Methods for comparing cumulative hazard functions in a semi-proportional hazard model

Graphical methods based on the analysis of differences between log cumulative hazard functions are considered for a two-group semi-proportional hazard model which allows for interaction between treatments and covariates. Confidence procedures and test statistics that can be used to test for interaction and for main effects are developed. Their use is illustrated by applying them to the analysis of kidney transplant data from the University of California, San Francisco.

Improved results with combined donor-specific transfusion (DST) and sequential therapy protocol

A combined DST-sequential CyA therapy protocol has been described that results in optimum graft survival for 1- and 2-haplotype mismatched living related donor-recipient combinations. In addition to the excellent graft survival obtained through 4 years, lower prednisone and CyA dosage levels are achieved with significantly decreased infection rates during the posttransplant period.

Donor-specific blood transfusions versus cyclosporine--the DST story

DST provides excellent graft survival in one- and zero-haplotype-matched donor-recipient pairs as well as a trend towards improving graft survival in HLA-identical matches; serum creatinine levels are good in functioning grafts; Imuran coverage does appear to decrease DST sensitization to the blood donor in nonsensitized patients undergoing a first transplant, which encourages early DST and transplantation in this group; flow cytometry has been extremely helpful in excluding subliminal anti-class 1 antigen activity in patients with positive B warm crossmatches alone; DST, in itself, does not appear to preclude subsequent cadaveric transplantation in patients sensitized to their blood donor; and the family history of the blood donor is known, with essentially no risk to the recipients of hepatitis, AIDS, etc. In regards to the issue of whether DST or Cs is better, both have merits, and one must be aware of the circumstances that relate to the optimum application of each therapy. Only a prospective study of DST- and Cs-treated patients with a long-term follow-up will probably resolve the issue of the optimum regimen for one-haplotype-matched living related donor-recipient pairs. The ultimate strategy may involve the selective use of each regimen for the most appropriate circumstances.

A seven-year experience with donor-specific blood transfusions. Results and considerations for maximum efficacy

Two hundred thirty-nine transplants have been performed following donor-specific blood transfusions (DSTs) since 1978. Graft and patient survival in 1- and 0-haplotype-matched transplants with DST pretreatment is comparable to HLA-identical results through 4 years. Graft survival in 174 consecutive nondiabetic, non-HLA-identical DST recipients shows that the transfusion effect persists for at least 4 years, with graft survival of 88 +/- 3% at that time, compared with 83 +/- 4% in the concurrent HLA-identical group. Graft function, as determined by serum creatinine, was the same in both groups. Graft and patient survival in 20 0-haplotype matched pairs with DST pretreatment is 100% at 2 years. Low-dose Imuran coverage during DST administration (n = 91) was compared with a concurrent group with no Imuran (n = 93). Imuran had its maximum effect in patients undergoing their first transplant and with a pre-DST PRA less than 10% (12% vs. 21% sensitization rate in the no-Imuran group). Imuran did not appear to confer any beneficial effect in primary transplants with high PRAs and in patients undergoing a second or third transplant. The majority of patients formally excluded from transplantation because of a post-DST positive B-warm crossmatch can now be successfully transplanted with the use of flow cytometry analysis to rule out previously undetectable low levels of anti-T-lymphocyte antibodies. Of 62 patients with a positive B-warm crossmatch alone since 1982, 73% had a subsequent negative fluorescence-activated cell sorter (FACS) crossmatch permitting transplantation. Preliminary results of a DST and cyclosporine treatment study are described. In conclusion, a long-term immunologic effect of DST has been confirmed and the indications and considerations for optimum use of the DST protocol have been more clearly defined.