The aim of this study is to investigate prospectively specific immune system factors in preterm neonates with late-onset sepsis and infection-free controls. Matched preterm neonates (n = 82) were divided into three groups: suspected infection (n = 25), sepsis (n = 17), and infection-free controls (n = 40). Serial measurements were made of interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNF-α), lymphocyte subsets [CD3+, CD4+, CD8+, natural killer (NK) cells, and B cells], the immunoglobulins (IgG, IgM, and IgA), C-reactive protein (CRP), and the total blood count, before, 2 days after initiation of treatment, and after stopping treatment. The percentages of NK and B cells were higher in the sepsis group, but those of CD3+, CD4+, and CD8+ showed no differences. IgG was lower in the sepsis group. IL-6 >30 pg/ml and TNF-α >30 pg/ml were sensitive sepsis predictors with sensitivity 1 (0.78-1) and 1 (0.79-1), respectively, but their specificity was poor. CRP was a specific [0.90 (0.80-0.96)] but not sensitive index [0.68 (0.48-0.85)], and its combination with IL-6 or TNF-α could enhance their diagnostic accuracy. It is concluded that NK and B cells may be elevated in late neonatal sepsis. IL-6 or TNF-α combined with CRP is a good diagnostic marker for late-onset sepsis in preterm neonates.

Investigation was made of changes in immune system parameters during the course of neonatal infection. The study population consisted of 95 full‐term neonates matched for chronological age and sex, divided into three groups: suspected infection (n = 20), sepsis (n = 25), infection‐free control subjects (n = 50). Serial measurements were made of the cytokines interleukin‐6 (IL‐6), interleukin‐1b (IL‐1b) and tumour necrosis factor‐α (TNF‐α), lymphocyte subsets [CD3+, CD4+, CD8+, natural killer (NK) cells and B cells], the immunoglobulins (Ig) (IgG, IgM and IgA), C‐reactive protein (CRP), and the total blood count, before, 2 days after initiation of treatment and after stopping treatment (time periods first, second and third, respectively). IL6, TNF‐α, IL1‐b and CRP were higher at the first time period in the sepsis group, and IL6 and TNF‐α continued to be higher in this group at the second period. IL‐6 and TNF‐α were precise sepsis predictors with sensitivity and specificity of 0.92, 0.98 and 0.91, 0.92, respectively. NK cells, B cells, CD3+, CD4+, CD8+ were higher in the sepsis and suspected infection groups, but the ratios CD3+/CD4+, CD3+/CD8+, CD4+/CD8+ showed no difference from the controls. IgG was lower and IgM higher in the sepsis group. In the control subjects CD3+, CD4+, CD8+ lymphocytes increased with increasing age. It is concluded that IL‐6 and TNF are good diagnostic markers of sepsis in full‐term neonates. Lymphocyte subsets were affected by both the clinical condition and the chronological age. NK and B cells may be elevated in suspected and documented sepsis, and further studies are needed to determine their clinical significance.

While in full-term and near-term SGA infants RKL is similar to or even higher than that of AGA infants, in smaller preterm babies (<36 weeks of GA) the RKL is impaired up to the second year of life.

Kidney length in preterm SGA infants (symmetrical and asymmetrical) follows closely the other auxological parameters during the first year of life.

Background. Very few data are available on longitudinal renal growth in small for gestational age (SGA) infants born at term. The aim of this prospective study was to estimate comparatively the renal growth in SGA infants and in infants born appropriate for gestational age (AGA) during the first 2 years of life. Methods. The study comprised groups of SGA and AGA infants with a gestational age (GA) of 36-41 weeks. The SGA group was classified into two subgroups of symmetrical and asymmetrical neonates according to the ponderal index. Serial renal ultrasonography (US) was performed at the ages of 41 weeks corrected age [GA (in weeks) plus age after birth (in weeks)] and at 3, 6, 12 and 24 months of chronological age and kidney length (KL) was related to other anthropometric indices. Results. A total of 312 infants participated in the study out of which 197 were SGA, and a total number of 802 measurements were performed. The symmetrical SGA infants and, to a lesser degree, the asymmetrical SGA infants had smaller kidneys at birth compared with the AGA infants (P < 0.0001 and P < 0.001, respectively). The symmetrical SGA infants had a lower body weight (BW) (P < 0.001, P < 0.01) and crown-heel length (CHL) (P < 0.01, P < 0.05) than controls at the ages of 12 and 24 months of chronological age. The asymmetrical SGA infants had a lower BW (P < 0.01, P < 0.05) than controls at the ages of 12 and 24 months of chronological age. On the contrary, the KL in both SGA groups was not different from that of the AGA infants after the 41st week of corrected age and up to the 2nd year of life. Conclusion. SGA term infants had shorter KL at birth compared with AGA infants but a similar length from the 3rd to the 24th month of life. Early catch-up kidney growth was observed in both SGA groups and is more prominent in the symmetrical SGA infants. This observation may represent either an accelerated renal maturation process or early compensatory kidney hypertrophy in this group of infants.