Serum levels of the soluble haemoglobin scavenger receptor CD163 in MPO-ANCA-associated renal vasculitis.
OBJECTIVE
The contribution of infections to the mortality of patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is important, and early and careful infection control is necessary. We investigated the usefulness of the serum-soluble haemoglobin scavenger receptor CD163 for detecting the presence of infectious complications regardless of disease activity.


METHODS
Soluble CD163 in serum obtained from 45 Japanese patients with myeloperoxidase (MPO)-AAV was measured by an enzyme-linked immunosorbent assay (ELISA). We evaluated 36 samples from active-vasculitis patients, 36 samples from inactive-vasculitis patients without infection, and 19 samples from inactive-vasculitis patients with infectious complications. Serum-soluble CD163 was also measured in 15 infectious patients without vasculitis and in 30 normal controls.


RESULTS
The mean serum-soluble CD163 level was higher in the patients with infectious complications than in the active-vasculitis patients, inactive-vasculitis patients, and normal controls. There were significant positive correlations between serum-soluble CD163 levels and white blood cell (WBC) count, serum C-reactive protein (CRP) levels, and serum albumin levels, but only serum CRP levels were correlated with serum-soluble CD163 levels in a multiple regression analysis. On the receiver-operating characteristic (ROC) curve, serum-soluble CD163 levels had 80.6% sensitivity and 86.7% specificity for differentiating patients with infection from those without infection. Among the active-vasculitis patients, the mean serum-soluble CD163 level of the patients with alveolar haemorrhage was significantly lower than that of the patients with interstitial lung diseases and that of the patients without pulmonary lesions.


CONCLUSIONS
The serum-soluble CD163 level may be a useful marker for the detection of infectious complications in MPO-AAV patients.
a Department of Nephrology , Tokyo Medical University , Shinjuku-ku , Tokyo.
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M
Nagai
b Department of Nephrology , Tokyo Medical University Ibaraki Medical Centre , Ami , Ibaraki , Japan.
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K
Hirayama
c Department of Nephrology , Mito Saiseikai General Hospital , Mito , Ibaraki , Japan.
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I
Ebihara
d Department of Immunology, Faculty of Medicine , University of Tsukuba , Ibaraki , Japan.
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T
Higuchi
b Department of Nephrology , Tokyo Medical University Ibaraki Medical Centre , Ami , Ibaraki , Japan.
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H
Shimohata
b Department of Nephrology , Tokyo Medical University Ibaraki Medical Centre , Ami , Ibaraki , Japan.
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M
Kobayashi
D000368:Aged; D000369:Aged, 80 and over; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000097:blood / Q000150:complications / Q000276:immunology; D015703:Antigens, CD / Q000097:blood*; D015214:Antigens, Differentiation, Myelomonocytic / Q000097:blood*; D001424:Bacterial Infections / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000276:immunology; D001991:Bronchitis / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000276:immunology; D002097:C-Reactive Protein / Q000276:immunology; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000097:blood* / Q000150:complications / Q000276:immunology; D007958:Leukocyte Count; D008297:Male; D055953:Microscopic Polyangiitis / Q000097:blood* / Q000150:complications / Q000276:immunology; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology; D010998:Pleurisy / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000276:immunology; D018410:Pneumonia, Bacterial / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000276:immunology; D011704:Pyelonephritis / Q000097:blood / Q000276:immunology; D012372:ROC Curve; D011956:Receptors, Cell Surface / Q000097:blood*; D012044:Regression Analysis; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000276:immunology; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000378:metabolism; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000276:immunology; D000098902:CD163 Antigen
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; D011956:Receptors, Cell Surface; D012709:Serum Albumin; D002097:C-Reactive Protein; D009195:Peroxidase