Evidence for associations between the purinergic receptor P2X(7) (P2RX7) and toxoplasmosis.

Congenital Toxoplasma gondii infection can result in intracranial calcification, hydrocephalus and retinochoroiditis. Acquired infection is commonly associated with ocular disease. Pathology is characterized by strong proinflammatory responses. Ligation of ATP by purinergic receptor P2X(7), encoded by P2RX7, stimulates proinflammatory cytokines and can lead directly to killing of intracellular pathogens. To determine whether P2X(7) has a role in susceptibility to congenital toxoplasmosis, we examined polymorphisms at P2RX7 in 149 child/parent trios from North America. We found association (FBAT Z-scores +/-2.429; P=0.015) between the derived C(+)G(-) allele (f=0.68; OR=2.06; 95% CI: 1.14-3.75) at single-nucleotide polymorphism (SNP) rs1718119 (1068T>C; Thr-348-Ala), and a second synonymous variant rs1621388 in linkage disequilibrium with it, and clinical signs of disease per se. Analysis of clinical subgroups showed no association with hydrocephalus, with effect sizes for associations with retinal disease and brain calcifications enhanced (OR=3.0-4.25; 0.004

Immunogenicity of hepatitis B vaccine in healthy very low birth weight infants.

We studied the immunogenic response to hepatitis B vaccine of infants weighing < or = 1500 gm at birth. Infants were divided into two groups: those weighing < or = 1000 gm (n = 22) and those weighing 1001 to 1501 gm (n = 28). When immunized early (3 days of age, n = 25), these infants had a response rate (defined as antibody to hepatitis B surface antigen titer > 10 mIU/ml) of 68%, whereas when the first vaccine was given at 1 month of age (n = 25), a 96% response rate was noted, irrespective of birth weight and weight at the time of immunization (p < 0.02).