Ribosomal P protein P0 as a candidate for the target antigen of anti-endothelial cell antibodies in mixed connective tissue disease.

OBJECTIVE: To evaluate the presence of anti-endothelial cell antibodies (AECA) in patients with mixed connective tissue disease (MCTD) compared to those with systemic sclerosis (SSc) and to determine the candidates for the endothelial auto-antigen that reacts with AECA in patients with MCTD using a molecular cloning strategy. METHODS: AECA were measured by a cellular enzyme-linked immunosorbent assay (ELISA) using fixed human umbilical vein endothelial cells (HUVEC) in 47 MCTD patients, 68 SSc patients, and 52 normal controls. A HUVEC cDNA expression library was immunoscreened with pooled sera from 6 patients with high AECA levels determined by cellular ELISA to explore the endothelial autoantigens in MCTD. An ELISA assay for anti-ribosomal protein P0 antibodies was used to assess the correlation with AECA levels. RESULTS: The candidate target proteins recognized by AECA in MCTD included: (i) ribosomal protein P0; (ii) a putative oncogene derived from dek mRNA; (iii) SS-B/La protein; (iv) U1 RNA-associated 70K protein; and (v) DNA-binding protein B. A significant correlation between the levels of AECA and anti-ribosomal protein P0 antibodies was demon-strated in MCTD, but not in systemic sclerosis. The sera containing high levels of AECA from patients with MCTD frequently cross-reacted with ribosomal protein P0. On the other hand, sera without AECA activity from patients with MCTD never reacted with ribosomal protein P0. CONCLUSION: AECA were more frequently seen in patients with MCTD than in patients with SSc. Ribosomal protein P0 may be one of the major target antigens of AECA in patients with MCTD.

Nonspecific interstitial pneumonia pattern as pulmonary involvement of rheumatoid arthritis.

The pathologic patterns of lung involvement were evaluated in 16 patients with rheumatoid arthritis (RA). They consisted of six females and ten males, with a median age of 67.5 years and diagnosed according to the American Rheumatism Association revised criteria. High-resolution computed tomography (HRCT) of the lungs was performed in all patients, and honeycomb formation was apparent in seven. Histopathologically, seven patients were diagnosed with usual interstitial pneumonia (UIP) pattern, seven with nonspecific interstitial pneumonia/fibrosis (NSIP) pattern, and two with UIP/NSIP hybrid pattern. There were no apparent honeycomb formations on HRCT in patients diagnosed with NSIP pattern. In conclusion, the present study demonstrates that NSIP pattern is also a significant histologic classification of interstitial pneumonia associated with RA.

KL-6, a human MUC1 mucin, is expressed early in premature lung.

KL-6, one of the MUC1 antigens, is a mucin-like high-molecular-weight glycoprotein, which is strongly expressed on type II pneumocytes. Serum levels of KL-6 have been shown to correlate with activity of interstitial pneumonia (IP). During embryonic development, MUC1 expression coincides with the onset of epithelial sheet and glandular formation. To investigate the potential role of KL-6 in lung morphogenesis, we examined KL-6 expression by immunohistochemistry on autopsied lung tissue specimens of 35 neonates and infants with gestational age from 23 to 40 weeks. Hyaline membranes (HMs) were detected in 13 of 35 cases. Simultaneously, antibody against surfactant protein A (SP-A) was employed in the study which is a distinct marker for type II pneumocytes. In all cases studied with gestational age above 23 weeks, staining for KL-6 was strongly positive in alveolar epithelial cells and in HMs found in 13 cases, whereas immunoreaction for PE10 varied depending on gestational age and duration of postnatal survival. Our findings suggest that KL-6 is expressed earlier in premature lung and may act as an important factor contributing to morphogenesis and function of developing lung in early gestation.

The appearance of S-100 protein-positive dendritic cells and the distribution of lymphocyte subsets in idiopathic nonspecific interstitial pneumonia.

Idiopathic interstitial pneumonia (IIP) is a progressive interstitial lung disease of unknown etiology. We investigated dendritic cells in idiopathic nonspecific interstitial pneumonia (NSIP) immunohistochemically, using anti-S-100 protein antibody and anti-HLA-DR antibody and also evaluated the relationship between the distribution of S-100 protein-positive dendritic cells (S- 100 DCs) and the lymphocytic subsets in the lung tissue of NSIP. Fifteen patients with the pathological diagnosis of idiopathic NSIP and six patients with usual interstitial pneumonia (UIP) were recruited into this study. Many S-100 DCs were observed in all the cases of idiopathic NSIP but S-100 DCs were not recognized in UIP cases invariably. In the mirror section method, most S-100 DCs showed a positive reaction of anti-HLA-DR antibody but a negative reaction for anti-CD1a antibody. CD8 and CD4 positive lymphocytes were infiltrated diffusely around S-100 DCs. It was demonstrated that the infiltration of CD8 positive lymphocytes predominated in the fibrosing areas and lymphoid follicles around S-100 DCs more so than CD4 positive lymphocytes.We speculate that the pathogenesis of NSIP is different from UIP and that DC and T cell-mediated immune mechanisms may play a role in the development and perpetuation of NSIP.

Transforming growth factor beta1 gene polymorphism in rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic inflammatory disease and synovial cells, antigen presenting cells, lymphocytes, and their cytokines might be associated with the disease. Transforming growth factor beta1 (TGFbeta1) has been reported to have important roles in unresolved inflammation, immune suppression, fibrosing processes, and angiogenesis. TGFbeta1 is highly expressed in joints in RA and is considered to be a regulator of anti-inflammation in RA. Polymorphisms of TGFbeta1 have been reported to be associated with the production of TGFbeta1 protein, and to increase the risk of acquiring several diseases. It was speculated that these polymorphisms might also be involved in RA, and therefore the TGFbeta1 codon 10 T869C polymorphism in a series of patients and controls was investigated. METHOD: A total of 155 patients with RA and 110 healthy subjects were studied. DNA was extracted from peripheral leucocytes and TGFbeta1 codon 10 T869C polymorphism was determined by polymerase chain reaction restriction fragment polymorphism. RESULTS: A significantly higher proportion of patients with RA with the T allele (CT type or TT type) was found compared with the CC type (p=0.039). CONCLUSION: The T allele, previously reported to be linked with production of TGFbeta1, may be associated with an increased risk of RA.

Nonspecific interstitial pneumonia as pulmonary involvement of primary Sjögren's syndrome.

The pathologic patterns of lung involvement in nine patients with Sjögren's syndrome (SjS) are evaluated. The patients consisted of three males and six females, with a median age of 59 years. The SjS was diagnosed according to the criteria of the First International Seminar on SjS. In all patients, high-resolution computed radiographic scanning (HRCT) of the lungs was performed, and apparent honeycomb or microhoneycomb formation was observed in six patients. Pathologically, six patients were diagnosed with usual interstitial pneumonia (UIP), and three were diagnosed with nonspecific interstitial pneumonia/fibrosis (NSIP) (group II). There were no apparent honeycomb formations on HRCT in patients diagnosed with NSIP. In conclusion, NSIP is also a possible histologic classification of interstitial pneumonia associated with SjS.

Transforming growth factor-beta gene polymorphism in sarcoidosis and tuberculosis patients.

SETTING: Transforming growth factor-beta (TGF-beta) plays an important role in many diseases, influencing as it does such processes as immune responses, fibrosing processes, and angiogenesis. Recently, polymorphisms have been described for TGF-beta that are associated with the risk of several diseases. In this study, we investigated whether TGF-beta 1 polymorphism has an effect on sarcoidosis and tuberculosis. OBJECTIVE: TGF-beta 1 Codon 10 T869C polymorphism was investigated in 110 healthy control subjects, 104 sarcoidosis patients, and 101 tuberculosis patients. DESIGN: The TGF-beta genotype was determined using polymerase chain reaction restriction fragment length polymorphism. RESULTS: We found no significant differences in TGF-beta genotypes between sarcoidosis patients and healthy controls or tuberculosis patients and controls. The long axis of the tuberculin skin test was larger in the CC type compared with the CT type. However, there was no association between the TGF-beta genotype and the roentgenographic stage, the disappearance of shadows, or organ involvement in sarcoidosis, nor any association between genotype, the extent or type of roentgenographic shadow, or detected volume of tubercle bacilli in tuberculosis. CONCLUSION: From the results, we believe that TGF-beta polymorphisms on the whole do not have a strong influence on disease onset or clinical progression in sarcoidosis and tuberculosis, although this polymorphism might have an effect on the immune response in a tuberculosis host.

Detection of antivimentin antibody in sera of patients with idiopathic pulmonary fibrosis and non-specific interstitial pneumonia.

It has been suggested that the humoral immune system plays a role in the pathogenesis of non-specific interstitial pneumonia (NSIP). Although some circulating autoantibodies to cytoskeletal protein(s) have been suggested, the antimyofibroblast antibody has not been investigated in patients with idiopathic pulmonary fibrosis (IPF) and NSIP. The purpose of this study is to evaluate the existence of antimyofibroblast antibody in the sera of patients with IPF and NSIP. The MRC5 cell line was used as a model of myofibroblast. The anti-MRC5 cell antibody was characterized in a patient with NSIP using Western blotting. Since we found that one of the anti-MRC5 antibodies was an antivimentin antibody, we established an enzyme-linked immunosorbent assay (ELISA) to measure the levels of antivimentin antibody in the sera of patients with IPF (n = 12) and NSIP (n = 23). Initially, two anti-MRC5 cell antibodies were detected in the sera of patients with NSIP, one of which was characterized as the antivimentin antibody by Western blotting. The other was characterized as an antivimentin fragment antibody. We established an ELISA to measure the antivimentin antibody and found significantly higher levels in patients with IPF and NSIP than in normal volunteers. One of the anti-MRC5 cell antibodies in the serum of a patient with NSIP was against vimentin. The serum levels of antivimentin antibody were increased in patients with IPF and NSIP compared with that of normal volunteers. These results suggest that the antivimentin antibody may be involved in the process of lung injury in IPF and NSIP.

Pulmonary AL amyloidosis in a patient with primary Sjögren syndrome.

Abstract The condition of a 29-year-old woman with primary Sjögren syndrome (SS) was complicated by amyloid light chains- (AL-) type amyloidosis in the paranasal sinus. She had not complained of respiratory symptoms, but her chest computed tomography (CT) scan revealed bilateral multiple nodular shadows. Lung biopsy specimens using video-associated thoracoscopy showed amyloidoma in a subpleural nodular lesion and amyloid deposits in the interstitial parenchymal walls and pulmonary vessels. Pulmonary AL amyloidosis, presumably related to a chronic inflammatory lymphoproliferative process in SS, has rarely been reported.

Reduced bone mineral density in Japanese premenopausal women with systemic lupus erythematosus treated with glucocorticoids.

Abstract We evaluated bone mineral density (BMD) in Japanese female patients with systemic lupus erythematosus (SLE) and assessed the influence of the use of glucocorticoids. Lumbar BMD was measured by dual x-ray absorptiometry (DXA) in 60 premenopausal females who previously had been receiving glucocorticoid therapy. Therapeutic- and disease-related variables for SLE were analyzed and bone resorption or formation markers were measured. Osteoporosis was defined as a T-score below 2.5 SD by DXA; 12 patients (20%) showed osteoporosis, and 30 (50%) had osteopenia. Compared with the nonosteoporotic group (n = 48), the osteoporotic group (n = 12) had a significantly longer duration of glucocorticoid treatment (P = 0.01), a cumulative prednisolone dose (P = 0.002), and an SLE damage index (SLICC/ACR). There was no difference in the incidence of osteoporosis either with or without the previous use of methyl-prednisolone pulse or immunosuppressive drugs. There was a significant positive correlation between urinary type I collagen cross-linked N-telopeptides (NTx) and serum bone-specific alkaline phosphatase (BAP) (r = 0.404, P = 0.002), but these bone metabolic markers showed no difference between the osteoporotic and nonosteoporotic groups. A good significant negative correlation was shown between BMD and the cumulative glucocorticoid dose (r = -0.351, P = 0.007). Stepwise logistic regression analysis showed that the cumulative glucocorticoid intake was independently associated with osteoporosis. Glucocorticoid-induced osteoporosis was frequently observed in Japanese SLE patients, as in Caucasian populations. The cumulative glucocorticoid dose was associated with an increased risk for osteoporosis. Bone metabolic markers such as NTx and BAP were not influenced by glucocorticoid treatment and could not predict current osteoporosis in SLE patients.

Non-specific interstitial pneumonia as pulmonary involvement of systemic sclerosis.

The pathological features of lung disease in nine patients with systemic sclerosis (SSc) were evaluated. The patients comprised one man and eight women, with a median age of 58 years. SSc was diagnosed according to the criteria of the American Rheumatism Association. In all patients, high resolution computed radiographic scanning of the lungs (HRCT) was performed, and apparent honeycomb formation was seen in four patients. Pathologically, four patients were diagnosed with usual interstitial pneumonia (UIP), three with non-specific interstitial pneumonia (NSIP) group II, one NSIP group II-III, and one NSIP group II with diffuse alveolar damage. HRCT showed no apparent honeycomb formations in patients diagnosed with NSIP. This is the first report describing NSIP as a pulmonary complication of SSc.

Expression of cyclin E and cyclin D1 in non-small cell lung cancers.

The relationships between overexpression of cyclin D1 or cyclin E and clinicopathological factors were investigated in 157 patients with non-small cell lung cancers (NSCLCs) using immunohistochemical analysis. Fifty-eight cases of NSCLCs (58/157, 37%) showed the overexpression of cyclin D1, and 64 cases (64/157, 41%) were positive for cyclin E. Cyclin E and cyclin D1 were infrequently concurrently overexpressed (17/157, 10.8%). Overexpression of cyclin E was more frequently observed in squamous cell carcinoma (29/57, 51%) compared with that in adenocarcinoma (28/86, 33%) (P<0.05). In addition, overexpression of cyclin E was more frequently observed in poorly or moderately differentiated NSCLCs (52/103, 50%) than in well-differentiated ones (12/54, 22%) regardless of their histological types (P<0.01). On the contrary, there was no statistically significant relationship between cyclin D1 overexpression and histological types or grade of tumor differentiation. These findings suggest that expression of cyclin E was frequently independent of that of cyclin D1 and played some roles in the grade of tumor differentiation in NSCLCs.

Lymphocyte subsets in lung tissues of interstitial pneumonia associated with untreated polymyositis/dermatomyositis.

This study was designed to evaluate the distribution of lymphocyte subsets in lung specimens obtained by surgical lung biopsy from 12 patients with interstitial pneumonia associated with untreated polymyositis/dermatomyositis (PM/DM). Differences of histological findings and distributions of lymphocyte subsets between PM and DM were also evaluated. Distributions of B lymphocytes, CD4-positive T lymphocytes, and CD8-positive T lymphocytes were evaluated immunohistochemically. Interstitial pneumonia was pathologically classified as basically nonspecific interstitial pneumonia (NSIP) in all patients. Immunohistochemically, the distribution of B lymphocytes was mostly restricted to inside and/or around lymphoid follicles. The CD4-positive T lymphocytes were distributed diffusely in fibrotic areas and unrelated to lymphoid follicles. Most CD8-positive T lymphocytes were diffusely distributed, especially in relatively normal alveoli. There were no significant differences in the distribution of lymphocyte subsets between PM and DM. Although the distribution of B lymphocytes and CD4- and CD8-positive T lymphocytes in the lung were different, there were no significant differences in distributions of lymphocyte subsets between PM and DM.

Non-specific interstitial pneumonia and Chlamydia pneumoniae infection.

Recently, the clinical features of non-specific interstitial pneumonia (NSIP) have been described. We hypothesize that recurrent infection caused by Chlamydia pneumoniae may play a role in the pathogenesis of NSIP. To prove this, we quantified serum IgA and IgG antibodies against C. pneumoniae using the enzyme linked-immunosorbent assay kit. The study included 15 patients diagnosed with NSIP, 20 patients with chronic obstructive pulmonary diseases (COPD) as disease group, and 27 control subjects. IgA antibody against C. pneumoniae was positive in 12 of 15 patients with NSIP, in 16 of 20 patients with COPD, and in 14 of 27 control subjects. IgG antibody against C. pneumoniae was positive in 14 of 15 patients with NSIP, in 17 of 20 patients with COPD, and in 16 of 27 control subjects. If the cut off value (mean +/- 2SD, index more than 3.0) was introduced, IgA and/or IgG antibodies against C. pneumoniae were positive in 8 of 15 patients with NSIP (53.3%), in 9 of 20 patients with COPD (45%), and in 2 of 27 control subjects (7.4%). These results suggest that infection of C. pneumoniae might play a role in the pathogenesis of NSIP.

[A case of Wegener's granulomatosis with pachymeningitis].

A 62-year-old woman who had been receiving corticosteroid therapy for pachymeningitis since 1997 was admitted to our hospital when an abnormal shadow was noticed in her chest radiograph. In bronchial and nasal mucosal biopsies, the findings of a necrotic granulomatous lesion and vasculitis were compatible with Wegener's granulomatosis, although this is rarely seen with pachymeningitis. After further corticosteroid therapy together with cyclophosphamide treatment, the size of the thoracic X-ray shadow decreased. Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from the sputum and the nasal fluid, and may have contributed to the advance of the disease in the airway. This case will require continuing careful observation.

Vitamin D receptor gene polymorphism and calcium metabolism in sarcoidosis patients.

BACKGROUND: Hypercalcemia has been recognized as an important complication of sarcoidosis, caused by overproduction of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) at sites of granulomatous reactions. Polymorphism of the vitamin D receptor (VDR) gene has recently been shown to be related to bone mineral density, and also associated with hyperparathyroidism and risk of granulomatous disease. In light of the possible impact on hypercalcemia of sarcoidosis, an investigation of calcium metabolism and polymorphism of the VDR gene in sarcoidosis patients was carried out. METHODS: Genotypes were determined using the polymerase chain reaction and restriction fragment length polymorphism. Maximum calcium, 1,25(OH)2D3, and intact PTH levels were also determined. RESULTS: Depressed PTH levels were found in sarcoidosis patients, especially in those with the bb genotype, but there was no difference in 1,25(OH)2D3 levels among the VDR genotypes, and this polymorphism also had no association with onset of hypercalcemia. CONCLUSION: From these results, we speculate that although the VDR gene polymorphism may affect the serum PTH level, it is not a risk factor for hypercalcemia in sarcoidosis.

Circulating cytokeratin 8:anti-cytokeratin 8 antibody immune complexes in sera of patients with pulmonary fibrosis.

BACKGROUND: It has been suggested that the humoral immune system plays a role in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and pulmonary fibrosis associated with collagen vascular disorders (PF-CVD). Although circulating immune complexes in patients' sera have been suggested, none of the antigens have been characterized. OBJECTIVES: The purpose of this study is to characterize the antigen of the immune complexes in patients' sera of pulmonary fibrosis. METHODS: As we previously established that one of the antibodies against A549 cells (lung alveolar type II cells) was anti-cytokeratin 8 (CK8), we confirmed the existence of anti-CK8 antibody in patients' sera by Western immunoblot. In addition, we tried to demonstrate circulating CK8:anti-CK8 immune complexes in patients' sera by Western immunoblot. Furthermore, we established an enzyme-linked immunosorbent assay to quantitate CK8:anti-CK8 immune complexes. RESULTS: In patients with pulmonary fibrosis, anti-CK8 antibodies were clearly demonstrated in sera by Western immunoblot. In addition, circulating CK8:anti-CK8 immune complexes were also clearly demonstrated by Western immunoblot. It was possible to establish ELISA to quantitate CK8:anti-CK8 immune complexes. If the cutoff value, which was determined based on the highest value of normal volunteers, was introduced, high CK8:anti-CK8 antibody complexes were demonstrated in 9 of 31 patients (29.0%) with IPF and PF-CVD. CONCLUSIONS: This is the first study to clarify the antigen of the circulating immune complex in sera of patients with IPF. These results suggest that circulating CK8:anti-CK8 immune complexes may have played a role in the process of lung injury in pulmonary fibrosis.

Elevation of anti-cytokeratin 18 antibody and circulating cytokeratin 18: anti-cytokeratin 18 antibody immune complexes in sera of patients with idiopathic pulmonary fibrosis.

In this study, we hypothesize that anti-cytokeratin 18 (CK18) antibody and CK18:anti-CK18 immune complex increase in sera in patients with idiopathic pulmonary fibrosis (IPF). To prove the existence of anti-CK18 antibodies in patients' sera, bovine CK18 was stained with patients' sera using a Western blotting. In patients with IPF, anti-CK18 antibodies were clearly demonstrated in sera by Western blotting. Then, we tried to establish an enzyme-linked immunosorbent assay (ELISA) to quantify anti-CK18 antibodies and CK18:anti-CK18 immune complexes in sera of patients with IPF. Levels of anti-human CK18 antibodies in sera of patients with IPF (0.81 +/- 0.31, mean +/- SD) measured by ELISA were significantly high compared with that of normal volunteers (0.45 +/- 0.06, p < 0.01). In addition, levels of CK18:anti-CK18 antibody complexes in patients' sera (0.64 +/- 0.35, man +/- SD) significantly increased compared with those of normal subjects (0.40 +/- 0.10, p < 0.01). These results suggest that anti-CK18 antibody and its immune complex may have played a role in the process of lung injury in IPF.

Role of carbohydrate antigens sialyl Lewis (a) (CA19-9) in bronchoalveolar lavage in patients with pulmonary fibrosis.

BACKGROUND: It has been reported that carbohydrate antigen sialyl Lewis (a) (CA19-9) levels are elevated in serum as well as in bronchoalveolar lavage fluid (BALF) of patients with pulmonary fibrosis. However, the biological significance of CA19-9 is unclear. OBJECTIVE: The purpose of the present study was to evaluate correlations between CA19-9 levels in BALF and several biochemical as well as clinical parameters in patients with pulmonary fibrosis. In addition, biological functions of CA19-9 were also examined. METHODS: We studied 24 patients with a diagnosis of pulmonary fibrosis: 16 with idiopathic pulmonary fibrosis (IPF) and 8 with pulmonary fibrosis associated with a collagen vascular disorder (PF-CVD). In BALF, carbohydrate antigens sialyl Lewis (a) (CA19-9), elastase: alpha(1)-proteinase inhibitor complex (E-PI), hepatocyte growth factor (HGF), LDH, IgG, IgA, albumin, and cell differentiation were measured. We also evaluated the effects of CA19-9 on neutrophil functions. RESULTS: CA19-9/albumin levels in BALF significantly correlated with HGF/albumin, elastase/albumin, LDH/albumin, total number of alveolar macrophages, and total number of neutrophils. Purified CA19-9 had a chemotactic activity for neutrophils. In addition, neutrophil chemotactic activity to C5a, fMLP, and interleukin 8 was significantly stimulated after incubation with purified CA19-9. Furthermore, CA19-9 increased the expression of CD15s on neutrophils. CONCLUSIONS: Our data demonstrated (i) CA19-9 in BALF correlated with other markers of inflammation in pulmonary fibrosis, and (ii) CA19-9 can modify neutrophil functions. These results suggest that CA19-9 may play a role in the process of lung injury in patients with pulmonary fibrosis.

Sequential changes of KL-6 in sera of patients with interstitial pneumonia associated with polymyositis/dermatomyositis.

OBJECTIVE: KL-6 is a mucin-like high molecular weight glycoprotein, which is strongly expressed on type II alveolar pneumocytes and bronchiolar epithelial cells. It has been demonstrated that the KL-6 antigen is a useful marker for estimating the activity of interstitial pneumonia. In this study, it is hypothesised that serum KL-6 is a useful marker to evaluate the activity of interstitial pneumonia associated with polymyositis/dermatomyositis (PM/DM). METHODS: KL-6 was measured in sera in 16 patients diagnosed with PM/DM. Five had non-specific interstitial pneumonia (NSIP), three had diffuse alveolar damage (DAD), and eight had no pulmonary involvement, and 10 were normal non-smokers as a control group. The correlation was also evaluated between the KL-6 level and each clinical course in patients with pulmonary involvement associated with PM/DM. Immunohistochemical analysis using monoclonal anti-KL-6 antibody was also performed. RESULTS: KL-6 concentrations in sera of patients with interstitial pneumonia associated with PM/DM were significantly high compared with those of PM/DM without interstitial pneumonia, and normal non-smokers. KL-6 concentrations in sera in patients with DAD significantly increased compared with those of other groups. KL-6 values in sera changed according to the progression or improvement of interstitial pneumonia. Immunohistochemical study using pulmonary tissues obtained from patients with DAD demonstrated that the hyaline membrane, proliferating type II pneumocytes, bronchial epithelial cells and some endothelial cells in pulmonary veins were stained by antihuman KL-6 antibody. CONCLUSION: These data demonstrate that measurement of serum KL-6 was a useful marker to evaluate the activity of acute interstitial pneumonia associated with PM/DM.