Severe infections after single umbilical cord blood transplantation in adults with or without the co-infusion of CD34+ cells from a third-party donor: results of a multicenter study from the Grupo Español de Trasplante Hematopoyético (GETH)

BACKGROUND

Umbilical cord blood transplantation (CBT) is an established alternative source of stem cells in the setting of unrelated transplantation. When compared with other sources, single-unit CBT (sCBT) is associated with a delayed hematologic recovery, which may lead to a higher infection-related mortality (IRM). Co-infusion with the sCBT of CD34+ peripheral blood stem cells from a third-party donor (TPD) (sCBT + TPDCD34+) has been shown to markedly accelerate leukocyte recovery, potentially reducing the IRM. However, to our knowledge, no comparative studies have focused on severe infections and IRM with these 2 sCBT strategies.

METHODS

A total of 148 consecutive sCBT (2000-2010, median follow-up 4.5 years) were included in a multicenter retrospective study to analyze the incidence and risk factors of IRM and severe viral and invasive fungal infections (IFIs). Neutrophil engraftment occurred in 90% of sCBT (n = 77) and 94% sCBT + TPDCD34+ (n = 71) recipients at a median of 23 and 12 days post transplantation, respectively (P < 0.01).

RESULTS

The 4-year IRM was 24% and 20%, respectively (P = 0.7), with no differences at day +30 (5% and 4%, respectively) and day +100 (10% and 8%, respectively). In multivariate analysis early status of the underlying malignancy, cytomegalovirus (CMV)-seronegative recipient and high CD34+ cell content in the cord blood unit before cryostorage (≥1.4 × 10(5) /kg) were protective of IRM. Among the causes of IRM, bacterial infections and IFIs were more common in sCBT (15% vs. 4%), while CMV disease and parasitic infections were more common in the sCBT + TPDCD34+ cohort (5% vs. 16%).

CONCLUSION

These data show that sCBT supported with TPDCD34(+) cells results in much shorter periods of post-transplant leukopenia, but the short- and long-term rates of IRM were comparable to those of sCBT, presumably because immune recovery is equally delayed in both graft types.

[Umbilical cord blood cell transplantation from an unrelated donor: dual transplantation]

Our team conducted an original procedure of hematopoietic transplantation of umbilical cord blood (UCB) from an unrelated donor. The procedure consists of co-infusing hematopoietic stem cells selected from the blood of a third-party donor; it is conceived as a tool to shorten the engraftment period without preventing the engraftment of the UCB, even when using units with relatively low cell content and a low HLA compatibility. Between 1999 and 2008 we performed 64 transplantations in 60 adult patients (35 men and 25 women) with a median age of 34 years (range: 76-60) and a median weight of 70 kg (range: 43-95), all of whom were diagnosed with a high risk hematologic neoplasm (leukemia in most cases). Fludarabine, cyclophosphamide, ATG, and whole body irradiation or busulfan were used as conditioners. UCB was infused at medians of 2.4 x 107 CNT/kg (range: 1.14-4.30 x 107), 0.11 x 106 CD34+/kg (range: 0.035-0.37 x 106). Then, hematopoietic stem cells selected from the third-party donor were infused (2.43 x 106/kg [range: 1.05-3.34 x 106], with 0.3 x 104 CD3+/kg [range: 0.05-1.56 x 104]). Granulocyte engraftment occurred (ANC > 0.5 x 109/L) at a median of 10 days (range: 9-34 days), and the granulocyte engraftment of the UCB occurred in 21 days (range: 13-57 days). Complete UCB chimerism was observed in 37 days (range: 11-186 days) (previously double complete chimerism, presence of third-party donor and of cord) and platelet engraftment > 20 x 109/L in 33 days (range: 13 98 days) and > 50 x 109/L in 58 days (range: 14-106 days). Overall 3-year survival reached 51%, and 5 10 year-survival was 47% (plateau). Disease-free survival was 48% at three years, and 45% at 5 to 10 years; the mean follow-up of survivors was 48 months (range: 13-123 months). (Kaplan-Meier). In conclusion, early granulocyte recovery occurred thanks to a foster engraftment of hematopoietic stem from the third-party donor, which are not HLA-restricted; this is associated with a lower morbidity and mortality from infections secondary to neutropenia. There was also a high rate of engraftment and final full UCB chimerism, even with non-histocompatible UCB units (2/6 HLA mismatches) and with relatively low cell counts. In most cases, a single unit of UCB was sufficient. The incidence of severe GVHD and the percentage of relapses have been low. Opportunistic infections have occurred over a long period of time. This procedures makes allogeneic hematopoietic transplantation accessible to almost all patients.

Cord blood transplants supported by co-infusion of mobilized hematopoietic stem cells from a third-party donor

This open label clinical study provides updated evaluation of the strategy of single unit cord blood transplants (CBTs) with co-infusion of third-party donor (TPD) mobilized hematopoietic stem cells (MHSC). Fifty-five adults with high-risk hematological malignancies, median age 34 years (16-60 years) and weight 70 kg (43-95 kg), received CBTs (median 2.39 x 10(7) total nucleated cell (TNC) per kg and 0.11 x 10(6) CD34+ per kg) and TPD-MHSC (median 2.4 x 10(6) CD34+ per kg and 3.2 x 10(3) CD3+ per kg). Median time to ANC and to CB-ANC >0.5 x 10(9)/l as well as to full CB-chimerism was 10, 21 and 44 days, with maximum cumulative incidences (MCI) of 0.96, 0.95 and 0.91. Median time to unsupported platelets >20 x 10(9)/l was 32 days (MCI 0.78). MCI for grades I-IV and III-IV acute GVHD (aGVHD) were 0.62 and 0.11; 12 of 41 patients (29%) who are at risk developed chronic GVHD, becoming severely extensive in three patients. Relapses occurred in seven patients (MCI=0.17). The main causes of morbi-mortality were post-engraftment infections. CMV reactivations were the most frequent, their incidence declining after the fourth month. Five-year overall survival and disease-free survival (Kaplan-Meier) were 56 % and 47% (63% and 54% for patients <or=40 years). In conclusion, CBT with single units of relatively low cell content and 0-3 HLA mismatches is feasible as a first choice option for adult patients who lack a readily available adequate adult donor.

De novo smoldering paroxysmal nocturnal hemoglobinuria: a flow cytometric diagnosis

An asymptomatic 26-year-old woman with mild macrocytic anemia (11.6 g Hb/dl) was studied. All biochemical parameters, bone marrow histology and cytogenetics were normal. The Ham's and sucrose tests were negative. A flow cytometric analysis revealed that CD55 and CD59 staining was absent in 20% and 21% of the granulocytes, but erythrocytes and CD34-positive bone marrow cells were CD55 and CD59 positive. Seven months after the initial study, the patient suffered an episode of hemoglobinuria, with mild anemia, moderate thrombocytopenia and a weak positive sucrose lysis test. A new flow cytometric analysis disclosed an increased percentage of CD55 and CD59 negative granulocytes and a 25% of erythrocytes with an intermediate pattern of fluorescence after CD59 labelling. At fourteen months, a population of CD55-deficient erythrocytes was detected and the Ham's test became positive. The present report is, to our knowledge, the first case of smoldering paroxysmal nocturnal hemoglobinuria in a patient with no previous aplastic anemia, or evident pancytopenia. The diagnosis was established by flow cytometry of peripheral blood granulocytes, with apparently phenotipically normal progenitor cells in an early stage of the disease. Flow cytometry appears to be a useful tool in our knowledge of paroxysmal nocturnal hemoglobinuria evolution.