Immunogenicity of a 7-valent pneumococcal conjugate vaccine (PCV7) and impact on carriage in Venezuelan children at risk of invasive pneumococcal diseases.

BACKGROUND AND AIMS: We evaluated the immunogenicity of the 7-valent pneumococcal conjugate vaccine (PCV7), and its impact on pneumococcal carriage in Venezuelan children at high risk for invasive pneumococcal disease (IPD). METHODS: 82 children (age 2-59 months) with sickle cell anemia (n=22), chronic heart disease (n=19), HIV infection (n=12), immune-suppressive therapy (n=11) and other IPD-predisposing conditions (n=18) were vaccinated with PCV7 according to CDC-recommended age-related immunization schedules. Blood samples were taken to determine the concentration of IgG antibody, and nasopharyngeal swabs were obtained to isolate Streptococcus pneumoniae, before the first vaccine dose and 1 month after completion of the vaccination schedule. RESULTS: Pneumococcal carriage prior to the first immunization was 27% (n=22), with the most frequently carried serotypes being vaccine serotypes 6B (22%) and 14 (13%). One month after completion of the vaccination scheme pneumococcal carriage was 22% (n=17), dominated by non-vaccine serotypes 19A (24%) and 7F (12%). Before immunization, 65% of the subjects had IgG antibody titers >0.35 µg/mL for five serotypes tested. Post-vaccination, 100% of the subjects showed titers >1.0 µg/mL for all PCV7 serotypes with geometric mean concentrations (GMC) ranging from 1.75 µg/mL (serotype 23F) to 17.16 µg/mL (serotype 14). Children previously colonized with serotype 6B had a significantly lower GMC to this serotype following immunization than children not carrying 6B prior to the first PCV dose (p<0.05). CONCLUSIONS: PCV7 is highly immunogenic in Venezuelan children at high-risk for IPD. Vaccination was associated with an immediate shift in nasopharyngeal carriage toward non-PCV7 serotypes. Finally, we observed serotype-specific hyporesponsiveness to immunization after natural carriage with the same serotype in high-risk children.

Clopromazina, L-carnitina y carbonato de litio: evaluación de efectos eriprotectores in vitro ante estrés mecánico y fotohemólisis UVB / Chlorpromazine, L-carnitine and lithium carbonate: evaluation of erythoprotective efects in vitro under mechanical stress and UVB photohemolysis

Se evaluaron los efectos eritroprotectores de: Clorpromazina (CPZ), L-Carnitina (LCN) y Carbonato de Litio (Li). A las muestras de sangre de cobayos (n=15, 6mL; 1mL/vial) se añadió ringer (20µL), CPZ (20 µL; 0,5 mg.mL-¹), LCN (20µL; 4mg.mL-¹) o Li (20µL; 0,08mg.mL-¹) incubándose por 30, 60 y 90 min en rotación lenta, luego se sometieron a agitación calibrada por 10min, centrifugación (2500rpm, 15min) y determinación de Hemoglobina libre (HbL) en el sobrenadante por espectrofotometría a 415 nm. Otra serie de muestras (n=5), fueron sometidas a fotohemólisis con luz ultravioleta B (UVB) por 10 min, agregándose previamente Ringer ó LCN, comparándose con muestras sin adiciones (controles). En estrés mecánico la CPZ mostró valores de HbL mayores al Ringer a los 30 min (Mann-Whitney; Z= -3,8; p<0,001); 60 min (Z= -3,6 p<0,001) y 90 min (Z= -3,6; p<0,001). La incubaci¢n con LCN ó Li mostró valores similares al Ringer en todos los tiempos (Z<2,56; p>0,05) y significativamente menores que la CPZ (Z>3,0; pz0,001) sin diferencias entre LCN vs. Li (Z<1,0; p>0,05). En fotohemólisis UVB, la incubación con Ringer mostró valores de HbL inferiores al control (t=5,57; p<0,05) y mucho menores que los de LCN (t= 18,06; p<0,001). Las muestras controles presentaron menor HbL que aquellas con LCN (t= 3,44; p<0.05). Los resultados indican que en estrés mecánico la CPZ tiene efecto hemolítico, mientras qye la LCN y el Li no mostraron diferencias con el Ringer. En fotohemólisis UVB, la LCN no mostró efecto eritroprotector