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Interleukin-1 secretion by blood monocytes of septic premature infants
Insights
Preterm infants with sepsis showed lower interleukin-1 (IL-1) secretion from monocytes during acute infection. Monocyte IL-1 secretion increased significantly in the convalescent period, suggesting impaired immune response in septic preterm infants.
Area of Science:
- Immunology
- Neonatal Medicine
- Infectious Diseases
Background:
- Sepsis is a serious concern in preterm infants, potentially leading to impaired immune responses.
- Interleukin-1 (IL-1) is a key cytokine involved in inflammatory and immune responses.
- Monocytes play a crucial role in innate immunity and cytokine production.
Purpose of the Study:
- To investigate the in vitro secretion of IL-1 by monocytes from preterm infants with and without sepsis.
- To compare IL-1 secretion levels during acute sepsis and convalescent periods in preterm infants.
- To explore the relationship between IL-1 secretion and clinical parameters in preterm sepsis.
Main Methods:
- Peripheral blood monocytes were isolated from preterm infants (healthy and septic) and full-term controls.
- Lipopolysaccharide (LPS) was used to stimulate in vitro IL-1 secretion.
- IL-1 levels in monocyte cultures were measured using standardized assays.
- Absolute blood neutrophil counts and body temperature were monitored.
Main Results:
- Monocytes from septic preterm infants exhibited lower IL-1 secretion during the acute phase compared to healthy controls and full-term infants.
- IL-1 secretion significantly increased in the convalescent period for septic preterm infants (p < 0.05).
- Septic preterm infants had significantly higher absolute neutrophil counts (p < 0.001) but normal body temperature.
Conclusions:
- Reduced IL-1 secretion by monocytes during acute preterm sepsis may impair immunological and inflammatory responses.
- In vivo processes during sepsis might limit the capacity of monocytes for LPS-stimulated IL-1 synthesis in vitro.
- These findings highlight potential immune dysregulation in preterm infants with sepsis.
Abstract:
This study examined lipopolysaccharide (LPS) induced in vitro secretion of interleukin-1 (IL-1) by peripheral blood monocytes from pre-term infants with and without sepsis. Thirteen pre-term babies were tested; eight were completely healthy and five suffered from six episodes of sepsis. The latter group was tested both in the acute septic phase and in the convalescent period. IL-1 secretion by monocytes derived from septic pre-term infants was lower, but not significantly different from healthy pre-term infants (7.1 +/- 1.0 U/ml versus 8.1 +/- 0.9 U/ml, respectively). IL-1 secretion by monocytes of eight control full-term babies was in the same range (8.4 +/- 0.6 U/ml). In the convalescent period IL-1 secretion by monocytes from septic pre-term babies increased (9.0 +/- 0.3 U/ml) and was significantly higher than values measured during acute infection (p less than 0.05). Septic premature babies were also found to have higher absolute blood neutrophil concentration (p less than 0.001), but their body temperature did not increase along the infectious stage. The decreased secretion of IL-1 by monocytes from pre-term babies in the acute phase of infection compared to the convalescent period may have contributed to their inability to mount appropriate immunological as well as inflammatory responses. Sepsis promoting IL-1 production in vivo may have limited the monocytes' capacity for LPS stimulated IL-1 synthesis in vitro.