Anti-HLA alloantibodies of the IgA isotype in re-transplant candidates part II: Correlation with graft survival.

We reported previously on the widespread occurrence of anti-HLA alloantibodies of the IgA isotype (anti-HLA IgA) in the sera of solid-organ re-transplantation (re-tx) candidates (Arnold et al., ). Specifically focussing on kidney re-tx patients, we now extended our earlier findings by examining the impact of the presence and donor specificity of anti-HLA IgA on graft survival. We observed frequent concurrence of anti-HLA IgA and anti-HLA IgG in 27% of our multicenter collective of 694 kidney re-tx patients. This subgroup displayed significantly reduced graft survival as evidenced by the median time to first dialysis after transplantation (TTD 77 months) compared to patients carrying either anti-HLA IgG or IgA (TTD 102 and 94 months, respectively). In addition, donor specificity of anti-HLA IgA had a significant negative impact on graft survival (TTD 74 months) in our study. Taken together, our data strongly indicate that presence of anti-HLA IgA, in particular in conjunction with anti-HLA-IgG, in sera of kidney re-tx patients is associated with negative transplantation outcome.

Interventions to reduce platelet prophylactic transfusions in patients with hypoproliferative thrombocytopenia: providing patients with the full benefit.

To reduce the infectious and immunologic complications of platelet transfusions in patients with hypoproliferative thrombocytopenia, three interventions have aimed to decrease the number of prophylactic platelet transfusions received by such patients for the prevention of bleeding. These are the reduction of the platelet count threshold triggering prophylactic transfusion, the administration of low-dose (as opposed to standard-dose) platelet transfusions, and the administration of therapeutic (as opposed to prophylactic) platelet transfusions. We demonstrate that--in terms of absolute risk reduction in all infectious and some immunologic complications of transfusion--patients can benefit more from the transition to all-apheresis platelet supply than from the reduction of the platelet count threshold from 20,000/microL to 10,000/microL (mean reduction in the number of donor exposures by 26.28 versus 9.6, respectively). Also, patients can benefit just as much from the transition to an all-apheresis platelet supply as from the transition to a new standard of care employing therapeutic platelet transfusions for selected patients with hypoproliferative thrombocytopenia (mean reduction in the number of donor exposures by 4.08 versus 3.24, respectively). Finally, policies of low-dose platelet transfusions can directly benefit patients with hypoproliferative thrombocytopenia, effecting a median reduction in the number of donor exposures by 12.5 compared with a setting transfusing platelet pools, only if they are combined with Patient Blood Management (PBM) and an all-apheresis platelet supply. Thus, whatever strategy is adopted from among these three interventions, the replacement of the current platelet pools with an all-apheresis platelet supply is necessary for providing patients with the full benefit.

Donor exposures in recipients of pooled platelet concentrates: a case-study in arithmetic, logic, "expert opinion", and the "peer review" process.

Advocacy for single-donor (rather than pooled) platelets has been based on the absolute increase in the risk of transfusion-transmitted infections (TTIs) from pooled (rather than single-donor) platelets in the population of platelet transfusion recipients. A recent study published in a prestigious medical journal advocated for pooled (rather than single-donor) platelets based on the relative increase in the risk of TTIs from pooled (rather than single-donor) platelets in patients transfused with any blood component. If this policy recommendation for use of pooled (rather than single-donor) platelets were followed in the US, there would be an annual increase in the risk of TTIs by 15-20 recipient infections for hepatitis B virus, 85-113 recipient infections for the next "West-Nile-virus-like" pathogen, and 528-704 recipient infections for the next "human-immunodeficiency-virus-like" pathogen to emerge in the future. We present the calculation of the increased risk and discuss the stark contrast between simple arithmetic and logic versus the end result of a process of "expert opinion" and "peer review".

Consistency and proportionality in policy decision-making in blood safety: the case for an all-apheresis platelet supply in Germany.

Recently, German investigators presented the first mathematical model finding a significant increase in the risk of HIV, HCV, and HBV transmission when pools of 4 whole-blood-derived buffy-coat platelets, rather than 1 single-donor (apheresis) component, are used to provide one platelet dose. Based, in both cases, on mathematical models employing the incidence/window-period method, the relative risk of transmission from pooled versus apheresis platelets (2.2 or 2.75 for HIV, 2.7 or 3.375 for HCV, and 3.2 or 4.0 for HBV, with pools of 4 or 5 concentrates, respectively) is similar to the difference in risk before (versus after) introduction of HIV-1 and HCV RNA screening. The absolute increase in the risk from pools (1 to 2 HIV-, HCV-, or HBV-infectious platelet doses annually) is much smaller than the yield from HIV-1 and HCV RNA screening projected in the 1990s, but it becomes similar to that yield (with up to 88 infectious platelet doses intercepted) when we consider the next transfusion-transmitted pathogen to emerge in the future. Although pathogen reduction (PR) of platelets would eliminate the difference in risk between pooled and apheresis platelets vis-a-vis viral transmission, PR is not ready for implementation because the safety of PR needs to be investigated further. German transfusion guidelines should be revised to indicate the difference in risk associated with pooled versus apheresis platelets, and transition toward an all-apheresis platelet supply should commence. These actions are consistent with and proportionate to the action taken in the 1990s when screening for HIV-1 and HCV RNA was implemented.

16(th) IHIW: anti-HLA alloantibodies of the of IgA isotype in re-transplant candidates.

In this multicentre study, sera from 803 retransplant candidates, including 775 kidney transplant recipients, were analysed with regard to the presence and specificity of anti-HLA alloantibodies of the IgA isotype using a modified microsphere-based platform. Of the kidney recipients, nearly one-third (n = 237, 31%) had IgA alloantibodies. Mostly, these antibodies were found in sera that also harboured IgG alloantibodies that could be found in a total of 572 (74%) of patients. Interestingly, IgA anti-HLA antibodies were preferentially targeting HLA class I antigens in contrast to those of the IgG isotype, which targeted mostly both HLA class I and II antigens. Donor specificity of the IgA alloantibodies could be established for over half of the 237 patients with IgA alloantibodies (n = 124, 52%). A further 58 patients had specificities against HLA-C or HLA-DP, for which no information regarding donor typing was available. In summary, these data showed in a large cohort of retransplant candidates that IgA alloantibodies occur in about one-third of patients, about half of these antibodies being donor specific.

Impact of MHC class I alleles on the M. tuberculosis antigen-specific CD8+ T-cell response in patients with pulmonary tuberculosis.

Challenged by scattered understanding of protective immunity to Mycobacterium tuberculosis (MTB), we have mapped peptide epitopes to human leukocyte antigen (HLA)-A*0101, A*0201, A*1101, A*2402, B*0702, B*0801 and B*1501 of the secreted mycobacterial antigen Ag85B, a vaccine candidate that may be associated with immune protection. Affinity (ED(50)) and half-life (t(1/2), off-rate) analysis for individual peptide species on HLA-A and HLA-B molecules revealed binding ranges between 10(-3) and 10(-7) M. After selection of the best matches, major histocompatibility complex class I/peptide tetramer complexes were constructed to measure the CD8+ T-cell responses directly ex vivo in peripheral blood mononuclear cells (PBMC) derived from 57 patients with acute pulmonary tuberculosis. Three patterns of (allele-) specific CD8+ recognition were identified: (a). Focus on one dominant epitope with additional recognition of several subdominant T-cell epitopes (HLA-A*0301, A*2402, B*0801 and B*1501); (b). Co-dominant recognition of two distinct groups of peptides presented by HLA-B*0702; and (c). Diverse and broad recognition of peptides presented by HLA-A*0201. Peptides that bound with slow off-rates to class I alleles, that is HLA-A*0201, were associated with low frequency of CD8+ T cells in PBMCs from patients with tuberculosis. HLA-B alleles showed fast off-rates in peptide binding and restricted high numbers (up to 6%) of antigen-specific CD8+ T cells in patients with pulmonary tuberculosis.

MHC class II tetramer guided detection of Mycobacterium tuberculosis-specific CD4+ T cells in peripheral blood from patients with pulmonary tuberculosis.

Novel diagnostic tools are needed to diagnose latent infection and to provide biologically meaningful surrogate markers to define cellular immune responses against Mycobacterium tuberculosis (MTB). Interferon gamma-based assays have recently been developed in addition to the more than 100-year-old tuberculin skin test (TST) for the immune diagnosis of MTB in blood. The advent of soluble MHC/peptide tetramer molecules allows to objectively enumerate antigen-specific T cells. We identified novel MHC class II-restricted MTB epitopes and used HLA-DR4 tetrameric complexes to visualize ex vivo CD4(+) T cells directed against the antigens Ag85B and the 19-kDa lipoprotein, shared between MTB and other Mycobacterium species, and CD4(+) T cells which recognize the MTB-associated ESAT-6 antigen. MTB-reactive CD4(+) T cells reside predominantly in the CD45RA(+) CD28(+) and CD45(-) CD28(+) T-cell subset and recognize naturally processed and presented MTB epitopes. HLA-DR4-restricted, Ag85B or ESAT-6-specific CD4(+) T cells show similar dynamics over time in peripheral blood mononuclear cells (PBMC) when compared with CD8(+) T cells directed against the corresponding HLA-A2-presented MTB epitopes in patients with pulmonary MTB infection and subsequent successful therapy. This was not found to be true for T-cell responses directed against the 19-kDa lipoprotein. The dissection of the cellular immune response in M. tuberculosis infection will enable novel strategies for monitoring MTB vaccine candidates and to gauge CD4(+) T cells directed against MTB.

[Necessity for blood transfusion in head and neck surgery]. / Notwendigkeit der Bluttransfusion bei ausgewählten Operationen im Kopf-Hals-Bereich.

INTRODUCTION: Sometimes, use of blood products is necessary in head and neck surgery, but blood transfusion also entails risks for the patients and causes high costs for the department. Therefore, we examined the surgical procedures in our department and analysed how often transfusion of blood was necessary and which expenses were incurred. METHODS: Of 3989 operations performed in 1989, 187 patients were found to be at an increased risk for blood loss. The costs for blood group analysis (euro 23.16), cross-testing (euro 13.91) and the transfusion itself (euro 70.35) were estimated in each patient. RESULTS: In 1998 more than 60% of the 187 patients had undergone extensive head and neck surgery for advanced squamous cell carcinoma. Only 17 patients (<15%) received nearly 45% of all units of stored blood transfused that year. In patients who had undergone skull base surgery, the probability of receiving blood was 30%. The transfusion-related costs were estimated to be euro 20,000 during the observation period. Potential savings could have been achieved in cross-testing. CONCLUSION: Preparations should be done on an individual basis. Such preparations are sometimes unnecessary even in patients undergoing surgical procedures with a high risk for blood loss.

Highly focused T cell responses in latent human pulmonary Mycobacterium tuberculosis infection.

The elucidation of the molecular and immunological mechanisms mediating maintenance of latency in human tuberculosis aids to develop more effective vaccines and to define biologically meaningful markers for immune protection. We analyzed granuloma-associated lymphocytes (GALs) from human lung biopsies of five patients with latent Mycobacterium tuberculosis (MTB) infection. MTB CD4+ and CD8+ T cell response was highly focused in the lung, distinct from PBL, as assessed by TCR-CDR3 spectratyping coupled with a quantitative analysis of TCR VB frequencies. GALs produced IFN-gamma in response to autologous macrophages infected with MTB and to defined MTB-derived HLA-A2-presented peptides Ag85a242-250, Ag85b199-207, early secreted antigenic target 6 (ESAT-6)28-36, 19-kDa Ag88-97, or the HLA-DR-presented ESAT-6(1-20) epitope. Immune recognition of naturally processed and presented MTB epitopes or the peptide ESAT-6(1-20) could be linked to specific TCR VB families, and in two patients to unique T cell clones that constituted 19 and 27%, respectively, of the CD4+ and 17% of the CD8+ GAL population. In situ examination of MTB-reactive GALs by tetramer in situ staining and confocal laser-scanning microscopy consolidates the presence of MHC class I-restricted CD8+ T cells in MTB granuloma lesions and supports the notion that clonally expanded T cells are crucial in immune surveillance against MTB.

Effect of platelet concentration in platelet-rich plasma on peri-implant bone regeneration.

This study analyzed the effect of the platelet count in platelet-rich plasma (PRP) on bone regeneration in vivo. Twenty male New Zealand white rabbits were used. PRP was produced using the Platelet Concentrate Collection System (PCCS) (3i, Miami, FL, USA). After inducing ketamine-xylazine anaesthesia, a self-tapping titanium screw (Branemark MK III TiUnite, 3.75 x 7 mm) was inserted in each distal femur; the femurs were randomized so that one side was treated with PRP while the other (control) was not. Intravital fluorochrome staining was performed on days 1, 7 (1.5 ml of 2% doxycycline/kg bodyweight), 14 (6% xylenol orange, 1.5 ml/kg), and 21 (1% calcein green, 5 ml/kg). Animals were euthanized on day 28 (n = 20). Specimens were prepared for histomorphological evaluation according to Donath and Breuner [J. Oral Pathol. 11 (1982) 318]. Comparing the bone regeneration (fluorochrome staining) in the 4-week implants (n = 19), the only significant difference (sign test, P = 0.004) was seen with intermediate platelet concentrations (n = 9,503,000-1,729,000 platelets/microl PRP). There were no differences in the bone/implant contact rates between the test and the control side among the three groups. The platelet concentration required for a positive PRP effect on bone regeneration seems to span a very limited range. Advantageous biological effects seem to occur when PRP with a platelet concentration of approximately 1,000,000/microl is used. At lower concentrations, the effect is suboptimal, while higher concentrations might have a paradoxically inhibitory effect. On the other hand, the effect of this type of platelet concentrate was not beneficial to accelerate the osseointegration of enosseous dental implants.

Prevalence, persistence and liver enzyme levels of HGV RNA-positive blood donors determined by large-scale screening and transmission by blood components.

Although it seems to be rather unlikely, it still remains unclear whether hepatitis G virus (HGV) is involved in post-transfusion hepatitis. Prevalence of HGV viremia and persistence in blood donors was determined. ALT and AST values of viremic and non-viremic donations of the donors were compared. 25,006 blood donations were tested for the presence of HGV RNA by reverse transcriptase polymerase chain reaction. ALT and AST were determined for every donation. Sequential serum samples of 105 HGV RNA-positive donors were tested for both HGV RNA and antibodies to the HGV-E2 antigen (anti-E2) by enzyme-linked immunosorbent assay. Stored serum samples of 66 patients from before and after transfusion of HGV RNA-positive units were also tested. 1.6% of the 25,006 blood donations were HGV RNA-positive. One of 105 HGV RNA-positive blood donors showed viremia for more than 6 years. Three donors showed viremia and HGV antibody at the same time. There is no significant difference in ALT and AST activity in HGV RNA-positive donors compared to a control group of healthy donors and also before and after seroconversion to HGV RNA-negative (p > 0.05). Transmission of HGV by blood components has been shown in transfused patients. The prevalence of HGV infection in patients (n = 66) is 17%. Transmission of HGV by blood components does occur. Patients have a significantly higher prevalence of HGV viremia compared to blood donors. In blood donors no liver affection by means of ALT or AST elevation can be seen. Long persistence of HGV viremia is common and the presence of anti-E2 does not exclude viremia.

Comparison of platelet, leukocyte, and growth factor levels in point-of-care platelet-enriched plasma, prepared using a modified Curasan kit, with preparations received from a local blood bank.

The potential use of autologous thrombocytic growth factors to accelerate bone regeneration requires improved methods of isolating platelet-rich plasma (PRP). In addition to discontinuous cell separation, a second method by which PRP is produced at the point-of-care has now become available. In this study, growth factor levels in PRP from these two sources were compared. Whole blood was drawn from 115 healthy donors (73 males, 42 females) aged 21 - 62 years (mean 36, SD 10). The PRP was separated by the blood bank (BB) using the discontinuous cell separation method or at the 'point-of-care' by the so-called 'buffy coat' method (analogous to the Curasan PRP Kit). Growth factor content differed significantly for TGF-beta1 (BB 268.65+/-70.77 ng/ml, Curasan 95.02+/-60.67 ng/ml (sign test P<0.001)) and PDGF-AB (BB 133.59+/-46.26 ng/ml, Curasan 233.70+/-111.86 ng/ml (P<0.001)), while the content of IGF-I (BB 85.37+/-25.58 ng/ml, Curasan 101.72+/-47.7 ng/ml (P<0.160)) showed no significant difference. The higher thrombocyte count in the BB PRP (BB 1434300+/-351960/ microl, Curasan 908.500+/-492.30/microl) seems to result in higher TGF-beta1 levels, while the higher leukocyte count in the Curasan PRP (BB 160+/-320/ microl, Curasan 30130+/-12500/microl) seems to result in higher PDGF-AB levels. The similar IGF-I levels in the two preparations might merely reflect similar amounts of plasma in the PRP produced by each approach.

Prevalence of human parvovirus B19 in blood donors as determined by a haemagglutination assay and verified by the polymerase chain reaction.

BACKGROUND AND OBJECTIVES: Transmission of human parvovirus B19 (PV B19) by transfusion of blood and blood products is well documented. Although PV B19 infection is connected with severe complications in some recipients, donor screening is not yet mandatory. In this study the prevalence of PV B19, as detected by a haemagglutination assay (the Human PV B19 Antigen-Test), was assessed. In addition, the persistence of B19 DNA and the serological status of blood donors was also assessed. The specificity and utility of the Human PV B19 Antigen-Test for donor screening was investigated and compared with other screening strategies. MATERIALS AND METHODS: The prevalence of PV B19 viraemia was assessed in 28 972 donations from 15,660 remunerated donors by means of the haemagglutination assay. Reactive results were confirmed by the polymerase chain reaction (PCR). RESULTS: Overall, 255 donations gave reactive or indeterminate results in the screening assay. Four donations/donors detected by the haemagglutination assay were confirmed as positive for B19 DNA by PCR. Therefore, a frequency was detected of 1:7243 B19-positive donations and 1:3915 positive donors. Specificity was determined to be 99.1%. Follow-up showed the persistence of viraemia in low concentrations for prolonged time-periods. CONCLUSION: Blood donations with a high level of human PV B19 viraemia can be detected by the haemagglutination assay, which is rapid and easy to perform. The presence of neutralizing antibody may inhibit specific haemagglutination.

Screening of blood donations by hepatitis C virus polymerase chain reaction (HCV-PCR) improves safety of blood products by window period reduction.

Introduction of the nucleic acid amplification technique (NAT) as a screening test for blood donors to detect HCV RNA became mandatory on 1 April 1999. Few automated commercial systems are available for HCV RNA detection at the moment. The Cobas Amplicor HCV 2.0 System is able to perform fully automated amplification and detection of nucleic acids. A concentration of 98 IU HCV RNA/ml can be detected by the Cobas Amplicor HCV 2.0 System (n = 233, in 100% of the cases). With a pool size of 40 donor samples, the guidelines of the Paul-Ehrlich-Institute concerning sensitivity (5,000 IU HCV RNA per mL in a single donation) were followed. One whole blood donation was identified as HCV-RNA positive (anti-HCV IgG negative, GPT < 30 U/L) during a period of 5 months. No false positive test results could be observed. The internal control and the run control are primarily helpful to monitor methodological problems.

Routine HCV PCR screening of blood donations to identify early HCV infection in blood donors lacking antibodies to HCV.

BACKGROUND: Detection of early hepatitis C infection of blood donors is still a major problem for blood transfusion. Common anti-HCV screening assays show differences in sensitivity and specificity. The often mild symptoms of acute hepatitis C also cause difficulties in the identification of early HCV infection. The feasibility and efficacy of routine screening of blood donations for HCV RNA were investigated. STUDY DESIGN AND METHODS: Blood donations (n = 251,737) were screened for HCV RNA over 4 years. RNA extraction, amplification, and detection were done by two commercial HCV PCR kits (HCV Cobas Amplicor and HCV Cobas Amplicor 2.0, Roche Diagnostics). Screening was done by pool testing with a maximum pool size of 40 serum samples. RESULTS: Three donations out of 251,737 were HCV RNA positive and anti-HCV negative. ALT levels of these donations were 271, 32, and 10 U per L. The HCV infection of a fourth HCV RNA-positive donor could not be identified by routine, second-generation HCV EIA (Abbott Diagnostika). In this case, two previous donations were also HCV RNA positive, and three second-generation test systems (Abbott) could not detect anti-HCV, whereas third-generation anti-HCV screening assays detected antibody with different sensitivity. The first HCV RNA-positive donation was identified only by the HCV ELISA 3.0 (Ortho Diagnostic Systems). The results of confirmatory assays like RIBA HCV 3.0 (Ortho) and Matrix (Abbott) indicate a restricted immune response to NS3 only. CONCLUSION: HCV RNA detection by PCR can be carried out routinely in blood donor screening without significant delay of release of the components. The residual risk of transmission can be reduced by identification of early infection, which can lead to an improved safety of blood components. RNA screening can also be advantageous in cases of incomplete or lack of antibody response to HCV.

Comparison of intermittent- and continuous-flow cell separators for the collection of autologous peripheral blood progenitor cells in patients with hematologic malignancies.

BACKGROUND: The transplantation of autologous peripheral blood progenitor cells (PBPCs) after high-dose chemotherapy is a valuable therapy for patients with hematologic and solid malignancies. Several methods are used for harvesting PBPCs. The efficiency of intermittent- and continuous-flow blood cell separators in collecting progenitor cells from the blood of patients undergoing myeloablative treatment for cancer was compared. STUDY DESIGN AND METHODS: PBPC components (n = 133) were obtained from 72 patients by leukapheresis with continuous-flow machines (Spectra, COBE; CS 3000 Plus, Baxter) and with an intermittent-flow machine (MCS 3P, Haemonetics). The data were analyzed retrospectively. Blood samples obtained from the patients before leukapheresis and samples of the leukapheresis components themselves were analyzed for their content of RBCs, WBCs, platelets, and CD34+ cells. RESULTS: The Spectra processed more than twice the blood volume in the shortest time (15 L in 178 min), whereas the Baxter CS 3000 Plus (10 L in 185 min) and the MCS 3P (4.8 L in 239 min) processed significantly smaller volumes in a longer time. The mean ACD consumption was 403 mL with the MCS 3P, 900 mL with the CS 3000 Plus, and 1000 mL with the Spectra. The product volumes were 50 mL (CS 3000 Plus), 69 mL (MCS 3P), and 166 mL (Spectra). In all groups, differences in the preapheresis hemograms were not significant, but the Spectra group had fewer CD34+ cells than the other groups. Despite this, the differences in the number of CD34+ cells in the leukapheresis components of all groups were without statistical significance. In the Spectra group, the collection of MNCs of 104 percent and CD34+ cells of 154 percent was significantly more efficient than that in the MCS 3P group (42.2% and 56%, respectively) or the CS 3000 Plus group (50.8% and 47.15%) as related to the patients' blood volume. CONCLUSION: PBPC collection can be performed successfully with continuous-flow and intermittent-flow blood cell separators. The Spectra had the best recovery of CD34+ cells within the shortest time. Leukapheresis with the MCS 3P is indicated if only a single venous access is available.

The impact of the intensity of serial automated plasmapheresis and the speed of deep-freezing on the quality of plasma.

BACKGROUND: Data are lacking on the impact that the intensity of serial donor plasmapheresis has on the quality of source plasma. A study was conducted to examine the quality of source plasma produced by intensive plasmapheresis and slow deep-freezing and to compare it to source plasma manufactured by moderate plasmapheresis and rapid freezing. STUDY DESIGN AND METHODS: Seventy-five plasma samples from intensive plasmapheresis programs (Group 1) and 75 plasma units from moderate plasmapheresis programs (Group 2) were examined. The plasma had been deep-frozen either slowly at -30 degrees C in walk-in freezers (Group 1) or rapidly within 1 hour to a core temperature below -30 degrees C (Group 2). Determinations were made of the plasma levels of citrate; total protein; albumin; IgG; fibrinogen; factors II, V, VII, VIII, and IX; vWF; antithrombin; protein C; D-dimers; and prothrombin fragments 1+ 2. RESULTS: Plasma units of Group 2 contained substantially greater levels of citrate, IgG, FVIII, and FV than samples of Group 1 (p<0.0001). Plasma levels of total protein, albumin, and fibrinogen also were higher in Group 2 (p<0.0001, p = 0.007, and p = 0.006, respectively). Neither plasmapheresis intensity nor freezing procedure had any influence on the levels of factors II, VII, and IX, antithrombin, or protein C. There was no evidence of substantial coagulation activation in the plasma units of either group. However, higher FVIII clotting activity/chromogenic substrate activity ratios in rapidly frozen plasmas and a significant correlation between these ratios and prothrombin fragment 1+ 2 levels suggest that rapid freezing yields both more native FVIII and greater partial activation of FVIII. CONCLUSION: Source plasma collected from donors undergoing intensified plasmapheresis contains markedly lower levels of IgG than plasma units produced by moderate serial plasmapheresis. The combination of intensified plasmapheresis and slower freezing of source plasma results in substantially lower levels of FV and FVIII than does moderate plasmapheresis with rapid freezing. Prospective studies should establish the optimum conditions required for the safe and economic production of source plasma for fractionation.

Effect of 6-hour exposure to 20 degrees C on the ATP content and other biochemical measures of CPDA-1 packed red cells.

Blood donations for clinical use are routinely stored at 2 degrees C to 6 degrees C for 35 to 42 days. It is common practice for RBCs exposed to temperatures above 10 degrees C to be destroyed, although the American Association of Blood Banks Technical Manual states "Blood exposed to temperatures above 10 degrees C is not necessarily unsuitable for transfusion". To clarify this issue we investigated the effect of 6-hour storage at 20 degrees C on the content of ATP and other biochemical measures of CPDA-1 packed red cells. CPDA-1 packed RBC units were exposed once at day 5 (group 1), day 15 (group 2) or day 30 (group 3) of their shelf life to 20 degrees C for 6 hours. Control groups were continuously refrigerated. Under all conditions of storage, the ATP concentrations decreased with time. Initial ATP levels of five-day old CPDA-1 packed RBCs were 3.94 mumol/g Hb in the test group and 3.73 mumol/g Hb in the control group. At day 30 after warming (day 35 of the shelf-life) the ATP concentrations declined to 2.78 mumol/g Hb (test group) and to 3.55 mumol/gHb (controls). In the test series which were warmed at day 15 and day 30 of shelf-life the ATP levels declined to 3.16 mumol ATP/g Hb and 2.92 mumol ATP/g Hb at day 35 of shelf-life. There was no significant difference between test and control group with respect to the lactate levels, whole-blood glucose, sodium and potassium. The percentage of hemolysis was lower than 0.5% under all conditions of storage. Our data show that a shorter period of moderate warming (6h, 20 degrees C) does not lead to a critical decline of ATP and glucose concentrations in CPDA-1 packed RBCs. The survival of RBCs stored in CPDA-1 is most highly correlated with maintaining ATP concentrations above a value of about 2 mumol per g of Hb [3]. The ATP levels in our study were well above this threshold.

[The gel centrifugation test: comparison of antibody identification at 37 degrees C with antibody identification at room temperature]. / Der Gelzentrifugationstest: Vergleich der Antikörpersuche bei 37 degrees C mit der Antikörpersuche bei Raumtemperatur.

The indirect antiglobulin test (antibody screening) (IAT) using the 'DiaMed-ID Micro Typing System' (ID system) was performed in two different ways: (1) incubation (Liss/Coombs version) at room temperature (RT) and (2) incubation (also Liss/Coombs version) at 37 degrees C. 106 antibody-containing sera were tested by IAT at RT and at 37 degrees C. The comparison of the results showed a high correlation between both methods: 49 of 106 antibodies were positive in the IAT at both RT and 37 degrees C, 51 antibodies were negative at both temperatures. Five antibodies were identified only in IAT performed at RT. 1/106 antibodies of the specificity anti-D (Rh prophylaxis) was not detected in the antibody screening at RT and in the conventional tube test. The antibody screening at RT using the ID System could be performed simultaneously with AB0 blood group typing without losing sensitivity and specificity. The modification of IAT using the ID System is more sensitive than the conventional tube test.