Marrow cell transplantation for infantile hypophosphatasia.
An 8-month-old girl who seemed certain to die from the infantile form of hypophosphatasia, an inborn error of metabolism characterized by deficient activity of the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP), underwent the first trial of bone marrow cell transplantation for this heritable type of rickets. After cytoreduction, she was given T-cell-depleted, haplo-identical marrow from her healthy sister. Chimerism in peripheral blood and bone marrow became 100% donor. Three months later, she was clinically improved, with considerable healing of rickets and generalized skeletal remineralization. However, 6 months post-transplantation, worsening skeletal disease recurred, with partial return of host hematopoiesis. At the age of 21 months, without additional chemotherapy or immunosuppressive treatment, she received a boost of donor marrow cells expanded ex vivo to enrich for stromal cells. Significant, prolonged clinical and radiographic improvement followed soon after. Nevertheless, biochemical features of hypophosphatasia have remained unchanged to date. Skeletal biopsy specimens were not performed. Now, at 6 years of age, she is intelligent and ambulatory but remains small. Among several hypotheses for our patient's survival and progress, the most plausible seems to be the transient and long-term engraftment of sufficient numbers of donor marrow mesenchymal cells, forming functional osteoblasts and perhaps chondrocytes, to ameliorate her skeletal disease.
Whyte
Michael P
MP
Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, Missouri 63131-3597, USA. mwhyte@shrinenet.org
Kurtzberg
Joanne
J
McAlister
William H
WH
Mumm
Steven
S
Podgornik
Michelle N
MN
Coburn
Stephen P
SP
Ryan
Lawrence M
LM
Miller
Cindy R
CR
Gottesman
Gary S
GS
Smith
Alan K
AK
Douville
Judy
J
Waters-Pick
Barbara
B
Armstrong
R Douglas
RD
Martin
Paul L
PL
D000469:Alkaline Phosphatase / Q000172:deficiency / Q000235:genetics; D001483:Base Sequence; D016026:Bone Marrow Transplantation; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D007014:Hypophosphatasia / Q000000981:diagnostic imaging / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D007223:Infant; D020125:Mutation, Missense; D011859:Radiography; D017154:Stromal Cells / Q000637:transplantation
D000469:Alkaline Phosphatase