Nonmyeloablative transplantation with or without alemtuzumab: comparison between 2 prospective studies in patients with lymphoproliferative disorders

Although nonmyeloablative conditioning regimen transplantations (NMTs) induce engraftment of allogeneic stem cells with a low spectrum of toxicity, graft-versus-host disease (GVHD) remains a significant cause of morbidity and mortality. In vivo T-cell depletion, using alemtuzumab, has been shown to reduce the incidence of GVHD. However, this type of maneuver, although reducing GVHD, may have an adverse impact on disease response, because NMTs exhibit their antitumor activity by relying on a graft-versus-malignancy effect. To explore the efficacy of alemtuzumab compared with methotrexate (MTX) for GVHD prophylaxis, we have compared the results in 129 recipients of a sibling NMT enrolled in 2 prospective studies for chronic lymphoproliferative disorders. Both NMTs were based on the same combination of fludarabine and melphalan, but the United Kingdom regimen (group A) used cyclosporin A plus alemtuzumab, whereas the Spanish regimen (group B) used cyclosporin A plus MTX for GVHD prophylaxis. Patients receiving alemtuzumab had a higher incidence of cytomegalovirus (CMV) reactivation (85% versus 24%, P <.001) and a significantly lower incidence of acute GVHD (21.7% versus 45.1%, P =.006) and chronic GVHD (5% versus 66.7%, P <.001). Twenty-one percent of patients in group A and 67.5% in group B had complete or partial responses 3 months after transplantation (P <.001). Eighteen patients in group A received donor lymphocyte infusions (DLIs) to achieve disease control. At last follow-up there was no difference in disease status between the groups with 71% versus 67.5% (P =.43) of patients showing complete or partial responses in groups A and B, respectively. No significant differences were observed in event-free or overall survival between the 2 groups. In conclusion, alemtuzumab significantly reduced GVHD but its use was associated with a higher incidence of CMV reactivation. Patients receiving alemtuzumab often required DLIs to achieve similar tumor control but the incidence of GVHD was not significantly increased after DLI.     

Respiratory virus infections in transplant recipients after reduced-intensity conditioning with Campath-1H: high incidence but low mortality

Respiratory virus infections can cause serious morbidity and mortality after conventional allogeneic stem cell transplantation. However, the incidence and outcome of these infections after reduced intensity conditioning has not been reported. Between 1997 and 2001, 35 episodes of respiratory virus infections were noted in 25 of 83 transplant recipients conditioned with fludarabine, melphalan and Campath-1H, and 80% of them received early antiviral therapy. Parainfluenza virus (PIV) 3 was the commonest isolate (45.7%) followed by respiratory syncytial virus (37%). Patients with myeloma were more susceptible to these infections [odds ratio (OR) 4.1, P = 0.01] which were often recurrent in patients with severe acute or chronic graft-versus-host disease (GVHD) (OR 10.6, P = 0.03). Infection within the first 100 d (OR 5.0, P = 0.05) and PIV 3 (OR 9.2, P = 0.01) isolation were risk factors for developing lower respiratory infection. Although more than half of the episodes progressed to lower respiratory infection, the mortality was only 8%. This could have been due to early initiation of antiviral therapy, but the attenuation of pulmonary damage due to the reduced-intensity conditioning, low incidence of GVHD and, paradoxically, the low CD4+ T-cell subset in this setting might also have been contributory factors.     

Reduced-intensity conditioning for allogeneic haematopoietic stem cell transplantation in relapsed and refractory Hodgkin lymphoma: impact of alemtuzumab and donor lymphocyte infusions on long-term outcomes

The introduction of reduced-intensity conditioning (RIC) has enabled the role of allogeneic transplantation to be re-evaluated in Hodgkin lymphoma (HL). While T-cell depletion reduces graft-versus-host disease (GvHD), it potentially abrogates graft-versus-tumour activity and increases infective complications. We compared the results in 67 sibling donor transplantations following RIC in multiply relapsed patients from two national phase II studies conditioned with fludarabine/melphalan. One used cyclosporine/alemtuzumab (MF-A, n = 31), the other used cyclosporine/methotrexate (MF, n = 36) as GvHD prophylaxis. There was a small excess of chemorefractory cases in the MF cohort (P = NS). MF-A resulted in significantly lower incidences of non-relapse mortality, acute and chronic GvHD, but no significant excess of relapse/progression. Post donor lymphocyte infusion (DLI) disease responses occurred in 8/14 (57%) and 6/11 (55%) patients in the MF-A and MF groups, respectively. Current progression-free survival (CPFS) was superior with MF-A (univariate analysis), with durable responses to DLI contributing to the favourable outcome (43% vs. 25%, P = 0.0356). Disease status at transplantation significantly influenced overall survival (P = 0.0038) and CPFS (P = 0.0014), retaining significance in multivariate analyses, which demonstrated a trend towards improved CPFS with T-cell depletion (P = 0.0939). These data suggest that alemtuzumab significantly reduced GvHD without resulting in a deleterious impact on survival outcomes following RIC in HL, and that durable responses to DLI may be more common following the inclusion of alemtuzumab in the conditioning protocol.     

Evolution of drug-resistance genes in Plasmodium falciparum in an area of seasonal malaria transmission in Eastern Sudan

We investigated the evolution of drug-resistant Plasmodium falciparum in a village in eastern Sudan. The frequencies of alleles of 4 genes thought to be determinants of drug resistance were monitored from 1990 through 2001. Changes in frequencies of drug-resistance genes between wet and dry seasons were monitored from 1998 through 2000. Parasites were also typed for 3 putatively neutral microsatellite loci. No significant variation in frequencies was observed for the microsatellite loci over the whole study period or between seasons. However, genes involved in resistance to chloroquine showed consistent, significant increases in frequencies over time (rate of annual increase, 0.027/year for pfcrt and 0.018/year for pfmdr1). Genes involved in resistance to the second-line drug used in the area (Fansidar) remained at low frequencies between 1990 and 1993 but increased dramatically between 1998 and 2000, which is consistent with the advent of Fansidar usage during this period. For mutant alleles of the primary drug-resistance targets for chloroquine and pyrimethamine, higher frequencies were seen during the dry season than during the wet season. This cyclical fluctuation in drug-resistance genes most likely reflects seasonal variation in drug pressure and differences in the fitness of resistant and sensitive parasites.     

Favorable outcomes with alemtuzumab-conditioned unrelated donor stem cell transplantation in adults with high-risk Philadelphia chromosome-negative acute lymphoblastic leukemia in first complete remission

Background

Approximately 40% of adults with Philadelphia chromosome-negative acute lymphoblastic leukemia achieve long-term survival following unrelated donor hematopoietic stem cell transplantation in first complete remission but severe graft-versus-host disease remains a problem affecting survival. Although T-cell depletion abrogates graft-versus-host disease, the impact on disease-free survival in acute lymphoblastic leukemia is not known.

Design and Methods

We analyzed the outcome of 48 adults (median age 26 years) with high-risk, Philadelphia-chromosome-negative acute lymphoblastic leukemia undergoing T-cell depleted unrelated donor-hematopoietic stem cell transplantation (67% 10 of 10 loci matched) in first complete remission reported to the British Society of Blood and Marrow Transplantation Registry from 1993 to 2005.

Results

T-cell depletion was carried out by in vivo alemtuzumab administration. Additional, ex vivo T-cell depletion was performed in 21% of patients. Overall survival, disease-free survival and non-relapse mortality rates at 5 years were 61% (95% CI 46–75), 59% (95% CI 45–74) and 13% (95% CI 3–25), respectively. The incidences of grades II–IV and III–IV acute graft-versus-host disease were 27% (95% CI 16–44) and 10% (95% CI 4–25), respectively. The actuarial estimate of extensive chronic graft-versus-host disease at 5 years was 22% (95%CI 13–38). High-risk cytogenetics at diagnosis was associated with a lower 5-year overall survival (47% (95% CI 27–71) vs. 68% (95% CI 44–84), p=0.045).

Conclusions

T-cell depleted hematopoietic stem cell transplantation from unrelated donors can result in good overall survival and low non-relapse mortality for adults with high-risk acute lymphoblastic leukemia in first complete remission and merits prospective evaluation.     

Predominant or complete recipient T-cell chimerism following alemtuzumab-based allogeneic transplantation is reversed by donor lymphocytes and not associated with graft failure

The clinical significance of mixed chimerism following allogeneic haematopoietic stem cell transplantation (HSCT) remains controversial. Its relevance and incidence are probably influenced by the conditioning regimen and incorporation of T‐cell depletion. The presence of recipient chimerism levels >40–50% following T‐cell replete reduced intensity transplantation correlates with a high risk of graft rejection, regardless of donor‐lymphocyte infusions, but it is unclear whether this finding translates to T‐cell depleted transplants. We conducted a retrospective single‐institution analysis of patients receiving alemtuzumab‐based HSCT. 27/152 (18%) evaluable cases had predominantly recipient T‐cell chimerism at 3 months or beyond. By contrast, coincident chimerism in the granulocyte lineage was predominantly of donor origin (median 100%) in all but one patient. Donor lymphocyte infusion effectively converted predominantly recipient T‐cell chimerism to ful donor chimerism in all evaluable cases including three cases with no detectable donor T cells. The only graft failure occurred in the patient with predominantly recipient myeloid chimerism in whom rejection occurred rapidly before donor lymphocytes could be administered. We conclude that predominant or complete recipient T‐cell chimerism following alemtuzumab‐based regimens does not have the same clinical implications as that following T‐cell replete transplants and can be effectively converted with donor lymphocytes without the need for lympho‐depleting agents or re‐conditioning.     

A fatal case of autoimmune thrombocytopenia with an IgM anti-GPIb/IX following one antigen mismatched unrelated donor bone marrow transplantation

We report the case of a 32-year-old patient with ALL who developed autoimmune thrombocytopenia 2 months following allogeneic bone marrow transplantation. An IgM autoantibody against the platelet glycoprotein Ib/IX complex was observed. Treatment with high-dose steroids and intravenous immunoglobulin G failed to produce any benefit and the thrombocytopenia led to fatal gastrointestinal haemorrhage. The possible factors contributing to post-allograft thrombocytopenia and potential management strategies are discussed.     

Use of MRI to identify preclinical vascular dementia in symptomatic small vessel disease

Background

Sporadic cerebral small vessel disease is an important cause of vascular dementia, and is a syndrome of cognitive impairment with evidence of vascular brain damage. At post-mortem examination pure vascular dementia is rare, with coexisting Alzheimer's disease pathology in 95% of cases. We aimed to use MRI to characterise the structural abnormalities during the preclinical phase of vascular dementia in symptomatic small vessel disease, and use these characteristics to accurately predict the development of future dementia.

High-level chloroquine resistance in Sudanese isolates of Plasmodium falciparum is associated with mutations in the chloroquine resistance transporter gene pfcrt and the multidrug resistance Gene pfmdr1

Polymorphisms were examined in 2 Plasmodium falciparum genes, as were chloroquine responses of clones and isolates from a village in eastern Sudan. There was a significant association between an allele of the P. falciparum chloroquine resistance transporter gene (pfcrt-T76) and both in vitro and in vivo resistance. There was a less significant association with the multidrug resistance gene pfmdr1-Y86 allele. A significant association between pfmdr1-Y86 and pfcrt-T76 was apparent among resistant isolates, which suggests a joint action of the 2 genes in high-level chloroquine resistance.     

Results of alemtuzumab-based reduced-intensity allogeneic transplantation for chronic lymphocytic leukemia: a British Society of Blood and Marrow Transplantation Study

We report results in 41 consecutive patients with chronic lymphocytic leukemia (CLL) who underwent allogeneic hematopoietic cell transplantation (HCT) after fludarabine, melphalan, and alemtuzumab conditioning. Donors were 24 HLA-matched siblings and 17 unrelated volunteers, 4 of them mismatched with recipients. All but 3 patients had initial hematologic recovery, but 5 more patients had secondary graft failure. Median intervals to neutrophil (greater than 0.5 x 10(9)/L) and platelet (greater than 20 x 10(9)/L) recovery were 14 days (range, 9-30 days) and 11 days (range, 8-45 days), respectively. Eleven (27%) patients had relapses and received escalated donor lymphocyte infusions, but only 3 of them had sustained responses. Acute and chronic graft-versus-host disease (GVHD) was observed in 17 (41%) and 13 (33%) patients, respectively. Seventeen (41%) patients have died, 5 of progressive disease. The 2-year overall survival and transplantation-related mortality (TRM) rates were 51% (95% confidence interval [CI], 33%-69%) and 26% (95% CI, 14%-46%), respectively. The alemtuzumabbased regimen was feasible and effective in patients with CLL with a relatively low rate of GVHD. However, TRM remains relatively high as a result of a variety of viral and fungal infections. Studies are ongoing to address the efficacy of reduced doses of alemtuzumab in this group of immunosuppressed patients.