Allergy to complex salts of platinum in refinery workers: prospective evaluations of IgE and Phadiatop status.

Background: Experience has shown some variation in the associations between IgE, atopy, and sensitization to platinum salts. Clarification of these associations, and the value of the parameters in predicting and diagnosing sensitization of workers at risk, required prospective investigation.

Objectives: Evaluation of total IgE and Phadiatop(R) status to establish baseline values, and changes during employment, predictive or associated with subsequent platinum salt sensitization.

Methods: A 24-month prospective study, in a South African primary platinum refinery, of a cohort of 78 healthy recruits without evidence of atopy (tested negative to skin prick test with common allergens). Subsequently they were categorized as 22 sensitized (positive skin prick test to platinum salts), 46 not sensitized (negative skin prick test and symptom free), and 10 symptomatic subjects not included in either category.

Results: (1) Pre-employment: four (18%) of the subsequently sensitized subjects and eight (17%) not sensitized were Phadiatop(R) positive. Levels of total IgE > 100 kU/L, present in 16 subjects were associated with positive Phadiatop(R) status and race. (2) During employment: Phadiatop(R) status converted from negative to positive in more sensitized (12/18) than unsensitized (6/38) subjects (P
Conclusion: Platinum salt sensitivity was not predicted by pre-employment Phadiatop(R) or IgE status, but was subsequently associated with conversion to positive Phadiatop(R) status, and an increase in total IgE (independent of Phadiatop(R) status).