Reduced Cord Blood Research Articles

Prenatal thyroid function abnormalities in infants with idiopathic respiratory distress syndrome.

Thyroxine (T4), triiodothyronine (T3), and thyrotropin (TSH) concentrations were measured on cord sera of 21 preterm infants with idiopathic respiratory distress syndrome (IRDS) and were compared to the values obtained from 15 healthy preterm infants. When log T3, log T4, and log TSH were considered as the dependent variables in the multivariate test Hotelling-Lawley-Trace, there was an overall difference between the two groups: F = 3.94, p = 0.03. When log T3 and log T4 were considered separately in an analysis of covariance, there was a significant difference between the two groups for log T3 after adjusting for birth weight and gestational age (F = 7.98, p = 0.008). However, for log T4 and TSH, there was no difference between the IRDS and control infants. These findings exclude the possibility of antenatal thyroid dysfunction in babies with IRDS. An explanation for reduced cord blood T3 concentration in infants with IRDS is lacking at present. Extrathyroidal factors that predispose to IRDS may also affect peripheral T3 generation. Alternatively, one might postulate that there is relative immaturity of both peripheral T3 generating pathway and lung development in infants who develop IRDS.

924 DIMINISHED T-LYMPHOCYTE COLONY FORMING CAPACITY OF HUMAN CORD BLOOD CELLS

Some aspects of cell-mediated immunity in newborns are normal while others are reported to be altered. We have evaluated cord blood mononuclear cells (MC) for their capacity to form T-lymphocyte colonies when stimulated with PHA. Compared to values obtained from blood MC from 15 normal adults, cord blood MC from 25 subjects demonstrated decreased colony formation (1351 ± 644 versus 592 ± 501, p < 0.05). This diminished colony forming capacity was not associated with impaired responsivenss to PHA nor to excessive suppressor cell activity. Depletion of adherent cells reduced cord blood MC colony formation by 39% (411 ± 186 versus 251 ± 196) while not affecting lymphocyte proliferation in liquid culture (233,294 cpm versus 279,171 cpm). Irradiation of cord blood cells with 125 R reduced colony formation by 78% (279 ± 139 versus 56 ± 67). Lymphocyte proliferation again was not affected. In contrast, the colony forming capacity of adult MC was not altered by either adherent cell depletion or irradiation. These results indicate that the progenitor cells of T-lymphocyte colonies in cord blood have distinct biologic characteristics when compared to colony progenitors present in normal adult blood. This assay may prove to be useful in our efforts to understand the differentiation of T-cell function in man.