D. H. Pamphilon

Outcome and clinical course of 100 patients with adenovirus infection following bone marrow transplantation

We conducted a retrospective review of the clinical features and outcome of adenovirus infection in 572 consecutive patients transplanted in a single centre over a 10 year period. One hundred patients (17%) had a total of 105 episodes of adenovirus infection diagnosed at a median of 18 days post transplant (range 2–150 days). The incidence was higher in children than adults (21% vs 9%, P < 0.001) and in unrelated donor vs matched sibling donor transplants (26% vs 9%, P < 0.001). Diarrhoea and fever were the most common presenting features. Reflecting these symptoms, the most common site of isolation was the stool. Serotypes 1, 2 and 7 were the most frequently seen (total of 41/68 or 60% of evaluable cases). In six patients (6%) adenovirus infection was the direct cause of death occurring at a median of 72 days post transplant (range 18–365 days). Five of these six patients had pulmonary involvement and four had associated graft-versus-host disease (GVHD). Three further patients were considered to have severe adenoviral disease (total incidence 9%). Isolation of virus from multiple sites correlated with a poor outcome (P < 0.001). Comorbid viral infection was common in this group with 50% of all patients having other viruses isolated (predominantly polyoma virus and cytomegalovirus). We conclude that adenovirus is commonly isolated after bone marrow transplant and is a cause of significant morbidity but was a rare cause of mortality (6/572 = 1%) in our patient group as a whole. The relative infrequency of severe infection will make it difficult for the transplant physician to decide which patients should receive experimental antiviral drugs such as ribavirin and cidofovir or immunomodulatory therapy with donor white cell infusions. Bone Marrow Transplantation (2000) 26, 1333–1338.

Unrelated donor bone marrow transplantation for children with relapsed acute lymphoblastic leukaemia in second complete remission

Allogeneic sibling bone marrow transplantation (BMT) is the recommended treatment for relapsed childhood acute lymphoblastic leukaemia (ALL), but appropriate donors are only available in 30% of cases. Unfortunately, BMT from unrelated donors (UD) has been associated with high rates of severe graft‐versus‐host disease (GvHD) and transplant‐related mortality (TRM). In an attempt to improve outcome in UD‐BMT we have assessed the impact of T‐cell depletion using CAMPATH‐1 (anti‐CD52) monoclonal antibodies in 50 consecutively referred patients with relapsed ALL in second remission. All were previously treated according to MRC protocols UKALL X and XI, and then given chemotherapy on MRC R1 from relapse until UD‐BMT. 19 patients had relapsed on and 31 off therapy.

Infections in adults undergoing unrelated donor bone marrow transplantation

This study retrospectively reviews infections over a 7‐year period in 60 consecutive adults (median age 25 years) undergoing their first unrelated donor bone marrow transplant (UD‐BMT). T‐cell depletion was employed in 93%. More than half the patients had one or more severe, potentially life‐threatening, infections. There was a high incidence of invasive fungal infections (Aspergillus 17, Candida four), despite the use of itraconazole or amphotericin prophylaxis. Ten Aspergillus infections occurred beyond 100  d. Two patients (11%) with invasive aspergillosis survived. Clustering of infections was noted, with invasive fungal infections significantly associated with bacteraemias (OR 3.73, P = 0.06) and multiple viral infections (OR 4.25, P = 0.05). There were 21 severe viral infections in 16 patients, with CMV disease occurring in four patients only; viral pneumonitis was predominantly due to ‘community respiratory’ viruses. Most early bacteraemias (68%) were due to Gram‐positive organisms. The majority of episodes of Gram‐negative sepsis were caused by non‐fastidious non‐fermentative bacteria, such as Pseudomonas spp. and Acinetobacterspp., historically regarded as organisms of low pathogenicity. In patients with successful engraftment and minimal graft‐versus‐host disease, late infections suggestive of continued immune dysfunction (shingles, recurrent lower respiratory infections, Salmonella enteritis and extensive warts) were common.

Minimal residual disease status as a predictor of relapse after allogeneic bone marrow transplantation for children with acute lymphoblastic leukaemia.

We have analysed the behaviour of minimal residual disease (MRD) after allogeneic bone marrow transplantation (allo-BMT) in 71 children with acute lymphoblastic leukaemia (ALL). The method relied on PCR of IgH, TCRdelta and/or TCRgamma gene rearrangements followed by electrophoretic size resolution and allele-specific oligoprobing. Patients were similarly conditioned; 55 received marrow from unrelated donors and 16 from related donors. MRD was assessed at various time-points up to 24 months after BMT. Three children were not evaluable due to transplant-related mortality. MRD was detected in 28/32 patients (88%) who relapsed post-BMT; 16 were positive at all times and 12 were initially negative but became positive at a median of 3 months (range 1.5-11) prior to relapse. In contrast, only eight of 36 (22%) patients who remained in continuing complete remission (CCR) (median follow-up 43 months, range 20-94) showed MRD at any time after BMT (P<0.0001). In these eight patients MRD was found up to 9 months after transplant and at low levels (0.01-0.001%). All eight (median follow-up 39 months, range 24-87) had at least two MRD-negative samples tested subsequently and five of the eight had evidence of grade I-II acute graft-versus-host disease (GvHD), raising the possibility of a graft-versus-leukaemia effect. In general, any evidence of MRD after allo-BMT is a poor prognostic sign. However, if immunotherapy were to be targeted towards patients with evidence of persisting MRD after BMT, the method described would expose only a small proportion of patients to unnecessary additional toxicity.

The outcome of 26 patients with respiratory syncytial virus infection following allogeneic stem cell transplantation

Respiratory syncytial virus (RSV) is known to cause acute lung injury in the immunocompromised host, especially recipients of bone marrow allografts. Specific prognostic factors for the development of severe life-threatening disease remain to be identified as does the optimum treatment of established disease. Over a 5-year period the incidence and outcome of RSV in BMT recipients was analysed retrospectively. Prognostic factors assessed included type of transplant, engraftment status at the time of infection, the presence of lower respiratory tract disease, viral genotype and treatment received. During the study period, 26 of 336 (6.3%) allogeneic stem-cell recipients were identified as having RSV. Five patients (19.2%) died as a direct result of RSV. One patient died secondary to an intracranial bleed with concomitant RSV. There were four patients with graft failure (two primary and two secondary) attributable to the presence of RSV, two of whom subsequently died of infections related to prolonged myelosuppression. The presence of lower respiratory tract infection and a poor overall outcome was the only statistically significant association. Unrelated donor transplants and AML as the underlying disease appeared to be associated with a poorer outcome. Engraftment status, viral genotype and RSV treatment received did not correlate with outcome. We conclude that future studies are required to identify early sensitive and reproducible prognostic factors of RSV in the immunocompromised host. The roles of intravenous and nebulised ribavirin need to be clarified by prospective controlled trials.

Improved outcome of alternative donor bone marrow transplantation in children with severe aplastic anaemia using a conditioning regimen containing low-dose total body irradiation, cyclophosphamide and Campath

The increasing success of human leucocyte antigen (HLA)‐matched sibling donor (MSD) transplants and combination immunosuppressive treatments have dramatically improved the prognosis of severe aplastic anaemia (SAA) in children and young adults. For patients who lack a MSD there is a significant minority who fail immunosuppressive therapy or suffer from a severe constitutional aplastic anaemia in which immunosuppression would be ineffective. Alternative donor bone marrow transplantation (AD‐BMT) has only had limited success in this context. We report the successful outcome of AD‐BMT in eight consecutive patients aged 7 months to 15 years, six of whom had acquired aplastic anaemia who had previously failed to respond to immunosuppression, and two of whom had a severe (non‐Fanconi) constitutional aplastic anaemia. All eight patients had received multiple red cell and platelet transfusions. We used a new combination of agents for pretransplant conditioning aiming to maximize immunosuppression and minimize toxicity, consisting of Campath‐1G or ‐1H, cyclophosphamide and low‐dose total body irradiation (LD TBI) or fludarabine. Toxicity was minimal and all eight children are alive, well and free of disease at a median follow‐up of 32 months. We suggest that this approach could facilitate the successful treatment of children with SAA in whom immunosuppressive therapy has failed or is not appropriate.

The outcome of children requiring admission to an intensive care unit following bone marrow transplantation

We report the results of a retrospective study of the role of intensive care unit (ICU) admission in the management of 367 children who underwent bone marrow transplantation (BMT) at a tertiary referral institution. 39 patients (11%) required 44 ICU admissions for a median of 6 d. 70% received marrow from unrelated donors, half of which were mismatched; 80% had leukaemia and two‐thirds were considered high‐risk transplants. Respiratory failure was the major reason for admission to ICU. 75% of admissions required mechanical ventilation (for a median of 5 d) and 20 patients had lung injury as defined by the criteria of the Seattle group. None of 11 patients with proven viral pneumonitis survived (P = 0.06) and only one of 20 patients with lung injury survived (P < 0.01). Six of seven patients with a primary neurological problem survived (P < 0.001); these appear to represent a good outcome group. Age, the presence of graft‐versus‐host disease, the use of inotropes, isolated renal or hepatic impairment, and paediatric risk of mortality (PRISM) score were not predictive of outcome. In total, 12 patients (27% of admissions) survived and were discharged from hospital 30 d or more after admission and eight (18%) survived >6 months. ICU admission can be beneficial to selected children post‐BMT but it may be less useful in proven viral pneumonitis. Where mechanical ventilation is required, the duration of this support should be limited unless there is rapid improvement.

Viral inactivation of fresh frozen plasma

The likelihood of transfusion of transmissible infection via blood components and fractionated blood products has declined dramatically in the last two decades. In the early 1970s, the risk of hepatitis transmission to recipients of blood or blood components was between 10% and 25% (Horowitz & Ben-Hur, 1995). Today, there is still a residual risk associated with labile blood components [fresh frozen plasma (FFP), platelets and red cells]. Recently, in the UK, this has been estimated for human immunodeficiency virus (HIV)-1 and -2 as 0 ́19/million donations, for hepatitis C virus (HCV) as 0 ́6/million donations and for hepatitis B virus (HBV) as 5±20/million donations (L. M. Williamson, personal communication). This risk reduction has been achieved largely by improved donor selection procedures and the screening of donated blood for agents that may cause transfusion-transmitted infections (TTI). Pooling of plasma donations to make fractionated blood products such as coagulation factor concentrates and intravenous immunoglobulin (IVIG) increases the chance of viral transmission. In the USA, between 1979 and 1985, 70% of severe haemophiliacs became infected with HIV-1 that contaminated factor VIII concentrates (Goedert et al, 1989). Since then, a number of viral inactivation strategies including dry heat, heating solution and solvent±detergent (SD) treatment have been developed for fractionated plasma products. These have resulted in an enormous reduction in risk such that the likelihood of viral transmission from such fractionated blood components can now only be estimated by calculations of probability. These are based on factors such as the risk per donor, quantity of virus that may be present in a unit that gives a negative test, the number of units pooled and estimations of virus killing and removal during the process. In 1990, this was determined for a factor VIII concentrate purified by a monoclonal antibody affinity method and SD treated. It was calculated that the risk for an HIV-1, HBV or HCV transmission was , 1 in 10, in 10 and in 10 vials administered respectively (Horowitz & Ben-Hur, 1995). This represented, at the time, a risk reduction of between 1000 and 10 billion compared with untreated single unit blood components. After licensing for the treatment of coagulation factor concentrates in 1985, it was shown at the New York Blood Center that SD treatment could be used for the viral inactivation of FFP (Horowitz et al, 1992). In 1991, it was estimated that . 3 million doses of SD-treated FFP prepared from pooled plasma had been administered in Europe (Horowitz et al, 1998). This process was licensed by the Food and Drug Administration (FDA) in 1999. During this time, it was also shown that the use of methylene blue (MB) in conjunction with visible light had significant antiviral activity (Lambrecht et al, 1991; Bachmann et al, 1995). In 1992, MB-FFP was introduced into clinical use by several Red Cross Transfusion Services in Germany and Switzerland (Mohr et al, 1997). In the 1990s, there were a number of reports describing the photodynamic treatment with psoralens and ultraviolet A (UVA) light to inactivate viruses in platelet concentrates (Dodd et al, 1991; Margolis-Nunno et al, 1997; Grass et al, 1998). Recently, viruses and other pathogens have been inactivated in FFP using a combination of the psoralen S-59 and UVA light (Grass et al, 1998). It is important to balance the potential benefits of reduced viral transmission against the cost and logistics of implementing viral inactivation strategies, although in theory it is desirable that the risk of TTI is minimized wherever possible. Therefore, there is a reluctance to ignore new strategies that may help to achieve this and a need to assess their potential contribution to blood safety. In this article, the use of SD treatment and the use of MB plus white light and the psoralen S-59 plus UVA light are discussed and progress made towards their clinical implementation is described.

Second allogeneic bone marrow transplants from unrelated donors for graft failure following initial unrelated donor bone marrow transplantation

Graft failure is a common and severe complication of unrelated donor bone marrow transplantation (UD-BMT). However, there are few reports of a second UD-BMT in this setting. We describe 12 patients with graft failure (five primary, seven secondary) who had a second transplant, five from their original donor and seven from a different donor. Their median age was 9 years. Two patients died before day 10 of regimen-related toxicity. Nine of 10 evaluable patients engrafted in a median of 17 days. Secondary graft failure was seen in one patient. Transplant-related morbidity was significant. Six of nine developed acute GHVD, there were five severe infections and five patients developed Bearman grade 3 or 4 extramedullary toxicity. Overall, five patients survive at a median of 38 months after the second BMT and two are in continuous complete remission. Second transplants from unrelated donors for graft failure can result in prolonged survival.

Pediatric marrow transplantation for acute leukemia using unrelated donors and T-replete or -depleted grafts: a case-matched analysis

A retrospective, case-matched analysis of the short-term toxicity, risk of GVHD and relapse as well as outcome in pediatric unrelated marrow transplantation was conducted by comparing recipients of T-replete and -depleted grafts in a two-center setting. Both groups contained 30 patients with acute leukemia matched by age at transplant, gender, primary diagnosis and disease status. Acute (90% vs 53%) and chronic (48% vs 0%) GVHD were more common among recipients of T-replete grafts. No significant differences in graft rejection/failure or viral infections were encountered between the two groups. Relapses were more prevalent (37% vs 15%) among recipients of T-depleted grafts. Outcome (EFS) was similar in the two groups. Consequently, in the analysis of transplant outcome, the higher risk of procedure-related, toxic complications among pediatric recipients of T-replete marrow grafts appears to be balanced by an increased risk of relapse among the recipients of T-depleted grafts. Bone Marrow Transplantation (2000) 25, 395–399.