Serum ferritin and transferrin levels as serologic markers of methylene diphenyl diisocyanate-induced occupational asthma.
BACKGROUND
Although methylene diphenyl diisocyanate (MDI) may induce occupational asthma in the workplace, the pathogenic mechanisms are unclear.


OBJECTIVE
By using bronchoalveolar lavage fluid, we sought to identify proteins that were differentially expressed between subjects with MDI-induced occupational asthma (MDI-OA) and asymptomatic exposed controls (AECs).


METHODS
To find proteins that were differentially expressed between the MDI-OA and AEC groups, 2-dimensional electrophoresis was performed by using bronchoalveolar lavage fluid obtained from subjects after MDI-specific inhalation challenge. The selected protein spots were then identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The clinical relevance of the differentially expressed spots was compared by ELISA using sera from the MDI-OA/eosinophilic bronchitis, AEC, and unexposed healthy control groups. Receiver operating characteristic curves were then plotted, and the sensitivity and specificity were determined.


RESULTS
Twenty-three protein spots were identified that distinguished the subjects with MDI-OA from those in the AEC group. Among them, ferritin expression was downregulated whereas transferrin expression was upregulated in subjects with MDI-OA compared with AEC; these results were validated by ELISA using sera from the MDI-OA/EB and AEC groups. To identify subjects with MDI-OA, the optimal serum cutoff levels were 69.84 ng/mL for ferritin and 2.48 microg/mL for transferrin. When these 2 parameters were combined, the sensitivity was 71.43% and the specificity was 85.71%.


CONCLUSIONS
Serum ferritin and transferrin levels are associated with the phenotype of MDI-OA.
Hur
Gyu-Young
GY
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea.
Choi
Gil-Soon
GS
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea.
Sheen
Seung-Soo
SS
Pulmonary and Critical Care Medicine, Ajou University School of Medicine, Suwon, South Korea.
Lee
Hyun-Young
HY
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea.
Park
Han-Jung
HJ
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea.
Choi
Sung-Jin
SJ
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea.
Ye
Young-Min
YM
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea.
Park
Hae-Sim
HS
Department of Allergy and Rheumatology, Ajou University School of Medicine, Suwon, South Korea. Electronic address: hspark@ajou.ac.kr.
D000328:Adult; D001249:Asthma / Q000097:blood* / Q000139:chemically induced*; D015415:Biomarkers / Q000097:blood; D001992:Bronchoalveolar Lavage Fluid; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005293:Ferritins / Q000032:analysis / Q000097:blood*; D006801:Humans; D007221:Industry; D017953:Isocyanates / Q000633:toxicity*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D014168:Transferrin / Q000032:analysis*; D001559:Benzhydryl Compounds
D015415:Biomarkers; D005293:Ferritins; D017953:Isocyanates; D014168:Transferrin; C005969:4,4'-diphenylmethane diisocyanate; D001559:Benzhydryl Compounds