Sickle cell disease: a chronic inflammatory condition.

Homozygous sickle cell disease (SCD) has a wide spectrum of clinical manifestations which varies from an almost asymptomatic condition to severe illness, despite the fact that all subjects with this disease have the same base change in their DNA. The source of this variation is partly environmental, but a large part of this variability can derive from the presence of genetic modulators which are not fully understood. It was postulated that some degree of immunodeficiency should be associated with this condition, but no deficiency, directly related to a given component of the immune system, was observed that could explain the high levels of recurrent infections presented by sickle cell disease patients. Reviewing data from the literature we suggest that the influence of the immune system in the variation of clinical manifestations presented by SCD patients is not related with any immunodeficiency but is rather the result of a chronic inflammatory condition.