ABSENCE OF RELATIONSHIP BETWEEN DEGREE OF NONSPECIFIC AND SPECIFIC BRONCHIAL RESPONSIVENESS IN OCCUPATIONAL ASTHMA DUE TO PLATINUM SALTS

There is evidence that bronchial responsiveness to allergen is quantit atively correlated with bronchial responsiveness to nonspecific stimul i in subjects with allergic asthma This association has been questione d in occupational asthma due to low molecular weight substances. It wa s the aim of this study to assess the quantitative association of bron chial responsiveness to methacholine (MCh) and platinum salts (Pt), in the form of hexachloroplatinic acid, in workers with occupational ast hma due to platinum salts. Fifty seven subjects with exposure to Pt, w ork-related asthma, and a positive bronchial challenge with Pt,underwe nt skin prick tests with Pt and bronchial challenge with MCh. Using th e provocation concentration causing a greater than or equal to 50% fal l in specific airway conductance (PC50sGaw(Pt)) as dependent variable, anamnestic data (period from first symptoms to removal, period betwee n removal from exposure and diagnosis, and smoking), season of the inv estigation, skin prick tests with environmental allergens, total immun oglobulin E (IgE), skin reactivity to Pt (Pt concentration causing a 2 mm wheal), and PC50sGaw(MCh) were included as independent variables f or regression analysis. Fifty two subjects (91%) showed a PC50sGaw(MCh ) <8 mg . mL(-1) (geometric mean for all subjects 1.6 mg . mL(-1). Res ponsiveness to Pt varied widely between subjects (geometric mean of PC 50sGnw 9x10(-5) mol . L(-1), range 2x10(-7) to 10(-2) mol . L(-1)). Th ere was no univariate correlation between bronchial responsiveness to MCh and Pt, but there was a correlation between skin reactivity to Pt and PC50sGaw(Pt) (r=0.6). This association could not be improved by co nsidering PC50sGaw(MCh), the period from first symptoms to removal, or the period between removal from exposure and diagnosis. The parameter s that showed the highest (negative) associations with PC50sGaw(Pt) we re skin reactivity to Pt and the period between removal from exposure and diagnosis (r=0.65). We conclude that there is a moderate associati on between bronchial responsiveness to platinum salts and skin reactiv ity to platinum salts. However, there is no association between methac holine responsiveness and bronchial responsiveness to allergen in occu pational asthma due to platinum salts.