Heterotopic ossification and HLA antigens.

Thirty patients with neurogenic (nontraumatic) heterotopic ossification following spinal cord injury in 20 and head injury in 10, were comprehensively screened for HLA antigens. The frequencies of 68 HLA-A, -B and -C antigens were examined. The HLA-A2 locus was present in 18 patients (60%) as compared to the phenotypically adjusted normal of 48.4% and was not statistically significant at the 0.05 level. No statistically significant increased frequency of the HLS-B18 or HLA-B27 antigens was detected. A positive correlation does not exist between the HLA antigen system and patient susceptibility to heterotopic ossification following head injury or spinal cord injury.