Sixty-nine premature infants and 60 full-term infants fulfilled the inclusion criteria.

Among these, 5 (3.9%) premature infants and 6 (10.0%) full-term infants were excluded because the parents abandoned the study prior to the blood collection for the immunity analyses. Thus, data on 118 patients (64 in the premature group and 54 in the control group) were analyzed (Fig. 1). Premature infants had mean gestational age of 29.9 ± 2.2 weeks (variation: 25.6–34.4 weeks), birth weight of 1185 ± 216 g (variation: 714–1480 g), 23 (35.9%) were small for gestational age, and 48 (75.0%) had antenatal corticosteroids DNA Damage inhibitor exposure. During the neonatal period, 36 (56.3%), 17 (26.6%), 29 (45.3%), 36 (56.3%), and 16 (25.0%) had respiratory distress syndrome, patent ductus arteriosus, clinical sepsis, intraventricular hemorrhage, retinopathy of prematurity, respectively. Also, during the neonatal period, 40 (62.5%) neonates were submitted to mechanical ventilation on median for 6 days (variation: 1–57 days), 25 (39.1%) were on need of oxygen therapy at 28 day of life, 6 (9.4%) received corticosteroids IOX1 during hospitalization in the neonatal unit, 31 (48.4%) received at least one red blood

cells transfusion, 2 (3.1%) received plasma and 4 (6.3%) received at least one platelet transfusion. Table 1 summarizes the differences between the premature and full-term infants. At the beginning of the study, the premature infants had lower weight (8119 ± 1122 g vs. 9743 ± 1100 g; p < 0.001), stature (69.9 ± 3.4 cm vs. 75.0 ± 2.8 cm, p < 0.001) and body mass index (BMI) (16.5 ± 1.5 vs. 17.3 ± 1.3; p = 0.005), in comparison to the full-term infants. Four premature infants (6.3%) had a BMI below the −2 z-score and 22 (34.3%) premature infants had a stature/age z-score < −2, Methisazone whereas all full-term infants were within the normal range for these indices. Regarding clinical evolution following discharge from the neonatal unit, 18 (28.1%) premature infants developed pneumonia, 41 (64.1%) exhibited

wheezing and 24 (37.5%) required prednisolone, 5.7 ± 4.5 months before booster dose at 15 months, at a dose of 1 mg/kg/day for five days. Moreover, 24 (37.5%) required hospitalization, with a median value of 1 (range: 1–12) hospitalization per premature infant hospitalized. Only one child in the control group developed pneumonia and required hospitalization. Mother’s milk was administered to 37 (57.8%) premature infants and 48 (88.9%) full-term infants (p < 0.001). Breastfeeding continued for more than six months among 9 (14.1%) premature infants and 32 (59.3%) full-term infants (p < 0.001) and for more than one year among 0 (0%) premature infants and 15 (27.8%) full-term infants (p < 0.001). Mean duration of breastfeeding was shorter among the premature infants (3.2 ± 3.7 months vs. 9.1 ± 6.3 months; p < 0.001).