Xylene is currently undergoing dossier evaluation under REACH. Isolated and inconsistent immune system findings have been reported across its dataset. On behalf of the Lower Olefins and Aromatics Xylene Working Group and the Cefic Aromatics Producers Association, the authors carried out a systematic literature review and weight of evidence evaluation of all available immunotoxicity data. This covered in vitro, in vivo and epidemiology studies, including previously unpublished guideline studies.
Searches of ProQuest and PubMed returned 2,703 unique records. The review examined haematology, globulin levels, and the immune system tissues: thymus, spleen, lymph nodes and gut-associated lymphoid tissue. No consistent or severe effects were found. The effects that were observed were sporadic, within historical control ranges, or occurred alongside general stress or systemic toxicity.
The weight of evidence supports that xylene substances are not immunosuppressants. It does not support the need for an immunotoxicity cohort in any subsequent extended one-generation reproductive toxicity study (EOGRTS). This avoids unnecessary animal testing, in line with ECHA’s commitment to the 3Rs.
Authors
Katy Wilson, Keith Morris-Schaffer, Neslihan Aygun Kocabas, Sara Hearon, Larry G. Higgins, Sarah Dahlberg, Frank Faulhammer, Elaine Freeman, Martijn Rooseboom
EUROTOX 2026, Poster P17-08 (Session PV01, Immunotoxicology), Abstract ID 766.