Nylon flock-associated interstitial lung disease

A work-related interstitial lung disease has been diagnosed in workers at f ive nylon flock facilities in three different states and a Canadian provinc e. The National Institute for occupational Safety and Health hosted a works hop at which consulting pulmonary pathologists reviewed lung tissue samples from all the cases for which lung biopsy material was available (15 of 20 cases known in January 1998). After independent review and scoring of these lung tissue specimens, the pathologists reached consensus that the histopa thological findings revealed a characteristic lesion-a lymphocytic bronchio litis and peribronchiolitis with lymphoid hyperplasia represented by lympho id aggregates. The pathologists noted that the pathological findings were d istinctive when compared with known lung conditions. The clinical presentat ion for the cases generally included cough, dyspnea, restrictive ventilator y defect with reduction in diffusing capacity, and interstitial markings on chest radiographs or high-resolution computed tomography (HRCT) scans. Six of the cases improved after removal from workplace exposure without medica l treatment. Six others, who had recovered with medical treatment and remov al from the workplace, had relapses in both symptoms and objective findings after attempting to return to nylon flock work. With this and other eviden ce supporting the existence of chronic interstitial pneumonitis associated with nylon flock processing, workshop participants recommended surveillance for early identification of affected workers and their removal from furthe r workplace exposure.