T-cell depletion of allogeneic peripheral blood stem cells

The high content of immunocompetent T-cells in apheresis products may expose recipients of allogeneic peripheral blood stem cells (PBSC) to an elevated risk of acute and chronic graft-versus-host disease (GvHD). Thus, the use of an appropriate T-cell reduction or depletion technique might reduce this risk. The hazards of rejection and of a higher relapse rate should be avoided by maintaining a portion of the T-cells in the graft or by increasing the number of transplanted stem cells. The positive selection of CD34+ cells from peripheral blood preparations simultaneously provides an approximately 1,000-fold reduction of T-cells. Purified CD34+ cells containing committed and pluripotent stem cells are suitable for allogeneic transplantation. In transplantation from HLA-mismatched or three HLA-loci different family donors the amount of stem cells can be increased for reducing the incidence of rejection without increasing the T-cell number. In cases of poor marrow graft function a 'boost' with stem cells from the same family donor can be given. The risk of GvHD in transplantation from volunteer-matched unrelated donors might be reduced by T-cell depletion. If T-cells are used for enhancing the graft-versus-leukaemia effect, CD34+ enriched cells can be given for haematopoietic engraftment.

Glass wool filtration leads to a higher percentage of spermatozoa with intact acrosomes: an ultrastructural analysis

We investigated the possibility of ultrastructural damage to human spermatozoa induced by different sperm preparation techniques. Ejaculates from 20 normozoospermic men were divided into equal aliquots and processed by glass wool filtration, Percoll density gradient centrifugation, and a simple two-step centrifugation procedure which served as a control. The evaluation of 60 spermatozoa from each of 20 test subjects (in all, n = 1200) ensured that a sufficiently large number of spermatozoa were investigated. Ultrastructural damage was assessed by scanning electron microscopy. We investigated the state of the acrosome after sperm preparation and measured the percentage of intact spermatozoal structures compared with that of the control. Compared with Percoll density gradient centrifugation, glass wool filtration yielded a significantly increased proportion of intact acrosomes. However, both preparations gave significantly better results than the control. In conclusion, both glass wool filtration and Percoll centrifugation are efficient techniques for the accumulation of spermatozoa with intact acrosomes. Because of the significantly higher percentage of intact acrosomes, glass wool filtration appears to be the more appropriate method. The significance of the conspicuous bending of sperm tails after Percoll centrifugation is not yet known.

The influence of different erythrocyte lysing procedures on flow cytometric determination of CD34+ cells in umbilical cord blood transplants

Since the correct determination of CD34+ cells is of great clinical importance for successful transplantation with haematopoietic progenitor cells (HPCs) from cord blood, we investigated the influence of different erythrocyte lysing techniques on the quantification of CD34+ cells in umbilical cord blood. Flow cytometric determinations of CD34+ cells were performed from 20 cord blood samples, using three different erythrocyte lysing procedures and two monoclonal CD34 antibodies (n = 360). Flow cytometric analysis showed characteristic patterns of the forward (FSC) and side (SSC) scatter light properties for the leucocyte subsets for each of the investigated erythrocyte lysing procedures, indicating that these reagents cause different morphological changes on leucocytes. Furthermore, significant differences of CD34+ cell counts were obtained for identical samples using different lysing techniques (P = 0.001 and P = 0.002). In some cases, a more than 100% difference was found comparing different erythrocyte lysing procedures. In contrast, the determination of CD34+ cells by two CD34 antibodies showed a good reproducibility without significant differences between both antibodies for each of the erythrocyte lysing techniques. We conclude that the erythrocyte lysing procedure represents a very critical and important step for accurate determination of CD34+ cells in whole blood samples. Especially for the quantification of HPCs in cord blood transplants, this influence may be of high clinical relevance.

Anaphylaxis during autologous peripheral blood progenitor cell infusion

Anaphylaxis has been reported in subjects receiving peripheral blood precursor cell (PBPC) infusions; however the etiologic agent is unclear. Basophils from a PBPC-allergic subject were challenged with each individual component of the stem cell infusion and with recombinant human (rh)DNAse. Histamine release data were compared with those using basophils from control subjects. Histamine release assays were repeated using basophils from a control subject passively sensitized with serum IgE from the patient. Skin testing with bovine DNAse was performed using standard techniques. Basophil histamine release occurred in the patient, but not in controls, with bovine DNAse. No release could be provoked by any of the other components of the infusate; no release could be detected with rhDNAse. Sensitivity to bovine DNAse could be transferred to basophils from a control subject with the serum IgE from the patient. Marked epicutaneous skin test reactivity to bovine DNAse was evident in the patient, but not in control subjects. We conclude that systemic reactions during peripheral blood precursor cell infusions may represent true IgE-mediated anaphylaxis to bovine DNAse in the infusate. Skin testing can detect such sensitivity, and the use of rhDNAse may obviate such reactions.

Analysis of the flow cytometer stain Hoechst 33342 on human spermatozoa

Several procedures exist for processing sperm cells for sex preselection. Flow cytometric separation using the fluorochrome stain Hoechst 33342, chemically known as bisbenzimide, is the most promising. The objective of this study was to determine the effect of bisbenzimide on spermatozoa assessed by means of the sperm survival test and to analyse the beta-globin gene in sperm DNA after exposure to increasing concentrations of bisbenzimide. Donor (n = 16) sperm specimens were pooled and washed in a discontinuous Percoll gradient 95:47%, divided and incubated in tubes containing bisbenzimide at concentrations 0 (control), 0.9, 9, 90, 900 and 9000 microM at 25 degrees C and scanned on a computer-aided sperm motility analyser at 0, 1, 4 and 24 h. Spermatozoa were also incubated in a known mutagen, ethidium bromide, as positive control. After 24 h of incubation, the treated sperm cells were processed through DNA extraction and polymerase chain reaction (PCR) performed with primers targeting the beta-globin gene. The amplified DNA products were analysed for evidence of mutation in 5% polyacrylamide gel electrophoresis and 20:80 denaturing gradient gel electrophoresis (DGGE) and further confirmed in 30:40 DGGE. The results showed complete cessation of motility in sperm incubated in the presence of 900 microM or higher concentrations of bisbenzimide. The beat cross frequency sperm parameter was significantly different at the 90 microM or higher concentration of bisbenzimide compared with the control. At concentrations < 900 microM bisbenzimide, there were no differences in the remaining sperm kinematic parameters (percentage rapid progressive, percentage total progressive, sperm velocities, linearity, straightness, amplitude of lateral head displacement and percentage hyperactive motility). PCR and DGGE analyses of spermatozoa treated with bisbenzimide showed no evidence of mutation in the representative region of the beta-globin gene at concentrations < 900 microM. The data suggest an inhibitory effect of bisbenzimide on human sperm motility at 900 microM or higher concentrations of bisbenzimide. The decrease in sperm motility and rapid progression were not due to changes in pH. Point mutation in the representative region of the beta-globin gene in human spermatozoa was detected only at high concentrations (> or = 900 microM) of bisbenzimide. The data suggest that incubating sperm in low concentrations of bisbenzimide (< 90 microM) for up to 24 h does not significantly affect all the sperm kinematic parameters including the beat cross frequency parameter when compared with the control.

Altered expression of cytochrome P-450 mRNAs, and potentially of other transcripts encoding key hepatic functions, are triggered during the isolation of rat hepatocytes

The abundance of 12 cytochrome P-450 (CYP) mRNAs was quantified in the caudate lobe of rat livers before dissociation of the organ into single cells by perfusion with 0.025% (w/v) collagenase. Comparison of the initial abundance of CYP-1A1, -1A2, -2A subfamily, -2B1/2, -2C7, -2C11, -2D subfamily, -2E1, -3A1/2 and -4A1 transcripts in the caudate lobe of the intact liver with the values found in freshly isolated hepatocytes demonstrated that the relatively brief (1 h) cell isolation and washing procedures routinely caused 2-3-fold increases in the mRNAs encoding CYP-1A2, -2B1/2, -3A1/2, and -4A1, concomitant with a 50% decline in CYP2C11 mRNA. Further changes in the expression of CYP mRNAs occurred when the hepatocytes were cultured. Thus CYP1A1 mRNA, which is not constitutively expressed in rat liver, became detectable in hepatocytes cultured for 1 h, and after 6 h CYP3A1/2 mRNA levels began to increase. In contrast, levels of all other CYP mRNAs studied had declined after 24 h of culture concomitant with the loss of total cytochrome P-450 content. Culture of hepatocytes with 0.5 mM metyrapone (which prevents the loss of total P-450 content) increased CYP1A1 and CYP3A1/2 mRNA levels still further, such that after 72 h of culture these transcripts were conservatively 10-18-fold higher than in hepatocytes prior to culture. This suggests that these two isoenzymes comprise the bulk of the total cytochrome P-450 content maintained by metyrapone. Collectively, these results demonstrate that the technique commonly used to isolate rat hepatocytes alters hepatic gene expression, as illustrated by the elevation of the mRNAs encoding CYP-1A2, -2B1/2, -3A1/2 and -4A1, and that such perturbations are exacerbated during culture under standard conditions by the loss of the constitutive CYP2C11 and the precocious induction of CYP1A1 and CYP3A1/2 mRNAs.

A comparison of the transient hyperprolactinaemic stress response obtained using two different methods of analgesia for ultrasound-guided transvaginal oocyte retrieval

Transient hyperprolactinaemia has been shown to accompany the procedure of oocyte retrieval under laparoscopic control. This study was concerned with establishing whether transvaginal oocyte retrieval was also associated with hyperprolactinaemia and whether the hyperprolactinaemic response was dependent on the method of anaesthesia/analgesia employed. Two distinct patterns were recorded. Oocyte retrieval under general anaesthesia was accompanied by a rapid rise in prolactin levels, which peaked after 40 min. Oocyte retrieval under intravenous sedation was associated with a slow rise in circulating prolactin concentrations. Significant differences in the prolactin rise between the general anaesthesia and sedation groups appeared within 10 min of the start of the procedure. It is concluded that although the surgical stress of oocyte recovery is associated with mild transient hyperprolactinaemia, most of the hyperprolactinaemic response is due to the anaesthetic.

Plateletapheresis program. I. Donor recruitment and commitment

A dedicated cytapheresis donor program was developed to meet the need for granulocytes and single-donor platelets. A study was undertaken to determine the most effective way to recruit a panel of 500 HLA-typed committed volunteer cytapheresis donors. Factors analyzed included ease of donor recruitment, information necessary to assure donor commitment, rate and reasons for donor attrition, and donor reaction to participation in the program. Audiovisual educational materials were tested as a part of the recruitment process in terms of both motivating volunteer donors and guaranteeing their continued participation. Over a 16-month interval, 793 repeat donors of whole blood expressed an interest in joining the program. A simple brochure was enough to stimulate the majority of these donors (661 or 83%) to consider participation. Overall, 481 (61%) joined the program and were HLA typed. Of these, 311 (65%) required no additional information other than a brief phone exchange to answer questions. The remaining 170 (35%), at their request, received further structured education prior to enrollment. Actual participation in cytapheresis procedures was the major factor that maintained donor enthusiasm. Only 66 (16%) of the donors left the program during the first year; the majority were unable to participate because of circumstances beyond their control.

Health risks to cytapheresis donors

Platelets and granulocytes collected by cytapheresis techniques are recognized as drugs by the US Food and Drug Administration. Though potentially life-saving, like all drugs or therapeutic modalities they have many side-effects, and untoward reactions occur in recipients. However, unlike any other class of drug, cytapheresis products cause untoward and occasionally serious reactions in humans during their preparation. Since the only source for these medications is healthy, human blood donors we should be doubly certain that we use them with care and for very specific indications. Primum non nocere--first, do no harm--is an old and valuable medical axiom , and it applies to our blood donors as well as to our patients. Careful review of our use of these products and intelligent monitoring of appropriate medical and laboratory data in our donors are absolute necessities that we owe to our patients and our various publics . To do less reduces medical practice to mere technology, a state of affairs already too commonplace.