Decrease of thymic hormone serum level in Cockayne syndrome

Previous reports concerning children with Cockayne syndrome had described decreased T cell proliferative responses and renal anomalies which could be associated with immunologic disturbances. Herein, the thymic function was evaluated by measuring the serum level of thymic hormone. This serum level was found to be undetectable or decreased in seven cases of Cockayne syndrome. Active serum concentrations varied between 0 and 1/8, whereas normal children of the same age show activity in the range between 1/16 and 1/64. In contrast, T cell function, explored by phytohemagglutinin and Concavalin A responses, and mixed lymphocyte cultures was normal. Whether or not this premature sign of immunological aging is primary or secondary to other manifestations of the syndrome is still difficult to assess.