Risk factors and outcome of graft failure after HLA matched and mismatched unrelated donor hematopoietic stem cell transplantation: a study on behalf of SFGM-TC and SFHI.

Graft failure remains a severe complication of hematopoietic stem cell transplantation (HSCT). Several risk factors have already been published. In this study, we re-evaluated them in a large cohort who had the benefit of the recent experience in HSCT (2006-2012). Data from 4684 unrelated donor HSCT from 2006 to 2012 were retrospectively collected from centers belonging to the French Society for Stem Cell Transplantation. Among the 2716 patients for whom HLA typing was available, 103 did not engraft leading to a low rate of no engraftment at 3.8%. In univariate analysis, only type of disease and status of disease at transplant for malignant diseases remained significant risk factors (P=0.04 and P<0.0001, respectively). In multivariate analysis, only status of disease was a significant risk factor (P<0.0001). Among the 61 patients who did not engraft and who were mismatched for 1 HLA class I and/or HLA-DP, 5 donor-specific antibodies (DSAs) were detected but only 1 was clearly involved in graft failure, for the others their role was more questionable. Second HSCT exhibited a protective although not statistically significant effect on OS (hazard ratio=0.57 [0.32-1.02]). In conclusion, only one parameter (disease status before graft) remains risk factor for graft failure in this recent cohort.

Identification of a novel HLA allele, HLA-B*53:39, in a Guadaloupean individual.

The novel HLA-B*53:39 allele differs from HLA-B*53:01 by a single nucleotide substitution at codon 45 (ACG>AAG).

Is there any impact of HLA-DPB1 disparity in 10/10 HLA-matched unrelated hematopoietic SCT? Results of a French multicentric retrospective study.

We retrospectively analyzed the impact of HLA-DPB1 mismatches in a large cohort of 1342 French patients who underwent 10/10 HLA-matched unrelated HSCT. A significant impact of HLA-DPB1 allelic mismatches (2 vs 0) was observed in severe acute GVHD (aGVHDIII-IV) (risk ratio (RR)=1.73, confidence interval (CI) 95% 1.09-2.73, P=0.019) without impact on OS, TRM, relapse and chronic GVHD (cGVHD). According to the T-cell epitope 3 (TCE3)/TCE4 HLA-DPB1 disparity algorithm, 37.6% and 58.4% pairs had nonpermissive HLA-DPB1, respectively. TCE3 and TCE4 disparities had no statistical impact on OS, TRM, relapse, aGVHD and cGVHD. When TCE3/TCE4 disparities were analyzed in the graft-vs-host or host-vs-graft (HVG) direction, only a significant impact of TCE4 nonpermissive disparities in the HVG direction was observed on relapse (RR=1.34, CI 95% 1.00-1.80, P=0.048). In conclusion, this French retrospective study shows an adverse prognosis of HLA-DPB1 mismatches (2 vs 0) on severe aGVHD and of nonpermissive TCE4 HVG disparities on relapse after HLA-matched 10/10 unrelated HSCT.

Long-term follow-up of corticosteroid refractory acute GVHD treated with an Inolimomab-based algorithm: a single center experience.

Acute corticosteroid refractory GVHD (aGVHD) remains a challenging problem after allogeneic hematopoietic SCT. Even though immunosuppressive therapies may achieve a response, unsatisfactory aGVHD control and toxicity of high cumulative doses of corticosteroids are frequent, notably with an increased infection rate. We report long-term follow-up of 33 consecutive patients who developed corticosteroid refractory aGVHD in our institution, treated homogeneously according to a unique algorithm combining an induction treatment (Inolimomab, 0.3 mg/kg per day), an associated immunosuppression (Mycophenolate Mofetil) and a predefined management of partial responses (PR) by the switch from Cyclosporin to Tacrolimus, together with an intensive infectious monitoring and supportive care. In this cohort, 17 patients (52%) achieved a complete response (CR) and 14 patients (42%) a PR, which converted to CR for 12 patients after Tacrolimus introduction. Transplant related mortality (TRM) was 15.5% and 29.7% at 1 and 3 years, respectively. OS was 54.5% at 3 years. Multivariate analysis identified CR after Inolimomab therapy as the unique prognostic factor on OS. Among the 30 evaluable patients, 19 (63%) developed extensive chronic GVHD. This Inolimomab-based algorithm allows for an efficient control of corticosteroid refractory aGVHD in a high proportion of patients with low toxicity, and deserves further investigation.

Mothers without HLA antibodies before transplantation have a low risk of alloimmunization post-transplantation.

Human leukocyte antigen antibodies (HLA Abs) are associated with poor renal graft outcome. We selected 134 first kidney transplant recipients without HLA Ab (LABScreen® Luminex) before transplantation despite previous allogeneic exposure whether through blood transfusion (BT) and/or pregnancy (PR). We screened these patients for HLA Ab post-transplantation (yearly) and determined the risk of HLA Ab and donor-specific antibody (DSA) appearance according to BT/PR in a univariate and a multivariate model. Among the 134 patients (43 males/91 females), 56 were BT+/PR-, 41 BT-/PR+ and 37 BT+/PR+. Median delay between last PR or BT and transplantation were 25.9 years (0.5-47.8) and 8 months (0.8-128.0), respectively. Median number of PR and BT were 2 (1-11) and 3 units (1-28), respectively. After transplantation (median follow-up: 47.5 months), 13 patients (9.7%) had HLA Ab and 10 DSA, mainly directed against class II HLA (HLA Ab: 10/13, DSA: 9/10). The risk of HLA Ab and DSA appearance was significantly lower in patients with PR before transplantation (P = 0.032 and P = 0.009, respectively). The risk of DSA appearance (hazard ratio = 0.17, P = 0.027) remained significantly lower after adjustment on donor age, acute rejection and number of class I/II HLA mismatches. In conclusion, we show that parous women non-immunized are at low risk of HLA Ab production after transplantation.

Relevance of KIR gene matching in unrelated hematopoietic stem cell transplantations.

The aim of this collaborative study was to evaluate the impact of killer cell immunoglobulin-like receptor (KIR) gene disparities on unrelated hematopoietic stem cell transplantations (HSCT) outcome. To address this question, we have determined the presence or absence of 14 functional KIR genes in HLA-matched (n= 164) or HLA-mismatched (n= 100) donor/recipient pairs and investigated whether KIR gene disparities had an impact on both the occurrence of acute graft-vs-host-disease incidence and overall survival. In a univariate analysis, our preliminary results suggest a detrimental effect of a few KIR gene disparities on patient survival that should be avoided in unrelated HSCT.

Comparison of quantitative and semiquantitative methods of assessing MIB-1 with the S-phase fraction in breast carcinoma.

Different methods of assessing cell proliferation in breast cancer are currently being evaluated. Inherent qualities are required for such methods to be used on a routine basis in a pathology laboratory. Such qualities include high sensitivity and specificity in recognizing proliferating cells, simplicity in execution, and reproducibility. The MIB-1 antibody permits the immunohistochemical detection of the Ki67 antigen in fixed and paraffin-embedded tissue sections. The aim of our study was to compare a semiquantitative and quantitative method of assessing MIB-1 immunostaining with the S-phase fraction (SPF) determined by flow cytometry in a series of 112 breast carcinomas. The median semiquantitative MIB-1 score (SQ-MIB-1) in our series was 27.5%. The median quantitative MIB-1 score (B.MIB-1) was 563 positive neoplastic cells per square millimeter of tumor, and, when corrected by the volume percentage nuclei (C.MIB-1), 2844 positive nuclei per square millimeter of total nuclear area. These three indices were strongly correlated to the SPF (r = 0.73, 0.72, 0.72, n = 78), respectively for SQ.MIB-1, B.MIB-1, and C.MIB-1, MIB-1, assessed quantitatively or semiquantitatively, correlated with the Scarff, Bloom, and Richardson grade, including the mitotic index and nuclear grade, as well as with the progesterone receptor status. SQ.MIB-1 determination was easier and faster than B.MIB-1 and C.MIB-1 determination. A high correlation was found for SQ.MIB-1 results between two observers in this series (r = 0.92, n = 112), but the SQ.MIB-1 repeatability coefficient was 17.6%. Semiquantitation of MIB-1 is strongly correlated to the SPF and is an easy and rapid method of assessing cell proliferation. More studies are necessary for additional assessment of its reproducibility and its prognostic value in breast cancer.

Production and characterization of monoclonal antibodies against the leukemia inhibitory factor low affinity receptor, gp190.

Leukemia inhibitory factor (LIF), oncostatin-M (OSM), ciliary neurotrophic factor (CNTF) and cardiotrophin-1 (CT1) act through transmembrane receptors which share the gp190 glycoprotein chain. The understanding of its involvement in the biology of these cytokines is of importance since these systems have recently been shown to participate in major inflammatory and neoplastic processes such as myelomatosis (Rose-John, S., Heinrich, P.C., 1994. Soluble receptors for cytokines and growth factors: generation and biological function. Biochem. J. 300, 281). In addition, this family of receptors also shares the gp130 transducing chain, with the IL6 and IL11 receptors. Because IL6 and gp130 were the first members to be discovered, most of the available reagents are directed at them. In this respect, monoclonal antibodies have played a major role in elucidating these receptor/ligand interactions and exploring the pathophysiological aspects of their biology. So far, no such reagents have been described for the gp190. We now report the production and characterization of 16 monoclonal antibodies directed against human gp190. They were obtained using recombinant chimeric or truncated proteins produced in a eukaryotic CHO cell line. One was able to block the biological activity of LIF. Because gp190 comprises two hematopoietin binding domains, crude epitope mapping was possible using the same reagents. While more of these antibodies are required, the present set validate the technological approach used for their preparation and should improve our understanding of this class of cytokines.