OUTBREAK OF BRONCHIOLITIS OBLITERANS ASSOCIATED WITH CONSUMPTION OF SAUROPUS-ANDROGYNUS IN TAIWAN

Background In August, 1995, there was an outbreak in Taiwan of rapidly progressive respiratory distress associated with consumption of uncoo ked Sauropus androgynus, a vegetable with a claimed yet unconfirmed ef fect on weight control. We report on 23 patients with strikingly simil ar clinical presentations. Methods A structured questionnaire for clin ical manifestations was completed. Radiographic findings, pulmonary ph ysiological changes, immunological and microbiological studies, and pa thological examination were evaluated. Findings All patients were youn g and middle-aged women (mean age 39 years [range 21-52]). They took u ncooked S androgynus juice, generally mixed with guava or pineapple ju ice, for a mean duration of 10 weeks. Progressive dyspnoea and persist ent cough were the main symptoms on presentation. Pulmonary function t esting uniformly revealed moderate to severe airflow obstruction with mean forced expiratory volume in 1 s (FEV(1)) of 0 . 66 L (26% of pred icted). No bronchodilator response was observed. Room-air arterial blo od gas analysis showed hypoxaemia (mean PaO2 9 . 6 [SD 1 . 6] kPa). Ch est radiographs were essentially normal. High-resolution computed tomo graphy showed bilateral bronchiectasis and patchy low attenuation of l ung parenchyma with mosaic perfusion. Ventilation-perfusion scintigrap hic findings were compatible with obstructive lung disease. Histopatho logy of open lung biopsy specimens in four patients confirmed the pres ence of bronchiolitis obliterans. Immunohistochemical stains of the op en lung biopsy specimens showed predominance of T cells over B cells. Immunofluorescent stains for IgG, IgM, IgA, C1q, C3, and C4 were negat ive. Serum concentrations of tumour necrosis factor a were higher than those of normal controls. Clinical response to prednisolone was limit ed. Interpretation We describe an unusual association between bronchio litis obliterans and ingestion of the vegetable S androgynus. T-cell m ediated immunity may be involved in the pathogenesis.