To analyze the immunoglobulin repertoire of human IgM ϩ B cells and the CD5ϩ and CD5 Ϫ subsets, individual CD19 ϩ / IgM ϩ /CD5 ϩ or CD5 Ϫ B cells were sorted and non-productive as well as productive V H gene rearrangements were amplified from genomic DNA and sequenced. In both subsets, the V H 3 family was overrepresented largely as a result of preferential usage of a small number of specific individual family members. In the CD5 ϩ B cell subset, all other V H families were found at a frequency expected from random usage, whereas in the CD5 Ϫ population, V H 4 appeared to be overrepresented in the nonproductive repertoire, and also negatively selected since it was found significantly less often in the productive compared to the nonproductive repertoire; the V H 1 family was significantly diminished in the productive rearrangements of CD5 Ϫ B cells. 3-23/DP-47 was the most frequently used V H gene segment and was found significantly more often than expected from random usage in productive rearrangements of both CD5

Liver transplant-associated GVHD is a progressive and fatal disease. Future approaches should focus on prevention and might include avoidance of closely matched human leukocyte antigen donors, treatment of the donor to reduce the number of lymphocytes, or reduction of immunosuppression in the early posttransplant period.

Invasive liver abscess syndrome, which is caused by hypervirulent Klebsiella pneumoniae subtypes, has been emerging worldwide over the past 2 decades. The syndrome is associated with the hypermucoviscosity phenotype of K. pneumoniae strains and with the magA and rmpA genes. We provide the first laboratory evidence of the presence of rmpA-positive K. pneumoniae in North America.

We tested the sensitivity of PCR-ssp typing of HLA DR/DQ for donor T-cells. At least one donor type was detected in all samples with 1% or more donor DNA.Thus, higher levels of donor T-cell chimerism, particularly with a high proportion of CD8+ T-cells, strongly supports a diagnosis of aGVHD.

Epstein-Barr virus (EBV)-induced lymphoproliferative disease is an important complication in the context