Solitary caging protects mice from ankylosing enthesopathy.

Murine ankylosing enthesopathy (ANKENT) is a spontaneous joint disease with numerous parallels to the human seronegative spondylarthropathies at the level of disease distribution, genetics and pathology. Although several genetic susceptibility factors have been identified previously, there is variation in disease susceptibility among genetically identical individuals, living in a stable environment. Preliminary observations indicate that males housed together with females rarely develop the disease, in contrast to males housed with other males (p < 0.25, p < 0.05, and p < 0.01). Furthermore, males caged under solitary conditions developed no ANKENT, whereas the disease did develop among individuals housed in groups of 4 (p < 0.01). The mechanism through which grouped caging induces a risk for ANKENT requires further study.