Incomplete chimerism in erythroid, myeloid and B lymphocyte lineage after T cell-depleted allogeneic bone marrow transplantation.

In 22 transplant patients who received T cell-depleted allogeneic bone marrow (alloBMT) we investigated the chimeric state using a mixed agglutination technique and isoenzyme determinations for the red cell lineage, an isoenzyme assay for the myeloid cells, immunoglobulin allotyping for B lymphocytes and cytogenetics for karyotyping. The median duration of follow-up for these patients was 25 months after BMT. Chimerism was evaluated after 6 months. In 14 (64%) of the 22 patients incomplete chimerism was found when the results of the different techniques were combined. Recipient type cells were detected in the red cell lineage in 36% of cases, recipient type myeloid cells in 7% of cases and recipient type mitotic cells in 25% of cases where the marker could provide discrimination. In 100% of the evaluable patients recipient type immunoglobulins persisted after BMT. The data indicate a high frequency of incomplete chimerism following T cell-depleted BMT which involved the broad series of hematological lineages. This frequency appears higher than that following non-T cell-depleted BMT.