[Kinetics of in vitro proliferation of lymphocytes from malnourished children].

Lymphocytes from five severely malnourished children were cultured with bromodeoxyuridine (BrdU) and stained by the differential sister chromatid procedure using cells harvested at 48, 60, 72, 84 and 96 hours of incubation. Our results show that from 48 to 84 hours, the proportion of cells going from first to second and second to third generation cycles are higher than those cells from well-nourished children used as controls. The most dramatic difference between groups was seen at 48 hours: the proportion of first cycle metaphases was 63% and those in second cycle were 36% in the malnourished children, whereas the control group showed mainly first cycle metaphases (96%) and few (4%) had gone through the second cycle. Mathematical analysis of first cycle metaphase kinetics indicates that in the well-nourished group, 100% of the metaphases were in first cycle after 43.6 hours of culture, whereas in the malnourished group the second cycle metaphases began to appear at 36.5 hours of culture. The analysis for the third kinetics showed that the time of appearance of these cells was 8 hours earlier in the malnourished group than in the control group. These results are controversial because some authors have reported delay in the cell cycle duration. Murthy et al studying lymphocytes in vitro from children with Kwashiorkor found that the extent of this increase was 4.5 hours for the first-division cells and 1.5 hours for third division cells. However, Mutchinick et al studying nine children with severe protein malnutrition, report that the proportion of 3rd or subsequent division metaphases was higher than that seen in the control group. Our results agree with them in terms of early appearance of 3rd cycle cells.