Ethanol

Immunotoxicity

Key value for chemical safety assessment

Effect on immunotoxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

40 000 mg/m³

Study duration:

subchronic

Species:

rat

Additional information

In two sequential developmental immunotoxicity studies, Wistar rats were exposed to ethanol concentrations from 1.5 to 14% and 0.25 -6.5% in drinking water from midway during pregnancy, lactation and up to PND70 (study 1) and PND 90 (study 2). Effects were seen on pup body and organ weights as well as on immune parameters examined. However, drinking water consumption and hence exposure to ethanol varied considerably over the studies, meaning that during the post-weaning developmental stage exposure to ethanol, actual consumption in g/kg fell by a factor of 3 at the lower doses and more at the higher doses. In addition, there was a clear overlap of the BMD statistical confidence intervals for signs of general toxicity, manifest as declines in organ weights (plus body weight) in the first study and apparent effects on the immune system. There was also some inconsistency in no effect (BMD) levels between the two studies. Finally, one study which inadvertently ended up with a recovery group showed that many of the effects seen were reversible. This may also account for the findings in the second (lower dose) study where many effects declined in severity during the study, which co-incided with the reduced substance intake. Overall, it is unclear from these studies whether adverse specific immunotoxic effects were seen and if so, at what doses such effects occur (Tonk, 2013).

In a study to assess the potential for developmental immunotoxicity in the offspring of rats exposed to ethanol, pregnant Long-Evans rats were exposed to ethanol vapour concentrations of 5000, 10000 and 21000ppm from GD9 -20. The offspring were subjected to humoral and cell-mediated immunity toxicity assays (ELISA and DTH respectively) at 6 weeks of age, a time point corresponding to immune system maturity in the rat. No overt toxicity in the dams was observed. Ethanol did not affect litter size or weight, or postnatal weight gain in the pups. Cell-mediated and humoral immunity were not affected by pre-natal ethanol exposure in 6-week-old offspring (Beasley, 2014).

Justification for classification or non-classification

No evidence to suggest adverse effects occur at a level that would trigger classification.