Antibody responses to viral infections are sustained for decades by long-lived plasma cells (LLPCs). However, LLPCs have yet to be characterized in humans. Here we used CD19, CD38, and CD138 to identify four PC subsets in human bone marrow (BM). We found that the CD19−CD38hiCD138+ subset was morphologically distinct, differentially expressed PC-associated genes and exclusively contained PCs specific for viral antigens to which the subjects had not been exposed for over 40 years. Protein sequences of measles- and mumps-specific circulating antibodies were encoded for by CD19−CD38hiCD138+ PCs in the BM. Finally, we found that CD19−CD38hiCD138+ PCs had a distinct RNA transcriptome signature and human immunoglobulin heavy chain (VH) repertoire that was relatively uncoupled from other BM PC subsets and likely represents the B cell response’s “historical record” of antigenic exposure. Thus, our studies define human LLPCs and provide a mechanism for the life-long maintenance of anti-viral antibodies in the serum.

patients (1-59 years old, median 23) with acute leukemia (67% not in remission) underwent ex vivo T-cell-depleted (TCD) bone marrow transplants (BMT) from partially mismatched related donors (PMRD; 92% mismatched for 2-3 HLA A, B, DR antigens). Conditioning comprised total body irradiation, cyclophosphamide, cytarabine, etoposide, anti-thymocyte globulin (ATG), and methylprednisolone. Graft-versus-host disease (GVHD) prophylaxis comprised partial TCD with OKT3 (n ¼ 143) or T10B9 (n ¼ 58), steroids, ATG, and cyclosporine. The engraftment rate was 98%. The cumulative incidences of grades II-IV acute GVHD and chronic GVHD were 13 and 15%, respectively. The 5-year cumulative incidences of relapse and transplant-related mortality (TRM) were 31 and 51%, respectively. The actuarial 5-year overall survival (OS) and disease-free survival (DFS) probabilities were 19 and 18%, respectively. Patient age 415 years, active disease at transplant, donor age 425 years, and 3-antigen donor mismatch (host-versus-graft) affected the outcome adversely. The actuarial 5-year OS of four groups of patients identified based upon these risk factors was 39, 20, 13, and 0%, respectively (Po0.0001). We conclude that PMRD BMT is a potential treatment option for patients with high-risk acute leukemia who require an alternative donor transplant and fall into a group with a reasonable expected outcome.

We compared outcomes of patients with severe aplastic anemia (SAA) who received G-CSF stimulated bone marrow (G-BM) (n=78), unstimulated bone marrow (BM) (n=547), or peripheral blood progenitor cells (PBPC) (n=134) from an HLA-matched sibling. Transplantations occurred in 1997–2003. Rates of neutrophil and platelet recovery were not different among the three treatment groups. Grade 2–4 acute graft-versus-host disease (GVHD) (RR 0.82, p=0.539), grade 3–4 acute GVHD (RR 0.74, p=0.535) and chronic GVHD (RR 1.56, p=0.229) were similar after G-BM and BM transplants. Grade 2–4 acute GVHD (RR 2.37, p=0.012) but not grade 3–4 acute GVHD (RR 1.66, p=0.323) and chronic GVHD (RR 5.09, p<0.001) were higher after PBPC transplants compared to G-BM. Grade 2–4 (RR 2.90, p<0.001), grade 3–4 (RR 2.24, p=0.009) acute GVHD and chronic GVHD (RR 3.26, p<0.001) were higher after PBPC transplants compared to BM. Mortality risks were lower after transplantation of BM compared to G-BM (RR 0.63, p=0.05). These data suggest no advantage to using G-BM and the observed higher rates of acute and chronic GVHD in PBPC recipients warrants cautious use of this graft source for SAA. Taken together, BM is the preferred graft for HLA matched sibling transplants for SAA.