The clinical significance of conversion of complement-dependent cytotoxic T cell crossmatch test after renal transplantation.

The purpose of this study was to investigate the clinical relevance of conversion of post-transplant T cell crossmatch between kidney donor and recipient. This study comprises 892 cadaveric renal transplantations performed on 874 adult patients between August 1991 and December 1997. Recipient selection was based on a negative complement-dependent cytotoxic T cell crossmatch test with current (< or = 2 months old) serum. For this study, on day 0 and day 14 after transplantation, serum samples were collected for later crossmatching. On day 14 after transplantation, the crossmatch had converted to positive in 76 transplantations (8.5%). Acute rejection occurred in 50% of the converters and 22% of the non-converters (P < 0.005), and graft survival was significantly poorer (P < 0.025), being 85 vs 94% at 1 and 68 vs 83% at 5 years, respectively. In patients with delayed graft function, 1-year graft survival was 77% in the converters and 91% in the non-converters (P < 0.05). Conversion of T cell crossmatch, especially in connection with delayed graft function, identifies a subgroup of patients at high risk of severe rejection and poor graft survival.

HLA antigens in ulcerative colitis and primary sclerosing cholangitis.

The aims of this study were to find out whether the alleles of the HLA class I or II region are associated with susceptibility to ulcerative colitis, and to show whether there is a difference or similarity in HLA associations between primary sclerosing cholangitis and ulcerative colitis. HLA-A, B, C and DR antigens were studied using the standard lymphocyte microcytotoxicity test in 24 Finnish patients with primary sclerosing cholangitis, 77 patients with ulcerative colitis, and 106 controls. HLA-B8 (54%) and DR3 (60%) were associated with primary sclerosing cholangitis. HLA-DR1 (46%) and DR6 (20%) seemed more common in ulcerative colitis than in controls. A positive association with Cw7 was common to both ulcerative colitis (25%) and primary sclerosing cholangitis (33%). Our results indicate that ulcerative colitis is more heterogeneous than primary sclerosing cholangitis in its HLA-DR associations.

Allelic differences in hemolytic activity and protein concentration of BF molecules are found in association with particular HLA haplotypes.

After separating the *F and *S alleles by electrophoresis the allele-specific hemolytic activity was detected by agarose overlay method using the programmable densitometer for scanning. The hemolytic activity of BF allotypes was analyzed from 81 individuals. In thirteen FS heterozygous serum samples BF F had lower hemolysis than BF S. Four FF homozygous samples also exhibited lower hemolysis than a homozygous control sample. The low hemolytic activity of F in FS heterozygotes was not due to decreased protein concentrations relative to S. On the contrary, BF F was associated with higher protein concentration than BF S. The relative quantitation of the allele specific BF protein was done by crossed immunoelectrophoresis. BF F with low hemolytic activity but with high protein concentration associated strongly with HLA B35 phenotype and the family material confirmed the association with the haplotypes A3, Cw4, B35, DR1, BFFB, C4A3BQO (or A2BQO, A3,2BQO). The results suggest that particular MHC haplotypes contain a factor B allele with encoding for poor hemolytic activity or that MHC haplotype specific regulatory elements affect pre- or post-translational activity levels.