Thrombocytopoenia as marker for HIV exposure in the neonate

Thrombocytopoenia is a well-described marker of human immunedeficiency viru s type 1 (HIV) infection of children. After documenting thrombocytopoenia i n a HIV-exposed neonate, who was subsequently shown not to be infected, we evaluated thrombocytopoenia (platelets < 150 X 10(9)/l) as a marker for HIV exposure in newborns. This is, to our knowledge, the first study of thromb ocytopoenia in MV-exposed neonates. A retrospective hospital-based descript ive study was performed over an 18-month period (July 1997-December 1998). Patients were recruited either through identification of known HIV-positive mothers or neonates with thrombocytopoenia who were then screened for HIV exposure. For eligibility, neonates with either HIV antibodies or direct ev idence of infection (p24 antigenaemia or HIV RNA detected by polymerase cha in reaction after I month of age) were included. Thirty-four HIV-exposed (H IV-ELISA positive) neonates were identified, of whom 16 (47 per cent) had t hrombocytopenia. In 12 (35 per cent), no underlying cause other than HIV wa s identified. Nine thrombocytopoenic babies were infected and seven uninfec ted. Unexplained thrombocytopoenia, while an imperfect marker, should alert the physician to the possibility of HIV exposure. It does not necessarily imply HIV infection. A prospective study is recommended to evaluate further the sensitivity and specificity of this marker.