice. CONCLUSION: These results suggest the inhibitory effect of ribbon-type decoy ODNs against NFAT on the induction of bronchial asthma. Adoptively transferred CD3+ T cells, which are transfected with NFAT decoy, may be an effective strategy for the treatment of asthma.

Analysis of pulmonary allergic vasculitis with eosinophil infiltration in asthma model of mice.

Here the authors report pulmonary allergic vasculitis with eosinophil infiltration in an asthma model of mice and investigated its pathogenesis. C57BL/6 and BALB/c mice were sensitized with ovalbumin (OVA). After the inhalation of OVA, the authors measured the cell number and cytokine concentration in the blood and bronchoalveolar lavage fluid (BALF). The authors also examined the histological changes of the pulmonary. The number of eosinophils increased in the blood and BALF in both strains; however, the number in C57BL/6 in BALF was significantly higher than that in BALB/c. Histological analysis demonstrated severe vasculitis of the pulmonary arteries with derangement of the muscle layer and smooth muscle cell hyperplasia in C57BL/6. Semiquantitative analysis of the severity of vasculitis in the pulmonary arteries revealed that the internal vascular space was highly reduced by smooth muscle hyperplasia in C57BL/6 compared to BALB/c mice. The concentrations of interleukin (IL)-4, IL-5, and interferon (IFN)-gamma in BALF of C57BL/6 were significantly high compared to those of BALB/c. C57BL/6 mice exhibited severe allergic vasculitis in the pulmonary arteries compared to BALB/c mice. The high concentrations of IL-4, IL-5, and IFN-gamma in the lung may play a critical role in the pathogenesis of allergic vasculitis in C57BL/6 mice.

[Case of systemic lupus erythematosus occurring after induced abortion and drug eruption].

We describe a19 year-old woman who was diagnosed as systemic lupus erythematosus (SLE) after abortion. She had taken anti-convulsants for epilepsy since she was 8 years old. Induced abortion surgery was performed at six weeks in her pregnancy. She showed pyrexia and a general rash 2 days after the abortion. She was introduced to our hospital because the administration of antibiotics was not effective. Since the anti-convulsants had been changed after pregnancy, we returned to those administered before pregnancy and followed her up. Her eruption improved, but she became aware of thirstiness and dry eye. She was diagnosed as Sjögren syndrome by ophthalmologic examination, lip biopsy, and elevation of an anti-SS-A antibody and an anti-SS-B antibody in the serum. Since we could not rule out SLE because of the low concentration of complement activity in blood, we followed her up carefully by checking serum markers of SLE. Protein urine developed after the improvement of the eruption 2 weeks later. Low complement activity was recognized and double stranded (ds)-DNA antibody became positive. In addition to these findings, she had an episode of hypersensitivity to sunlight and was therefore diagnosed as SLE. Since induced abortion and drug eruption might be associated with the onset of SLE, the case is thought to be a valuable from the view point of understanding the mechanism of SLE onset.

Klinefelter's syndrome associated with systemic lupus erythematosus and autoimmune hepatitis.

Klinefelter's syndrome (KFS) tends to be associated with immunological disorders. We describe a 37-year-old man who presented signs of testicular atrophy and decreased body hair. He showed pancytopenia and elevated levels of liver enzymes. Chromosome analysis revealed 47XXY karyotype; therefore, he was diagnosed with KFS, with systemic lupus erythematosus and autoimmune hepatitis. Treatment with a high dose of methylprednisolone and methyltestosterone improved thrombocytopenia and symptoms, suggesting that methyltestosterone may have a clinical benefit in the treatment of KFS with a low level of testosterone accompanying immunological disorders.

[Cytoprotective effects of heat shock protein-70 in bronchial epithelium against neutrophil elastase-induced cell injury].

BACKGROUND: Neutrophil releases several mediators during inflammation, including neutrophil elastase (NE) that impairs bronchial epithelial function. The stress response and stress proteins protect cells against a variety of cytotoxic conditions. Accordingly, we tested the hypothesis that bronchial epithelial heat shock protein (Hsp-70) would protect a NE-induced cell injury. METHODS: Bronchial epithelial cells (BECs) obtained by bronchial brushing under bronchoscopy were cultured and used for experiments. Expression of Hsp-70 in BECs was confirmed by Western blot and flowcytometric analysis. To test Hsp-70 in BECs, induction of Hsp-70 protein into BECs was carried out by liposome-based delivery system. Introduction of Hsp-70 into BECs were examined by direct fluorescence microscope examination and flowcytometric analysis. NE-induced cytotoxicity was evaluated by cell culture supernatant LDH assay and cell detachment assay. RESULTS: Higher expressions of Hsp-70 were observed in BECs, which were induced by sodium arsenite. Over expression of Hsp-70 in BECs reduced NE-induced cell injury. Introduction of Hsp-70 protein into BECs by liposomal delivery decreased LDH release, and inhibited necrosis and apoptosis of the cells by NE as compared to untreated control. CONCLUSION: These data suggested that Hsp-70 in BECs may inhibit NE-induced airway epithelial damage. Liposomal delivery of Hsp-70 into BECs may be a possible means of protecting bronchial epithelium against inflammatory airway diseases including acute and chronic bronchitis.

[A possible role of anti-endothelial cell antibody in the sera of MCTD patients on pulmonary vascular damage relating to pulmonary hypertension].

OBJECTIVES: Pulmonary hypertension (PH) is one of the major fatal causes in patients with mixed connective tissue disease(MCTD), which showed remarkable angiopathy from large to small vessels in the lungs. However, the etiology of PH in MCTD is still unknown. Even the lung tissues of MCTD patients without overt clinical PH represent minor vascular damages such as microthrombus or slight intimal thickening. These findings suggest some serum factors cause endothelial cell damage especially to pulmonary micro vessels, which leads to PH in MCTD. To elucidate the mechanisms of PH in MCTD we studied the anti-endothelial cell antibodies (AECA) in the sera of MCTD patients, which are considered to correlate with activity in some collagen diseases, and compared the three kinds of endothelial cells, especially the effects on pulmonary endothelial cells. MATERIALS AND METHODS: Sera from 14 MCTD patients who satisfied the Kasukawa's criteria in Japan including 4 cases of PH, 8 cases of non-PH and 3 untreated cases, and 5 healthy controls were analyzed as follows: (1) AECA to human pulmonary arterial endothelial cells (HPAEC), pulmonary microvascular endothelial cells (HMVE-L) and human aortic endothelial cells(HAEC) were analyzed by an indirect immunofluorescence method using flow cytometry. (2) Effects of MCTD patients' and healthy controls' sera on cell proliferation and induction of apoptosis on cultured HPAEC were investigated by methods of MTS and TUNEL. (3) A cytotoxic effect of patients' sera in combination with activated NK cells on HPAEC were studied by a method of LDH concentration. RESULTS: (1) Patients' sera from MCTD have IgG type AECA, and sera from MCTD patients with PH showed a higher intensity of AECA compared with non-PH and control cases (P < 0.01). (2) Only patient's sera revealed no potency of cell proliferation and induction of apoptosis in every kinds of endothelial cells compared with controls. (3) Sera from MCTD patients with PH, and from untreatment patients were high intensity of AECA, which shows cytotoxicity by addition of activated NK cells. CONCLUSIONS: Apoptosis of pulmonary arterial endothelial cells induced by AECA in combination with activated NK cells may be the fist step of vascular damage associated with pulmonary hypertension in patients with MCTD.