Clinical impact of early absolute lymphocyte count after allogeneic stem cell transplantation

The role of repopulating lymphocytes after allogeneic stem cell transplantation (SCT) includes the prevention of serious infections and attacking residual tumour cells in the early post-transplant phase. Therefore, the current study analysed the role of the absolute lymphocyte count (ALC) on day 21 after SCT in predicting transplant outcomes of 82 patients in terms of the risk of opportunistic infections and recurrence of original disease. The median dose of CD34(+), CD3(+) and mononuclear cells (MNC) infused was 6.41 x 10(6)/kg, 1.96 x 10(8)/kg and 6.81 x 10(8)/kg respectively. The high ALC group (high ALC on day 21; greater than or equal to0.35 x 10(9)/l) was associated with the use of peripheral blood stem cells, matched sibling donors and higher cell doses of MNC CD3(+) and CD4(+) cells. The high ALC group also exhibited a better overall survival (56.3% vs. 17.7%) and disease-free survival (50.1% vs. 15.9%) after 3 years and lower incidences of relapse (33.6% vs. 67.1%) and fungal infections (3.0% vs. 19.5%) after 1 year. The incidence of cytomegalovirus antigenaemia was lower in the high ALC group (47.7% vs. 73.7%). Accordingly, identifying the ALC on day 21 would appear to be a useful and simple measurement to predict those patients with a high risk of opportunistic infections and relapse after allogeneic SCT.