Further studies to evaluate methods of leucoreduction to prevent alloimmune platelet refractoriness and induce tolerance in a dog platelet transfusion model.

OBJECTIVES: Three leucoreduction filters were evaluated - when used alone or combined with centrifuge leucoreduction (C-LR) - to prevent alloimmune platelet refractoriness in a dog platelet transfusion model. MATERIALS AND METHODS: Donor platelet-rich plasma (PRP) or buffy coat (BC) platelets were either filter leucoreduced (F-LR) or F-LR/C-LR, (51) Cr radiolabelled and transfused. Weekly transfusions were given for up to 8 weeks or until platelet refractoriness. Recipients who accepted treated transfusions were then given non-leucoreduced (non-LR) platelets to determine whether donor-specific tolerance had been induced. RESULTS: Acceptance of F-LR PRP transfusions ranged from 29% to 66%. F-LR/C-LR transfusions prepared from PRP were accepted by 92%, from BC by 63% and from pooled PRP by 75% of recipients (p=NS); overall acceptance rate of F-LR/C-LR transfusions was 83%. Tolerance to subsequent non-LR transfusions occurred in 45% of the F-LR-/C-LR-accepting recipients unrelated to DR-B compatibility between donors and recipients (P = 0·18). CONCLUSION: In a dog platelet transfusion model, acceptance of donor platelets required combining F-LR with C-LR as apparently each process removes different immunizing WBCs.

Factor VIII mutation and desmopressin-responsiveness in 62 patients with mild haemophilia A.

Utilization of the synthetic vasopressin analogue (1-deamino-8-D-arginine-vasopressin, DDAVP) in treatment of mild haemophilia A (MHA, specific clotting factor VIII activity level 0.05-0.4 IU mL(-1) ) is convenient and effective for many but not all patients. Genetic testing for patients with MHA is increasingly recognized as providing valuable information for patient care beyond informing reproductive decisions, and as more patients are genotyped, mutation data can be utilized to individualize treatment decisions. To determine if genetic information informs response to DDAVP, a retrospective chart review was performed under Institutional Review Board approval to extract patient data with MHA, genetic mutation results, and response to DDAVP challenge. 62 patients met inclusion criteria. Complete responses (C) presented in mean value IU mL(-1) (range), were recorded for 32 of 62(52%) subjects: pre 0.19(0.04-0.45) and post 0.78(0.5-1.95); partial responses (P) were recorded for 15 of 62(24%) subjects: pre 0.1(0.06-0.15) and post 0.4(0.3-0.47); responses that were not clinically significant (N) were recorded for 15 of 62(24%) subjects: pre 0.17(0.02-0.34) and post 0.25(0.03-0.44). Subjects (related and unrelated) with the same mutation showed a trend towards a similar response to DDAVP. Eight genotypes were common to two or more subjects (n = 26). Two genotypes were concordant in all subjects [p.Ser2192Ile n = 3(C), p.Ala2220Pro n = 2(P)]. Of mutations in the C1 or C2 domains, 13 of 15(87%) subjects responded to DDAVP [C = 9(60%); P = 4(27%); n = 2(13%)]. Baseline FVIII:C did not predict magnitude of response to DDAVP. Genetic mutation results can assist with predicting DDAVP responsiveness, but baseline FVIII:C may not.

Extended storage of autologous apheresis platelets in plasma.

BACKGROUND AND OBJECTIVES: The purpose of our studies was to determine the effects of extended platelet storage on poststorage platelet viability. MATERIALS AND METHODS: Normal subjects were recruited to donate platelets using two different apheresis systems: either the COBE Spectra (n = 58) or the Haemonetics MCS+ (n = 84). Platelet recovery and survival data from the two systems were compared with each other and with in vitro measurements of the stored platelets. RESULTS: There were no significant differences in either platelet recoveries or survivals between the two machines between 1 and 8 days of storage. Combining the data from both machines, platelet recoveries decreased by 2.6% and survivals by 0.3 days/storage day. In vitro assays did not predict either platelet recoveries or survivals during storage for 5-8 days. After 9 days of storage, pHs were unacceptable (≤ 6.1), suggesting that 8 days will be the longest possible storage time. CONCLUSIONS: These data suggest that, if stored platelet bacterial contamination issues are resolved, significant extension of platelet storage times is possible.

Improving the efficacy of preoperative autologous blood donation in patients with low hematocrit: a randomized, double-blind, controlled trial of recombinant human erythropoietin.

The effects of therapy with recombinant human erythropoietin (Epoetin alfa) on erythropoiesis, preoperative autologous blood donation, and risk of exposure to allogeneic blood were evaluated in 204 patients scheduled to undergo elective orthopedic surgery. Study protocol required patients to have a baseline hematocrit < or = 39% and surgery scheduled 25-35 days in advance. Patients were randomized to two equal groups and were seen at study centers every 3-4 days within the 21-day trial period. At each visit, phlebotomy(< or = 450 mL) was performed if the hematocrit was > or = 33%, and Epoetin alfa (600 U/kg) or placebo was administered intravenously. A total of 173 patients were assessable; 31% of placebo recipients and 20% of Epoetin alfa recipients required allogeneic transfusion (p = 0.09). Logistic regression modeling showed that the risk of allogeneic transfusion was reduced by Epoetin alfa (p = 0.025). When patients receiving > 6 units of blood (necessitating allogeneic units) were excluded from analysis, 29% of placebo recipients and 14% of Epoetin alfa recipients were exposed to allogeneic blood (p = 0.015). Epoetin alfa recipients predonated more autologous units than did placebo recipients (4.5 vs 3.0 units, respectively; p < 0.001), and their production of red blood cells increased significantly more over baseline production values (668 vs 353 mL, respectively; p < 0.05). These results demonstrate that administration of Epoetin alfa stimulates erythropoiesis, allows predonation of more units of autologous blood, and reduces the risk of exposure to allogeneic blood. Optimal dosing regimens and surgical patients most likely to benefit fro Epoetin alfa therapy must be established.

The effect of recombinant human erythropoietin on the efficacy of autologous blood donation in patients with low hematocrits: a multicenter, randomized, double-blind, controlled trial.

BACKGROUND: This randomized controlled study was undertaken to determine the effect of recombinant human erythropoietin (rHuEPO) on erythropoiesis, autologous blood collection, and allogeneic transfusion risk in elective surgery patients with low baseline hematocrits. STUDY DESIGN AND METHODS: Patients (n = 204) with low baseline hematocrits ( < or = 39%), scheduled for orthopedic surgery within 25 to 35 days, were seen every 3 to 4 days for 21 days. At each visit, 450 mL of blood was collected if the hematocrit was > or = 33 percent, and rHuEPO (600 U/kg) or placebo was administered intravenously. RESULTS: One hundred seventy-three patients were evaluable. The number of autologous units collected from the rHuEPO and control groups, respectively, was 4.5 +/- 1.0 and 3.0 +/- 1.1 (p < 0.001), and marrow production of red cells increased by 668 +/- 222 and 353 +/- 155 mL over and above baseline production (p < 0.05). Allogeneic blood transfusion was required by 31 percent of control and 20 percent of rHuEPO patients (p = 0.09). Excluding 8 patients who received > 6 units, 29 percent of control and 14 percent of rHuEPO patients required allogeneic blood (p = 0.015). Logistic regression modeling determined that the risk of allogeneic transfusion was reduced by rHuEPO (p = 0.025). CONCLUSION: The use of rHuEPO stimulates erythropoiesis, permits the storage of more autologous blood, and reduces allogeneic transfusion risk in patients with low hematocrits who are undergoing elective orthopedic surgery. Additional studies are necessary to determine the optimal schedules of rHuEPO administration and autologous blood collection as well as the cost-effectiveness of this strategy.

Red cell collection by apheresis technology.

To determine the feasibility of collecting 2 units (450 mL) of red cells per donation by apheresis technology, apheresis red cell collections were compared to whole-blood donations. Forty blood donors were equally divided between the two study arms on the basis of gender and iron supplementation (650 mg ferrous gluconate/day vs. no supplementation). During the 1-year study period, the apheresis participants donated 450 mL of red cells three times, and the whole-blood donors gave 225 mL of red cells (1 unit of blood) on six occasions. There were no reported side effects during the 102 whole-blood donations, whereas symptoms were noted in 83 percent of the 59 apheresis procedures. The most common symptoms were numbness and tingling, which were relieved by a decrease in the plasma-return rate or by the administration of oral calcium supplements. Seven donors dropped out or were deferred during the study. Two whole-blood donors left with medical problems unrelated to the study, one apheresis donor and one whole-blood donor dropped out of the study because of excessive fatigue, and three non-iron-supplemented whole-blood donors had unacceptably low hematocrit levels. By the end of the study, 70 percent of the apheresis donors considered the procedure acceptable, 15 percent were undecided, and 15 percent thought it was not acceptable. As measures of iron balance, the serum ferritin and the red cell zinc protoporphyrin:heme ratios were significantly more abnormal in the non-iron-supplemented donors than in the iron-supplemented donors. However, there were no differences in iron balance according to the donation method.

Strategies to recruit plateletpheresis donors from a registry of HLA-typed, unrelated, bone marrow donors.

Rising demand for single-donor platelet components--from random donors, to maintain platelet inventories, or from HLA-compatible donors, to support alloimmune platelet-refractory patients--necessitated increasing the size of a community plateletpheresis donor registry. This study compares two strategies for recruiting whole-blood donors into a plateletpheresis program. The whole-blood donors who were asked to participate in this study had recently joined an unrelated bone marrow donor registry and had been HLA-typed as part of that process. An in-person recruitment strategy, which was time-intensive for the apheresis donor coordinator, served as the standard. A by-mail strategy involved the mailing of recruitment materials to marrow-donor registry participants. Marrow-donor registry participants were approached about apheresis participation after they had indicated an interest in the plateletpheresis program by returning a tear-off section of an informational brochure that was sent to them along with their marrow-donor registry materials. A total of 852 marrow-donor registry participants were randomly assigned to one of two recruitment strategies, and the recruitment rates were the same (46%) for both methods. In addition, levels of apheresis participation and attrition rates of donors recruited by either strategy were comparable. Thus, the simple strategy of mailing information about a plateletpheresis program is a very cost-effective method of recruiting donors.

Increasing participation of blood donors in a bone-marrow registry.

In an experiment to increase recruitment of unrelated bone-marrow donors, Ss were selected from a list of people who had donated blood within the past 24 months. They were randomly assigned to 3 groups. Members of the experimental group, 2 months before receiving a mailed brochure about a bone-marrow registry, were complimented on being blood donors and asked to complete a self-descriptive questionnaire. One control group received only the mailed brochure, and the other did not receive any mailing. The experimental group joined the registry at over 2 times the control-group rates. These results appear to be attributable to an attitude change associated with being recognized as a special group that contributed to the community's welfare.

The effect of variable environmental arsenic contamination on urinary concentrations of arsenic species.

Urinary arsenic species have been determined for approximately 3000 urine samples obtained from residents of a community surrounding an arsenic-emitting copper smelter. Levels of inorganic, monomethylated and dimethylated arsenic species ranged from less than 1 microgram/L (the instrumental detection limit) to 180 micrograms/L seen for dimethyl arsenic. Comparison of a subsample of this population that had the least environmental contamination with the subsample having highest environmental arsenic concentrations showed small but statistically significant differences in urinary arsenic levels for all species except dimethylated arsenic. However, for children under 7 years of age living in areas with increased environmental arsenic contamination, there was a larger and equally significant (p less than 0.001) increase in all urinary species. This effect was more pronounced in males (5-fold increase in median sum of species concentration over control group) than in females (2-fold increase in median sum of species concentration over control group) and was observed as a weaker effect in the next higher age group (7-13 years of age). Reported consumption of seafood also was significantly related to increased urinary dimethyl arsenic, but changes in distribution among the urinary arsenic species detected was not a sensitive indicator of recent seafood consumption.

Pathways of human exposure to arsenic in a community surrounding a copper smelter.

Several studies have found elevated levels of urinary arsenic among residents living near a copper smelter in Tacoma, Washington. To assess pathways of exposure to arsenic from the smelter, biological and environmental samples were collected longitudinally from 121 households up to 8 miles from the smelter. The concentration of inorganic and methylated arsenic compounds in spot urine samples was used as the primary measure of exposure to environmental arsenic. Urinary concentration of arsenic dropped off to a constant background level within one-half mile of the smelter in contrast to environmental concentrations, which decreased more steadily with increasing distance. Among all age-sex-specific groups in all areas, only children ages 0-6 living within one-half mile of the smelter had elevated levels of arsenic in urine. A separate analysis of data for these children suggests that hand-to-mouth activity was the primary source of exposure. Inhalation of ambient air and resuspension of contaminated soil were not important sources of exposure for children or adults.

A model to determine required pool size for HLA-typed community donor apheresis programs.

Community donor plateletpheresis programs must have adequate numbers of HLA-typed donors to support the transfusion needs of alloimmunized patients, and donor pool size calculations should reflect the fact that each patient needs more than one donor to provide his or her support. The average number of donors needed to provide a patient's support was estimated as a function of donor usage and commitment. A model was developed for determining an appropriate size of the donor pool for a community donor plateletpheresis program that would incorporate the average number of donors needed per patient, the level of HLA compatibility to be maintained between patient and donor, and the frequencies of patient and donor HLA phenotypes. A database of 4338 plateletpheresis transfusions given to 591 patients from a pool of up to 870 community donors over a 3-year period was analyzed retrospectively to validate the estimates of the average number of donors needed to support a patient, which ranged from 4 to 33 donors. This database was also used to illustrate the application of the pool size determination model. Model results suggest that plateletpheresis donor pools of 1000 to 3000 donors are capable of meeting the transfusion needs of most patients at an HLA-match grade of B2 or better.

Double-blind, placebo-controlled trial comparing long-term suppressive with short-term oral acyclovir therapy for management of recurrent genital herpes.

A total of 156 patients with frequently recurring genital herpes were enrolled in a randomized, double-blind, one-year trial comparing long-term suppressive and intermittent oral acyclovir therapy with placebo in the management of recurrent genital herpes. Subjects received either suppressive treatment with acyclovir, 400 mg twice daily for one year, and 200 mg five times per day for five days, for short-term treatment of recurrences; intermittent treatment with placebo, twice daily for one year, and oral acyclovir, 200 mg five times per day for five days, for short-term treatment of recurrences; or treatment with placebo, twice daily for one year, and five times per day for five days for short-term treatment of recurrences. Median time to first recurrence was 250 days for the suppressive group, 28 days for the intermittent group, and 23 days for the placebo group (p = 0.001). The median number of days per month with active disease was 0.32 for the suppressive group, 4.18 for the intermittent group, and 4.72 for the placebo group (p less than 0.001), with a median recurrence rate per 30-day treatment period of 0.08 recurrences/patient in the suppressive group, 0.70 in the intermittent group, and 0.74 in the placebo group (p less than 0.001). Median duration of recurrence was 5.0 days in the suppressive group compared with 6.0 days in the combined intermittent acyclovir plus placebo group (p = 0.001), and was reduced from 7.0 to 6.0 days when intermittent acyclovir treatment was compared with placebo treatment (p = 0.05). Daily administration of oral acyclovir for one year is superior to intermittent or placebo treatment in the management of patients with frequently recurring genital herpes.

Diminished B cell secretory capacity in patients with noninsulin-dependent diabetes mellitus.

In order to assess whether patients with noninsulin-dependent diabetes mellitus (NIDDM) possess normal insulin secretory capacity, maximal B cell responsiveness to the potentiating effects of glucose was estimated in eight untreated patients with NIDDM and in eight nondiabetic controls. The acute insulin response to 5 g intravenous arginine was measured at five matched plasma glucose levels that ranged from approximately 100-615 mg/dl. The upper asymptote approached by acute insulin responses (AIRmax) and the plasma glucose concentration at half-maximal responsiveness (PG50) were estimated using nonlinear regression to fit a modification of the Michaelis-Menten equation. In addition, glucagon responses to arginine were measured at these same glucose levels to compare maximal A cell suppression by hyperglycemia in diabetics and controls. Insulin responses to arginine were lower in diabetics than in controls at all matched glucose levels (P less than 0.001 at all levels). In addition, estimated AIRmax was much lower in diabetics than in controls (83 +/- 21 vs. 450 +/- 93 microU/ml, P less than 0.01). In contrast, PG50 was similar in diabetics and controls (234 +/- 28 vs. 197 +/- 20 mg/dl, P equals NS) and insulin responses in both groups approached or attained maxima at a glucose level of approximately 460 mg/dl. Acute glucagon responses to arginine in patients with NIDDM were significantly higher than responses in controls at all glucose levels. In addition, although glucagon responses in control subjects reached a minimum at a glucose level of approximately 460 mg/dl, responses in diabetics declined continuously throughout the glucose range and did not reach a minimum. Thus, A cell sensitivity to changes in glucose level may be diminished in patients with NIDDM. In summary, patients with NIDDM possess markedly decreased maximal insulin responsiveness to the potentiating effects of glucose. Such a defect indicates the presence of a reduced B cell secretory capacity and suggests a marked generalized impairment of B cell function in patients with NIDDM.