V(H)3 and V(H)6 immunoglobulin M repertoire reconstitution after hematopoietic stem-cell transplantation in children.
BACKGROUND
Immune reconstitution after hematopoietic stem-cell transplantation (HSCT) occurs gradually. Thus, a variable period of immunodeficiency may be present, leading to immunomediated complications, such as graft-versus-host disease (GVHD) and opportunistic infections.


METHODS
To better understand the kinetics of B-cell repertoire reconstitution in children, 49 pediatric patients were analyzed before and after transplantation by immunoglobulin (Ig) HCDR3 fingerprinting, which is a molecular technique that analyzes one of the hypervariable segments of the Ig heavy chain, which provides the amino acid residues that are essential to interact with antigens.


RESULTS
In healthy donors, the CDR3 fingerprinting profile shows 16 to 20 bands, and each band corresponds to a particular length of CDR3. This situation is considered polyclonal. Patients analyzed just after transplantation show strong oligoclonality, because only a few CDR3 bands are detected within the first 3 to 6 months.


CONCLUSIONS
The authors' data show a significant lag in diversification of the B-cell repertoire, which reaches the polyclonal situation of normal healthy donors approximately 6 months after HSCT. This period may vary depending on the type of transplant (autologous vs. allogeneic) and on the immunosuppressive therapy related to GVHD.
Di Martino
Daniela
D
Laboratory of Hematology, Department of Pediatric Hematology and Oncology, G. Gaslini Institute, Genoa, Italy. danieladimartino@ospedale-gaslini.ge.it
Terranova
M Paola
MP
Scuderi
Francesca
F
Di Michele
Paola
P
Iacovone
Sofia
S
Scarso
Lucia
L
Dallorso
Sandro
S
Dini
Giorgio
G
Morreale
Giuseppe
G
Valetto
Angelo
A
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D022801:Complementarity Determining Regions / Q000032:analysis*; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007075:Immunoglobulin M / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007223:Infant; D008297:Male; D010449:Peptide Mapping; D016133:Polymerase Chain Reaction
D022801:Complementarity Determining Regions; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region