Investigation of antihypothalamus and antipituitary antibodies in amateur boxers: is chronic repetitive head trauma-induced pituitary dysfunction associated with autoimmunity?

Abstract

Current data clearly demonstrate that sports-related chronic repetitive head trauma due to boxing might result in hypopituitarism. However, the mechanism of sports-related traumatic brain injury-induced pituitary dysfunction is still unclear. In order to understand whether autoimmune mechanisms could play a role in the pituitary dysfunction due to sports-related head trauma, we investigated the presence of antipituitary antibodies (APAs) and antihypothalamus antibodies (AHAs) in amateur boxers. Sixty-one actively competing (n=44) or retired (n=17) male boxers (mean age, 26 years; range, 17-53) who had been evaluated regarding pituitary functions previously were included in the study. In all boxers and in 60 age/sex-similar normal controls, AHAs and APAs were investigated by an indirect immunofluorescence method. AHAs were detected in 13 of 61 boxers (21.3%), and APAs were detected in 14 of 61 boxers (22.9%), but in none of the normal controls. Pituitary dysfunction was significantly higher in AHA-positive boxers (46.2%) than in AHA-negative boxers (10.4%) (P=0.003). There was a significant association between AHA positivity and hypopituitarism due to boxing (odds ratio: 7.37, 95% confidence interval 1.8-30.8). There was no significant association between APA positivity and hypopituitarism. This study demonstrates for the first time the presence of AHAs and APAs in boxers who were exposed to sports-related head trauma. Moreover, the present investigation provides preliminary evidence that AHAs are associated with the development of pituitary dysfunction in boxers, thus suggesting that autoimmunity may have a role in the pathogenesis.