Immune reconstitution after allogeneic marrow transplantation compared with blood stem cell transplantation

Allogeneic peripheral blood stem cell grafts contain about 10 times more T and B cells than marrow grafts. Because these cells may survive in transpla nt recipients for a long time, recipients of blood stem cells may be less i mmunocompromised than recipients of marrow. immune reconstitution was studi ed in 115 patients randomly assigned to receive either allogeneic marrow or filgrastim-mobilized blood stem cell transplantation. Between day 30 and 3 65 after transplantation, counts of most lymphocyte subsets were higher in the blood stem cell recipients. The difference was most striking for CD4 T cells (about 4-fold higher counts for CD45RA(high) CD4T cells and about 2-f old higher counts for CD45RA(low/-)CD4 T cells; P < .05). On assessment usi ng phytohemagglutinin and herpesvirus antigen-stimulated proliferation, T c ells in the 2 groups of patients appeared equally functional. Median serum IgG levels were similar in the 2 groups. The rate of definite infections af ter engraftment was 1.7-fold higher in marrow recipients (P =.001). The rat e of severe (inpatient treatment required) definite infections after engraf tment was 2.4-fold higher in marrow recipients (P =.002), The difference in the rates of definite infections was greatest for fungal infections, inter mediate for bacterial infections, and lowest for viral infections. Death as sociated with a fungal or bacterial infection occurred between day 30 and d ay 365 after transplantation in 9 marrow recipients and no blood stem cell recipients (P = .008), In conclusion, blood stem cell recipients have highe r lymphocyte-subset counts and this appears to result in fewer infections.( Blood, 2001;97:3380-3389) (C) 2001 by The American Society of Hematology.