Long-term results of the Italian Association of Pediatric Hematology and Oncology (AIEOP) Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia.

We analyzed the long-term outcome of 4865 patients treated in Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia (ALL) of the Italian Association of Pediatric Hematology and Oncology (AIEOP). Treatment was characterized by progressive intensification of systemic therapy and reduction of cranial radiotherapy. A progressive improvement of results with reduction of isolated central nervous system relapse rate was obtained. Ten-year event-free survival increased from 53% in Study 82 to 72% in Study 95, whereas survival improved from 64 to 82%. Since 1991, all patients were treated according to Berlin-Frankfurt-Muenster (BFM) ALL treatment strategy. In Study 91, reduced treatment intensity (25%) yielded inferior results, but intensification of maintenance with high-dose (HD)-L-asparaginase (randomized) allowed to compensate for this disadvantage; in high-risk patients (HR, 15%), substitution of intensive polychemotherapy blocks for conventional BFM backbone failed to improve results. A marked improvement of results was obtained in HR patients when conventional BFM therapy was intensified with three polychemotherapy blocks and double delayed intensification (Study 95). The introduction of minimal residual disease monitoring and evaluation of common randomized questions by AIEOP and BFM groups in the protocol AIEOP-BFM-ALL 2000 are expected to further ameliorate treatment of children with ALL.

Treatment and long-term results in children with acute myeloid leukaemia treated according to the AIEOP AML protocols.

Since 1982, four consecutive studies on childhood acute myeloid leukaemia (AML) (namely LAM-82, -87, -87M and -92) have been conducted in Italy by the Associazione Italiana di Ematologia e Oncologia Pediatrica (AIEOP) group. The induction therapy of the first three studies consisted of daunorubicin and cytarabine structured in a 3+7 backbone. In the most recent protocol (LAM92), patients received two induction courses including idarubicin, cytarabine and etoposide. Patients with acute promyelocytic leukaemia (20% of diagnoses) were included in LAM-87 and 87M studies. Postremissional therapy significantly changed over time, with an ever-increasing role given to stem cell transplantation (SCT). The long-term outcome of patients enrolled in the LAM-82, 87 and 87M studies was comparable, whereas that of children treated according to LAM-92 study was significantly better (P<0.005). Either allogeneic or autologous SCT was employed as consolidation therapy in more than 75% of cases enrolled in this latter study. Patients enrolled in the LAM-92 study were stratified in standard and high-risk groups with different outcome (67 vs 47%, respectively, P=0.04). Altogether, the results obtained in these four studies have permitted a progressive refinement of treatment, contributing to the structure of the ongoing LAM-2002 protocol that stratifies patients according to the presence of definite genetic anomalies and response to induction therapy.

Differences in the proportions of fluoroquinolone-resistant Gram-negative bacteria isolated from bacteraemic children with cancer in two Italian centres.

The proportion of ciprofloxacin-resistant Gram-negative bacteria isolated from the blood of children with cancer (not receiving prophylaxis) was 10% in a paediatric hospital (Genoa) where the use of quinolones was highly restricted, compared with 41% in a department of haematology (Rome) where leukaemic adults, who received fluoroquinolone prophylaxis, were also treated (p < 0.0001). Moreover, simultaneous resistance to ciprofloxacin and ceftazidime, amikacin or imipenem-cilastatin was 11% in Genoa compared with 37% in Rome (p < 0.001). Ciprofloxacin resistance was more frequent in children who shared an environment with adults who were receiving ciprofloxacin prophylaxis.

Pre-transplant prognostic factors for patients with high-risk leukemia undergoing an unrelated cord blood transplantation.

From July 1995 to December 2001, 42 patients with leukemia aged 1-42 years underwent cord blood transplant (CBT) from unrelated, < or = 2 antigen HLA mismatched donors. In all, 26 patients were in < or = 2nd complete remission and 16 in more advanced phase. Conditioning regimens, graft-versus-host disease (GVHD) prophylaxis and supportive policy were uniform for all patients. The cumulative incidence of engraftment was 90% (95% CI: 0.78-0.91). The cumulative incidence of III-IV grade acute- and chronic-GVHD was 9% (95% CI: 0.04-0.24) and 35% (95% CI: 0.21-0.60), respectively. The 4-year cumulative incidence of transplant-related mortality (TRM) and relapse was 28% (95% CI: 0.17-0.47) and 25% (95% CI: 0.14-0.45), respectively. The 4-year overall survival (OS), leukemia-free survival (LFS) and event-free survival (EFS) were 45% (95% CI: 0.27-0.63), 47% (95% CI: 0.30-0.64) and 46% (95% CI: 0.30-0.62), respectively. In multivariate analysis, the most important factor affecting outcomes was the CFU-GM dose, associated with CMV serology (P=0.003 and 0.04, respectively) in influencing OS and with patient sex (P=0.008 and 0.03, respectively) in influencing LFS. Finally, CFU-GM dose was the only factor that affected EFS significantly (P=0.02). In conclusion, the infused cell dose expressed as in vitro progenitor cell growth is highly predictive of outcomes after an unrelated CBT and should be considered the main parameter in selecting cord blood units for transplant.

Allogeneic stem cell transplant from HLA-identical sibling for chronic granulomatous disease and review of the literature.

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency caused by an abnormal function of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in the phagocytic cells, which results in an increased susceptibility to severe bacterial and fungal infections. We report on a 12-year-old boy with X-linked CGD who was successfully treated with allogeneic bone marrow transplantation from an HLA-identical sibling following a conditioning regimen consisting of busulphan (BU, 16 mg/kg) and cyclophosphamide (CY, 200 mg/kg). At >2 years from transplant, the boy is in excellent clinical and hematological condition with full chimerism. Our patient is the 24th case of CGD transplanted from an HLA-identical sibling. A review of the literature revealed that 20 of 24 CGD patients are alive and disease free 1-7 years after transplant. Most of these patients were conditioned with the BUCY combination, which should be considered the recommended regimen.

Ear involvement in acute promyelocytic leukemia at relapse: a disease-associated 'sanctuary'?

Extramedullary (EM) involvement occurs infrequently in acute promyelocytic leukemia (APL) and usually involves skin and CNS. We describe seven patients (four observed at a single institution) who relapsed in various sites of the auditory apparatus, including the external canal and middle ear (temporal bone). Front-line treatment included ATRA and chemotherapy (six patients) or chemotherapy alone (one patient). Three patients had concomitant hematologic relapse, two had molecular relapse and two were in hematologic and molecular remission when ear localization was documented. Local symptoms that stimulated further diagnostic studies included ear bleeding/discharge in the first patient, but were mild in the others (hypoacusia, five patients; earache, two patients). Ear involvement by leukemia was documented by histological and/or molecular studies after local surgery in five cases, and by CT scan or NMR in the remaining patients. We suggest that the ear might represent a specific sanctuary for disease involvement in APL.

Listeriosis in recipients of allogeneic bone marrow transplants from unrelated donors.

Two cases of listeriosis in patients submitted to matched unrelated donor bone marrow transplantation are reported. The patients developed listerial septicemia and listerial septicemia with meningitis and encephalitis 39 and 29 days after transplantation, respectively. Including the present two cases, 19 Listeria monocytogenes infections in related and unrelated donor allogeneic bone marrow transplant recipients have been reported to date. Infection occurred earlier in unrelated donor transplant recipients. Listeriosis is a rare complication in allogeneic bone marrow transplant recipients; however, the widespread practice of performing transplants from a donor-alternative to a human leukocyte antigen-compatible sibling and, in this setting, the need for intensified immunosuppression may predict an increasing and earlier occurrence of listeriosis.

Idarubicin intensified BUCY2 regimen in allogeneic unmanipulated transplant for high-risk hematological malignancies.

Twenty-nine consecutive patients with high-risk hematological malignancy aged from 3 to 58 years underwent an unmanipulated graft from an HLA-identical sibling after an irradiation-free preparative regimen consisting of idarubicin (IDA), 21 mg/m2/day administered by continuous infusion on days -12 and -11, followed by busulphan (BU), 4 mg/kg/day orally from day -7 to -4, and cyclophosphamide (CY), 60 mg/kg/day intravenously on days -3 and -2 (IDA-BUCY2). Most clinically relevant extra-hematological regimen-related toxicities consisted of stomatitis observed in all subjects and hemorrhagic cystitis occurred in five cases (17%) within 100 days after transplant. Six patients (21%) developed a grade 2 acute graft-versus-host disease (GVHD) and three (10%) a grade 3 or 4; extensive chronic GVHD was assessed in nine of 22 (41%) evaluable patients. So far, 12 patients have died and 17 are alive, 16 of whom disease-free, 5-41 months after transplant (median, 15 months). The causes of death were related to GVHD in three patients, to sepsis in one and to disease recurrence in the remaining eight. At present, only one of nine relapsed patients is alive. For all patients the actuarial probability of survival (OS) at 1 and 2 years +/- standard error (s.e.) was 63 +/- 9% and 52 +/- 10%, respectively. The actuarial probabilities of disease-free survival (DFS), relapse and transplant-related mortality (TRM) at both 1 and 2 years +/- s.e. were 53 +/- 9%, 35 +/- 9% and 16 +/- 7%, respectively. These results are encouraging but not substantially different from those obtained in 28 patients with malignancy in advanced phase transplanted after the standard BUCY2 regimen, who had an actuarial probability of OS, DFS, relapse and TRM projected at 10 years +/- s.e. of 54 +/- 10%, 57 +/- 9%, 36 +/- 9% and 11 +/- 6%, respectively. Although the retrospective comparison between the two groups does not seem to show any advantage in the use of the IDA intensified regimen, only a prospective randomized trial could answer this question.

Umbilical cord blood transplant from unrelated HLA-mismatched donors in children with high risk leukemia.

In the last 3 years, 14 children with high-risk leukemia (11 ALL, 2 AML and 1 CML) underwent cord blood transplantation from unrelated HLA-mismatched donors at a median of 99 days from the start of search. Eight patients were transplanted in second CR, one in accelerated phase, three at relapse and two patients in first CR. Conditioning regimen (fractionated TBI, etoposide, CY and anti-lymphocyte serum) and prophylaxis of GVHD (CsA and 6-methylprednisolone) were identical for all patients. Neutrophils >0.5x10(9)/l were reached at a median of 33 days from transplant, but in four cases we observed an autologous hematopoietic reconstitution (three spontaneous, one after autologous BM rescue). Acute and chronic GVHD were observed in 10/14 and 3/8 evaluable cases, respectively. Three patients died of transplant-related toxicity and three patients relapsed. The probabilities of event-free, disease-free and overall survival were 50, 53 and 64%, respectively. Cord blood transplant from HLA-mismatched unrelated donor is a valid option for the treatment of children with high-risk leukemia. With our eligibility criteria, conditioning regimen and prophylaxis of graft-versus-host disease, the main obstacles to successful transplant were represented by graft failure and fatal acute GVHD.

Myelodysplastic syndrome, juvenile myelomonocytic leukemia, and acute myeloid leukemia associated with complete or partial monosomy 7. European Working Group on MDS in Childhood (EWOG-MDS).

We reviewed the clinical features, treatment, and outcome of 100 children with myelodysplastic syndrome (MDS), juvenile myelomonocytic leukemia (JMML), and acute myeloid leukemia (AML) associated with complete monosomy 7 (-7) or deletion of the long arm of chromosome 7 (7q-). Patients with therapy-induced disease were excluded. The morphologic diagnoses according to modified FAB criteria were: MDS in 72 (refractory anemia (RA) in 11, RA with excess of blasts (RAEB) in eight, RAEB in transformation (RAEB-T) in 10, JMML in 43), and AML in 28. The median age at presentation was 2.8 years (range 2 months to 15 years), being lowest in JMML (1.1 year). Loss of chromosome 7 as the sole cytogenetic abnormality was observed in 75% of those with MDS compared with 32% of those with AML. Predisposing conditions (including familial MDS/AML) were found in 20%. Three-year survival was 82% in RA, 63% in RAEB, 45% in JMML, 34% in AML, and 8% in RAEB-T. Children with -7 alone had a superior survival than those with other cytogenetic abnormalities: this was solely due to a better survival in MDS (3-year survival 56 vs 24%). The reverse was found in AML (3-year survival 13% in -7 alone vs 44% in other cytogenetic groups). Stable disease for several years was documented in more than half the patients with RA or RAEB. Patients with RA, RAEB or JMML treated with bone marrow transplantation (BMT) without prior chemotherapy had a 3-year survival of 73%. The morphologic diagnosis was the strongest prognostic factor. Only patients with a diagnosis of JMML fitted what has previously been referred to as the monosomy 7 syndrome. Our data give no support to the concept of monosomy 7 as a distinct syndrome.

Umbilical cord blood (UCB) transplant from unrelated mismatched donor in patients with high risk (HR) leukemia.

Ten consecutive children with high risk leukemia have been submitted to UCB transplant from unrelated HLA mismatched donors. All patients received an identical regimen for conditioning and GVHD prophylaxis. The median dose of viable nucleated cells infused was 2.6 x 10(6)/kg b.w. Among the nine patients evaluable for engraftment the hematopoiesis was of full donor origin in six patients and autologous in three. At a median follow-up of 9 months, six of nine (67%) patients are alive in CR.

Umbilical cord blood transplant from HLA-mismatched unrelated donor in high-risk leukemia.

Twelve consecutive children with high-risk leukemia have been submitted to UCB transplant from unrelated 1 or 2 loci HLA-mismatched donor. All patients received an identical regimen for conditioning and GVHD prophylaxis. The median dose of viable nucleated cells infused was 2.8 x 10(7)/kg bw (range 1.4-7.9). Of 11 patients evaluable for engraftment, the hematopoiesis was of full donor origin in seven patients and autologous in four. The probability of disease-free survival at 1 and 2 years from UCB transplant is 60 and 42%, respectively.

Unrelated donor marrow transplantation for inborn errors.

From December 1989 to December 1997 40 children aged 1 year to 19 years with inborn errors other than severe combined immunodeficiencies underwent unrelated donor (UD) bone marrow transplantation (BMT) in one of 10 institutions of the Italian Bone Marrow Transplant Group participating in this program. The diseases leading to BMT included Fanconi Anemia (10), Thalassemia (8), Wiskott Aldrich syndrome (5), haemophagocytic lymphohystiocytosis (6), osteopetrosis (3), storage diseases (6), Chediak Higashi syndrome (1), Schwachman syndrome (1). Thirty-three pairs were A, B, DRB1 matched. Three pairs were one antigen mismatched and one pair was two antigens mismatched. The remaining three pairs lacked information on molecular biology. Twelve children underwent a preparative regimen including radiotherapy. The remaining 28 children were conditioned with a chemotherapy regimen which included Busulfan. GvHD disease prophylaxis included CSA and MTX alone (9) or associated with ALG (17) or in vivo Campath 1G (12). The remaining two children received CSA alone. Thirty-five children showed donor engraftment; three children with thalassemia and one with osteopetrosis failed to engraft. Five children developed secondary graft failure. Actuarial 5 year disease-free survival was 62%; grade III-IV acute GvHD developed in seven of 38 evaluable children (18%); chronic GvHD developed in seven of 27 evaluable children (26%). We confirm that Wiskott Aldrich syndrome, HLH, and osteopetrosis represent an absolute indication for UD-BMT. Prognosis of UD-BMT for FA could improve in children grafted in an early phase, but a better preparative regimen has to be identified. UD-BMT in thalassemia is acceptable only in a restricted subset of patients selected for poor compliance to therapy.

Autologous bone marrow transplantation for treatment of isolated central nervous system relapse of childhood acute lymphoblastic leukemia. AIEOP/FONOP-TMO group. Associzione Italiana Emato-Oncologia Pediatrica.

The purpose of this study was to assess the role of ABMT in children with ALL who are in 2nd CR after an early isolated CNS relapse. All children experiencing an isolated CNS relapse at 10 AIEOP centers (Associazione Italiana Emato-Oncologia Pediatrica) from 1986 to 1992 were eligible for this study. The series included 69 patients who relapsed within 3 years from diagnosis: 19 underwent ABMT, nine patients underwent ALLO-BMT from an HLA-identical sibling, and 41 received conventional chemotherapy (CHEMO). Statistical analysis was performed using a Cox's regression model, adjusting for the waiting time before transplantation and prognostic factors. The 5 years DFS was 56.3% (s.e. 12.3) for patients in the ABMT group. This compared favorably with the poor result (12.6% (s.e. 5.9)) seen in the CHEMO group. The risk of failures was reduced by one-third in the ABMT group as compared to the CHEMO group in the multivariate analysis (P < 0.01). In the ALLO group four out of nine patients were in CCR 4-5 years post-transplant. This study suggests that ABMT may also represent a valuable therapeutic choice for patients lacking a matched familiar donor in 2nd CR after an early isolated CNS relapse.

Management of advanced acute lymphoblastic leukemia in children and adults: results of the ALL R-87 protocol. AIEOP and GIMEMA Cooperative Groups.

Fifty-seven patients aged < 55 years with acute lymphoblastic leukemia (ALL) in second or third bone marrow (BM) relapse or refractory to first-line therapy were enrolled in an Italian cooperative study. The ALL R-87 protocol included idarubicin (IDA) plus intermediate dose cytarabine (IDARA-C) and Prednisone (PDN) as induction, followed by a consolidation phase and BMT. Complete remission (CR) was achieved in 41/57 patients (72%). The CR rate was significantly higher in patients aged < 15 years at diagnosis and at time of treatment compared to those aged > or = 15 (84% vs 50%, p=0.01 and 85% vs 54%, p = 0.02, respectively). Nineteen of 41 responders (46.3%) underwent bone marrow transplant (BMT) (10 autologous and 9 allogeneic). The estimated probabilities of event free survival (EFS +/- SE) and survival +/- SE at 6 years were 0.13 +/- 0.05 and 0.20 +/- 0.06, respectively, for all enrolled patients. Univariate analysis showed that children had a better EFS rate compared to adults (0.16 +/- 0.07 vs 0.08 +/- 0.07, p = 0.014). The estimated probability of disease free survival (DFS +/- SE) at 6 years was 0.18 +/- 0.07 for all responders. No differences in DFS were observed between patients submitted to allogeneic or autologous BMT (0.33 +/- 0.16 vs 0.25 +/- 0.15). Among patients treated in second or third relapse, a first CR length > or = 48 months favorably influenced both DFS (p = 0.014) and EFS (p = 0.018). Our results show the efficacy of the intermediate dose ARA-C plus IDA schedule for high risk adult and childhood ALL patients. No differences in disease outcome were observed between allogeneic and autologous BMT.

ALL R-87 protocol in the treatment of children with acute lymphoblastic leukaemia in early bone marrow relapse.

Seventy-three children with acute lymphoblastic leukaemia (ALL) in first bone marrow (BM) relapse, occurring within 30 months from complete remission (CR), were enrolled in an Italian cooperative study (ALL R-87 protocol). This treatment programme consisted of an induction phase with intermediate-dose cytarabine (IDARA-C) plus idarubicin (IDA) and prednisone (PDN), followed by a multidrug consolidation therapy and bone marrow transplant (BMT). 55/73 children achieved CR (75.3%); 15 (20.5%) failed to respond and three (4.2%) died during induction. The response rate was significantly higher for children with a first CR duration > or = 12 months (P=0.0005) and for those with a white blood cell (WBC) count at relapse < 20 x 10(9)/l (P=0.004). The estimated disease-free survival (DFS +/- SE) at 82 months was 0.18 +/- 0.05 for all responders, and 0.70 +/- 0.14 for allotransplanted patients versus 0.05 +/- 0.05 for those autografted (P=0.001). The estimated probabilities of survival +/- SE and event-free survival (EFS +/- SE) at 83 months were 0.16 +/- 0.07 and 0.13 +/- 0.04, respectively. for all enrolled children. Univariate analysis showed that age < 10 years at initial diagnosis and B-lineage immunophenotype favourably influenced both DFS (P=0.001) and EFS probabilities (P=0.0014 and P=0.012, respectively), whereas a first CR duration > or = 12 months and a WBC count at relapse < 20 x 10(9)/l were associated only with a better EFS rate (P=0.026 and P=0.004, respectively). Our results show the efficacy of the IDA plus IDARA-C schedule used in the ALL R-87 protocol in high-risk relapsed ALL children. Allogeneic BMT proved effective for patients with an HLA sibling donor. In a multivariate analysis, age > or = 10 years at initial diagnosis (P=0.016) and WBC count at relapse > or = 20 x 10(9)/l (P=0.048) were independently associated with a worse disease outcome.

A single high dose of idarubicin combined with high-dose ABA-C (MSKCC ALL-3 protocol) in adult and pediatric patients with acute lymphoblastic leukemia. Experience at the University La Sapienza of Rome.

BACKGROUND AND OBJECTIVE: The anthracycline analogue idarubicin, either alone or in combination with other antineoplastic drugs, has shown antileukemic activity in relapsed and refractory acute lymphoblastic leukemia (ALL). In an attempt to minimize the non-hematologic toxicity and obtain a potent antileukemic effect, MSKCC activated a pilot study in previously treated adult ALL, using HD-ARA-C combined with idarubicin administered as a single high-dose infusion. We herein report our experience with a series of pediatric and adult high risk ALL and NHL patients treated with the protocol above, which confirms its feasibility, response rate and individual compliance. METHODS: In a clinical phase II study the combination of a single high dose (HD) idarubicin and HD cytosine-arabinoside (ARA-C), as designed at the Memorial Sloan Kettering Cancer Center, was applied to 70 adults and children with refractory or early relapse acute lymphoblastic leukemia (ALL) and T-cell lymphoblastic non-Hodgkin's lymphoma (NHL). Therapy consisted of HD-ARA-C 3 g/m2/d on days 1-5, idarubicin 40 mg/m2 on day 3, prophylactic intrathecal methotrexate on days 1 and 4, and G-CSF 5 mg/kg/d s.c. from day 7 to hematopoietic reconstitution (PMN > 0.5 x 10(9)/L). RESULTS: Fifty-five of the 70 patients (78%) achieved complete remission (CR), four died in aplasia due to infection and 11 were non-responders. Recovery of blood counts occurred at a median of 21 days from the start of treatment. Non-hematologic side effects were extremely limited and consisted predominantly of infections. INTERPRETATION AND CONCLUSIONS: In view of the highly unfavorable series of patients selected, this study confirms the feasibility and antileukemic activity of the HD-idarubicin + HD- ARA-C combination in patients with refractory and early relapse ALL and NHL. The excellent tolerance to this regimen does not preclude bone marrow transplantation as post-remission treatment.

Langerhans' cell histiocytosis in adults: a clinical and therapeutic analysis of 11 patients from a single institution.

BACKGROUND: Langerhans' cell histiocytosis (LCH) is a rare disorder of uncertain etiology, characterized by a wide clinical spectrum and varied behavior. METHODS: This retrospective study analyzed 11 adult patients with a diagnosis of LCH observed at the study institution between April 1988 and March 1993. RESULTS: Based on the sites and extent of disease at diagnosis, patients were divided into four categories. Group A was comprised of four patients with unifocal bone disease who had surgical curettage. At last follow-up only 1 patient was in continuous complete response (CCR) at 29+ months. The other 3 patients recurred at 3, 12, and 30 months, respectively, after surgery and at last follow-up were found to be in CR at 16+, 48+, and 124+ months, respectively, after therapy with vinblastine (VBL) and high dose methylprednisolone (HDMP). Group B was comprised of three patients with multifocal bone disease. Two of these patients received VBL + HDMP; at last follow-up, 1 patient was in CCR 8 months after completion of therapy, and the other developed progressive disease 11 months later. The third patient was treated with interferon (IFN) and at last follow-up was in CCR at 35+ months. Group C was comprised of 2 patients with bone and visceral disease who were treated with etoposide (VP-16) + HDMP; at last follow-up, 1 patient was in CCR at 42+ months and the other patient, who had isolated vulvar recurrence 16 months later, was in CR with treatment with local IFN. Group D was comprised of two patients with lung and lymph node involvement, one of whom was treated with VP-16 + HDMP and the other with cyclophosphamide, doxorubicin, vincristine, and prednisone; at last follow-up, both were in CCR at 30+ and 71+ months, respectively. CONCLUSIONS: VBL + HDMP showed efficacy in patients with bone disease, in particular those treated for recurrent LCH after surgery. Therapy with VP-16 and HDMP was successfully employed in patients with visceral disease. IFN was effective both for localized disease and in patients with multiple bone lesions.

Immunophenotype of adult and childhood acute lymphoblastic leukemia: changes at first relapse and clinico-prognostic implications.

The immunologic features of leukemic cells at the time of 1st hematologic relapse were compared to those obtained at initial diagnosis in 128 patients (69 children and 59 adults) with acute lymphoblastic leukemia (ALL) treated at a single institution. An immunophenotypic change was observed in 59 cases (46%), more frequently in T (20/25) than in B (39/103) lineage ALL (80 vs 38%, P=0.0008), but with a similar incidence in adults and children. Of these cases, 34 (24 B- and 10 T-ALL) changed at relapse their intralineage subgroup affiliation, although no complete shift from B to T lineage ALL, or vice versa, was observed. The myeloid antigens CD13 and/or CD33 were frequently lost (2/5 cases) or acquired (12/123 cases) at relapse. In 21 cases, the immunophenotype at relapse was more undifferentiated than at diagnosis, while it was more differentiated in 13 cases. Initial treatment intensity or preceding treatment with teniposide did not affect the phenotypic profile at relapse. Complete response (CR) rate to salvage therapy and event-free survival were not influenced by the immunophenotypic shifts, nor by the presence, at relapse, of leukemic cells expressing the myeloid antigens CD13 and/or CD33. Univariate analysis suggested that prognosis after relapse was dependent on the duration of 1st CR, patients' age and immunophenotype at the time of diagnosis, with a worse outcome for patients with T lineage ALL and for patients with the less differentiated subgroup of B lineage ALL (CD19+ and CD10-). Multivariate analysis showed that only two factors, duration of 1st CR and grade of immunologic differentiation at diagnosis, have independent prognostic value in relapsed ALL.