Prevalence of baseline hypocalcemia and symptomatic hypocalcemia during leukapheresis.

Symptoms of hypocalcemia are reported in up to 50% of patients undergoing leukapheresis procedures. There is no set standard of practice for administering calcium supplementation in the prevention or treatment of hypocalcemia symptoms. The goal of this descriptive, retrospective study was to determine the prevalence of baseline hypocalcemia and symptomatic hypocalcemia during leukapheresis with acid citrate dextrose solution A and to identify patient characteristics associated with symptomatic hypocalcemia. Three percent of patients were found to have hypocalcemia before leukapheresis with 35% experiencing hypocalcemia symptoms during leukapheresis. Older age, higher albumin levels, and longer procedure time were associated with increased risk of hypocalcemia symptoms.

An alternative procedure to leukapheresis for peripheral hematopoietic progenitor cell collection in very-low-weight children: A single pediatric center experience.

BACKGROUND: PBSC collection using a blood cell separator in very low weight patients can be frequently complicated by severe adverse effects and technical difficulties. MATERIAL AND METHODS: From March 2013 to January 2017, 14 PBSC collections were performed in 12 children weighing less than 10 kg, affected by different solid tumours. PBSC collection was performed with a "homemade" aseptically assembled circuit. The circuit is composed by a 150 mL collection bag connected with a 4 stopcock ramp, perfused with ACD. This circuit allows collection of a specific total blood amount from CVC, depending on CD34+ /kg target. RESULTS: Mean CD34+ cell performance per collection was 9.3 × 106 /kg. Tolerance to the procedure was very good as none of the patients experienced complications, with the exception of a patient who showed mild cyanosis and pallor after collection. Moreover, no bleeding or thrombotic complications have been observed. To date, 16 PBSC reinfusions have been performed in 7 children with a mean CD34+ cells viability of 98.1% ± 2.7 and mean WBC viability of 57% ± 10. Cell recovery after thawing was 87% ± 10.8. A rapid graft intake for both neutrophils and platelets, between day 7 and 20 after reinfusion was observed. DISCUSSION: The procedure of total blood collection without the use of a cell separator is feasible and allows a good PBSC collection without significant side effects in very low-weight children. Moreover, this method could represent a valid and safe alternative to leukapheresis in patients where classic procedure could be difficult to apply.

Leukocytapheresis Therapy for Rheumatoid Arthritis: Results Compared with Control Trial.

CONTEXT: Rheumatoid arthritis (RA) is a chronic multisystem autoimmune disease, mainly characterized by synovitis and with symmetrical joint involvement. LCAP therapy for RA patients has been shown to be safe and efficacious in some developed countries for over a decade. OBJECTIVE: The study intended to evaluate the efficacy and safety of leukocytopheresis (LCAP) for treatment of rheumatoid arthritis (RA) and to study the influence of treatment on the levels of various serum cytokines. DESIGN: The study was a nonblinded, nonrandomized, controlled trial. SETTING: The study took place in the Department of Rheumatology and Immunology at Beijing Hospital at the National Center of Gerontology in Beijing, China. PARTICIPANTS: Participants were 51 patients with RA at the hospital with a 28-joint disease activity score (DAS28) exceeding the 3.20 needed to fulfill the classification criteria of the American College of Rheumatology (ACR). INTERVENTION: Participants were divided into 2 groups. One group (intervention group) received LCAP therapy (n = 20), while the control group (n = 31) received disease-modifying antirheumatic drugs (DMARDs). Patients receiving the LCAP therapy were treated using a Cellsorba column every 5 days for a total of 5 treatments. OUTCOME MEASURES: Clinical assessment of participants' symptoms included: (1) a tender-joint count, (2) a swollen-joint count, (3) erythrocyte sedimentation rates (ESR), (4) C-reactive protein levels (CRP), (5) a visual analog scale (VAS) for pain, (6) the DAS28 C-reactive protein (DAS28-CRP) scores, and the Health Assessment Questionnaire Disability Index (HAQ-DI). The study also evaluated participants' scores for the American College of Rheumatology (ACR) Core Data Set. Serum collected before and after therapy from both groups was analyzed for the levels of bradykinin, serotonin, heat shock protein 70, human CXC-chemokine ligand 16 (CXCL16), prostaglandin E2, and macrophage inflammation protein 1α. RESULTS: At week 4 for participants receiving the LCAP therapy, ACR20, ACR50, and ACR70 were observed in 55%, 30%, and 20% of patients, respectively, compared to 19.4%, 3.2%, and 0% for patients in the control group (P < .05). Also, at week 24 of LCAP therapy, ACR20, ACR50, and ACR70 were observed in 70%, 50%, and 30% of patients, respectively, which was significantly higher than the 25.8%, 12.9%, and 3.2% of patients in the control group (P < .05). The serum levels of CXCL16 and serotonin were significantly reduced in the LCAP group compared with control group. CONCLUSIONS: This study indicated that LCAP therapy can significantly decrease RA disease activity and is a safe and effective alternative therapy. LCAP therapy significantly reduced serum CXCL16 and serotonin levels, offering a putative mechanism by which it improves the articular symptoms of RA.

Treatment options for children and adolescents with inflammatory bowel disease: is granulomonocytapheresis an effective alternative to drug therapy?

INTRODUCTION: Patients with inflammatory bowel diseases (IBD) require life-long medications, which even if effective have the potential to cause adverse effects as additional morbidity factors. In pediatric patients, drug therapy has more serious limitations, including impaired physical and mental development. A non-drug therapeutic option is believed to be depletion of elevated and activated granulocytes and monocytes known to release inflammatory cytokines, like the CD14+CD16+ monocyte phenotype known to release tumor necrosis factor-α. Areas covered: Granulomonocyteapheresis (GMA) with an Adacolumn as a treatment option for IBD patients has been applied for the past 15 years. This article reviews the argument that GMA is a relevant and effective non-pharmacologic intervention in pediatric IBD setting. Expert commentary: GMA with an Adacolumn has shown promise in adult, pediatric, and adolescent patients with active IBD. There is evidence of post-GMA immunomodulation in terms of increased regulatory T-cell and B-cell activities. Additionally, patients who respond to GMA may attain a favorable long-term clinical course by avoiding pharmacologicals during an early phase of their active IBD. GMA has a good safety profile, especially in difficult-to-treat and pediatric settings. An additional trial is warranted to assess the efficacy of GMA in the early phase of pediatric IBD to optimize patient selection.

Therapeutic plasma exchange performed in tandem with hemodialysis without supplemental calcium in the apheresis circuit.

Therapeutic plasma exchange (TPE) and hemopoietic progenitor cell (HPC) collection are apheresis procedures that can safely be performed in tandem with hemodialysis. Despite the return of citrate-anticoagulated blood to the patient during HPC collection, it is not necessary to administer supplemental calcium during these procedures because the ionized calcium concentration is restored as the returning blood passes through the dialyzer. It is not known whether this applies to TPE, in which a mixture of blood and pharmaceutical albumin, an avid binder of plasma ionized calcium, is returned to the patient through the dialyzer. We report on three dialysis-dependent patients who required TPE and underwent tandem treatments without supplemental calcium in the apheresis circuit. Overall, ionized calcium fell 4-12% (P = 0.0.024) and patients reported no symptoms of hypocalcemic toxicity. Tandem hemodialysis/TPE can be performed without supplemental calcium in the apheresis circuit. J. Clin. Apheresis 32:154-157, 2017. © 2016 Wiley Periodicals, Inc.

Bradykinin and cysteinyl leukotriene concentrations in cell-salvaged blood before and after passage through negatively charged filters during clinical use in cancer patients: a pilot study.

It has been suggested that giving cell-salvaged blood through a leucocyte depletion filter can cause hypotension due to bradykinin released when factor XII and platelets are activated by the negatively charged surface of the filter. We measured the concentration of bradykinin and cysteinyl leukotrienes in cell-salvaged blood sampled before and after passage through a negatively charged leucodepletion filter in 24 consecutive patients with gynaecological or bowel cancer undergoing elective surgery with cell salvage. In no case was an increase in bradykinin concentration observed after passage through the filter; in 23 patients the post-filtration bradykinin concentration was zero (p = 0.007). The change in the concentration of cysteinyl leukotrienes detected during passage across the filter was not statistically significant (p = 0.1). Our findings do not support the suggestion that either bradykinin or cysteinyl leukotrienes are generated in cell-salvaged blood during passage through leucodepletion filters.

Increased risk of citrate reactions in patients with multiple myeloma during peripheral blood stem cell leukapheresis.

The citrate based anticoagulant ACD is commonly used in apheresis procedures. Due to its ability to decrease ionized calcium, citrate may cause unpleasant symptoms, such as paresthesias and muscle cramps, in patients undergoing therapeutic and donor apheresis. We noticed that patients with multiple myeloma (MM) undergoing autologous stem cell leukapheresis appeared to have more citrate reactions when compared to other patients undergoing the same procedure. A retrospective chart review was performed to evaluate 139 (of 151) consecutive patients with MM, amyloidosis, hematological and solid malignancies who had autologous peripheral blood stem cell collection between January 2007 and February 2008. Citrate reactions, ranging from mild (e.g., perioral tingling and parasthesias) to severe (e.g., nausea/vomiting and muscle cramps) were noted for 35 patients. Twenty-three of 63 patients with MM had documented citrate reactions, which was significantly higher than those with other hematological and solid malignancies (37% vs. 20%; P < 0.05, Relative Risk (RR) = 1.9). The severities of citrate reactions were the same in both groups; approximately 50% of patients in each group received i.v. calcium gluconate for treatment of hypocalcemia. No correlation between bisphosphonate therapy and citrate reactions were noted in our study group. Examination of available laboratory values related to calcium homeostasis, liver, and renal function failed to reveal a mechanism for the increase in citrate reactions observed. In summary, this single institution retrospective study indicates that patients with MM are more sensitive to citrate-induced hypocalcemia during leukapheresis when compared to patients with other hematological and solid malignancies. Strategies for decreasing citrate reactions (e.g., supplemental calcium and slowing return rates) should be considered for patient safety and comfort, especially in the MM population, on a prophylactic rather than reactive basis.

Severe hypotension related to cell salvaged blood transfusion in obstetrics.

SUMMARY: Intra-operative blood cell salvage has recently been adopted for use in women at risk of significant haemorrhage during caesarean section. It has also been advocated for use in those patients who refuse allogenic blood transfusion. A 37-year-old pregnant woman (gravida 3, para 2) underwent an elective lower segment caesarean section at 36 weeks for an anterior, major placenta accreta (grade 4). The volume of cell salvaged blood collected during the procedure was 1870 ml. On starting the cell-salvaged blood transfusion, the blood pressure was noted to fall and this was temporally related to the transfusion of the cell-salvaged blood. We review the recent literature and case reports on hypotension related to cell-salvaged blood transfusion.

Acute hypotension associated with leucocyte depletion filters during cell salvaged blood transfusion.

Summary Intra-operative cell salvage is used in more than 75% of NHS hospitals in the United Kingdom and is a safe and cost effective alternative to allogenic blood transfusion. We report a case of acute hypotension during reinfusion of cell salvaged blood through a leucocyte depletion filter that occurred during a caesarean section. We review the literature of hypotension associated with the use of bedside leucocyte depletion filters.

Fotoféresis / Photopheresis

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Fotoféresis extracorpórea en Dermatología / Extracorporeal Photopheresis in Dermatology

La fotoquimioterapia extracorpórea o fotoféresis es una terapia inmunomoduladora que combina la leucoféresis con la fototerapia. Después de la separación de un plasma rico en leucocitos, se administra ex vivo un fotosensibilizante junto con radiación ultravioleta A y posteriormente se reinfunde en el paciente. El mecanismo de acción exacto de la fotoféresis no se conoce completamente, aunque se piensa que la inducción de apoptosis de linfocitos y la formación de células dendríticas desempeña un papel fundamental en el desarrollo de una respuesta inmunológica contra las células patógenas. Esta terapia se utilizó inicialmente para el tratamiento del linfoma cutáneo de células T. Desde entonces, basándose en su eficacia y seguridad, se ha empleado en múltiples patologías tanto cutáneas como no cutáneas, con resultados variables. Los distintos centros han utilizado diferentes criterios de selección de pacientes, pautas de tratamiento y protocolos de monitorización, lo que podría contribuir a la diferencia de resultados (AU)

Extracorporeal photochemotherapy or photopheresis is an immunomodulatory therapy that combines leukapheresis with phototherapy. Blood from the patient is processed to give a leukocyte-rich plasma, which is then treated ex vivo with a photosensitizer and ultraviolet A radiation before reinfusion back into the patient. The exact mechanism of action of photopheresis has not been fully elucidated although it is thought that induction of leukocyte apoptosis and formation of dendritic cells is essential for the development of an immune response to pathogenic cells. Extracorporeal photophoresis was initially used for treating cutaneous T-cell lymphoma. Since then, in view of its efficacy and safety, it has been used in a number of cutaneous and noncutaneous diseases with uneven results, which can in part be explained by the different patient selection criteria, therapy regimens, and follow-up protocols used in different hospitals (AU)

Leucocyte filtration of salvaged blood during cardiac surgery: effect on red blood cell function in concentrated blood compared with diluted blood.

OBJECTIVE: Leucocyte filtration of salvaged blood has been suggested to prevent patients from receiving activated leucocytes during auto-transfusion in cardiac surgery. This study examines whether leucocyte filtration of salvaged blood affects the red blood cell (RBC) function and whether there is a difference between filtration of the concentrated and diluted blood on RBC function. METHODS: Forty patients undergoing cardiac surgery with cardiopulmonary bypass were randomly divided into a group receiving leucocyte filtration of concentrated blood (High-Hct, n=20) and another group receiving leucocyte filtration of the diluted blood (Low-Hct, n=20). During operation, all the salvaged blood, as well as the residual blood, from the heart-lung machine was filtered. In the High-Hct group, blood was concentrated with a cell saver prior to filtration, whereas in the Low-Hct group, blood was filtered without concentration. RBC function was represented by RBC aggregation and deformability measured by a laser-assisted optical rotational cell analyser and by the RBC 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) contents with conventional biochemical tests. RESULTS: Leucocyte filtration of diluted blood with a low haematocrit (14+/-4%) did not affect RBC function. However, when the concentrated blood with a high haematocrit (69+/-12%) was filtered, there was a reduction of ATP content in RBCs after passing through the filter (from 1.45+/-0.57 micromol g(-1) Hb to 0.92+/-0.75 micromol g(-1) Hb, p<0.05). For patients who received the concentrated blood, their in vivo RBC function did not differ from those who received diluted blood. CONCLUSIONS: Leucocyte filtration of the diluted salvaged blood during cardiac surgery does not affect RBC function, but it tends to deplete the ATP content of RBCs as the salvaged blood has been concentrated prior to filtration.

Recovery and safety profiles of marrow and PBSC donors: experience of the National Marrow Donor Program.

The National Marrow Donor Program (NMDP) has been facilitating hematopoietic cell transplants since 1987. Volunteer donors listed on the NMDP Registry may be asked to donate either bone marrow (BM) or peripheral blood stem cells (PBSC); however, since 2003, the majority of donors (72% in 2007) have been asked to donate PBSC. From the donor's perspective these stem cell sources carry different recovery and safety profiles. The majority of BM and PBSC donors experienced symptoms during the course of their donation experience. Pain is the number 1 symptom for both groups of donors. BM donors most often reported pain at the collection site (82% back or hip pain) and anesthesia-related pain sites (33% throat pain; 17% post-anesthesia headache), whereas PBSC donors most often reported bone pain (97%) at various sites during filgrastim administration. Fatigue was the second most reported symptom by both BM and PBSC donors (59% and 70%, respectively). PBSC donors reported a median time to recovery of 1 week compared to a median time to recovery of 3 weeks for BM donors. Both BM and PBSC donors experienced transient changes in their WBC, platelet, and hemoglobin counts during the donation process, with most counts returning to baseline values by 1 month post-donation and beyond. Serious adverse events are uncommon, but these events occurred more often in BM donors than PBSC donors (1.34% in BM donors, 0.6% in PBSC donors) and a few BM donors may have long-term complications. NMDP donors are currently participating in a randomized clinical trial that will formally compare the clinical and quality-of-life outcomes of BM and PBSC donors and their graft recipients.

Placebo-controlled study of intravenous magnesium supplementation during large-volume leukapheresis in healthy allogeneic donors.

BACKGROUND: Marked decreases in ionized magnesium (iMg) levels occur during large-volume leukapheresis (LVL); however, the effect of intravenous (IV) magnesium supplementation in this setting has not been carefully studied. STUDY DESIGN AND METHODS: Thirty healthy allogeneic peripheral blood progenitor cell donors receiving citrate anticoagulant with IV calcium prophylaxis were randomized to receive either IV magnesium (0.2 mg Mg per mL acid citrate dextrose-A) or placebo during LVL, with a double-blind design. RESULTS: Thirty subjects underwent 75 LVL pro- cedures, 37 with magnesium and 38 with placebo. Group characteristics were similar for sex, weight, citrate infusion rate (1.36 mg/kg/min vs. 1.37 mg/kg/min), and volume processed (16 L vs. 17 L). Serum iMg levels remained within the reference range with magnesium supplementation, but decreased 39+/-11 percent below baseline (p<10(-10)) after placebo, with greater decreases after consecutive procedures. Subjects receiving magnesium had more vigorous parathyroid hormone responses and higher glucose levels and also tended to have higher serum potassium and ionized calcium levels. Mild paresthesias, coldness, and nausea occurred in 28, 20, and 7 percent of donors, respectively, with no significant differences between groups. Severe symptoms (chest tightness) occurred in only one subject receiving placebo. CONCLUSION: IV magnesium supplementation exerts a significant impact on serum magnesium levels, but does not reduce the frequency or severity of the relatively mild citrate-related effects observed in LVL performed with continuous IV calcium prophylaxis.

Adacolumn for selective leukocytapheresis as a non-pharmacological treatment for patients with disorders of the immune system: an adjunct or an alternative to drug therapy?

Inflammatory and/or autoimmune diseases like ulcerative colitis (UC) or Crohn's disease (CD) are debilitating chronic disorders that poorly respond to pharmacological interventions. Further, drug therapy has adverse effects that add to disease complications. The current thinking is that disorders like inflammatory bowel disease (IBD) reflect an over exuberant immune activation driven by cytokines including TNF-alpha. Major sources of cytokines include myeloid leukocytes (granulocytes, monocytes/macrophages), which in IBD are elevated with activation behavior and are found in vast numbers within the inflamed intestinal mucosa. Accordingly, myeloid cells should be the targets of therapy. Adacolumn is filled with cellulose acetate beads that selectively adsorb and deplete myeloid cells and a small fraction of lymphocytes (FcgammaR and complement receptors bearing cells). In one study, 20 steroid naive patients with moderate (n = 14) or severe (n = 6) UC according to Rachmilewitz despite 1.5-2.25 g/day of 5-aminosalicylic acid received 6 to 10 Adacolumn sessions at 2 sessions/week. Efficacy was assessed 1 week after the last session. The majority of patients responded to 6 sessions, 17 (85%) achieved remission. In 2 of the 3 non-responders, CAI was 8 and 12 in 1; all 3 had deep colonic ulcers at study initiation. Decreases were seen in total leukocytes (P = 0.003), % neutrophils (P = 0.003), % monocytes (P = 0.004), an increase in lymphocytes (P = 0.001), decreases in C-reactive protein (P = 0.0002), and rises in blood levels of soluble TNF-alpha receptors I (P = 0.0007), II (P = 0.0045). In a separate study, a case with very severe steroid refractory UC who received up to 11 sessions responded well and avoided colectomy. Further, myeloid cell purging with Adacolumn has been associated with the release of IL-1 receptor antagonist, suppression of TNF-alpha, IL-1beta, IL-6, IL-8, down-modulation of L-selectin and the chemokine receptor CXCR3. In conclusion, selective depletion of myeloid cells appears to induce anti-inflammatory effects and represents a non-pharmacological treatment for patients with active IBD. The treatment has a clear drug-sparing role. Changes in blood levels of inflammatory and anti-inflammatory factors are thought to contribute to the efficacy of this procedure.

Granulocytapheresis is useful as an alternative therapy in patients with steroid-refractory or -dependent ulcerative colitis.

BACKGROUND: Recently, granulocyte and monocyte adsorption apheresis (GCAP) has been shown to be safe and effective for active ulcerative colitis (UC). We analyzed the safety and efficacy of GCAP (G-1 Adacolumn) in patients with steroid-refractory and -dependent UC. G-1 Adacolumn is filled with cellulose acetate carriers that selectively adsorb granulocytes and monocytes/macrophages. METHODS: Forty-four patients with UC were treated with GCAP. These patients received 5 apheresis sessions over 4 weeks. Twenty patients had steroid-refractory UC (group 1) and 10 had steroid-dependent UC (group 2). Fourteen patients who did not want readministration of steroids were treated with GCAP at the time of relapse, just after discontinuation of steroid therapy (group 3). RESULTS: Of 44 patients treated with GCAP, 24 (55%) obtained remission (CAI < or = 4), 9 (20%) showed a clinical response, and 11 (25%) remained unchanged. Only 2 of 10 patients (20%) with severe steroid-refractory UC (CAI > or = 12) achieved remission, whereas 7 of 10 patients (70%) with moderate steroid-refractory UC achieved remission (p < 0.05). The dose of corticosteroids was tapered in 9 of 10 (90%) patients with steroid-dependent UC after GCAP therapy. Twelve (86%) of 14 patients in group 3 showed an improvement in symptoms and could avoid re-administration of steroids after GCAP. No severe adverse effects occurred. CONCLUSIONS: The findings of this study suggest that GCAP may be a useful alternative therapy for patients with moderate steroid-refractory or -dependent UC, although cyclosporin A or colectomy is necessary in patients with severe UC. GCAP may also be useful for avoiding re-administration of steroids at the time of relapse. Randomized, controlled clinical trials are needed to confirm these findings.

Extracorporeal monocyte granulocytapheresis was effective for a patient of erythema nodosum concomitant with ulcerative colitis.

We report an erythema nodosum (EN) patient whose condition became apparent during the clinical course of ulcerative colitis (UC). The patient relapsed frequently in spite of taking a high dose adrenocortical steroid during his morbidity period of UC. Monocyte-granulocytapheresis (M-GCAP) was combined with 5-aminosalicylic acid 2250 mg/day peroral and once a day of steroid enema. Monocyte-granulocytapheresis was performed once a week for 5 weeks, and succeeded in inducing clinical remission for both UC and EN. The immunological and clinical connections between UC and EN have never been fully elucidated. In this case, because the symptoms of UC and EN revealed parallel improvement after his inflammatory reaction had been brought under control by combining M-GCAP therapy, we hypothesize that the onset of EN appeared as a result of the patient's long-term, treatment-resistant immuno-disturbance, which first appeared as symptoms of UC. Immunomodulative effects induced by M-GCAP might help to control other chronic non-specific inflammations not concerned with targeted organ(s).

Autologous blood cell transplantation in multiple myeloma: impact of CD34+ cell selection with long follow-up.

Positive CD34(+) selection to purge blood cell harvests is one way to attempt to reduce the high relapse risk after high-dose chemotherapy (HDT) supported by autologous blood cell transplantation (ABCT) in patients with multiple myeloma (MM). Until recently, however, the impact of CD34(+) selection, if any, on long-term clinical outcome in MM has remained obscure. We have analyzed engraftment kinetics, response to HDT, progression-free survival (PFS), and overall survival (OS) for 64 consecutive MM patients who have been treated with up-front HDT plus ABCT at our institution between 1993 and 1998. Nonrandomized comparisons were made between transplants with unselected (39 patients) and CD34(+)-selected (25 patients) grafts. The engraftment kinetics, need of blood product support, discharge time from hospital, and response to HDT were similar for both unselected and selected transplants. The median PFS was also similar (26 and 30 months, respectively) for the both groups. With a median follow-up time for the survivors of 67.5 months, the median OS (78 and 75 months, respectively) did not differ between transplants with unselected and selected grafts. In conclusion, this nonrandomized study suggests that positive CD34(+) selection has no beneficial impact on long-term outcome of patients with MM.

High-dose melphalan with G-CSF-stimulated whole blood rescue followed by stem cell harvesting and busulphan/cyclophosphamide with autologous stem cell transplantation in multiple myeloma.

In 90 consecutive patients with multiple myeloma, we investigated the feasibility of administering a tandem high-dose therapy regimen, using whole blood for rescue after the first and leucapheresis harvested between the two high doses, for rescue after the second high dose. After 5 days of G-CSF 1 litre of whole blood (WB) was obtained, left undisturbed at 4 degrees C and reinfused 24 h after HDM (140 mg/m(2)). Patients not in progression after 3-6 months were again mobilised, leucapheresed and treated with busulphan 16 mg/kg and cyclophosphamide 120 mg/kg (Bu/Cy) and reinfusion. In 90 patients, WB contained a mean (range) of 0.57 (0.02-3.22) x 10(6)/kg CD34(+) cells. Recovery after HDM was in 13 days for granulocytes and in 18 days for platelets, with 11 patients not recovering within 3 months. There were three toxic deaths. Sixty-six patients qualified for harvesting after HDM. In the first 11, marrow was harvested. The subsequent 55 patients were mobilised and in 45 the preset minimum of 1.5 x 10(6) CD34(+) cells was obtained. Forty-nine patients actually received Bu/Cy. Recovery after Bu/Cy and marrow reinfusion was in 35 days for granulocytes and 20 days for platelets, with two of five patients not recovering after 3 months. After Bu/Cy and leucapheresis reinfusion, recovery was in 17 days for granulocytes and in 34 days for platelets. Nine patients did not recover within 3 months. There were four toxic deaths. The median overall survival from diagnosis for patients receiving HDM was 49 months and for patients also receiving Bu/Cy, 84 months. We conclude that WB rescue after HDM followed by leucapheresis and a second transplant is feasible in the majority of patients. Better mobilisation techniques are required to increase the number of patients who can receive the second transplant.

The "vanishing counting bead" phenomenon: effect on absolute CD34+ cell counting in phosphate-buffered saline-diluted leukapheresis samples.

BACKGROUND: Using a single-platform protocol to count absolute CD34+ hematopoietic precursor cell (HPC) levels with different reference microbeads, we recorded occasionally artifactually high CD34+ HPC counts in some leukapheresis bags, whereas dual-platform calculations were always consistent. Abnormal countings were observed only when phosphate-buffered saline (PBS)-diluted leukapheresis samples were vortexed before analysis. A large series of blood samples analyzed similarly for CD34+ and CD4+ absolute counts did not show any sample or vortexing effect. With the volumetric absolute counting cytometer Partec-PAS, lower counts were also observed when different reference beads were vortexed before the instrument checking procedures. The counting abnormality was caused by a drop in microbead concentration (the "vanishing bead phenomenon"). This phenomenon reduced the total and relative bead event number in experimental and routine samples and in calibration procedures. This altered the bead denominator used to calculate absolute CD34+ HPC levels and it also reduced the concentration of standard calibration beads. METHODS: Using the Partec-PAS to measure volumetrically the actual bead concentration, we studied the vanishing bead phenomenon. Different types of counting and reference microbeads were resuspended in media with or without proteins or cells. Replicates were submitted either to gentle manual mixing or to vortexing before counting. RESULTS: Vortex agitation almost invariably induced the vanishing bead phenomenon when beads were resuspended in saline media or when an insufficient protein concentration was present, such as in diluted leukapheresis samples. Different bead types showed various degrees of sensitivity to vortexing. The bead disappearance was not caused by bubble formation or disruption. The addition of small amounts of protein completely prevented the vanishing bead phenomenon. The causative effect of the electrostatic charging of tube induced by vortexing is hypothesized. CONCLUSIONS: Sample suspensions containing counting beads for single-platform analysis must be resuspended in media with protein supplements to prevent the vanishing bead phenomenon and to ensure accurate counting.