Nonmyeloablative stem cell transplantation for the treatment of cancer and life-threatening nonmalignant disorders: past accomplishments and future goals.

Allogeneic bone marrow transplantation (BMT) or blood stem cell transplantation represents an important therapeutic tool for the treatment of otherwise incurable malignant and nonmalignant diseases. Until recently. autologous and allogeneic BMT or mobilized blood stem cell transplantation was used primarily to replace a malignant, genetically abnormal, or deficient immunohematopoietic compartment, and therefore highly toxic myeloablative regimens were considered mandatory for eradication of all undesirable host-derived hematopoietic elements. Our preclinical and ongoing clinical studies have indicated that more effective eradication of host immunohematopoietic system cells could be achieved by adoptive allogeneic cell therapy with donor lymphocyte infusion following BMT. Thus eradication of blood cancer cells, especially in patients with chronic myelogenous leukemia and less frequently in patients with other hematologic malignancies, can frequently be achieved despite complete resistance of such tumor cells to the maximum tolerated doses of chemoradiotherapy. Our cumulative experience suggests that graft vs leukemia (GVL) effects might be a useful tool for eradication of otherwise resistant tumor cells of host origin. Based on the cumulative clinical experience and experimental data in animal models of human diseases, it appears that induction of host vs graft tolerance as the first step may allow durable engraftment of immunocompetent donor lymphocytes, which may be used for induction of effective biologic warfare against host-type immunohematopoietic cells that need to be replaced, whether they are malignant, genetically abnormal, or self-reactive. Based on this rationale, we speculate that the therapeutic benefit of BMT may be increased by using safer conditioning as part of the transplantation procedure, with the goal of inducing host vs graft tolerance to enable subsequent induction of GVL, possibly graft vs tumor, or even graft vs autoimmunity effects, rather than attempting to eliminate host cells with hazardous myeloablative chemoradiotherapy. Our hypothesis suggests that effective BMT procedures might be accomplished without lethal conditioning of the host, using new, well-tolerated nonmyeloablative regimens, possibly minimizing immediate and late side effects related to myeloablative procedures. Recent clinical data suggest that effective BMT procedures may be accomplished with nonmyeloablative stem cell transplantation (NST) regimens, with no major toxicity. Thus new NST approaches may make BMT procedures safer for a spectrum of clinical indications in children and elderly individuals without lower or upper age limits, while minimizing procedure-related toxicity and mortality. Our cumulative data suggest that high-dose chemotherapy and radiation therapy may be successively replaced by more effective alloreactive donor lymphocytes, thus setting the stage for innovative therapeutic procedures with safer and more effective treatment of patients requiring BMT.

Non-myeloablative stem cell transplantation and donor lymphocyte infusion for the treatment of cancer and life-threatening non-malignant disorders.

Allogeneic bone marrow or blood stem call transplantation (BMT) represents an important therapeutic tool for the treatment of otherwise incurable malignant and non-malignant diseases. Until recently, autologous and allogeneic bone marrow and mobilized blood stem cell transplantations were used primarily to replace malignant, genetically abnormal or deficient immunohematopoietic compartments, and therefore highly toxic myeloablative regimens were considered to be mandatory for the effective eradication of all undesirable host-derived hematopoietic elements. Our preclinical and ongoing clinical studies have indicated that much more effective eradication of the host immunohematopoietic system cells can be achieved by adoptive allogeneic cell therapy with donor lymphocyte infusion following BMT. Thus, eradication of blood cancer cells, especially in patients with chronic myeloid leukemia and, less frequently, in patients with other hematologic malignancies, can frequently be accomplished despite the complete resistance of such tumor cells to maximally tolerated doses of chemoradiotherapy. Our cumulative experience has suggested that graft-vs.-leukemia (GVL) effects might be a useful tool for the eradication of otherwise resistant tumor cells of host origin. Based on the cumulative clinical experience and experimental data in animal models of human diseases, it appears that the induction of host-vs.-graft tolerance as an initial step may allow the durable engraftment of donor immunocompetent lymphocytes, which may be used for the induction of effective biologic warfare against host-type immunohematopoietic cells that need to be replaced, including malignant, genetically abnormal or self-reactive cells. Based on the aforementioned rationale, we speculated that the therapeutic benefit of BMT may be improved by using safer conditioning as part of the transplant procedure, with the goal being to induce host-vs.-graft tolerance to enable subsequent induction of GVL, possibly graft-vs.-tumor or even graft-vs.-autoimmunity effects, rather than attempting to eliminate host cells with hazardous myeloablative chemoradiotherapy. This hypothesis suggested that effective BMT procedures could be accomplished without lethal conditioning of the host, using new well-tolerated non-myeloablative regimens, thus possibly minimizing immediate and late side-effects related to the myeloablative procedures until recently considered to be mandatory for the conditioning of BMT recipients. Recent clinical data presented in this review suggest that effective BMT procedures may be accomplished with well-tolerated non-myeloablative stem cell transplantation (NST) regimens, with no major toxicity. Thus, new NST approaches may offer the feasibility of safer BMT procedures for a large spectrum of clinical indications in children and elderly individuals, without lower or upper age limits, while minimizing procedure-related toxicity and mortality. Taken together, our data suggest that high-dose chemotherapy and radiation therapy may be successfully replaced by a more effective biologic tool, alloreactive donor lymphocytes, thus setting the stage for innovative therapeutic procedures for safer and more effective treatment of patients in need of BMT.

Cyclosporin A in the treatment of refractory immune thrombocytopenia purpura in children.

Patients with refractory autoimmune thrombocytopenia do not respond to standard therapy with high-dose corticosteroids, intravenous immunoglobulin, and splenectomy. We describe the cases of two patients with refractory autoimmune thrombocytopenia treated with oral cyclosporin A (CsA) to evaluate the efficacy of this alternative therapy. Blood pressure and hepatic and renal function were in the normal range before initiation of treatment. Induction therapy with pulses of high-dose methylprednisolone was used for 3 consecutive days to improve the initial immune suppression. Gradual dose reduction of CsA, according the platelet count, minimized the long-term adverse effects of CsA. Oral CsA with pulses of high-dose methylprednisolone induced remission of the thrombocytopenia. Gradual weaning of CsA over months, according the platelet count, produced no observable adverse effects of the CsA. Rapid dose reduction caused thrombocytopenia, which resolved with higher dosages of CsA. Our cases show the efficacy of CsA for refractory immune thrombocytopenia. This therapeutic option with oral CsA as an additional salvage option may avoid splenectomy and the adverse effects of long-term corticosteroids. Larger clinical investigations are necessary to establish the indications and therapeutic regimen for CsA in immune thrombocytopenia.

Immunotherapy of relapsed resistant chronic myelogenous leukemia post allogeneic bone marrow transplantation with alloantigen pulsed donor lymphocytes.

Allogeneic cell-mediated immunotherapy with donor lymphocyte infusion (DLI) can successfully reverse chemoradiotherapy-resistant relapse in patients with chronic myeloid leukemia treated by allogeneic bone marrow transplantation (BMT). We describe the first successful attempt in 1992 to treat DLI-resistant relapse in a patient with CML in full hematologic relapse, using immunized donor lymphocytes. Donor lymphocytes were pulsed in vitro with a mixture of irradiated peripheral blood lymphocytes (PBL) obtained from both parents, in order to trigger alloactivation of donor lymphocytes against host alloantigens presented by parental cells, using as stimulating cells maternal PBL expressing the shared maternal haplotype and paternal PBL expressing the shared paternal haplotype of the patient. Full hematologic, cytogenetic and molecular remission was induced for the first time, independently of GVH, and has persisted for more than 9 years. To the best of our knowledge, this report represents the first successful immunotherapy with donor lymphocytes activated against host-type antigens. We suggest that immune donor PBL may be superior to DLI, possibly effective even when all other modalities fail, perhaps even independently of GVHD.

Effective preventive central nervous system therapy with extended triple intrathecal therapy and the modified ALL-BFM 86 chemotherapy program in an enlarged non-high risk group of children and adolescents with non-B-cell acute lymphoblastic leukemia: the Israel National Study report.

BACKGROUND: Preventive cranial radiotherapy (CRT) in childhood acute lymphoblastic leukemia (ALL), although effective, may be associated with neurologic sequelae and second malignancies. Attempts to replace CRT with intensified intrathecal therapy (IT) have shown promise in lower risk subgroups. In the Israel National Study (INS) 89 trial, the efficacy of extended triple IT (TIT) alone for cranial prophylaxis in an enlarged non-high risk group (Non-HRG) was assessed in the context of a modified ALL-Berlin-Frankfurt-Munster (BFM) systemic chemotherapy program. METHODS: Non-HRG patients included the standard-risk group (SRG) and the risk group (RG), as defined in ALL-BFM 86. In the INS 89 protocol, all Non-HRG patients were treated with extended TIT x 18 times and systemic therapy based on the BFM 86 protocol, with the addition of etoposide x 4 times. The HRG patients, classified according to BFM 86 criteria, were treated with the BFM 90 HRG protocol including CRT. RESULTS: A total of 250 patients were enrolled. At a median follow-up of 58 months (range, 2-8.5 years), the overall 5-year event free survival (EFS) was 73.5% +/- 3% (standard error ¿SE), and the cumulative central nervous system (CNS) recurrence rate was 4.3% +/- 1.4% (SE) (isolated, 2.3%; combined, 2%). Of the 220 eligible children, 189 (86%) were in the Non-HRG group, and their 5-year EFS was 77.8% +/- 3% (SE). The cumulative CNS recurrence rate for patients without CNS disease at presentation was 3.1% +/- 1% (SE) (isolated, 1.7%; combined, 1.4%). Within the risk subsets defined by the BFM 86 of the Non-HRG, the 5-year EFS rates of the RG (148 patients) and the SRG (41 patients) were 74.8% +/- 4% (SE) and 89.5% +/- 5% (SE), respectively, and the rates of CNS recurrence (isolated and combined) were 4% and 0%, respectively. For the HRG (31 patients), the 5-year EFS and CNS recurrence rates were 47.9% +/- 9% (SE) and 8. 5% +/- 6% (SE), respectively. CONCLUSIONS: Early extended TIT therapy in the context of modified BFM 86 systemic chemotherapy was found to provide adequate CNS protection and systemic leukemia control in patients with non-high risk ALL. However, no benefit for etoposide could be proven in this study.

Engraftment of marrow allografts treated with Campath-1 monoclonal antibodies.

We have analyzed the factors associated with engraftment in 216 recipients of T-cell depleted allogeneic HLA identical sibling marrow transplants using Campath 1 monoclonal antihuman lymphocyte (CD52) antibodies. The patient population consisted of 168 patients with hematologic malignancies, 26 with severe aplastic anemia (SAA), and 22 with hemoglobinopathies, half of whom received marrow treated in vitro with Campath-1M (IgM) and half received marrow with Campath-1G (IgG2b isotype). Patients with durable engraftment had fast hematopoietic recovery: SAA patients reached ANC > 0.5 x 10(6)/L on Day 14; those with leukemia attained ANC > 0.5 x 10(6)/L on Days 18, 17, and 15 for ANLL, ALL and CML respectively, while patients with thalasemia reached ANC > 0.5 x 10(6)/L on Day 21. Overall, 24 patients (17 with leukemia, 4 with SAA, and 3 with thalassemia) suffered graft failure: 10 patients (all grafted with Campath-1M) rejected their grafts, while 14 others (9 grafted with Campath-1M, and 5 with 1G isotype) never engrafted (p = 0.009). Multivariate analysis revealed that neither pretransplant protocol, nor stage of disease or type of antibody used, donor sex and ABO match had any impact on engraftment. The variables favorably associated with engraftment were older age (p = 0.030, RR = 1.016) and CFU-GM number (p = 0.013, RR = 1.001). Patients with ANLL or SAA had a better chance to engraft (p = 0.027, RR = 1.400; and p = 0.003, RR = 2.677, respectively) compared to patients with thalassemia (p = 0.001, RR = 0.551). A higher concentration of Campath-1 antibody in vitro and in vivo adversely affected engraftment. Our data show that satisfactory engraftment can be achieved in patients transplanted with Campath-1 treated marrow allografts. However, despite the measures undertaken to prevent rejection, graft failure still poses a problem. Further pretransplant immunosuppression and perhaps more selective T-cell depletion may reduce the increased graft failure in these patients.

The role of thiotepa in allogeneic bone marrow transplantation for genetic diseases.

Graft-versus-host disease (GVHD), graft rejection, disease recurrence and long-term toxicity remain significant obstacles to successful allogeneic bone marrow transplantation (BMT) in children with genetic diseases. In an attempt to improve results, we used a preparative regimen consisting of three alkylating agents, busulfan (BU), thiotepa (TTP) and cyclophosphamide (CY), for T cell-depleted allogeneic bone marrow transplantation instead of the conventional BU-CY protocol. The effect of this intensified regimen was investigated in 26 consecutive children with genetic diseases who underwent T cell-depleted BMT from HLA-identical siblings. Sixteen patients were males and 10 females, of median age 5 (0.2-14) years. The diseases included beta-thalassemia major, osteopetrosis, severe combined immunodeficiency, Wiskott-Aldrich syndrome, familial agranulocytosis, congenital idiopathic hemolytic anemia (CIHA), Gaucher's disease, Niemann-Pick disease, Hurler's syndrome, and adrenoleukodystrophy. The conditioning regimen consisted of BU 4 mg/kg x 4 days (-8 to -5), TTP 5 mg/kg x 2 days (-4 and -3), and CY 60 mg/kg x 2 days (-2 and -1). Engraftment was as expected, with WBC >1.0 x 10(9)/l at day +19 (10-33), ANC >0.5 x 10(9)/l at day +22 (10-56) and platelets >25 x 10(9)/l at day +32 (18-131). Transplant-related mortality was 19%. Overall survival and disease-free survival (DFS) at 60 months follow-up were both 77%. Our results with the BU-TTP-CY regimen followed by T cell-depleted BMT in genetic diseases may provide a basis for prospective comparison with the standard conditioning regimen of BU-CY in the management of children suffering from these conditions.

Nonmyeloablative stem cell transplantation and cell therapy as an alternative to conventional bone marrow transplantation with lethal cytoreduction for the treatment of malignant and nonmalignant hematologic diseases.

Myeloablative conditioning associated with hazardous immediate and late complications is considered as a mandatory first step in preparation for allogeneic blood or marrow transplantation (allogeneic BMT) for the treatment of malignant hematologic disorders and genetic diseases. Immune-mediated graft-versus-leukemia (GVL) effects constitute the major benefit of allogeneic BMT. Therefore, we have introduced the use of relatively nonmyeloablative conditioning before allogeneic BMT aiming for establishing host-versus-graft tolerance for engraftment of donor immunohematopoietic cells for induction of GVL effects to displace residual malignant or genetically abnormal host cells. Our preliminary data in 26 patients with standard indications for allogeneic BMT, including acute leukemia (n = 10); chronic leukemia (n = 8), non-Hodgkin's lymphoma (n = 2), myelodysplastic syndrome (n = 1), multiple myeloma (n = 1), and genetic diseases (n = 4) suggest that nonmyeloablative conditioning including fludarabine, anti-T-lymphocyte globulin, and low-dose busulfan (8 mg/kg) is extremely well tolerated, with no severe procedure-related toxicity. Granulocyte colony-stimulating factor mobilized blood stem cell transplantation with standard dose of cyclosporin A as the sole anti-graft-versus-host disease (GVHD) prophylaxis resulted in stable partial (n = 9) or complete (n = 17) chimerism. In 9 patients absolute neutrophil count (ANC) did not decrease to below 0.1 x 10(9)/L whereas 2 patients never experienced ANC < 0.5 x 10(9)/L. ANC > or = 0.5 x 10(9)/L was accomplished within 10 to 32 (median, 15) days. Platelet counts did not decrease to below 20 x 10(9)/L in 4 patients requiring no platelet support at all; overall platelet counts > 20 x 10(9)/L were achieved within 0 to 35 (median 12) days. Fourteen patients experienced no GVHD at all; severe GVHD (grades 3 and 4) was the single major complication and the cause of death in 4 patients, occurring after early discontinuation of cyclosporine A. Relapse was reversed by allogeneic cell therapy in 2/3 cases, currently with no residual host DNA (male) by cytogenetic analysis and polymerase chain reaction. To date, with an observation period extending over 1 year (median 8 months), 22 of 26 patients (85%) treated by allogeneic nonmyeloablative stem cell transplantation are alive, and 21 (81%) are disease-free. The actuarial probability of disease-free survival at 14 months is 77.5% (95% confidence interval, 53% to 90%). Successful eradication of malignant and genetically abnormal host hematopoietic cells by allogeneic nonmyeloablative stem cell transplantation represents a potential new approach for safer treatment of a large variety of clinical syndromes with an indication for allogeneic BMT. Transient mixed chimerism which may protect the host from severe acute GVHD may be successfully reversed postallogeneic BMT with graded increments of donor lymphocyte infusions, thus resulting in eradication of malignant or genetically abnormal progenitor cells of host origin.

Cytosine arabinoside as a major risk factor for Streptococcus viridans septicemia following bone marrow transplantation: a 5-year prospective study.

The incidence and clinical course of nosocomial septicemia with Streptococcus viridans was evaluated prospectively in 242 consecutive bone marrow transplant (BMT) recipients throughout their 15-213 days' (median 47) hospitalization, including 4-58 days (median 18) of neutropenia. Initial empiric therapy for febrile neutropenia consisted of mezlocillin, gentamicin and cefazolin; glycopeptide was excluded. S. viridans septicemia occurred in 23/209 (11%) subjects with underlying malignant disease, and only during neutropenia with concomitant mucositis: in 20 subjects (four with ampicillin-resistant strains), S. viridans septicemia occurred at onset of febrile neutropenia, 1-5 days (median 4.5) post-BMT. All survived with an uncomplicated clinical course. Thus, glycopeptide seems unnecessary in the initial empiric antibiotic regimen. The other three subjects demonstrated S. viridans septicemia (two with ampicillin-resistant strains) on day 11 post-BMT; two died. The major risk identified was cytosine arabinoside administration in the conditioning regimen (P < 0.01).

Analysis of beta-globin mutations shows stable mixed chimerism in patients with thalassemia after bone marrow transplantation.

Beta-thalassemia major (TM) is caused by any of approximately 150 mutations within the beta-globin gene. To establish the degree of chimerism after bone marrow transplantation (BMT), we have performed molecular analysis of beta-globin mutations in 14 patients with TM over a period of 10 years. All patients underwent T cell-depleted allogeneic BMT from HLA-identical related donors, using either in vitro T-cell depletion with CAMPATH 1M and complement or in vivo depletion using CAMPATH 1G in the bone marrow collection bag. To date, at different time periods after BMT, seven patients have some degree of chimerism; six of these patients, all blood transfusion-independent, have donor cells in the range of 70% to 95%, with stable mixed chimerism (MC). The seventh patient has less than 10% donor cells with, surprisingly, only minimal transfusion requirements. The detection of beta-globin gene point mutation, as used here, is a highly specific and sensitive marker for engraftment and MC in patients with thalassemia. In light of its specificity, the method is applicable in all cases of TM, as it is independent of sex and other non-globin-related DNA markers. The high incidence of MC found in our patients may be a consequence of the pre-BMT T-cell depletion. Because MC was associated with transfusion independence, complete eradication of residual host cells for effective treatment of TM and possibly other genetic diseases may prove not to be essential.

Sequential respiratory syncytial virus and cytomegalovirus pneumonia following bone marrow transplantation.

A 6-month-old child with familial hemophagocytic lymphohistiocytosis (FHL) experienced early sequential pneumonia due to respiratory syncytial virus (RSV) and cytomegalovirus (CMV) following bone marrow transplantation (BMT). The patient was deficient in natural killer (NK) cell activity (as found frequently in patients with FHL), and this risk factor may have played a major role in the concomitant infection by the two viral pathogens. Rapid diagnostic methods for both viruses are essential and early specific treatment may serve to ameliorate RSV- and CMV-induced lung injury in these life-threatening infections.

T-cell-depleted allogeneic bone marrow transplantation for acute leukaemia using Campath-1 antibodies and post-transplant administration of donor's peripheral blood lymphocytes for prevention of relapse.

One hundred and forty-six patients with acute leukaemia (81 with ANLL and 65 with ALL) received allogeneic bone marrow transplantation from their fully matched siblings. 121 patients underwent T-cell depletion (TCD) using Campath 1 monoclonal rat anti-human lymphocyte (CDw52) antibodies; 67 with Campath 1M and 54 with Campath 1G isotypes. Patients were conditioned for transplant using either total body irradiation combined with chemotherapy (125 patients) or busulfan and cyclophosphamide (21 patients). 112 recipients of T-cell depleted allografts received in addition total lymphoid irradiation (TLI) for prevention of rejection. Engraftment of neutrophils (> 0.5 x 10(9)/l) and platelets (> 25 x 10(9)/l) occurred on days 15 and 18, and on days 18 and 20 in recipients of Campath 1M and Campath 1G treated marrows respectively. Rejection was documented in 6.8% of T-cell depleted transplants. Leukaemia relapse-free survival at 2 years was 83% for patients transplanted in first CR, 76% in second CR (P2 = 0.34) and 42% in advanced leukaemia (P2 = 0.009). 81 marrow recipients, 38 with Campath 1M and 43 with Campath 1G treated marrow, received post-transplant graded increments of donor's peripheral blood lymphocytes (PBL) to induce graft-versus-leukaemia (GVL) effects. Administration of donor's PBL was associated with clinically significant GVHD and with decreased relapse rate especially in patients with ALL. Our data suggest that in patients receiving marrow allografts depleted of T cells by Campath 1 monoclonal antibodies, rejection can be reduced by adequate pregrafting immunosuppression. In patients with advanced disease, post-transplant cell-mediated immunotherapy (CMI) using donor's PBL may be beneficial; however, further studies are needed to define the optimal schedule of CMI for safe and effective prevention of relapse following TCD bone marrow transplantation in malignant haematological diseases.

Total lymphoid irradiation, anti-lymphocyte globulin and Campath 1-G for immunosuppression prior to bone marrow transplantation for aplastic anemia after repeated graft rejection.

Allogeneic BMT for severe aplastic anemia is associated with a significant rate of graft rejection, especially in patients who have been previously transfused. We report a child with aplastic anemia who rejected donor marrow twice despite adequate immunosuppression as part of the conditioning therapy but engrafted successfully following combined administration of three modalities of immunosuppression: antithymocyte globulin, total lymphoid irradiation and the monoclonal antibody Campath-1G. Restriction fragment length polymorphism studies > 1 year after BMT show full donor hematopoiesis with no evidence of autologous recovery.

Successful T cell-depleted allogeneic bone marrow transplantation in a child with recurrent multiple extramedullary plasmacytomas.

Multiple plasmacytomas with IgA paraproteinemia, a low grade lymphoid neoplasm of differentiated B cells rarely seen in the young, were encountered in a 10-year-old child. T cell-depleted allogeneic bone marrow transplantation (BMT) was performed because of progressive disease despite chemotherapy. Donor T cells were infused after transplantation in gradually increasing numbers to achieve a graft-versus-tumor effect. Complete eradication of all tumor masses was achieved following BMT with normalization of serum immunoglobulin levels. The patient remains in complete remission 4 years after BMT. Allogeneic BMT should be considered early in the course of low-grade lymphoid malignancy in the younger age group.

High-performance liquid chromatographic analysis of free palmitic and stearic acids in cerebrospinal fluid.

A relatively simple method for extraction of free fatty acids from cerebrospinal fluid with aminopropyl bonded-phase columns, and the estimation of palmitic acid (C16:0) and stearic acid (C18:0) concentrations by high-performance liquid chromatographic analysis is described. The values of C16:0 and C18:0 in patients with non-neurological disorders lie within a narrow range, with a mean (+/- S.D.) of 4.02 +/- 0.33 micrograms/ml for C16:0 and 2.72 +/- 0.39 micrograms/ml for C18:0.

Prevention of herpes simplex virus (HSV) infection in recipients of HLA-matched T-lymphocyte-depleted bone marrow allografts.

The occurrence of HSV infection and the effect of prophylaxis with oral acyclovir were evaluated prospectively in 34 consecutive patients undergoing bone marrow transplantation (BMT). All allogeneic BMT procedures involved T-lymphocyte depletion for prevention of graft-vs.-host disease (GVHD). Five HSV-seronegative patients did not receive acyclovir, and they did not develop HSV infection. Oral acyclovir was administered to 15 HSV-seropositive BMT recipients; 14 untreated HSV-seropositive BMT recipients served as a control group. The adult dose of acyclovir was 400 mg three times a day on Days -6 to +14 and 200 mg three times a day on Days +15 to +90. Children received 500 mg/m2 per day divided into three equal doses on Days -6 to +14 and 250 mg/m2 per day again divided into three on Days +15 to +90. In the group on prophylaxis, only one developed HSV infection during the time prior to engraftment. In the reference group, 12 of 14 (85.7%) developed oral HSV infection within 0 to 16 days (median 11 days) after the transplantation. Time for engraftment (duration of neutropenia) was shorter in patients receiving acyclovir. After engraftment, HSV infection was not observed during administration or following discontinuation of acyclovir on Day 90, but occurred in three patients in whom acyclovir was discontinued on Days 25, 35 and 40 after BMT. In the untreated group, two patients had recurrence of HSV infection on Days 40 to 60, and one had two infectious episodes. GVHD occurred in only two recipients, neither of whom had HSV infection. We conclude that the incidence of HSV infection during the period until engraftment in recipients of T-lymphocyte-depleted BMT is high, similar to that reported by others in recipients of whole BMT. Relatively low-dose oral acyclovir administered for 90 days can effectively prevent HSV infections in previously HSV-seropositive BMT recipients and may also shorten the period until engraftment.

Disturbed patterns of globin chain synthesis in childhood monosomy 7 myeloproliferative syndrome.

Two children with typical clinical and haematological features of monosomy 7 myeloproliferative syndrome are presented. Both children displayed decreased production of beta-globin chains and unbalanced high alpha/non-alpha synthetic ratios similar to those characteristic of homozygous beta-thalassaemia. These provide further evidence for the involvement of the erythroid line as part of the malignant clone, indicating neoplastic transformation of a pluripotential stem cell in this disease.