Analysis of reconstituting T cell receptor repertoires in bone marrow transplant recipients.

Allogeneic bone marrow transplantation (BMT) has become the treatment of choice for a variety of hematopoietic disorders. An important factor limiting the use of allogeneic BMT is delayed restoration of immune function. A quantitative understanding of immune reconstitution of the T cell compartment based on an efficient method of analysis would be of benefit. Distinct lineages of T cells which have resulted from previous and ongoing clonal expansion can be identified by their unique T cell receptors (TCR). Thus, TCR complexity can be used as a measure of repertoire complexity. Here we use a polymerase chain reaction-based approach which visualizes the size heterogeneity of the third complementarity determining region (CDR3) to study T cell reconstitution in adult bone marrow transplant recipients. We find that repertoire complexity, as determined by the number of bands of different length for each V family, reflects the general immune status of individuals tested. Contractions and gaps in repertoires are revealed in individuals suffering from recurrent infections associated with T cell impairment. This approach provides a new tool in the analysis of reconstitution of alpha/beta T cell repertoires and it can be also be applied to B cells and gamma/delta T cells.