Serum TDI-specific IgG and IgE results are shown in Table II, with no significant differences noted between the groups of workers. Of note, one worker, a maintenance worker with prior occupational TDI exposure, exhibited an elevated TDI-specific IgG (titer 1:160) pre-employment, which was then negative at 6 and 12 months after employment at this new plant. Another worker developed a positive TDI-IgG (titre 1:40) between employment and the 6-month follow-up, which then resolved by 12 months, during which time the worker had been transferred to a low exposure job. All TDI-specific IgE tests were negative at 6 months, and not tested at the other time points due to sample limitations