UMBILICAL-CORD BLOOD CONTAINS NORMAL FREQUENCIES OF CYTOTOXIC T-LYMPHOCYTE PRECURSORS (CTLP) AND HELPER T-LYMPHOCYTE PRECURSORS AGAINST NONINHERITED MATERNAL ANTIGENS AND NONINHERITED PATERNAL ANTIGENS
Jhf. Falkenburg et al., UMBILICAL-CORD BLOOD CONTAINS NORMAL FREQUENCIES OF CYTOTOXIC T-LYMPHOCYTE PRECURSORS (CTLP) AND HELPER T-LYMPHOCYTE PRECURSORS AGAINST NONINHERITED MATERNAL ANTIGENS AND NONINHERITED PATERNAL ANTIGENS, Annals of hematology, 72(4), 1996, pp. 260-264
Umbilical cord blood (UCB) has been successfully used as an alternativ
e source of hematopoietic stem cells for allogeneic transplantation. A
relatively low incidence and severity of graft-versus-host disease (G
VHD) following UCB transplants has been reported, and it has been sugg
ested that this may be caused by a low frequency of alloreactive lymph
ocytes in UCB. Low frequencies of alloreactive T lymphocytes in UCB ma
y allow transplantation across major MHC barriers with an acceptable r
isk of GVHD. We investigated cytotoxic T-lymphocyte precursor (CTLp) a
nd helper T-lymphocyte precursor (HTLp) frequencies in UCB. Normal fre
quencies of CTLp and HTLp were measured against 1-2 HLA class I and 0-
1 HLA-DR mismatched stimulator cells. Since it has been postulated tha
t due to maternal fetal transfusion during pregnancy, fetal blood lymp
hocytes may become tolerant for noninherited maternal antigens (NIMA),
allowing transplantation over certain HLA barriers, reactivity of 24
umbilical cord blood samples was analyzed against both parents. The me
dian frequencies of CTLp against NIMA with 1 class-I mismatch was 79 p
er 10(6) nucleated cells (range 16-428) and with 2 class I mismatches
121 (range 33-748). CTLp frequencies against noninherited paternal ant
igens (NIPA) were not statistically different from those against NIMA,
with a median of 115 (range 8-336) and 176 (range 50-725) for 1 or 2
HLA class I mismatches, respectively. HTLp frequencies in UCB against
parents with 0 or 1 HLA-DR antigen mis-matches were similar with respe
ct to NIMA (median 74, range 43-233 and 88, range 16-777, respectively
) and NIPA (median 125, range 18-174, and 110, range 28-350, respectiv
ely). In four cases, UCB from two HLA-identical siblings was tested ag
ainst both parents. A correlation between the frequencies of CTLp and
HTLp from HLA-identical individuals was found, illustrating that these
frequencies are genetically determined. These results illustrate that
UCB contains normal frequencies of CTLp and HTLp against MHC alloanti
gens.