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Biomedical subjects

B Speck

Publications and source records attributed to B Speck.

At least 19 recordsLinked to original sources

T-cell depletion of bone marrow transplants for leukemia from donors other than HLA-identical siblings: advantage of T-cell antibodies with narrow specificities.

T-cell depletion of donor marrow decreases graft-versus-host disease resulting from transplants from unrelated and human leukocyte antigen (HLA)-mismatched related donors. However, there are diverse strategies for T-cell-depleted transplantation, and it is uncertain whether any improve leukemia-free survival (LFS). To compare strategies for T-cell-depleted alternative donor transplants and to compare T-cell depleted with non-T-cell-depleted transplants, we studied 870 patients with leukemia who received T-cell-depleted transplants from unrelated or HLA-mismatched related donors from 1982 to 1994. Outcomes were compared with those of 998 non-T-cell-depleted transplants. We compared LFS using different strategies for T-cell-depleted transplantation considering T-cell depletion technique, intensity of pretransplant conditioning, and posttransplant immune suppression using proportional hazards regression to adjust for other prognostic variables. Five categories of T-cell depletion techniques were considered: narrow-specificity antibodies, broad-specificity antibodies, Campath antibodies, elutriation, and lectins. Strategies resulting in similar LFS were pooled to compare T-cell-depleted with non-T-cell-depleted transplants. Recipients of transplants T-cell depleted by narrow-specificity antibodies had lower treatment failure risk (higher LFS) than recipients of transplants T-cell depleted by other techniques. Compared with non-T-cell-depleted transplants (5-year probability +/- 95% confidence interval [CI] of LFS, 31% +/- 4%), 5-year LFS was 29% +/- 5% (P = NS) after transplants T-cell depleted by narrow-specificity antibodies and 16% +/- 4% (P <.0001) after transplants T-cell depleted by other techniques. After alternative donor transplantation, T-cell depletion of donor marrow by narrow-specificity antibodies resulted in LFS rates that were higher than those for transplants T-cell depleted using other techniques but similar to those for non-T-cell-depleted transplants. (Blood. 2000;95:3996-4003)

Adolescent↗

Treatment of solid tumors following allogeneic bone marrow transplantation.

Second solid tumors are well known late complications after bone marrow transplantation. Treatment strategies are ill defined. We retrospectively evaluated treatment and outcome in a single institution. From August 1974 to July 1996, six solid tumors were observed in five of 387 patients 2 to 13 years after BMT, corresponding to a probability of developing a second solid tumor of 9% (1-17%, 95 CI) at 15 years: these comprised endometrial carcinoma, carcinoma of the thyroid gland, cervical carcinoma, sarcoma of the small intestine, osteosarcoma of the tibia and ovarian carcinoma. All five patients were treated as intensively as they would be without a history of BMT. At last follow-up four of the five patients were alive and without signs of tumor. We postulate that second solid tumors after BMT should be treated as de novo tumors. Early detection based on consequent clinical follow-up of the transplant patients might explain the relatively good outcome.

Adenocarcinoma↗

High incidence of transiently appearing complement-sensitive bone marrow precursor cells in patients with severe aplastic anemia--A possible role of high endogenous IL-2 in their suppression.

In a prospective long-term study on the incidence of paroxysmal nocturnal hemoglobinuria (PNH), 115 consecutive patients with severe aplastic anemia (SAA), 97 treated with antilymphocyte globulin (ALG) and 18 with bone marrow transplantation (BMT), were observed over a period of 4-18 years and tested for the presence of complement-sensitive hematopoietic precursor cells with the bone marrow (BM) sucrose test. Sixteen (14%) of the ALG-treated patients developed clinical signs of PNH between 0.5 and 8 years after treatment. Complement-sensitive BM precursors were found in 89% of the SAA patients at some time during their disease, but in none of 18 normal donors. At diagnosis, their proportion was significantly higher in patients who later developed PNH than in patients who later achieved disease-free complete remission (CR). After ALG, the abnormal population was found in both groups, but it was gradually replaced by normal precursors in remission patients. After BMT, the complement-sensitive population decreased to very low numbers in patients with a stable graft, but increased again in 3 patients upon graft rejection. Mimicking the PNH defect by enzymatic removal of glycosyl-phosphatidylinositol (GPI)-linked proteins from CD34+ cells resulted in their complement sensitivity, suggesting that the BM sucrose test identifies precursor cells carrying the PNH defect. In 66 patients, white blood cells (WBC) in peripheral blood (PB) were examined for GPI-deficient populations by flow cytometry (FACS). Ten patients with signs of clinical or laboratory PNH had over 25% complement-sensitive precursor cells in the BM and a GPI-deficient WBC population in the PB. Of 56 SAA patients without PNH, 8 had an abnormal population detectable with both tests, 26 only with the BM sucrose test, 4 only with PB FACS analysis, and in 18, no abnormal cells were detected with either test. In search for parameters which might explain why in some patients the abnormal population expands, while it regresses or disappears in others, we tested the release of IL-2 as a parameter of immune competence. At diagnosis, IL-2 release was approximately 50% of normal in patients who later developed PNH, while it was double the normal value in patients who later achieved CR. We conclude that the majority of SAA patients transiently harbor complement-sensitive precursor cells in the BM. Patients with more than 25% abnormal BM precursors and low endogenous IL-2 release are at risk of progression to clinical PNH.

Anemia, Aplastic↗

[Optimizing plasma cell content in bone marrow aspirates].

Bone marrow samples used for flow cytometric analysis of plasma cells frequently provide a low plasma cell content. Regularly, samples used for flow cytometry are provided by second step aspiration while the first aspirate is used for cytologic examination. We investigated whether the use of secondary aspirates leads to a systematic underestimation of the bone marrow plasma cell content as a consequence of an increased blood contaminant. To test the hypothesis, plasma cell (CD38bright) percentages were established by flow cytometry in 13 pairs of primary/secondary aspirates. In all cases we found lower plasma cell contents in secondary as compared to primary aspirates (p = 0.0015). Median plasma cell counts in secondary aspirates were 57% lower compared to primary aspirates. We conclude that the use of secondary aspirates leads to systematic underestimation of the bone marrow plasma cell content.

Bone Marrow↗

[Immunophenotype of blast crisis in chronic myeloid leukemia].

The blast crisis in chronic myeloid leukaemia (CML) is morphologically well defined. The aim of this report was to analyze whether immunophenotyping can divide CML blast crises into subtypes as is done in acute de novo leukaemia, and whether a specific CML pattern exists. Between 1991 and 1997 we reevaluated all the immunophenotypes of patients with CML blast crises with special regard to immunological subclassification, expression of CD34, presence of aberrant markers and number of immunological clusters. Twenty-nine CML blast crises were analyzed. Seventeen were myeloid, 11 lymphoid and one biphenotypic. The blast crises were divided into subtypes as de novo acute leukaemias: of the 17 myeloid blast crises 6 were undifferentiated, 5 differentiated and 6 had monocytic differentiation. In the lymphoid blast crises there were no pro-B, 8 common-B and 3 mature-B. No T-lymphoid blast crises were observed. In 26/29 analyses (90%) CD34 was expressed in the blasts. In 17/29 analyses (59%) one or two aberrant markers were found. In summary, immunophenotyping is important in distinguishing between myeloid and lymphoid blast crises. A subclassification, as in acute leukaemias, is possible. We found no specific immunophenotypic CML pattern. A study directly comparing immunophenotyping of CML blast crises with acute de novo leukaemia is planned.

Adolescent↗

Repeated treatment with horse antilymphocyte globulin for severe aplastic anaemia.

In a single-centre study the feasibility and efficacy of repeated antilymphocyte globulin (ALG) for patients with severe aplastic anaemia (SAA) not responding to an initial ALG treatment or relapsing after initial response to ALG was evaluated. 139 consecutive patients with newly diagnosed SAA were treated with ALG between 1976 and 1995. 89 patients responded to a first course; 50 patients did not become transfusion independent. Of the 89 responders, 66 remained in remission, 23 relapsed. 43 patients received a second or subsequent course of ALG for failure to respond (n = 25) or relapse (n = 18) and were given a total of 53 courses. Acute reactions in the multiply exposed patients occurred during the first ALG treatment in 11 (26%) and during subsequent exposures in 16/53 courses (30%; P > 0.2). Incidence of serum sickness was 63% (27/43) after the initial course compared to 57% (30/53) after subsequent courses (P > 0.2), but clinical signs of serum sickness occurred earlier after repeated (median 6 d) as compared to initial exposure (13d; P = 0.008). Transfusion-independent haemopoiesis was achieved in 27/43 (63%) and survival probabilities for the 43 patients receiving multiple courses of ALG was 52 +/- 8% at 10 years. The probability of developing a late clonal disorder was 53 +/- 10% after multiple, as compared to 34 +/- 7% after single exposure (P = 0.15). No difference in results was observed between patients retreated for failure to first ALG or for relapse. ALG of the same species can be repeated without increased risks of side-effects in patients with SAA. A second or subsequent course of ALG from the same source can be effective when the first course has failed.

Adolescent↗

Bone marrow transplantation for severe aplastic anemia: has outcome improved?

Bone marrow transplants for severe aplastic anemia were first performed in the 1970s. Transplant regimens, supportive care, and patient selection have changed substantially since then. Our objective was to determine the impact of these changes on transplant outcome. We studied 1,305 recipients of HLA-identical sibling transplants for aplastic anemia between 1976 and 1992, reported to the IBMTR by 179 centers. We compared survival of transplants performed in three intervals (1976 through 1980 [n = 186], 1981 through 1987 [n = 648], and 1988 through 1992 [n = 471]) using Cox proportional hazards regression. Five-year survival (+/-95% confidence interval) increased from 48% +/- 7% in the 1976-1980 cohort to 66% +/- 6% in the 1988-1992 cohort (P < .0001). Risks of graft-versus-host disease (GVHD) and interstitial pneumonia decreased over time, but the risk of graft failure did not. Higher long-term survival resulted primarily from decreased mortality in the first 3 months posttransplantation. Late mortality risks were low and changed little over the intervals studied. In multivariate analysis, changes in transplantation strategies accounted for most but not all of the improved outcome. Use of cyclosporine to prevent GVHD was the most important factor. Changes in patient selection did not seem to explain improved survival. Survival after HLA-identical sibling bone marrow transplantations for aplastic anemia has improved since 1976. Changes in GVHD prophylaxis account for much of this improvement. Other changes may also operate.

Age Factors↗

Celiac disease transmitted by allogeneic non-T cell-depleted bone marrow transplantation.

We observed the occurrence of celiac disease following allogeneic bone marrow transplantation in a patient transplanted for acute leukemia. The marrow donor was his HLA-identical sister, who had suffered from celiac disease since birth. The post-transplant period was characterized by recurrent episodes of diarrhea. Detailed workup showed atrophic intestinal mucosa on histology and anti-gliadin and anti-endomysium antibodies in the serum, features that were not present before transplantation. GVHD was absent at that time. The patient remains free of symptoms on gluten-free diet and slight immunosuppression. This case suggests transmission of celiac disease by bone marrow transplantation and supports the T cell concept in celiac disease.

Acute Disease↗

Survival of patients with chronic myelogenous leukaemia relapsing after bone marrow transplantation: comparison with patients receiving conventional chemotherapy.

Treatment with busulphan and/or hydroxyurea rarely produces remission in patients with chronic myelogenous leukaemia (CML) in chronic phase. HLA-identical sibling transplants almost always produce remission, and only about 20% of patients relapse post-transplant. The increased anti-leukaemic efficacy of transplants results from intensive pretransplant treatment and immune-mediated anti-leukaemia effects. We studied 433 patients surviving > or = 2 years after diagnosis of CML to determine if patients who have relapsed after a transplant in chronic phase have longer survival from diagnosis than comparable subjects receiving chemotherapy. The chemotherapy cohort included 344 adults < 50 years of age treated on consecutive trials of the Italian Cooperative Study Group on CML between 1973 and 1986. The transplant cohort included 89 patients reported to the International Bone Marrow Transplant Registry who relapsed after an HLA-identical sibling bone marrow transplant carried out between 1978 and 1992. Survivals in the two groups were compared using Cox proportional hazards regression to adjust for prognostic variables. Median survival was 65 months in the chemotherapy cohort and 86 months in the transplant cohort. The 7-year probability (95% confidence interval) of survival was 34% (28-39%) in the chemotherapy cohort and 57% (43-70%) in the transplant cohort (P=0003). There was no difference in survival of patients relapsing after T-cell depleted and non-T-cell-depleted transplants. We conclude that patients who relapse after an HLA-identical sibling bone marrow transplant for CML in chronic phase have longer survival from diagnosis than comparable patients receiving chemotherapy. This effect is most likely to be the result of intensive chemotherapy and/or radiation given for pretransplant conditioning.

Adolescent↗

Flt3 ligand level reflects hematopoietic progenitor cell function in aplastic anemia and chemotherapy-induced bone marrow aplasia.

Flt3 ligand (flt3L) is a member of a small family of cytokines acting as tyrosine kinase receptor ligands that stimulate the proliferation of primitive hematopoietic progenitors in vitro. To gain insight into the physiological role of flt3L in early hematopoiesis, levels of flt3L were determined in serum of patients with multilineage bone marrow failure and related to the severity of stem cell depletion. In patients with aplastic anemia (AA) and in cancer patients with chemotherapy-induced transient suppression of hematopoiesis, flt3L fluctuated in an inverse relationship to the degree of bone marrow failure. In severe AA at diagnosis, levels of circulating soluble flt3L were highly elevated (2,653 +/- 353 pg/mL) as compared with normal blood serum values of 14 +/- 39 pg/mL. Flt3L returned to near normal levels within the first 3 months following successful bone marrow transplantation and in autologous remission induced by immunosuppressive therapy with antilymphocyte globulin (ALG; 100 +/- 31 and 183 +/- 14 pg/mL, respectively). In contrast, rejection of the graft or relapse of the disease after ALG was accompanied by an increase to high pretreatment concentrations of the circulating cytokine (3,770 +/- 2,485 and 1,788 +/- 233 pg/mL, respectively). Flt3L in serum inversely correlated with the colony-forming ability of AA bone marrow precursors in vitro (R = -.86), indicating that the concentration of the ligand reflects hematopoiesis at the progenitor cell level. Flt3L increased to 2,500 pg/mL in the serum of leukemia patients during chemoradiotherapy-induced bone marrow suppression and returned to normal values along with hematopoietic recovery. Expression of the membrane-bound form of flt3L was significantly elevated in mononuclear bone marrow and peripheral blood cells from patients with severe pancytopenia, suggesting de novo synthesis of the factor in response to bone marrow failure. The data provide a strong argument for the involvement of flt3L in the regulation of early hematopoiesis in vivo.

Anemia, Aplastic↗

Outbreak of invasive mycoses caused by Paecilomyces lilacinus from a contaminated skin lotion.

BACKGROUND: Invasive mycoses are an important cause of illness and death in immunocompromised patients. Infections with molds other than aspergilli have been increasingly seen in patients with hematologic cancers, but epidemics of these infections have not yet been reported. OBJECTIVE: To describe an outbreak of invasive mycoses with Paecilomyces lilacinus in severely neutropenic patients. DESIGN: An outbreak investigation. SETTING: The hematology-oncology isolation and bone marrow transplantation unit of the University Hospital, Basel, Switzerland. PATIENTS: 25 consecutive patients admitted between 17 August 1993 (the date of the first manifestation of P. lilacinus infection) and 31 October 1993 (when the unit was closed). MEASUREMENTS: Clinical and microbiological data, including histologic findings; cultures from several patient sites; and environmental examinations of potential airborne, parenteral, enteric, and horizontal routes of transmission. Infections were defined by the isolation of P. lilacinus from clinically evident skin eruptions. RESULTS: 12 of the 25 patients (48%) were infected or colonized. Nine patients (36%), including all bone marrow transplant recipients, had documented invasive P. lilacinus infections. All 9 infected patients had papular, pustular, or necrotic skin eruptions. Two patients with severe graft-versus-host disease died with refractory fungal disease; 1 also had microbiologically documented endophthalmitis and kidney infiltrates. Seven affected patients no longer had P. lilacinus after recovery of bone marrow function. The organism was resistant in vitro to amphotericin B, itraconazole, and fluconazole. Patients did not respond clinically to these agents. The outbreak was ultimately traced to a contaminated, commercially available, pharmaceutically prepared skin lotion. The outbreak ended after the skin lotion was recalled and has not recurred after a follow-up period of 2 years. CONCLUSION: Contaminated skin lotion is a potential cause of opportunistic fungal infections in immunocompromised hosts. Paecilomyces lilacinus is a common saprophytic mold that can cause, by direct cutaneous inoculation, invasive infections associated with illness and death.

Adolescent↗

[Oral All-transretinoic acid administration in intubated patients with acute promyelocytic leukemia].

In acute promyelocytic leukemia (APL), disseminated intravascular coagulation is frequently observed. Massive alveolar bleeding can lead to respiratory insufficiency, requiring tracheal intubation and mechanical ventilation. Today all-transretinoic acid (ATRA) is part of induction chemotherapy in acute promyelocytic leukemia. The administration of ATRA is oral. No intravenously administered form is available. ATRA can be administered to intubated patients in the following manner: the daily amount of ATRA is placed in a sterile 50 ml tube. After addition of about 20 ml of sterile water the tube is heated in a waterbath to a temperature of 37 degrees C until the capsules melt and the suspension is completely liquid. The resulting oily fluid is then administered via nasogastric tube. We have treated 2 patients with acute promyelocytic leukemia intubated due to massive alveolar bleeding in this manner, and have observed a differentiation of promyelocytes to granulocytes and complete remission in both patients, indicating that the ATRA administered had been resorbed intestinally.

Adolescent↗

[Bernard-Soulier thrombocytopenia: clinical significance of a rare disorder].

We present 5 cases with thrombocytopenia and abnormal platelet function. The diagnosis of Bernard-Soulier syndrome was suspected in some subjects of advanced age on the ground of morphologic changes in the thrombocytes and of low platelet counts with or without prolonged bleeding time. The platelets showed normal aggregation with adrenalin, ADP and collagen but abnormal agglutination with ristocetine. All patients had normal von Willebrand factor levels in plasma. Flow cytometry demonstrated on thrombocytes lack of GP Ib expression of varying degree in comparison to normal controls, using various anti-GP Ib-antibodies (CD42b). The combination of these findings confirmed the diagnosis of Bernard-Soulier syndrome with varying expression of GP Ib. Flow cytometry and the use of specific monoclonal antibodies may be a rapid and reliable diagnostic tool. Differential diagnosis and treatment strategies are discussed. A congenital thrombopathy should always be considered in patients with thrombocytopenia of unknown origin and abnormal platelet morphology.

Adult↗

[Transplantation of allogeneic peripheral hematopoietic progenitor cells instead of bone marrow].

In a pilot study we tested the feasibility and safety of peripheral blood precursor cells instead of bone marrow cells for allogeneic transplantation. 13 patients, 7 male and 6 female between 24 and 52 years of age with hematological malignancies (10 with acute leukemias, 3 with myeloproliferative syndromes-were conditioned for bone marrow transplantation with VP-16, cyclophosphamide and total body irradiation followed by graft-versus-host disease prophylaxis with cyclosporin and methotrexate. Precursor cells were mobilized in the donors by granulocyte colony stimulating factor (G-CSF, Neupogen) 10 micrograms/kg s.c. from day-5 on. A total of 14.05 x 10(8) nucleated cells/kg recipient body weight (range 9.52-20.23 x 10(8)/kg), corresponding 6.82 x 10(6)/kg CD 34+ cells (range 1.43-15.84 x 10(8)/kg) or 113.9 x 10(4) CFU/kg (range 45.15-431.64 x 10(4)/kg) were collected by 3 phereses (1 patient 5 phereses) of 27-45 liters and infused without further manipulation. All patients engrafted with a recovery of total white blood cell count > 1 x 10(9)/l on day 15 (day 10-26) and of platelets > 20 x 10(9)/l on day +18 (day 12-39). 11 of the 12 patients developed aGvHD, 8 with grade II, 3 with grade > or = II. 9 of 13 patients are alive and well +4 to +16 months posttransplant, 3 patients died of aGvHD, one of veno-occlusive disease. These preliminary results confirm the capacity of peripheral blood precursor cells for rapid and complete engraftment in the allogeneic setting. Whether they induce more or equal aGvHD is an open question. Their value in allogeneic transplantation is currently under investigation in prospective randomized trials.

Adult↗

[Autologous transplantation of hematopoietic precursor cells following CD34 selection].

Peripheral blood is increasingly used instead of bone marrow as a source of hemopoietic precursor cells for transplantation. The optimal technique still needs to be defined. Selection of CD34+ cells in transplant material may be of benefit in allogeneic and autologous peripheral blood precursor cell transplantation (PBPCT), since it allows elimination of unwanted CD34-negative cells, such as T-cells and contaminating tumor cells. We have evaluated the feasibility of CD34 selection in PB transplants and studied hemopoietic reconstitution after autologous transplantation of CD34 selected precursor cells. Between August 1994 and June 1995 CD34 selection was performed on 12 transplants for 9 patients with malignant disease (non-Hodgkin lymphoma [n = 5]; Ewing sarcoma [n = 1]; chronic lymphocytic leukemia [n = 1]; breast cancer [n = 1]; multiple myeloma [n = 1]). PBPC were collected with a Fenwall CS 3000 harvester after stimulation with G-CSF. For selection of CD34+ cells the Ceprate LC34 system (CellPro) was used. A median CD34 purity of 73% (range 40-94%) was achieved. The median number of CD34 positive cells per transplant was 4.8 x 10(6)/kg body weight (range 0.7-15.8). The median number of colony forming cells per transplant was 31 x 10(4)/kg body weight (range 1.5-131.3). For autologous PBPCT the minimal number of CD34 positive cells required in the transplantate was arbitrarily set at 1.0 x 10(6)/kg body weight. This number was achieved in 10 of the 12 transplants. The median loss of CD34+ cells during selection was 1.5 x 10(6)/kg body weight (range 0.2-6.4). In 2 patients the total number was reduced to below the critical value of 1.0 x 10(6)/kg. 7 of the 9 patients received the CD34 selected transplant after intensive chemotherapy and irradiation. The median follow-up time after PBPCT was 196 days (range 62-278). All 7 patients are now alive and with normal hemopoietic function. A granulocyte count above 0.5 x 10(9)/l and a platelet count above 20 x 10(9)/l was achieved on day 14 (median), and on day 19 after PBPCT. We conclude that CD34 selection is technically feasible and that CD34 selected cells can be used for PBPCT. The procedure is time consuming and expensive; it requires complex organization at laboratory level, and the benefit of CD34 selection with regard to T-cell depletion and tumor purging still needs to be proven. However, CD34+ selection is likely to open new perspectives in transplantation medicine.

Adolescent↗

Severe neutropenia in T-large granular lymphocyte leukemia corrected by intensive immunosuppression.

Optimum treatment of severe neutropenia, a major factor for morbidity and mortality in T-large granular lymphocyte (LGL) leukemia, is undefined. We observed a rapid improvement of the neutrophil count in a patient with T-LGL leukemia and severe neutropenia after the combined administration of antilymphocyte-globulin (ALG), cyclosporin A, prednisone, and granulocyte colony-stimulating factor (G-CSF). Although G-CSF treatment was terminated after 7 days, the neutrophil count has persisted above 1.0 x 10(9)/1 for up to 6 months now. Oral methotrexate is given continuously as treatment for T-LGL leukemia. The response to this immunosuppressive regimen suggests a T-cell-mediated mechanism as the underlying cause for neutropenia in T-LGL leukemia.

Humans↗

Splenectomy as an adjuvant measure in the treatment of severe aplastic anaemia.

The role of splenectomy in aplastic anaemia (AA) is controversial. The hazards of operating on a severely pancytopenic patient, the fear of compromising the patient's immune function, and the improvement of non-surgical treatment have made splenectomy unpopular in this disease. We have evaluated positive and adverse effects of splenectomy in 80 patients with severe aplastic anaemia (SAA) treated with antilymphocyte globulin (ALG) (group A), using 52 nonsplenectomized ALG patients as controls (group B). All patients survived the operation. Nonfatal complications of surgery occurred in 10 (12.5%). Splenectomy induced a significant increase of peripheral blood neutrophils, reticulocytes and platelets within 2 weeks, followed by a continuous increase of all values over the following weeks. 28/132 patients (21%) developed a late clonal disorder of haemopoiesis, paroxysmal nocturnal haemoglobinuria (PNH) or myelodysplastic syndrome (MDS), or both. Their incidence was identical in groups A and B. 13/28 (59%) died, 10/17 (59%) in group A and 3/11 (27%) in group B (not significant (n.s.)). Overall probability of survival at 18 years after ALG was 51+/-6% for group A and 61+/-7% for group B (n.s.). We conclude that splenectomy in AA is safe. It induces an immediate increase of peripheral blood counts and, thereafter, a continuous improvement of haemopoiesis. It does not increase the incidence of late clonal complications but has a borderline effect on mortality from these disorders. Splenectomy should be reconsidered in selective nontransplanted patients who have prolonged transfusion requirements despite otherwise optimal treatment.

Adolescent↗