Serum β2-Microglobulin as a Marker of Congenital Toxoplasmosis and Cytomegalovirus Infection in Preterm Neonates

Abstract

Background: Fetal serum β₂-microglobulin (β₂M) has been reported as a reliable indicator of fetal infectious diseases. Objectives: To evaluate serum β₂M as a marker of congenital toxoplasmosis or cytomegalovirus (CMV) infection in neonates. Methods: β₂M was retrospectively measured in 72 neonatal serum samples from preterm neonates. Of these, 32 originated from neonates with serological evidence of congenital toxoplasmosis (n = 12) and CMV infection (n = 20), while 40 samples from neonates in which both infections were serologically excluded served as controls. β₂M levels were compared between the infection and control groups. Results: Mean (±SEM) β₂M levels were significantly higher in the groups of neonates infected with Toxoplasma (5.64 ± 0.61 mg/l) (p = 0.014) and CMV (6.06 ± 0.66 mg/l) (p < 0.0001) than in the control group (3.80 ± 0.2). Against the cut-off level of 5 mg/l, β₂M was normal in 36 of the 40 uninfected neonates examined, indicating a specificity of 90%. In contrast, it was elevated in 66.7% (8/12) and 65% (13/20) of the Toxoplasma and CMV-infected neonates, respectively, indicating an overall sensitivity of 66%. Conclusions: In the absence of urogenital disorders, an increase in β₂M in neonates is likely to be infection-induced. We showed that serum β₂M is increased in congenital toxoplasmosis and CMV infection in the first weeks of life.