Presence ofRHDin serologically D-, C/E+ individuals: a European multicenter study

BACKGROUND

RHD blood group alleles with reduced or absent antigen expression are a clinically significant and heterogeneous group.

STUDY DESIGN AND METHODS

To detail population genetics data on apparently D- individuals in central Europe, a six-center study was performed with participants from Austria, Germany, Slovenia, Switzerland, and Russia. A total of 1700 serologically D- samples, positive for C and/or E, were investigated.

RESULTS

Observed unexpressed RHD alleles were 59 RHD-CE-D+ hybrid alleles, 9 apparently regular RHD, 1 new RHD(Y401X); DELs were 8 RHD(M295I), 6 RHD(IVS3+1G>A), and 1 new RHD(X418L); and weakly expressed RHDs were 2 weak D type 5, 1 weak D type 1, 1 RHD category VI type 1, and 1 novel weak D type 26. Although weak D type 26 was shown to have one of the lowest D antigen densities ever observed, it gave rise to anti-D immunization in a transfused D- individual.

CONCLUSION

The relative occurrence of RHD among serologically D- samples, positive for C and/or E, differed significantly in the investigated central European regions. Considering the growing use of molecular typing techniques, correct identification of blood group alleles with scarce or missing antigen expression is of utmost clinical importance and requires reliable population-based frequency data.

Early minimal residual disease (MRD) analysis during treatment of Philadelphia chromosome/Bcr-Abl-positive acute lymphoblastic leukemia with the Abl-tyrosine kinase inhibitor imatinib (STI571)

The Abl kinase inhibitor imatinib mesylate (STI571) has significant and rapid antileukemic activity in Philadelphia chromosome/Bcr-Abl-positive acute lymphoblastic leukemia (Ph(+) ALL) but such activity is usually of short duration except for a small proportion of patients. To determine the prognostic significance of early Bcr-Abl levels and changes in peripheral blood (PB) and bone marrow (BM), serial samples of 56 patients with relapsed or refractory Ph(+) ALL treated in phase 2 trials of imatinib were analyzed by quantitative polymerase chain reaction (PCR). Imatinib induced a complete hematologic response (CHR) or complete marrow response (marrow-CR) in 40 patients (good responders) and a partial (n = 2) or no (n = 14) remission in the remaining patients (poor responders). Compared with baseline, the median Bcr-Abl/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) ratios decreased significantly in PB by 2.65, 2.64, and 3.11 log steps after 2 weeks, 4 weeks, and at the time of best response, respectively. In BM, the decline of median Bcr-Abl/GAPDH was 0.75, 1.37, and 2.78 logs, respectively. Thus, Bcr-Abl levels decreased more rapidly in PB than in BM (median time to best level 31 vs 39 days). Low Bcr-Abl/GAPDH ratios below 10(-4) in PB and below 10(-2) in BM after 2 weeks were significantly associated with good responses after 4 weeks. Moreover, Bcr-Abl levels (< 10(-2)) in BM of good responders after 4 weeks discriminated between 2 groups of patients with significantly different median time to progression (139 vs 22 days). The data show that Bcr-Abl levels in PB and BM after 2 weeks of imatinib treatment and in BM after 4 weeks have predictive relevance and may guide the application of additional therapies.

Serial minimal residual disease (MRD) analysis as a predictor of response duration in Philadelphia-positive acute lymphoblastic leukemia (Ph+ALL) during imatinib treatment

Patients with refractory or relapsed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) rarely have prolonged responses to salvage therapy, including imatinib, resulting in a short opportunity for potentially curative stem cell transplantation. To identify minimal residual disease (MRD) parameters predictive of imminent relapse, we quantitated Bcr-Abl expression by real-time PCR in peripheral blood (PB) and bone marrow (BM) of 24 Ph+ALL patients after achieving a complete response and MRD minimum. The ratio of Bcr-Abl and glyceraldehyde-3-phosphate dehydrogenase copies, magnitude of increase and velocity of increase were evaluated regarding subsequent time intervals to relapse, death or censoring. High Bcr-Abl levels >/=5 x 10(-4) in PB (n=23) and >/=10(-4) in BM (n=18) were significantly associated with short time periods to relapse. Bcr-Abl increases >2 logarithmic units (log) in PB, but not in BM preceded short-term relapse. The velocity of Bcr-Abl increases predicted response duration in PB (cutoff: 1.25 log/30 days) and BM (0.6). Bcr-Abl level and velocity of increase in BM as well as magnitude of increase in PB correlated with remaining periods of survival and predicted relapse within 2 months in nine of 10, 10 of 11 and four of four patients, respectively. Thus, these MRD parameters may guide timing and intensity of therapeutic modifications.

An endogenous retroviral long terminal repeat at the HLA-DQB1 gene locus confers susceptibility to rheumatoid arthritis

Human endogenous retrovirus (HERV) long terminal repeat (LTR) elements contain regulatory sequences that can influence the expression of adjacent cellular genes, which may contribute to breakdowns of the immune function leading to autoimmune disease. Rheumatoid arthritis (RA) is associated with particular HLA-DR/DQ haplotypes that modulate the pathogenesis of this autoimmune disease. We have therefore studied a solitary LTR element (DQ-LTR3) of the HERV-K family at the HLA-DQB1 locus for a possible disease association among 228 RA patients and 311 unrelated blood donors. The DQ-LTR3 was significantly more frequent among patients (76% vs 33%, OR = 5.07,p < 0.0001), with the majority of patients being heterozygous for the DQ-LTR3 (61% vs 22%, p < 0.0001). HLA-DRB1*04 positive patients did still differ for the presence of the DQ-LTR3 (88% vs 70%, OR = 3.03, p < 0.001), with an increase of both DQ-LTR3 homozygous and heterozygous patients, when compared to DRB1*04 positive controls (p = 0.0015). HLA-DR/DQ genotype analysis among HLA-DRB1*04 positive individuals revealed significantly more DQ-LTR3 homozygotes among HLA-DRB1*04-DQBI*03 homozygous patients (72% vs 27%, P = 0.015), and the number of DQ-LTR3 homozygous (23% vs 19%) and heterozygous (66% vs 53%) individuals was also increased among HLA-DRB1*04 heterozygous patients (p = 0.034). The presence of the DQ-LTR3 element increased both the relative risk and the positive predictive value for either DRB1*04-DQB1*03 positive/negative individuals when compared to the presence of HLA-DRB1*04-DQB1*03 alone. In conclusion, these data suggest that this DQ-LTR3 enhances susceptibility to RA.

Purging in BCR-ABL-positive acute lymphoblastic leukemia using immunomagnetic beads: comparison of residual leukemia and purging efficiency in bone marrow vs peripheral blood stem cells by semiquantitative polymerase chain reaction

Twenty autologous bone marrow (BM) and 25 peripheral blood stem cell (PBSC) grafts were collected from a total of 40 consecutive patients with BCR-ABL+ acute lymphoblastic leukemia (ALL) in first (n = 37) or second (n = 3) complete morphological remission and subsequently purged with a cocktail of anti-CD19, -CD10, AB4 MoAbs and immunomagnetic beads (IMB). Residual BCR-ABL-positive cells before purging were detected in 19 of 20 BM grafts at a median of 4 (range 0-6) logs and in 17 of 25 evaluable PBSC grafts at a median of 1 (range 0-3) log above the limit of detection assessed by a semiquantitative limiting log10-dilution RT-PCR (P < 0.0001). IMB purging depleted a median of 2.5 (range 1-4) log of residual BCR-ABL+ cells from BM and a median of 1 (range 0-2) log from PBSC grafts, achieving RT-PCR negativity in 1/20 BM and 12/25 PBSC grafts after purging. Cell recoveries were 62% and 86% (P < 0.0001) of MNC and 74% and 97% (P = 0.065) of CD34+ cells after BM and PBSC purging, respectively. BM purging was superior using the triple MoAb cocktail which depleted 2.64 +/- 0.4 log (n = 14) compared to 1.6 +/- 0.4 log (n = 5) using the MoAb cocktail not including AB4 (P = 0. 02). We conclude that unpurged BM grafts contain 2-3 log more residual BCR-ABL+ cells than unpurged PBSC grafts and that purging efficacy is superior in BM compared to PBSC grafts, but median titers in purged BM grafts still exceed those in purged PBSC grafts. Bone Marrow Transplantation (2000) 25, 97-104.

Weak D type 1.1 exemplifies another complexity in weak D genotyping

BACKGROUND

Weak D expression is caused by a large number of RHD alleles. Increasingly recommendations for D+ or D- transfusions are based on polymerase chain reaction (PCR) identification of certain RHD alleles. Possible sources of error are rare D variants that are inadvertently carrying known polymorphisms of frequent weak D types.

STUDY DESIGN AND METHODS

Weak D donors were checked by direct column agglutination. In donors with unusually weak expression of D, the molecular weak D type was determined by weak D PCR and nucleotide sequencing. The serologic profile of a weak D type 1 variant was determined by agglutination serology and flow cytometry.

RESULTS

Several donors in whom direct agglutination barely revealed any D expression were shown to carry the new RHD(L18V,V270G) allele dubbed weak D type 1.1. Initially, such donors had been mistyped as weak D type 1 by PCR. In a systematic study, weak D type 1.1 was shown to be present in 7 of 23 donors with very weak D expression who all lived in a restricted area of Northern Germany. Although weak D type 1.1 was typed D- or barely D+ by direct agglutination, it was easily detected by antiglobulin technique and was shown to carry about 600 antigens D per red blood cell.

CONCLUSION

The observation of weak D type 1.1 with its distinct phenotype pinpointed to two general problems of current RHD genotyping strategies: Mistyping of alleles with additional mutations and striking geographic variation of the allele distributions.

Detection of nucleic acid sequences from bacterial species with molecular genetic methods

While blood products become more safe in terms of viral contamination, the risk of transfusion-related bacterial infection has re-emerged to one of the major hazards in transfusion medicine. In recent prospective studies the rate of contaminated platelets ranged from 0.04 to 0.5%, and a rate of transfusion reactions between 0.007% and 0.046%. It is generally agreed that most of the organisms isolated from donated blood originate from the normal skin flora or from the environment. As it is unlikely that antiseptic methods can achieve absolute sterilization of the skin before venepuncture, blood banks have to rely on laboratory tests to detect contaminated blood products before release. But most of the currently available methods detecting bacterial contaminations do not have the potential to be sensitive and fast enough for a routine contamination screening in transfusion services. Here we present two alternative strategies based on molecular genetic techniques (Real-Time-PCR and Haystack processing) that detect or semi-quantify bacterial rRNA gene sequences for the majority of bacterial species. In addition we discuss some aspects on target selection, routine preparation and residual 16S-rDNA-contamination of enzymes.

RHCE alleles detected after weak and/or discrepant results in automated Rh blood grouping of blood donors in Northern Germany

BACKGROUND

More than 170 weak or partial RHD alleles are currently known. A similar heterogeneity of RHCE alleles may be anticipated, but a large-scale systematic analysis of the molecular bases of altered C, c, E, and e antigenicity in European blood donors was lacking.

STUDY DESIGN AND METHODS

Between November 2004 and October 2006, samples collected from 567,105 blood donors in the northwest of Germany were surveyed for weakened and/or discrepant serologic reaction patterns of the C, c, E, or e antigens in automated testing. Samples from 187 donors with systematic typing problems were further investigated by manual typing and in 122 donors by DNA typing. The polymorphisms determining C, c, E, and e, as well as three repeatedly found substitutions, M167K, G96S, and L115R, were tested by PCR-SSP. Further analysis consisted of sequencing of the exons of RHCE. In addition, 13 referred samples were analyzed.

RESULTS

RHcE(M167K) known as E variant I was the most frequent allele, found in 70 of 122 analyzed donors. Among 13 referred samples, C typing problems predominated. Overall, 34 different underlying alleles were detected, 23 of which were new. Molecular causes included single-amino-acid substitutions, gene conversions, multiple dispersed amino acid substitutions, protein extensions, and in-frame amino acid deletions.

CONCLUSION

In addition to RHcE(M167K), a large number of different alleles are underlying CcEe typing problems. Molecular mechanisms parallel those found in RHD. Elucidation of the molecular bases of variant antigens is important to improve serologic and molecular typing methods.

In-frame triplet deletions in RHD alter the D antigen phenotype

BACKGROUND

The deletion of three adjacent nucleotides in an exon may cause the lack of a single amino acid, while the protein sequence remains otherwise unchanged. Only one such in-frame deletion is known in the two RH genes, represented by the RHCE allele ceBP expressing a "very weak e antigen."

STUDY DESIGN AND METHODS

Blood donor samples were recognized because of discrepant results of D phenotyping. Six samples came from Switzerland and one from Northern Germany. The molecular structures were determined by genomic DNA nucleotide sequencing of RHD.

RESULTS

Two different variant D antigens were explained by RHD alleles harboring one in-frame triplet deletion each. Both single-amino-acid deletions led to partial D phenotypes with weak D antigen expression. Because of their D category V-like phenotypes, the RHD(Arg229del) allele was dubbed DVL-1 and the RHD(Lys235del) allele DVL-2. These in-frame triplet deletions are located in GAGAA or GAAGA repeats of the RHD exon 5.

CONCLUSION

Partial D may be caused by a single-amino-acid deletion in RhD. The altered RhD protein segments in DVL types are adjacent to the extracellular loop 4, which constitutes one of the most immunogenic parts of the D antigen. These RhD protein segments are also altered in all DV, which may explain the similarity in phenotype. At the nucleotide level, the triplet deletions may have resulted from replication slippage. A total of nine amino acid positions in an Rhesus protein may be affected by this mechanism.

TRALI-new challenges for histocompatibility and immunogenetics in transfusion medicine

Antibodies against human leukocyte antigens (HLAs) have long been associated with transfusion-related acute lung injury (TRALI). In contrast to febrile transfusion reactions and refractoriness to platelet transfusions in immunized patients, the causative antibodies in TRALI are present in the transfused blood component, i.e. they are formed by the blood donor and not by the recipient. Consequently, blood components with high plasma volume are particularly associated with TRALI. In addition to antibodies against HLAs, antibodies directed against human neutrophil antigens (HNAs) present in the plasma of predominantly multiparous female blood donors can induce severe TRALI reactions. Especially, antibodies to HLA class II and HNA-3a antigens can induce severe or even fatal ALI in critically ill patients. Over the last decade, the clinical importance of TRALI as major cause for severe transfusion-related morbidities has led to the establishment of new guidelines aimed at preventing this condition, including routine testing for HLA and -HNA antibodies for plasma donors with a history of allogeneic sensitization. This, in turn, poses new challenges for close collaboration between blood transfusion centers and histocompatibility and immunogenetics laboratories, for sensitive and specific detection of the relevant antibodies.

Platelet recovery and survival measured in patients by quantitative polymerase chain reaction of mitochondrial DNA

BACKGROUND

Mitochondrial (mt) DNA markers have been identified as potential targets for the quantification of endogenous and allogeneic platelets (PLTs) in the blood of individuals who received transfusions. Our goal was to develop a routine polymerase chain reaction (PCR) assay for ex vivo monitoring of PLT survival in patients after transfusion.

STUDY DESIGN AND METHODS

Targets were selected for real-time (RT)-PCR of mt DNA based on the frequency distribution of nucleotide polymorphisms and assay sensitivity in vitro. The assays were then evaluated with ex vivo samples to measure PLT survival and recovery of therapeutic doses of apheresis PLTs in hematooncologic patients with thrombocytopenia.

RESULTS

Nucleotides in two positions (73/310 hypervariable region [HVR] 2) and three positions (295 HVR 2, 16069/16311 HVR 1) had allele frequencies of approximately 0.5 and 0.85, respectively, in a population of 960 Caucasian PLT donors. They provided targets for sensitive assays detecting at least 1 × 10(3) PLTs per whole blood sample with adequate reproducibility (interassay coefficient of variation <4.0%). Transfusions of single-donor PLT concentrates in patients with thrombocytopenia (n = 30) were monitored with these markers. The mean 24-hour corrected count increment was 8.3 and the mean calculated survival time was 3.3 days. Results for a second marker were available for 13 transfusions. The survival time values derived from both markers for the same transfusion were almost identical (linear regression: r(2)  = 0.957, slope = 0.87).

CONCLUSION

This RT-PCR method detects mt DNA polymorphisms in Caucasians for a highly sensitive and reproducible quantification of endogenous and allogeneic PLT numbers in blood samples from transfused patients with thrombocytopenia.

Efficacy of UVC-treated, pathogen-reduced platelets versus untreated platelets: a randomized controlled non-inferiority trial

Pathogen reduction (PR) technologies for blood components have been established to reduce the residual risk of known and emerging infectious agents. THERAFLEX UV-Platelets, a novel ultraviolet C (UVC) light-based PR technology for platelet concentrates, works without photoactive substances. This randomized, controlled, double-blind, multicenter, non-inferiority trial was designed to compare the efficacy and safety of UVC-treated platelets to that of untreated platelets in thrombocytopenic patients with hematologic-oncologic diseases. The primary objective was to determine non-inferiority of UVC-treated platelets, assessed by the 1-hour corrected count increment (CCI) in up to eight per-protocol platelet transfusion episodes. Analysis of the 171 eligible patients showed that the defined non-inferiority margin of 30% of UVC-treated platelets was narrowly missed as the mean differences in 1-hour CCI between standard platelets versus UVC-treated platelets for intention-to-treat and per-protocol analyses were 18.2% (95% Confidence Interval [CI]: 6.4-30.1) and 18.7% (95% CI: 6.3-31.1), respectively. In comparison to the control, the UVC group had a 19.2% lower mean 24-hour CCI and was treated with an about 25% higher number of platelet units, but the average number of days to the next platelet transfusion did not differ significantly between both treatment groups. The frequency of low-grade adverse events was slightly higher in the UVC group and the frequencies of refractoriness to platelet transfusion, platelet alloimmunization, severe bleeding events, and red blood cell transfusions were comparable between groups. Our study suggests that transfusion of pathogen-reduced platelets produced with the UVC technology is safe but non-inferiority was not demonstrated. (clinicaltrials gov. Identifier: DRKS00011156).

Establishment and characterization of a novel CD34-positive human myeloid leukemia cell line: MHH225 growing in serum-free culture

A new human multilineage myeloid leukemia cell line, MHH225, has been established in our laboratory from the bone marrow of a 60-year-old patient suffering from acute megakaryoblastic leukemia (M7); it provides a unique model for studying the effect of biologic and chemical agents on the lineage specificity of a multipotent myeloid leukemia clone containing a mixed population of megakaryoblast, erythroblast, and myeloblast cells in a serum-free culture. Morphologically, all 225 cells are large blast cells with basophilic cytoplasm containing no granules, large round nucleus containing 2-3 prominent nucleoli, and fine chromatin structure and a large nuclear/cytoplasm ratio. The MHH225 cells are CD34+HLA-DR+CD33+CD13+ with 57.6%, 28.3%, and 7.8% of them being CD41+, glycophorin A+, and CD15+, respectively, and all lymphoid-specific antigens are negative. The karyotype analysis of MHH225 cells revealed a deletion of the short arm of chromosome 7: del(7)(p13)-, a whole-arm translocation between the long arms of chromosomes 9 and 21: t(9;21)(q10;q10), and a chromosome 11 with an elongated long arm due to duplication of chromosome 11 material as well as to translocation of part of chromosome 9 onto 11q+. Also, chromosome 21 was deleted in some metaphases or showed a ring formation in other metaphases. Utrastructurally, MHH25 cells display a strong platelet peroxidase activity in the nuclear envelope and the endoplasmic reticulum. The MHH25 cells have been grown exponentially without growth factors or conditioned media or serum only in RPMI1640 culture medium. None of the myelopoietic growth factors, i.e., interleukin-3, GM-CSF, G-CSF, erythropoietin, or interleukin-6, has any effect on the proliferation and differentiation of MHH25 cells. The two, hematopoietic inhibitory cytokines, interferon-alpha and tumor necrosis factor-alpha, have only minimal growth inhibitory effect. Stem cell factor showed only weak growth-stimulatory effect on MHH225 cells but significantly inhibited chemotherapy-induced apoptosis in these cells. The new cell line MHH225 should constitute a useful model for studying stem cell antigen (CD34)-positive human multilineage myeloid leukemia cells carrying a deletion in the short arm of chromosome 7 and an aberration in chromosome 11 and provide a unique tool for investigating human hematopoietic stem cell biology and its cytokine regulation in serum-free cultures. To our knowledge, the MHH225 cell line is the first human CD34-positive leukemia cell line growing in serum-free cultures to be established.

Platelet engraftment after allogenic stem cell transplantation is monitored by digital polymerase chain reaction without interference by platelet support

Platelet engraftment after allogeneic hematopoietic stem cell transplantation is conventionally monitored by daily platelet counts. Platelet transfusions are frequently required and obscure the detection of platelet engraftment. Digital polymerase chain reaction (ddPCR) of mitochondrial DNA isolated from platelets reliably quantifies circulating platelets derived from the stem cell graft and allows us to distinguish them from transfused single-donor apheresis platelets. In a feasibility study, consecutive daily peripheral blood samples from day 7 to day 20 after transplantation were analyzed by ddPCR in 22 patients after allogeneic transplantation. Platelet engraftment according to ddPCR was defined as the third of at least 3 consecutive days of increasing levels exceeding 1000/µL endogenous platelets. Platelet counts were also assessed according to the engraftment cri`teria of the Center for International Blood & Marrow Transplant Research (CIBMTR) and the European Society for Blood and Marrow Transplantation (EBMT). Out of the 22 patients, five did not achieve platelet engraftment within 20 days by any of the predefined criteria. A subgroup of nine patients did show platelet engraftment by all three definitions. In five patients, engraftment was detectable according to ddPCR and EBMT, whereas in three patients, platelet engraftment within 20 days was only confirmed by ddPCR. The detailed findings suggest that the day of platelet engraftment according to the EBMT criteria closely reflected the ddPCR detection of transplantation-derived platelets. The results from this feasibility study demonstrate that ddPCR offers a sensitive approach to detect platelet engraftment reliably and without interference from the individual noise of platelet counts due to platelet transfusions.

Accreditation of histocompatibility and immunogenetics laboratories: Achievements and future prospects from the European Federation for Immunogenetics Accreditation Programme

The importance of demonstrating adherence to good practice in the provision of clinical services is well recognised, and there are many legislative and regulatory requirements that aim to ensure that services are appropriately reviewed and certified. Therefore, for regulatory purposes, laboratories must provide assurance of the quality of the services they provide. Additionally in the field of transplantation, where donor organs and stem cells are exchanged across national boundaries, adoption of a common set of standards by laboratories across many different countries is an important factor. The European Federation for Immunogenetics (EFI) Accreditation Programme was established to provide assurance that Histocompatibility & Immunogenetics laboratories providing services for transplantation, transfusion, and disease association testing meet the requirements of the specialty specific EFI standards. The first H&I laboratories achieved EFI accreditation in 1995, and currently there are over 260 EFI accredited laboratories in 36 countries. The programme depends on the voluntary participation of the inspectors, who are all experts in the field of H&I, and who, over the last 22 years, have performed over 1400 onsite inspections of laboratories. Inspection findings show the areas that are most frequently found to be deficient in meeting the requirements of the standards, and this can be used to inform educational and other activities with the aim of improving laboratory compliance with the standards. The EFI standards have been regularly updated to reflect the changes in the field with 19 versions over the last 22 years, and the data from the accreditation programme show how laboratories have changed their practices to incorporate new techniques that support patient care.

RHCE-D-CE hybrid genes can cause false-negative DNA typing of the Rh e antigen

BACKGROUND AND OBJECTIVES

DNA typing of the human Rh blood groups generally shows good agreement with serologically defined phenotypes. However, in the present report we describe four individuals who were declared Rh e negative by genotyping although they express the Rh e antigen.

MATERIALS AND METHODS

Serotyping was performed using mono- and polyclonal Rh antisera. Fluorescent multiplex sequence-specific polymerase chain reactions (PCR-SSPs) identified RHD exons and the polymorphisms usually associated with the Rh E/e or Rh C/c/C(W) antigens. Additional PCR amplification reactions, which were carried out to reveal RHCE-D-CE hybrid genes, analysed exon 5 of the RH genes, the location of the polymorphism (676C-->G) coding for the Rh E and Rh e antigens.

RESULTS

Four individuals were identified who expressed Rh e antigens but were negative by PCR-SSP typing for common Rhe-coding sequences. In one family analysed in detail, an RHCE-D5-CE hybrid gene associated with Rh e antigen expression was identified. A concomitant RHcE allele accounted for a seemingly regular typing pattern by conventional RH PCR.

CONCLUSIONS

The presence of RHCE-D5-CE hybrid alleles may cause false-negative DNA-typing results for the Rh e antigen that are easily overlooked unless appropriate RH hybrid PCR-SSPs are incorporated into conventional DNA-typing protocols. These and previous data strongly caution against an uncritical interpretation of RH DNA-typing results.

Long-term outcome in patients with follicular lymphoma following high-dose therapy and autologous stem cell transplantation

OBJECTIVE

To contribute data on long-term outcome and potential curative impact of ASCT in FL, especially following HDT with the BEAM protocol (BCNU, etoposide, cytarabine and melphalan), given very limited data on this topic in the literature.

PATIENTS AND METHODS

Patients with FL (n = 76) were treated in our institution with HDT and ASCT. In the case of long-term remission (≥8 years), peripheral blood was tested for minimal residual disease by t(14;18)- and IGH-PCR, including the last follow-up.

RESULTS

10-year overall survival, progression-free survival, and freedom from progression (FFP) after first-line ASCT (n = 20) were 80%, 60%, and 69%, after second-line ASCT (n = 48, following BEAM) 66%, 38%, and 41%, after third/fourth-line ASCT (n = 8) 33%, 25%, and 25%, respectively. Prognostic factors for FFP were treatment line and FLIPI (Follicular Lymphoma International Prognostic Index). 10-year FFP for second-line ASCT and low-risk FLIPI at relapse was 69%, intermediate-risk 28%, and high-risk 25% (P < .05). 26 patients developed sustained long-term clinical and molecular remissions of up to 27 years.

CONCLUSIONS

Sustained long-term clinical and molecular complete remissions up to 27 years can be achieved following ASCT (including HDT with BEAM in second treatment line), indicating a potential curative impact of ASCT in FL.

Evaluation of droplet digital PCR for quantification of residual leucocytes in red blood cell concentrates

BACKGROUND AND OBJECTIVES

Enumeration of residual white blood cells in leucoreduced blood components is essential part of quality control. Digital PCR has substantially facilitated quantitative PCR and was thus evaluated for measurements of leucocytes.

MATERIALS AND METHODS

Target for quantification of leucocytes by digital droplet PCR was the blood group gene RHCE. The SPEF1 gene was added as internal control for the entire assay starting with automated DNA extraction. The sensitivity of the method was determined by serial dilutions of standard samples. Quality control samples were analysed within 24 h, 7 days and 6 months after collection. Routine samples from leucodepleted red blood cell concentrates (n = 150) were evaluated in parallel by flow-cytometry (LeucoCount) and by digital PCR.

RESULTS

Digital PCR reliably detected at least 0·4 leucocytes per assay. The mean difference between PCR and flow-cytometric results from 150 units was -0·01 (±1·0). DNA samples were stable for up to at least six months. PCR measurement of leucocytes in samples from plasma and platelet concentrates also provided valid results in a pilot study.

CONCLUSION

Droplet digital PCR to enumerate leucocytes offers an alternative for quality control of leucoreduced blood products. Sensitivity, specificity and reproducibility are comparable to flow-cytometry. The option to collect samples over an extended period of time and the automatization introduce attractive features for routine quality control.

Herpes Zoster prophylaxis with low-dose acyclovir in patients with malignant lymphoma and multiple myeloma treated with autologous stem cell transplantation (ASCT)

BACKGROUND

Herpes zoster (HZ) is a frequent complication after autologous stem cell transplantation (ASCT). The option of zoster prophylaxis with an antiviral drug is described in the literature, but there is no consensus on the drug and the dosage.

PATIENTS AND METHODS

We analyzed the records of 310 patients treated with ASCT who were controlled regularly regarding HZ inter alia for at least 24 months following ASCT. Since 01/2015 patients received prophylactic low-dose acyclovir (400 mg per day) during the first 12 months following discharge after ASCT (n=107).

RESULTS

Twenty percent of patients without this kind of prophylaxis and 2.8% of patients with prophylaxis developed HZ (p<0.001). No patient with this prophylaxis developed HZ in the first year after ASCT, 2.8% of patients in the second year after ASCT. A prognostic factor was the kind of diagnosis: 30% of lymphoma patients and 14% of myeloma patients developed HZ in the first 24 months after ASCT without prophylaxis, but only 6.3% and 0% of patients with prophylaxis, respectively. Neither an increase of HZ cases following prophylaxis nor acyclovir refractory HZ cases were observed.

CONCLUSIONS

Zoster prophylaxis with low-dose acyclovir over 12 months after ASCT is effective and well tolerated. This article is protected by copyright. All rights reserved.

Long-term remissions in patients with early relapse of diffuse large B-cell lymphoma following high-dose chemotherapy, autologous stem cell transplantation, and radiotherapy of residual disease

PURPOSE

The prognosis of an early relapse of diffuse large B-cell lymphoma (DLBCL) appears to be poor following autologous stem cell transplantation (ASCT). The aim of this study is to contribute data to the open question on whether additional radiotherapy can improve the outcome.

PATIENTS AND METHODS

Forty-eight patients with an early relapse (median 4 months after the end of initial immunochemotherapy, range 1-11) of DLBCL have been treated in our institution with high-dose therapy (usually the BEAM protocol) and ASCT since 2008 (median age 61 years, range 28-73). Twenty-three patients received ASCT in a second treatment line, 25 in a third line (19 refractory to second-line salvage therapy, 5 after second relapse). Fifteen of these 48 patients received radiotherapy (36-50 Gy, median 40) of residual masses after ASCT.

RESULTS

Three-year overall survival (OS) and progression-free survival (PFS) after second-line ASCT were 61 and 57%, after third-line ASCT 47 and 44%, respectively, without significant differences. A prognostic factor was the International Prognostic Index (IPI) at the start of salvage therapy. Three-year OS and PFS in low-risk patients were 69 and 69%, in low-intermediate-risk 63 and 53%, and in high-intermediate-risk 23 and 23%, respectively (p = 0.033). Twenty-three patients achieved a sustained complete remission (13-146 months, median 62).

CONCLUSION

Sustained long-term remissions can be achieved in patients with early relapse of DLBCL following ASCT in a second or third treatment line, particularly in patients with low- and low-intermediate-risk IPI, following radiotherapy of residual disease after ASCT. Further investigations are required to clarify which patients need an alternative therapy (potentially CAR T‑cells or allogeneic transplantation).