The development of a serological marker for early diagnosis of isocyanate-induced occupational asthma (isocyanate-OA) may improve clinical outcome. Our previous proteomic study found that expression of vitamin D-binding protein (VDBP) was upregulated in the patients with isocyanate-OA. In the present study, we evaluated the clinical relevance of VDBP as a serological marker in screening for isocyanate-OA among exposed workers and its role in the pathogenesis of isocyanate-OA. Three study groups including 61 patients with isocyanate-OA (group I), 180 asymptomatic exposed controls (AECs, group II), 58 unexposed healthy controls (NCs, group III) were enrolled in this study. The baseline serum VDBP level was significantly higher in group I compared with groups II and III. The sensitivity and specificity for predicting the phenotype of isocyanate-OA with VDBP were 69% and 81%, respectively. The group I subjects with high VDBP (> or = 311 microg/ml) had significantly lower PC20 methacholine levels than did subjects with low VDBP. The in vitro studies showed that TDI suppressed the uptake of VDBP into RLE-6TN cells, which was mediated by the downregulation of megalin, an endocytic receptor of the 25-hydroxycholecalciferol-VDBP complex. Furthermore, toluene diisocyanate (TDI) increased VEGF production and secretion from this epithelial cells by suppression of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] production. The findings of this study suggest that the serum VDBP level may be used as a serological marker for the detection of isocyanate-OA among workers exposed to isocyanate. The TDI-induced VEGF production/secretion was reversed by 1,25(OH)2D3 treatment, which may provide a potential therapeutic strategy for patients with isocyanate-OA.
Adult ; Animals ; *Asthma/blood/chemically induced/pathology ; Cell Line ; Epithelial Cells ; Female ; Gene Expression/drug effects ; Humans ; Isocyanates/toxicity ; Male ; Middle Aged ; *Occupational Diseases/blood/chemically induced/pathology ; Rats ; Toluene 2,4-Diisocyanate/toxicity ; Vitamin D-Binding Protein/*blood

OBJECTIVETo explore the effect of treatment with immunocyte therapy on benzene-induced haemopoietic dysfunction.

METHODSMono-nuclear cells (MNC) were separated from 40 - 50 ml peripheral blood in patients and mixed with interleukin-2 and granulocyte macrophage colony stimulating factor (GM-CSF) for six day cultivation. The new formed immunocytes were collected and transfused into the patients. Bone marrow aspiration and biopsy were taken before and after therapy for all patients with severe benzene poisoning. Blood samples were stained by flow cytometry for detecting CD(4) and CD(8) positive cells.

RESULTSOf 20 patients with chronic benzene poisoning, 9 were severe benzene poisoning. All examination including blood count, bone marrow biopsy and T cell subpopulation restored to normal after immunocyte therapy. Laboratory tests (liver and kidney function, and myocardial enzymes) were observed periodically and showed normal during therapy. Follow-up study (the longest time was more than 15 months) showed that bone marrow haemopietic function of all treated patients were in normal range.

CONCLUSIONBone marrow haemopoietic dysfunction caused by benzene poisoning may be closely related to disorder of immune function. Immunocyte therapy may significantly improve bone marrow haemopoietic dysfunction induced by benzene poisoning.

Adult ; Anemia, Aplastic ; chemically induced ; immunology ; therapy ; Benzene ; poisoning ; Bone Marrow ; immunology ; pathology ; Female ; Flow Cytometry ; Follow-Up Studies ; Humans ; Male ; Occupational Diseases ; chemically induced ; immunology ; therapy ; Peripheral Blood Stem Cell Transplantation ; methods ; Treatment Outcome