Myeloablative conditioning associated with hazardous immediate and late complications is considered as a mandatory first step in preparation for allogeneic blood or marrow transplantation (allogeneic BMT) for the treatment of malignant hematologic disorders and genetic diseases. Immune-mediated graft-versus-leukemia (GVL) effects constitute the major benefit of allogeneic BMT. Therefore, we have introduced the use of relatively nonmyeloablative conditioning before allogeneic BMT aiming for establishing host-versus-graft tolerance for engraftment of donor immunohematopoietic cells for induction of GVL effects to displace residual malignant or genetically abnormal host cells. Our preliminary data in 26 patients with standard indications for allogeneic BMT, including acute leukemia (n = 10); chronic leukemia (n = 8), non-Hodgkin's lymphoma (n = 2), myelodysplastic syndrome (n = 1), multiple myeloma (n = 1), and genetic diseases (n = 4) suggest that nonmyeloablative conditioning including fludarabine, anti–T-lymphocyte globulin, and low-dose busulfan (8 mg/kg) is extremely well tolerated, with no severe procedure-related toxicity. Granulocyte colony-stimulating factor mobilized blood stem cell transplantation with standard dose of cyclosporin A as the sole anti-graft-versus-host disease (GVHD) prophylaxis resulted in stable partial (n = 9) or complete (n = 17) chimerism. In 9 patients absolute neutrophil count (ANC) did not decrease to below 0.1 × 109/L whereas 2 patients never experienced ANC <0.5 × 109/L. ANC ≥ 0.5 × 109/L was accomplished within 10 to 32 (median, 15) days. Platelet counts did not decrease to below 20 × 109/L in 4 patients requiring no platelet support at all; overall platelet counts >20 × 109/L were achieved within 0 to 35 (median 12) days. Fourteen patients experienced no GVHD at all; severe GVHD (grades 3 and 4) was the single major complication and the cause of death in 4 patients, occurring after early discontinuation of cyclosporine A. Relapse was reversed by allogeneic cell therapy in 2/3 cases, currently with no residual host DNA (male) by cytogenetic analysis and polymerase chain reaction. To date, with an observation period extending over 1 year (median 8 months), 22 of 26 patients (85%) treated by allogeneic nonmyeloablative stem cell transplantation are alive, and 21 (81%) are disease-free. The actuarial probability of disease-free survival at 14 months is 77.5% (95% confidence interval, 53% to 90%). Successful eradication of malignant and genetically abnormal host hematopoietic cells by allogeneic nonmyeloablative stem cell transplantation represents a potential new approach for safer treatment of a large variety of clinical syndromes with an indication for allogeneic BMT. Transient mixed chimerism which may protect the host from severe acute GVHD may be successfully reversed postallogeneic BMT with graded increments of donor lymphocyte infusions, thus resulting in eradication of malignant or genetically abnormal progenitor cells of host origin.

Systemic lupus erythematosus (SLE) is the prototype of human autoimmune diseases. Its genetic component has been suggested by familial aggregation (lambdas = 20) and twin studies. We have screened the human genome to localize genetic intervals that may contain lupus susceptibility loci in a sample of 188 lupus patients belonging to 80 lupus families with two or more affected relatives per family using the ABI Prism linkage mapping set which includes 350 polymorphic markers with an average spacing of 12 cM. Non-parametric multipoint linkage analysis suggests evidence for predisposing loci on chromosomes 1 and 18. However, no single locus with overwhelming evidence for linkage was found, suggesting that there are no 'major' susceptibility genes segregating in families with SLE, and that the genetic etiology is more likely to result from the action of several genes of moderate effect. Furthermore, the support for a gene in the 1q44 region as well as in the 1p36 region is clearly found only in the Mexican American families with SLE but not in families of Caucasian ethnicity, suggesting that consideration of each ethnic group separately is crucial.

The direct involvement of the human leukocyte antigen class II DR-DQ genes in type 1 diabetes (T1D) is well established, and these genes display a complex hierarchy of risk effects at the genotype and haplotype levels. We investigated, using data from 38 studies, whether the DR-DQ haplotypes and genotypes show the same relative predispositional effects across populations and ethnic groups. Significant differences in risk within a population were considered, as well as comparisons across populations using the patient/control (P/C) ratio. Within a population, the ratio of the P/C ratios for two different genotypes or haplotypes is a function only of the absolute penetrance values, allowing ranking of risk effects. Categories of consistent predisposing, intermediate ('neutral'), and protective haplotypes were identified and found to correlate with disease prevalence and the marked ethnic differences in DRB1-DQB1 frequencies. Specific effects were identified, for example for predisposing haplotypes, there was a statistically significant and consistent hierarchy for DR4 DQB1*0302s: DRB1*0405 ¼ *0401 ¼ *0402 > *0404 > *0403, with DRB1*0301 DQB1*0200 (DR3) being significantly less predisposing than DRB1*0402 and more than DRB1*0404. The predisposing DRB1*0401 DQB1*0302 haplotype was relatively increased compared with the protective haplotype DRB1*0401 DQB1*0301 in heterozygotes with DR3 compared with heterozygotes with DRB1*0101 DQB1*0501 (DR1). Our results show that metaanalyses and use of the P/C ratio and rankings thereof can be valuable in determining T1D risk factors at the haplotype and amino acid residue levels.

Myeloablative conditioning associated with hazardous immediate and late complications is considered as a mandatory first step in preparation for allogeneic blood or marrow transplantation (allogeneic BMT) for the treatment of malignant hematologic disorders and genetic diseases. Immune-mediated graft-versus-leukemia (GVL) effects constitute the major benefit of allogeneic BMT. Therefore, we have introduced the use of relatively nonmyeloablative conditioning before allogeneic BMT aiming for establishing host-versus-graft tolerance for engraftment of donor immunohematopoietic cells for induction of GVL effects to displace residual malignant or genetically abnormal host cells. Our preliminary data in 26 patients with standard indications for allogeneic BMT, including acute leukemia (n = 10); chronic leukemia (n = 8), non-Hodgkin's lymphoma (n = 2), myelodysplastic syndrome (n = 1), multiple myeloma (n = 1), and genetic diseases (n = 4) suggest that nonmyeloablative conditioning including fludarabine, anti–T-lymphocyte globulin, and low-dose busulfan (8 mg/kg) is extremely well tolerated, with no severe procedure-related toxicity. Granulocyte colony-stimulating factor mobilized blood stem cell transplantation with standard dose of cyclosporin A as the sole anti-graft-versus-host disease (GVHD) prophylaxis resulted in stable partial (n = 9) or complete (n = 17) chimerism. In 9 patients absolute neutrophil count (ANC) did not decrease to below 0.1 × 109/L whereas 2 patients never experienced ANC <0.5 × 109/L. ANC ≥ 0.5 × 109/L was accomplished within 10 to 32 (median, 15) days. Platelet counts did not decrease to below 20 × 109/L in 4 patients requiring no platelet support at all; overall platelet counts >20 × 109/L were achieved within 0 to 35 (median 12) days. Fourteen patients experienced no GVHD at all; severe GVHD (grades 3 and 4) was the single major complication and the cause of death in 4 patients, occurring after early discontinuation of cyclosporine A. Relapse was reversed by allogeneic cell therapy in 2/3 cases, currently with no residual host DNA (male) by cytogenetic analysis and polymerase chain reaction. To date, with an observation period extending over 1 year (median 8 months), 22 of 26 patients (85%) treated by allogeneic nonmyeloablative stem cell transplantation are alive, and 21 (81%) are disease-free. The actuarial probability of disease-free survival at 14 months is 77.5% (95% confidence interval, 53% to 90%). Successful eradication of malignant and genetically abnormal host hematopoietic cells by allogeneic nonmyeloablative stem cell transplantation represents a potential new approach for safer treatment of a large variety of clinical syndromes with an indication for allogeneic BMT. Transient mixed chimerism which may protect the host from severe acute GVHD may be successfully reversed postallogeneic BMT with graded increments of donor lymphocyte infusions, thus resulting in eradication of malignant or genetically abnormal progenitor cells of host origin.

Copolymer 1 (Cop 1) is a synthetic basic random copolymer of amino acids that has been shown to be effective in suppression of experimental allergic encephalomyelitis and is being tested as a