PATRICIA PALMEIRA DAENEKAS JORGE
Projetos de Pesquisa
Unidades Organizacionais
LIM/36 - Laboratório de Pediatria Clínica, Hospital das Clínicas, Faculdade de Medicina
5 resultados
Resultados de Busca
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- Immunology of breast milk(2016) PALMEIRA, Patricia; CARNEIRO-SAMPAIO, MagdaIn the critical phase of immunological immaturity of the newborn, particularly for the immune system of mucous membranes, infants receive large amounts of bioactive components through colostrum and breast milk. Colostrum is the most potent natural immune booster known to science. Breastfeeding protects infants against infections mainly via secretory IgA (SIgA) antibodies, but also via other various bioactive factors. It is striking that the defense factors of human milk function without causing inflammation; some components are even anti-inflammatory. Protection against infections has been well evidenced during lactation against, e.g., acute and prolonged diarrhea, respiratory tract infections, including otitis media, urinary tract infection, neonatal septicemia, and necrotizing enterocolitis. The milk's immunity content changes over time. In the early stages of lactation, IgA, anti-inflammatory factors and, more likely, immunologically active cells provide additional support for the immature immune system of the neonate. After this period, breast milk continues to adapt extraordinarily to the infant's ontogeny and needs regarding immune protection and nutrition. The need to encourage breastfeeding is therefore justifiable, at least during the first 6 months of life, when the infant's secretory IgA production is insignificant.
- Passive acquisition of anti-Staphylococcus aureus antibodies by newborns via transplacental transfer and breastfeeding, regardless of maternal colonization(2016) NADAF, Maria Isabel Valdomir; LIMA, Laila; STRANIERI, Ines; AKIKOTAKANO, Olga; CARNEIRO-SAMPAIO, Magda; PALMEIRA, PatriciaOBJECTIVE: To investigate the transmission of anti-Staphylococcus aureus (Sa) IgG, IgG1 and IgG2 via placental transfer and the transfer of IgA via the colostrum according to maternal Sa carrier status at delivery. METHODS: We evaluated anti-Sa IgG, IgG1 and IgG2 in maternal and cord sera and IgA in colostrum from a case (n=49, Sa(+)) and a control group (n=98, Sa(-)). RESULTS: Of the 250 parturients analyzed for this study, 49 were nasally colonized with S. aureus (prevalence of 19.6%). Ninety-eight non-colonized subjects were selected for the control group. The anti-Sa IgG, IgG1 and IgG2 levels and the IgG avidity indexes in the maternal and cord sera did not differ between the groups, with a low transfer ratio of anti-Sa IgG to the newborns in both groups. The anti-Sa IgG2 titers were significantly higher than the IgG1 titers in the maternal and cord sera. Inversely, the transfer ratios were higher for anti-Sa IgG1 compared with IgG2; however, no differences between the groups were detected. The Sa-specific IgA levels and avidity indexes in the colostrum were equivalent between groups. CONCLUSIONS: Maternal Sa nasal colonization at delivery is not associated with higher antibody levels in the mother or newborns. The high titers of anti-Sa IgG2 found in the cord serum indicate a greater reactivity with non-protein antigens, which may further contribute to the susceptibility to staphylococcal infections at birth. The presence of IgA in the colostrum with avidity to S. aureus reinforces the importance of breastfeeding shortly after birth.
- Healthy Preterm Newborns Show an Increased Frequency of CD4(+)CD25(high)CD127(low)FOXP3(+) Regulatory T Cells with a Naive Phenotype and High Expression of Gut-Homing Receptors(2016) RENNO, C.; NADAF, M. I. V.; ZAGO, C. A.; CARNEIRO-SAMPAIO, M.; PALMEIRA, P.Treg cells are crucial to prevent immune dysregulation, but little is known about the frequency of these cells in neonates, particularly in very/moderate and late preterm newborns studied as separate groups. The CD4(+)CD25(hi)CD127(lo)FOXP3(+) Treg population was phenotypically characterized to assess maturation markers and gut-homing integrins by flow cytometry in the cord blood of healthy preterm newborns born at 30-33(6/7) gestation weeks (Group 1), at 34-36(6/7) gestation weeks (Group 2) and term newborns born at 37-41 gestation weeks (Group 3), compared to healthy adults. An inverse correlation of the Treg percentage and gestational age was found, with significantly higher frequencies in Group 1 compared to Groups 2 and 3 and in Group 2 compared to Group 3, and significantly higher Treg frequencies and numbers in the neonates compared to the adults. All of the newborns exhibited increased Treg frequencies with a naive phenotype compared to adults. Cytotoxic T-lymphocyte-associated protein 4 CTLA-4 expression in the naive Treg was decreased in both preterm groups compared with those from term newborns and adults, and in the memory Treg from Group 1 compared with the other groups. The frequencies of Treg expressing alpha 4 beta 7 and alpha 4 beta 1 integrins were higher in both preterm groups, but significantly different only in Group 1, when compared with those from the term newborns and the adults. In conclusion, although a high frequency of Treg is present in newborns, an immature phenotype with a higher expression of CD45RA and alpha 4 beta 7/alpha 4 beta 1 and a lower expression of CTLA-4 is found, particularly in the very preterm group.
- Usefulness of a 16S rDNA real-time PCR to monitor neonatal sepsis and to assist in medical decision to discontinue antibiotics(2016) STRANIERI, Ines; KANUNFRE, Kelly Aparecida; RODRIGUES, Jonatas Cristian; YAMAMOTO, Lidia; NADAF, Maria Isabel Valdomir; PALMEIRA, Patricia; OKAY, Thelma SuelyObjective: To monitor the bacterial load in newborns with proven infections on the day of admission, 48 h and 7 days after treatment. Methods: Real-time PCR (qPCR) targeting the 16S rDNA. Results: The study recruited 17 newborns and the bacterial load was in general low (<50 CFU/mL). In three of four deaths, the bacterial load values increased, and in 11 of the 13 survivors the values decreased until the third evaluation. Conclusion: Considering the extreme sensitivity and high negative predictive value of qPCR, this test could help to monitor the treatment of neonatal sepsis and to assist in medical decision to discontinue antibiotics.
- TLR expression, phagocytosis and oxidative burst in healthy and septic newborns in response to Gram-negative and Gram-positive rods(2016) SILVEIRA-LESSA, Ana Lucia; QUINELLO, Camila; LIMA, Laila; REDONDO, Ana Carolina Costa; CECCON, Maria Esther Jurfest Rivero; CARNEIRO-SAMPAIO, Magda; PALMEIRA, PatriciaThe objective was to investigate whether phagocytes from healthy and septic newborns have a developmental deficiency in their capacity to recognize, phagocytize and generate hydrogen peroxide (H2O2) in response to Escherichia coli and Staphylococcus aureus. TLR expression and phagocytic ability of neutrophils and monocytes from 44 healthy preterm and term neonates, from 13 newborns with late onset sepsis and from 24 healthy adults were determined using flow cytometry, and H2O2 production was measured by dihydrorhodamine test. TLR-2 and TLR-4 expressions were similar among the groups. The phagocytic ability of monocytes and neutrophils exposed to E. coli and S. aureus in healthy and septic neonates was significantly reduced compared to that of adults. Monocytes from septic newborns exposed to E. coli had higher H2O2 production than those of the other groups. The oxidative burst of monocytes exposed to S. aureus was reduced in preterm newborns compared with term ones and those with sepsis, and no differences were found in the oxidative burst of neutrophils. Even with the ability to recognize bacteria, a decreased clearance of pathogens can cause an imbalance in the immune response, which could lead to a predisposition to sepsis. Once established, the increased production of cytokines and ROS in an attempt to control the infection as well as the lack of full phagocytic activity leads to persistence of the pathogen and a state of constant inflammation.