ALBERT

Description: Abstract 2840 Poster Board II-816 Multiple myeloma (MM) remains incurable with a median survival of 3–4 years. Despite high dose therapy and autologous stem cell transplant (ASCT) most patients relapse with median progression-free survival (PFS) of 2.5–4 years and overall survival (OS) of 4–5 years. Although allogeneic SCT (allo-SCT) is potentially curative due to a graft-versus-myeloma effect, its applicability is significantly limited by high transplant related mortality (TRM). Therefore, the identification of additional independent biological predictors of outcome is required in order to tailor therapy to disease. Natural killer (NK) cells provide first line defence against tumors. NK cells have been shown to recognize and kill myeloma cells both in the allogeneic and autologous settings and donor NK genotype has been shown to influence leukemia free survival following allo-SCT. The aim of this study was to investigate the impact of KIR genotype on event-free (EFS) and OS following ASCT for MM. We performed KIR genotyping on 190 patients with MM receiving a first autologous transplant. KIR genotype and haplotype frequencies were comparable to those published for normal controls. Factors found on univariate analysis to be associated with a shorter EFS included haplotype Bx (containing at least 1 of the KIR B haplotype-defining loci- KIR2DL5, 2DS1, 2DS2, 2DS3, 2DS5, or 3DS1) (median 547 vs 656 days, P = 0.036), ≥3 activating KIR genes (median 547 vs 615 days, P = 0.046), the presence of activating KIR genes KIR2DS1 and KIR3DS1 (median 456 vs 589 days, and 464 vs 619 days, P=0.045 and 0.01 respectively). Disease status at ASCT was the most highly predictive factor for EFS. In patients with good risk disease (CR or PR at ASCT) KIR3DS1 status was highly predictive for EFS 464 days (341–586) vs 731 days (599–862) (P = 0.003) and OS 807days (713-901) vs 967 (925-1009) (P=0.023). KIR3DS1 was not predictive in patients with poor risk disease (P=0.36). Of note KIR3DS1+ve patients were equally represented in good risk (CR and PR) and poor risk (refractory or relapsed) groups at ASCT (around 30% in both groups). Notably the median EFS for KIR3DS1+ good risk patients was not significantly different to poor risk disease patients (P = 0.061). ASCT outcome was then determined according to 3 main groups based on disease status and KIR3DS1 status; A: Good Risk, KIR3DS1-ve; B: Good Risk, KIRDS1+ ve; and C Poor risk (KIR3DS1+ve or -ve). The RR of relapse or death was 1.0, 1.9 (P=0.002, 95% CI 1.3-3.1), and 3.0 (P=0.0001, 95% CI 1.9-4.8) respectively. By multivariate analysis, after adjusting for the presence of adverse cytogenetics and serum albumin and β2m, the KIR3DS1 status and grouping remained highly predictive of poor EFS, RR of 1.0, 2.7 (P= 0.021, 95%CI 1.2-6.2) and 5.3 (P= 〈 0.0001, 95%CI 2.4-11.7) respectively. The prognostic value of KIR3DS1 however, was greatest in patients in whom the ligand for the corresponding inhibitory KIR3DL1, Bw4 was missing. KIR3DS1+ KIR3DL1+ HLA-Bw4 negative patients had significantly reduced median EFS of 400d (315-495) vs 615 (545-684) for all other patients (P=0.048). Again this was most striking in good risk patients. Patients who had the genotype KIR3DS1+ KIR3DL1+ HLA-Bw4 –ve had a significantly shorter EFS survival of 372 days compared to 509 days in KIR3DS1+KIR3DL1+HLA-Bw4+ patients and 793 days for KIR3DS1 negative individuals (P=0.004). In conclusion: Our data from 190 patients with MM suggests that KIR3DS1, a gene previously linked to an increase risk of progression to invasive cervical carcinoma, independently predicts for poor EFS and OS following ASCT. A significant proportion (30%) of patients who are defined as good risk at ASCT (CR and PR) are KIR3DS1+ve and have an EFS which is not significantly different from patients who have refractory/relapsed disease at ASCT. This effect of KIR3DS1 is more significant in the absence of HLA-Bw4, the ligand for the inhibitory receptor KIR3DL1. The mechanism for this is effect is unclear and we are currently performing functional studies to further understand these findings. Disclosures: Apperley: Novartis: Consultancy, Honoraria. Marin:Novartis: Consultancy, Research Funding.

Description: Abstract 1697 There is increasing evidence for the role of KIR genetics in predicting outcome of haematological malignancies. We recently showed that donor (but not recipient) KIR genes 2DS1, 3DS1 and 2DL5a are associated with significantly less relapse in AML patients following matched sibling allogeneic stem cell transplantation. Interestingly, this effect was not seen in patients with AML secondary to MDS but only in de novo AML.1 To explore whether outcome of non-transplant treatment for AML might be affected by KIR genetics we performed KIR genotyping on the DNA sample archive from the Medical Research Council UK AML 10 and 15 trials. All patients underwent four courses of chemotherapy according to MRC protocols. KIR genotyping was performed using Qiagen SSP PCR KIR genotyping kits as previously described.1 We measured KIR gene frequencies in AML samples obtained at diagnosis from 469 de novo AML, and 38 secondary AML and compared the gene distribution with that of a normal control population of 246 individuals. To allow for multiple comparisons, significance was set at p

Description: The pathogenesis of immune thrombocytopenia (ITP) is multifactorial, with both cellular and humoural immune dysfunction. The role of NK cells has not been well defined in ITP but in other diseases NK cells have a role in rejecting “foreign” eg transplanted organ or tumor, and also acting against self as occurs in autoimmunity. NK cell activity is orchestrated by the balance of activating vs. inhibitory signalling, in particular via the killer cell immunoglobulin-like receptor (KIR) family of receptors. Significant variation exists in KIR allelic subtype and copy number for the KIR between individuals, and associations have been made with certain haplotypes and a number of autoimmune disorders including rheumatoid arthritis, scleroderma and diabetes. Previous reports have demonstrated a reduction in natural killer (NK) cell number and function in ITP and expression of inhibitory KIR genes is increased in patients in remission vs. active ITP. Methods To explore whether a particular KIR haplotype might predispose to ITP, and also affect response to ITP treatment, we performed KIR genotyping using the Invitrogen SSP kit on 92 patients attending a haematology centre in New York and compared the results to data from 213 controls taken from the USA Eastern Database. Genomic DNA was typed for the inhibitory KIR genes KIR2DL1, KIR2DL2, KIR2DL5A (alleles 001 and 002), KIR2DL5B (alleles 002-004, 06, and 007), KIR3DL1, KIR3DL3; the activating KIR genes KIR2DS1, KIR2DS2, KIR2DS3, KIR2DS4, KIR2DS5, KIR3DS1; the framework genes KIR2DL3, KIR2DL4, KIR3DL2, KIR3DP1; and the pseudogene KIR2DP1. The patients with ITP had been or were receiving treatment with IVIG (n=64), corticosteroids (72) and rituximab (37). Bleeding symptoms were recorded. Response to treatment was defined as complete - platelet count increase to 〉 100 x 109/mL; partial - platelet count increase to 〉 50 x 109/mL; or no response. For the purpose of analysis, PRs and CRs were combined. A comprehensive database allowed a logistic regression, assessing both responses to treatments, platelet counts, neutrophil counts, CRP, lymphocyte subsets and bleeding symptoms. Results The expression of two inhibitory KIR genes, 2DL1 and 3DL1, was significantly lower in the patients with ITP as compared to controls (87% 2DL1 and 87% 3DL1 compared to 99% in controls - P 〈 0.02). Response to rituximab was strongly related to KIR haplotype expression. 2DL1 expression was higher among nonresponders to Rituximab (100% of non responders compared to 82% of responders), whereas 2DL3 expression was significantly lower (79% compared to 90%) (P 〈 0.05, Figure 1B). Separately, patients with the 2DS3 allele, an activatory KIR, were 5.5 times more likely to have experienced significant bleeding. Conclusions Although these findings are preliminary and require further investigation, these data suggest that increased cytotoxic autoimmunity due to reduced KIR inhibition may be associated with the development of ITP and possibly contribute importantly to the pathogenesis. Anti-CD20 targeting therapy directed at B cells was strongly influenced by 2 different KIRs (1 upregulated and one down-regulated) emphasizing the potential role of NK cells in elimination of tissue-based (nodal) B cells. Finally a more pronounced clinical phenotype with a markedly higher incidence of severe bleeding associated with an increased activatory KIR expression demonstrates the role of NK cells in bleeding presumably via their effects on either endothelial cells or platelet function. These exciting findings will be pursued for confirmation in a larger number of patients. Disclosures: Bussel: Amgen: Family owns stock Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Cangene: Research Funding; Genzyme: Research Funding; GlaxoSmithKline: Family owns stock, Family owns stock Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; IgG of America: Research Funding; Immunomedics: Research Funding; Ligand: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Shionogi: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Sysmex: Research Funding; Symphogen: Membership on an entity’s Board of Directors or advisory committees.