[Variants of pathomorphological changes in the thymus of in utero infected extremely low birth weight neonatal...

To analyze pathomorphological changes in the thymus of extremely low birth weight (ELBW) neonatal infants who have developed in the presence of in utero infection.

A study group included 105 ELBW neonates who had developed in the presence of in utero infection. The main causes of their death were the following conditions: generalized viral and bacterial infection of mixed genesis (n = 56 (53.3%)), congenital pneumonia (n = 27 (25.7%)), bilateral hemorrhage into the ventricular system of the brain (n = 12 (11.4%)), congenital sepsis (n = 3 (2.8%)), and visceral malformations (n = 7 (6.7%)). A comparison group consisted of 30 ELBW babies; the main cause of their deaths was asphyxia resulting from acute uteroplacental circulatory disturbances. Transplancentally transmitted infections were not identified in this group. Thymic structural features in the examined groups were studied using a set of current morphological studies.

Histological, immunohistochemical, electron microscopic, and morphological studies revealed three variants of thymic structural changes: normoplastic, retardant and dysplastic. Anomalies of the shape, ectopia, and hypoplasia of the thymus, impaired corticomedullary differentiation in the lobules, and decreased CD1a, CD3 T-cell expression were shown to be the morphological signs of dyschronic development of the thymus.

The morphological criteria for the retardant and dysplastic types of dyschronic thymic development were determined, which constitute the structural basis of immunodeficiency states in in utero infected ELBW newborn infants.