Comparison of proliferative responses to PHA in the early and late transplantation groups.

Shown are the mean (± SEM) counts per minute of^3Hthymidine incorporation. Comparisons were made at the following intervals: before transplantation, 1 through 30 days, 31 through 60 days, 61 through 90 days, 91 through 120 days, 121 through 180 days, 181 through 270 days, 271 through 365 days, 1 to 2 years, 2 to 3 years, 3 to 4 years, 4 to 5 years, 5 to 6 years, 6 to 9 years, and more than 9 years after transplantation. Mean values were plotted at the midpoint of each interval. Infants receiving transplants within the first 28 days of life (n = 20) had increased T-cell proliferation to PHA at 91 through 120 days, 121 through 180 days, and 181 through 270 days after transplantation compared with those receiving transplants late (n = 69) (P < .05); n = total number of individuals analyzed in each group over the last 19.2 years.