Insufficiency of the immune system in fetuses and infants with sepsis: Morphological and morphometric studies

The pathology of lymphoid organs was studied with morphological, morphometr ic, and immunohistochemical methods in 73 fetuses and newborns who died of different diseases, including sepsis. Gestation ages ranged from 22 to 42 w eeks and death had occurred no later than 28 days after birth. We have foun d previously that in fetuses and newborns with pneumonia the immune respons e to microbial effects is manifested in specific morphological features dif ferent from those in children and adults. Such immune response was meant as insufficiency. In fetuses and newborns with sepsis, the signs of decompens ation of the lymph system were found to be the main peculiarities in the im mune response of these organisms to infection. Decompensation manifested by a significant decrease in the number of cells, especially B and T lymphocy tes. As a result, the number of follicles in the spleen decreased, and deva station of lymph nodes was observed. The thymus showed weak morphological c hanges, especially in low-birth-weight fetuses and newborns. Sepsis is disc ussed in terms of the outcome of general decompensation of the immune syste m under conditions of bacterial aggression.