Autoimmune Effects of JP

No studies that addressed the effects of JP-8 exposure on development or exacerbation of autoimmune disease were found. 

No histopathologic effects related to the immune system were found in F344 rats and C57BL/6 mice exposed continuously to JP-8 vapors at concentrations up to 1,000 mg/m3 for 90 days. No additional studies that tested the toxicity of JP-8 vapors in experimental animals were located. 

Harris et al. reported that inhalation exposure of C57BL/6 mice to JP-8 aerosols at a concentration of 100 mg/m3 for 1 hr/day for 7 days led to decreased cellularity of the thymus, exposure at 500 mg/m3 for 1 hr/day for 7 days led to decreased spleen weight and cellularity, and exposure at 1,000 mg/m3 for 1 hr/day for 7 days led to decreased ability of spleen cells to mediate several immune responses. Those studies raise concern about the potential of JP-8 to cause immunotoxicity. The subcommittee reviewed the methods used to generate the exposure atmospheres in the studies by Harris et al. and suspects that the total JP-8 concentration in the atmosphere may have been underreported. However, even if the actual concentration was 10 times as high as the lowest concentration at which effects were observed (100 mg/m3) (i.e., if exposure was at a concentration of 1,000 mg/m3), the observation of positive effects from a short exposure duration (1 hr/day for 7 days) at that concentration leads the subcommittee to conclude that the interim permissible exposure level of 350 mg/m3 might be too high to be protective of human health (assuming the application of commonly used uncertainty factors). 

Dermal exposure of mice to JP-8 in multiple small doses (50 pL/day for 4-5 days) or in larger single doses (300 pL) resulted in local and systemic effects on the immune system (e.g., suppressed contact- and delayed-hypersensitivity responses). 

The subcommittee recommends that human blood samples from JP-8-exposed persons be assayed for indicators of immunotoxicity to determine whether effects in experimental animals are observed in humans. 

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