The effects of dexamethasone on the production of interleukin (IL) 1β, IL-6, and tumor necrosis factor alpha were studied in preterm newborns, term infants, and adults. Twenty preterm and 22 term newborns and 30 healthy adults were included in the study. Mononuclear cells (MC) isolated from cord blood of newborns and peripheral blood of adults were incubated without or with lipopolysaccharide in the absence or presence of dexamethasone at concentrations between 10^–8 and 10^–5 M. The cytokine concentration in the supernatants was tested using enzyme-linked immunosorbent assay kits. Although a dose-dependent inhibition of the cytokine production was observed at pharmacological doses of dexamethasone in individuals of the three groups, differences in the intensity of the effect were observed between the groups. Spontaneous secretion of IL-1β or IL-6 by MC of preterm neonates was less inhibited by dexamethasone as compared with cells from adults. In contrast, the inhibitory effect of the drug on lipopolysaccharide-induced IL-6 and tumor necrosis factor alpha production was more pronounced on neonatal cells. As for term newborns, MC were more sensitive to the inhibitory effect of the drug on LPS-induced IL-6 production than cells of adults. The results suggest that dexamethasone treatment of preterm newborns may affect cytokine production with a consequent modulation of the host’s immune response.

A genetic predisoposition to rheumatic fever (RF) has been suspected by several researchers. Ten years ago, using monoclonal antibodies, the B-cell alloantigen D8/17 was identified in 90-100% of patients with RF. The aim of the present study was to evaluate whether the marker is found in patients with RF in Israel, where the population is made up of diverse ethnic groups. The Schneider Children's Medical Center in Petah Tikva, Israel, was the setting for this study. The population included 22 children with RF and nine ethnically matched, disease-free individuals who served as controls. Each of the patients and controls were tested for the B-cell antigen with flow cytometry assay by using monoclonal antibodies. The main outcome measure was the difference in the presence of the D8/17 B-cell marker between the patients with RF and the controls. The mean percentage of B-cells expressing the marker was 11.5 +/- 2.9 in the patients and 4.24 +/- 2.7 in the controls (P < 0.001). There was no statistically significant difference in the frequency of the marker by ethnic origin. The present results support earlier studies suggesting that D8/17 is a disease-specific marker with a world-wide distribution which may potentially serve as an additional diagnostic tool in patients with suspected RF.

The effect of dexamethasone on interleukin 2 (IL-2) and interleukin 3 (IL-3) production by mononuclear cells in preterm and term infants and adults was evaluated. The capacity of mononuclear cells to produce these cytokines, in preterm infants with bronchopuhmonary dysplasia (BPD) and treated with dexamethasone, was compared with that before treatment.Twenty six preterm and 36 term neonates and 24 healthy adults were included in the study. Mononuclear cells isolated from neonatal cord blood (CBMC) and adult peripheral blood (PBMC) were stimulated with phytohaemagglutinin (PHA) in the absence or presence of dexamethasone at concentrations between 10-8M and 10-5M. IL-2 and IL-3 activities in the supernatant fluids were tested using bioassays. The in vivo effect ofthe drug on the production of these cytokines by PBMC in 10 preterms was determined before and 24 hours after dexamethasone administration (0.5 mglkglday).The production of both cytokines was inhibited in a dose dependent manner. A difference in the sensitivity of mononuclear cells to the inhibitory effect of the drug was found between neonatal cord blood cells and adult PBMC, the former being more sensitive. PBMC from preterm infants treated with dexamethasone for BPD produced significantly less IL-2 and IL-3 as early as 24 hours after the initiation of the treatment (43% and 31%; P<0.05, respectively).It is concluded that mononuclear cells from preterm and term neonates are more sensitive to the inhibitory effect of dexamethasone on IL-2 and IL-3 production. (Arch Dis Child 1996;75:F197-F201)

CD14 expression and the capacity of mononuclear cells (MC) from preterm and term neonates to secrete the proinflammatory cytokines interleukin (IL) 1β, tumor necrosis factor α and IL-6 in response to lipopolysaccharide (LPS) was investigated and compared to that of adults. MC were incubated with various doses of LPS, and the cytokine level in the supernatants was tested. CD14 receptors on MC and the intensity of their expression were analyzed. MC of preterm and term neonates and adults responded to LPS with low, medium and high proinflammatory cytokine production, respectively. CD14 expression was lowest in preterm infants, intermediate in term infants and highest in adults. The difference between term and preterm neonates for both parameters was significant. The results suggest a possible correlation between the lower expression of CD14 receptor on neonatal cells and the reduced secretion of proinflammatory cytokines by these cells. This decreased production may possibly contribute to the low ability of neonates to develop fever.

The effect of colostrum of mothers of preterm and full-term newborns on the phagocytic activity for latex particles by normal peripheral blood polymorphonuclear cells was examined. The results showed that human colostrum contains a phagocytosis-promoting factor(s), which not only increases the number of phagocytic cells, but also stimulates the phagocytic activity of the individual cell. This factor(s) was more active in preterm colostrum. Thus, while term colostrum increased the number of phagocytic cells by 95% in comparison with the control, preterm colostrum enhanced the number of phagocytic cells by 300%. Similarly, term colostrum increased the phagocytic capacity of the individual cell by 51%, whereas preterm colostrum by 137%. The difference between the results in all experimental points was statistically highly significant.