First-line R-CVP versus R-CHOP induction immunochemotherapy for indolent lymphoma with rituximab maintenance. A multicentre, phase III randomized study by the Polish Lymphoma Research Group PLRG4.

R-CVP (cyclophosphamide, vincristine, prednisone) and R-CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone + rituximab) are immunochemotherapy regimens frequently used for remission induction of indolent non-Hodgkin lymphomas (iNHLs). Rituximab maintenance (RM) significantly improves progression-free survival (PFS) in patients with complete/partial remission (CR/PR). Here we report the final results of a randomized study comparing R-CVP to R-CHOP both followed by RM. Untreated patients in need of systemic therapy with symptomatic and progressive iNHLs including follicular (FL) and marginal zone lymphoma (MZL), mucosa-associated lymphoid tissue (MALT), small lymphocytic (SLL), and lymphoplasmacytic (LPL) lymphoma were eligible. Patients were randomized to receive R-CVP or R-CHOP for eight cycles or until complete response (CR). All patients with CR/PR (partial response) received RM 375 mg/m2 q 2 months for 12 cycles. Primary endpoint was event-free survival (EFS). Two-hundred and fifty patients [FL 42%, MZL/MALT 38%, LPL/ Waldenström Macroglobulinaemia (WM) 11%, SLL 9%] were enrolled and randomized (R-CHOP: 127, R-CVP: 123). Median age was 56 years (21-85), 44% were male, 90% were in stage III-IV, 43% of FL patients had a Follicular Lymphoma International Prognostic Index (FLIPI) score ≥3, and 33·4% of all patients had an IPI score ≥3. At the end of induction treatment, the CR/PR rate was 43·6/50·9% and 36·3/60·8% in the R-CHOP and R-CVP groups (P = 0·218) respectively. After a median follow-up of 67, 66, and 70 months, five-year EFS was 61% vs. 56% (not significant), progression-free survival (PFS) was 71% vs. 69% (not significant) and overall survival (OS) was 84% vs. 89% in the R-CHOP vs. the R-CVP arm respectively. Grade III/IV adverse events (65 vs. 22) occurred in 40 (33·1%) and 18 (15·3%) patients, P = 0·001; neutropenia in 16 (11·6%) and 4 (3·4%) patients, P = 0·017; infection in 14 (10·7%) and 3 (2·5%) patients,; P = 0·011; and a second neoplasm in three versus seven patients., in the R-CHOP and the R-CVP groups respectively. This multicentre randomized study with >five-year follow-up shows similar outcome in patients with indolent lymphoma in need of systemic therapy treated with R-CVP or R-CHOP immunochemotherapy and rituximab maintenance in both arms. The minor toxicity of the R-CVP regimen makes it a reasonable choice for induction treatment, leaving other active agents like doxorubicin or bendamustin for second-line therapy.

Atypical chronic myeloid leukaemia: A case of an orphan disease-A multicenter report by the Polish Adult Leukemia Group.

Atypical chronic myeloid leukaemia (aCML) belongs to myelodysplastic/myeloproliferative neoplasms. Because of its rarity and changing diagnostic criteria throughout subsequent classifications, data on aCML are very scarce. Therefore, we at the Polish Adult Leukemia Group performed a nationwide survey on aCML. Eleven biggest Polish centres participated in the study. Altogether, 45 patients were reported, among whom only 18 patients (40%) fulfilled diagnostic criteria. Among misdiagnosed patients, myelodysplastic/myeloproliferative syndrome unclassifiable and chronic myelomonocytic leukaemia were the most frequent diagnoses. Thirteen patients were male, median age 64.6 years (range 40.4-80.9). The median parameters at diagnosis were as follows: white blood cell count 97 × 109 /L (23.8-342) with immature progenitors amounting at 27.5% (12-72), haemoglobin 8.6 g/dL (3.9-14.9), and platelet count 66 × 109 /L (34-833). Cytoreductive treatment was used in all patients, and 2 patients underwent allogeneic hematopoietic stem cell transplantation. The median overall survival was 14.1 months (95% CI, 7.2), with median acute myeloid leukaemia-free survival of 13.3 months (95% CI, 3.6-22.6). Cumulative incidence of acute myeloid leukaemia transformation after 1 year in aCML group was 12.5% (95% CI, 0%-29.6%). To conclude, aCML harbours a poor prognosis. Treatment options are limited, with allogeneic hematopoietic stem cell transplantation being the only curative method at present, although only a minority of patients are transplant eligible. Educational measures are needed to improve the quality of diagnoses.

Are myelodysplastic syndromes underdiagnosed in Poland? A report by the Polish Adult Leukaemia Group.

OBJECTIVES: The epidemiology of myelodysplastic syndromes (MDS) differs among countries. Here, we present the first epidemiological indices determined for Poland. METHODS: Twenty-one haematological centres participated in the study. Patients diagnosed with MDS and acute myeloid leukaemia (AML) with 20-29% blasts were enrolled. Data collection was conducted for strictly predefined period. RESULTS: The overall crude incidence rate for all MDS subtypes was 1.95 (95% CI, 1.81-2.09) per 100 000 person-years: 2.46 (95% CI, 2.24-2.69) for males and 1.47 (95% CI, 1.31-1.65) for females; after excluding AML cases, the indices were as follows: 2.35 (95% CI, 2.08-2.66) for males and 1.27 (95% CI, 1.08-1.5) for females. Prevalence rate was 6.2 per 100 000 persons (95% CI, 5.96-6.45), that is 6.86 (95% CI, 6.49-7.24) for males and 5.58 (95% CI, 5.26-5.92) for females. Both incidence and prevalence increased with increasing age. The most frequently diagnosed MDS subtype was refractory cytopenia with multilineage dysplasia (RCMD), responsible for 30.3% of all newly diagnosed MDSs. CONCLUSIONS: RCMD is the most frequent MDS subtype in Poland. Incidence and prevalence indices are lower than those reported for other populations, which probably results from inadequate diagnosis of potential cases of this disease.

Immune thrombocytopenia in patients with chronic lymphocytic leukemia treated with cladribine-based regiments or chlorambucil--follow-up of PALG-CLL randomized trials.

OBJECTIVES: The relationship between treatments of chronic lymphocytic leukemia (CLL) with cladribine (2-CdA) or chlorambucil and immune thrombocytopenia (IT) has not been yet determined. METHODS: The records of 777 patients in two randomized Polish Adult Leukemia Group (PALG)-CLL programs treated with these agents were retrospectively analyzed. RESULTS: Immune thrombocytopenia occurred in 55 of 777 (7.1%) patients. No significant differences in IT prevalence were seen between patients on chlorambucil or 2-CdA-based regiments (P = 0.33). IT developed at a median time of 0.499 yr (0.06-4.8) from the start of CLL therapy. This time was significantly longer in patients treated with chlorambucil (2.03 yr, 95% CI: 0.06-4.22) in relation to patients treated with 2-CdA-based regiments (0.52 yr, 95%CI: 0.34-0.69, P = 0.049). Overall survival (OS) of patients with IT and those without IT were similar (2.65 yr vs. 3.2 yr P = 0.23) but the severity of bleeding was more pronounced in the 2-CdA group. The responses to IT therapy were 35%, 54% and 75% for steroids, chemotherapy and splenectomy, respectively. CONCLUSIONS: In this study, an unexpectedly high percentage of IT incidence was demonstrated in patients with CLL requiring chemotherapy. Although no marked differences were seen in IT frequency in patients treated with 2-CdA-based regiments compared to chlorambucil regimen, the clinical course of hemorrhagic diathesis was more severe in 2-CdA group. Also, the time elapsed from study screening to IT diagnosis was significantly shorter in the 2-CdA group than in the chlorambucil group suggesting a causative relationship. The appearance of IT did not influence the median time of OS.

The early reduction of leukemic blasts in bone marrow on day 6 of induction treatment is predictive for complete remission rate and survival in adult acute myeloid leukemia; the results of multicenter, prospective Polish Adult Leukemia Group study.

The aim of this study was to prospectively evaluate the impact of early bone marrow response on complete remission (CR) rate and long-term outcome in adults with acute myeloid leukemia. Bone marrow cytology was assessed on day 6 of induction treatment in 164 patients, revealing the presence of ≥5% blasts in 61 cases. In this subgroup the CR rate was significantly lower compared to the remaining patients (P < 0.00001) resulting in decrease of the overall survival (P = 0.002). Persistence of ≥5% blasts in bone marrow on day 6 of induction is an easily available surrogate marker to be used for treatment decisions.

A single weekly dose of imatinib is sufficient to induce and maintain remission of chronic eosinophilic leukaemia in FIP1L1-PDGFRA-expressing patients.

Hypereosinophilic syndrome (HES) is defined as chronic, unexplained hypereosinophilia with organ involvement. A subset of HES patients presents an interstitial deletion in chromosome 4q12, which leads to the expression of an imatinib-responsive fusion gene, FIP1L1-PDGFRA. These patients are diagnosed as chronic eosinophilic leukaemia (CEL). We treated seven CEL and HES patients, six of which expressed FIP1L1-PDGFRA, with imatinib using initial daily doses ranging from 100 to 400 mg. In a remission maintenance phase, the patients were treated with imatinib once weekly. All imatinib-treated patients achieved a complete haematological remission (CHR), and five of the six patients with FIP1L1-PDGFRA expression exhibited molecular remission. The decreased imatinib doses were as follows: 200 mg/week in three patients, 100 mg/week in two patients and 100 mg/d in the remaining two patients. For remission maintenance, imatinib doses were set at 100 mg/week in five patients and 200 mg/week in two patients. At a median follow-up of 30 months all patients remained in CHR and FIP1L1-PDGFRA expression was undetectable in five of the six FIP1L1-PDGFRA-expressing patients. These data suggest that a single weekly dose of imatinib is sufficient to maintain remission in FIP1L1-PDGFRA- positive CEL patients.

Status of minimal residual disease after induction predicts outcome in both standard and high-risk Ph-negative adult acute lymphoblastic leukaemia. The Polish Adult Leukemia Group ALL 4-2002 MRD Study.

The treatment of adults with Philadelphia-negative acute lymphoblastic leukaemia (ALL) depends on the presence of risk factors including age, white blood cell count, immunophenotype and time to complete remission. In recent years, status of minimal residual disease (MRD) has been postulated as an additional risk criterion. This study prospectively evaluated the significance of MRD. Patients were treated with a uniform Polish Adult Leukemia Group (PALG) 4-2002 protocol. MRD status was assessed after induction and consolidation by multiparametric flow cytometry. Out of 132 patients included (age, 17-60 years), 116 patients were suitable for analysis. MRD level >/=0.1% of bone marrow cells after induction was found to be a strong and independent predictor for relapse in the whole study population (P < 0.0001), as well as in the standard risk (SR, P = 0.0003) and high-risk (P = 0.008) groups. The impact of MRD after consolidation on outcome was not significant. The combination of MRD status with conventional risk stratification system identified a subgroup of patients allocated to the SR group with MRD <0.1% after induction who had a very low risk of relapse of 9% at 3 years as opposed to 71% in the remaining subjects (P = 0.001). We conclude that MRD evaluation after induction should be considered with conventional risk criteria for treatment decisions in adult ALL.

Red Blood Cell Transfusion Dependency and Hyperferritinemia Are Associated with Impaired Survival in Patients Diagnosed with Myelodysplastic Syndromes: Results from the First Polish MDS-PALG Registry.

BACKGROUND: Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal stem cell disorders characterized by ineffective hematopoiesis, cytopenias and a risk of progression to acute myeloid leukemia (AML). Anemia is the most frequent cytopenia diagnosed in patients with MDS. Regular RBC transfusions are the only treatment option for about 40% of patients. Transfusion-dependent patients develop secondary iron overload. The influence of serum ferritin (SF) concentration on survival and acute myeloid leukemia transformation in MDS patients remains controversial. The data for the Central European population is scarce and so far there is no description for Poland. OBJECTIVES: The aim of this study was to perform a retrospective analysis of the relationship of SF concentration with red blood cell transfusion dependency, survival and transformation to acute myeloid leukemia. MATERIAL AND METHODS: We retrospectively evaluated the data of the 819 MDS patients (58% male; median age 70 years) included in the MDS Registry of the MDS Section of the Polish Adult Leukemia Group (PALG). RESULTS: Analyses were performed on 190 patients diagnosed with MDS, maximal 6 months before inclusion to the registry in order to avoid selection bias (a shorter survival of higher risk MDS patients). Patients with hyperferritinemia higher than 1000 ng/L vs. patients with SF concentration lower than 1000 ng/L had a median survival of 320 days vs. 568 days, respectively (p log-rank = 0.014). The following factors were found to significantly worsen survival: RBC-transfusion dependence (p = 0.0033; HR 2.67L), platelet transfusion dependence (p = 0.0071; HR 3.321), hemoglobin concentration lower than 10 g/dL (p = 0.0036; HR 2.97), SF concentration higher than 1000 ng/L (p = 0.0023; HR = 2.94), platelet count lower than 10 G/L (p = 0.0081 HR = 5.04), acute leukemia transformation (p = 0.0081; HR 1.968). CONCLUSIONS: Taking into account the relatively low number of patients in previous studies exploring hyperferritinemia in MDS, the results of the first Polish MDS Registry provide important insights. Hyperferritinemia higher than 1000 ng/L can be an important indicator of poor prognosis in MDS.

Successful treatment of pure red cell aplasia with repeated, low doses of rituximab in two patients after ABO-incompatible allogeneic haematopoietic stem cell transplantation for acute myeloid leukaemia.

We describe two patients with acute myeloid leukemia successfully treated with anti-CD20 antibody for pure red cell aplasia (PRCA) following ABO-mismatched allogeneic hematopoietic stem cell transplantation (HSCT). PRCA following HSCT is associated with major ABO incompatibility between donor and recipient and is due to an inhibition of donor erythroid precursors by residual host isoagglutinins. The first patient developed PRCA resistant to several treatment options including donor-derived leukocyte infusions (DLI), high-dose erythropoietin (EPO), and rapid tapering of cyclosporin A (CsA). This patient also received anti-viral therapy as CMV and parvovirus B19 infections were regarded as additional causes of PRCA. Due to a loss of donor chimerism, he underwent second HSCT, but PRCA still persisted. He showed no evidence of graft-versus-host disease (GVHD). Finally he was administered anti-CD20 antibody (rituximab) at a dose of 150/m2 and PRCA resolved in a short period of time. The case was complicated by life-threatening pulmonary aspergillosis with septic shock, successfully treated with anti-fungal therapy. The second case concerns a patient, who revealed PRCA after major ABO-incompatible HSCT from his brother. Considering our experience with the previously described patient, he proceeded to rituximab at a dose of 150/m2 as first line treatment. We observed rapid recovery from PRCA without any side effects. We conclude that rituximab seems to be a promising therapeutic option in patients with PRCA after ABO-mismatched HSCT, in whom conventional treatment fails.

[Clinical application of anagrelide as a selective inhibitor of megakaryocyte system]. / Kliniczne wykorzystanie anagrelidu jako selektywnego inhibitora ukladu megakariocytowego.

Anagrelid is, in our country, comparatively a new compound selectively affecting the megakaryocyte line in bone marrow leading to its reversal inhibition, simultaneously showing some exceptional, interesting pharmacological features. Essential trombocythemia, being a sole indication for the drug administration, is one of the chronic myeloproliferative disorders which exposes individuals to significantly increased risk for thrombohaemorrhagic complications. Regarding the latest literature data, the most present therapeutic modalities in this disease were presented focusing the interest on anagrelid being, in majority of cases, the drug of choice in uncontrolled megakaryocyte proliferation. The drug therapeutic value and characteristics were presented on the background of another compounds regarded as standard therapeutic options for essential thrombocythemia.

Role of rituximab in the first-line therapy of high-risk diffuse large B-cell lymphoma: a retrospective analysis by the Polish Lymphoma Research Group.

INTRODUCTION: R-CHOP immunochemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) is a standard first-line treatment for diffuse large B-cell lymphoma (DLBCL). None of the randomized trials have proved a statistically significant overall survival (OS) benefit in high-risk subgroups according to the International Prognostic Index (IPI). OBJECTIVES: We retrospectively investigated the role of adding rituximab to anthracycline-based chemotherapy in patients with high-risk DLBCL according to the IPI. PATIENTS AND METHODS: A total of 371 patients with high-risk DLBCL treated at 15 Polish hematology centers were retrospectively analyzed in 2 distinct age groups: older than 60 years and 60 years old or younger. Response rates, OS, and progression-free survival (PFS) were compared and analyzed. RESULTS: The overall response rate (ORR) of high-risk DLBCL patients significantly improved in rituximabtreated patients compared with patients treated without rituximab (76.7% vs 95.6%; P <0.05). The R-CHOP immunochemotherapy prolonged survival in both older and younger subgroups. The 5-year projected OS and PFS in younger patients treated with rituximab vs chemotherapy alone were 42% vs 38% and 46% vs 27%, respectively (P <0.05), while the 5-year projected OS and PFS in older patients treated with rituximab vs chemotherapy alone were 82% vs 52% and 67% vs 45%, respectively (P <0.05). CONCLUSIONS: With all the limitations of a retrospective analysis, the superiority of adding rituximab to CHOP combination chemotherapy has been clearly demonstrated regarding ORR, OS, and PFS in both age subgroups of patients with high-risk DLBCL.

Cladribine combined with cyclophosphamide is highly effective in the treatment of chronic lymphocytic leukemia.

The aim of the study was to evaluate the activity and toxicity of cladribine (2-CdA) in combination with cyclophosphamide (CY), the CC schedule, in patients with previously untreated B-cell chronic lymphocytic leukemia (B-CLL). From November 1998 to May 2002 82 patients with advanced or progressive B-CLL received treatment with 2-CdA at a dose of 0.12 mg/kg for three consecutive days and CY at a dose of 650 mg/m(2) on day 1. The cycles were repeated at four week intervals or longer if severe myelosuppression occurred. Guidelines for the evaluation of response and toxicity were those developed by the National Cancer Institute sponsored Working Group. Minimal residual disease (MRD) was detected by immunophenotyping only in patients with CR by standard criteria. In the analysed group an overall response (OR) rate (CR+PR) of 87.8% (95% CI 80.7-94.9%) was achieved, including complete response (CR) in 29.3% patients (95% CI 19.4-39.1%). Twenty-two of 24 patients with CR and 39 of 48 patients with PR are still in remission. Median duration of follow-up in these patients is 11.8 months (range 3-25.4). MRD was only detected in six out of 24 (25%) patients with CR. Grade III/IV thrombocytopenia was seen in four patients (4.9%) and neutropenia in 10 (12.2%). Severe infections were noted in 21 (25.6%) patients. Thirteen patients died, including seven with treatment related toxicity, one because of CLL progression and five because of reasons not related to CLL. In conclusion, the CC schedule is a highly active regimen in previously untreated B-CLL, with acceptable toxicity. The efficacy of the regimen seems to be higher than observed earlier after treatment with 2-CdA alone. A randomized clinical trial is in progress in our institutions.

[Preliminary results of monotherapy with thalidomide in recurrent and treatment resistant cases of multiple myeloma]. / Wstepne wyniki monoterapii talidomidem w nawrotowych i opornych na leczenie postaciach szpiczaka mnogiego.

Thalidomide is an antiangiogenic drug, but its mechanism of action is not well known and demands further studies. The recent literature suggests that thalidomide is an effective drug in multiple myeloma patients. The objective of the study was to estimate the efficacy of thalidomide monotherapy in the treatment of refractory and relapsed cases of multiple myeloma. We treated with thalidomide 17 patients (12 males, 5 females), average age 51 (range 42-73 years), mean time since diagnosis to the start of thalidomide treatment was 24 months (range 5-48). All patients revealed the features of progressive disease. The mean number of prior chemotherapy schemes was 2. Three out of 17 patients received high dose chemotherapy followed by autologous stem cell transplantation. Thalidomide was administered as monotherapy at a dose of 200 mg (n = 8), 300 mg (n = 1) and 400 mg (n = 8). The mean time of drug intake was 3 months (1-12). The criteria of clinical response were decline of paraprotein at least 25%, 50% and 75% in comparison to value before the treatment. In 5 cases (33%) 25% reduction of paraprotein was observed, 1 patient achieved 50% decline. In the responder group a tendency to decrease marrow plasmocytosis, total serum protein, beta M-2 and LDH was noticed. The good tolerance of the drug, especially in lower doses, and lack of myelosuppression effect allows to expect, that the combination of thalidomide with other cytostatic drugs will improve the efficacy in patients with refractory or relapsed myeloma.

[Current principles of Wilson's disease--diagnosis and treatment]. / Aktualne zasady diagnostyki i leczenia choroby Wilsona.

Wilson's disease defined also as hepatolenticular degeneration is an important clinical problem of young adults still causing diagnostic difficulties. In the course of the last decade, genetic background of the disease has been definitely established and elucidated, confirming the variety of genetic mutations, responsible for its origin. The current scheme of the disease treatment has been elaborated and established. It aims to eliminate the excess of toxic copper ions from the organism as fast as possible. In the initial phase of the treatment, traditional and recently introduced chelating agents administration usually results in prompt tissue copper deposits excretion and copper metabolism balance maintenance. In the chronic therapy, zinc compounds, inducing intestinal and hepatic metallothionein synthesis, have been gaining more common application. Life-long, constant, pharmacological Wilson's disease therapy, administered after its early diagnosis, allows for long periods of patients survival, frequently comparable to the normal population.

Long-term results of the Polish Adult Leukemia Group PALG-CLL2 phase III randomized study comparing cladribine-based combinations in chronic lymphocytic leukemia.

Long-term outcomes following newer therapies for chronic lymphocytic leukemia (CLL) have rarely been reported. This article presents the results of the final analysis of the Polish Adult Leukemia Group PALG-CLL2 study performed 10 years from final patient enrollment. With the extended follow-up time, it was found that cladribine (2-CdA)-based combinations CMC (2-CdA, cyclophosphamide, mitoxantrone) and CC (2-CdA, cyclophosphamide) administered as first-line treatment of progressive CLL resulted in significantly longer progression-free survival, but similar overall survival compared to 2-CdA monotherapy. Furthermore, the risk of potentially fatal late adverse events including infections, autoimmune complications and, particularly, secondary neoplasms was comparable among patients treated with CMC, CC or 2-CdA. The results of our analysis support the importance of long-term outcome monitoring of randomized trials in CLL.

Comparison of cladribine plus cyclophosphamide with fludarabine plus cyclophosphamide as first-line therapy for chronic lymphocytic leukemia: a phase III randomized study by the Polish Adult Leukemia Group (PALG-CLL3 Study).

PURPOSE Little is known about comparison of the activity of different purine nucleoside analogs in chronic lymphocytic leukemia (CLL). We conducted a randomized phase III trial to compare efficacy and safety of cladribine and fludarabine, each combined with cyclophosphamide, in previously untreated progressive CLL. PATIENTS AND METHODS Patients received cladribine at 0.12 mg/kg combined with cyclophosphamide at 250 mg/m(2) for 3 days intravenously (CC regimen) or fludarabine at 25 mg/m(2) combined with cyclophosphamide at 250 mg/m(2) for 3 days intravenously (FC regimen), every 28 days for up to six cycles. The primary end point was complete response (CR) rate. Secondary end points included overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and treatment-related toxicity. RESULTS Of 423 randomly assigned patients (211 to CC and 212 to FC), 395 were evaluated in the final analysis. The CR and ORR reached 47% and 88% in the CC arm and 46% and 82% in the FC arm (P = .25 and P = .11, respectively). The median PFS was 2.34 years with CC and 2.27 years with FC (P = .51). OS and grade 3/4 treatment-related toxicity were also comparable. Moreover, we did not observe any significant differences in CC and FC efficacy across different patient prognostic subgroups that included patients with 17p13 (TP53 gene) deletion who had poor survival in both study arms. CONCLUSION Cladribine and fludarabine in combination with cyclophosphamide are equally effective and safe first-line regimens for progressive CLL. Both combinations have unsatisfactory activity in patients with 17p13 (TP53 gene) deletion.

Pure red-cell aplasia following major and bi-directional ABO-incompatible allogeneic stem-cell transplantation: recovery of donor-derived erythropoiesis after long-term treatment using different therapeutic strategies.

Blood group incompatibility between donor and recipient of allogeneic stem cell transplants may be associated with post-transplant erythroid aplasia. A total of 548 patients (pts) received allogeneic transplant for malignant and non-malignant hematologic disorders. In a retrospective analysis, the prevalence and outcome of pure red-cell aplasia (PRCA) in 44 pts with major and bi-directional ABO-mismatch were investigated. Bone marrow grafts were major ABO incompatible in 30 pts; there was bi-directional mismatch in the remaining 14 pts. The median number of transplanted mononuclear cells (NC) was 4.74 x 10(8)/kg (range 0.1-26.4) including CD34+ cells, 3.02 x 10(6)/kg (range 0.9-21.7). Granulocyte engraftment >0.5 x 10e9/l occurred after a median of 21 days (7-32), and platelet exceeded >50 x 10e9/l after a median of 23.5 days (12-109). Acute and chronic graft vs host disease (GVHD) developed in 23 (52%) and 26 (59%) of the patients, respectively. Six (13%) patients transplanted with major and bi-directional ABO-incompatibility developed PRCA. The treatment of PRCA consisted of plasmapheresis (PEX), rapid cyclosporine (CsA) discontinuation, donor lymphocyte infusions (DLI), erythropoietin (EPO), azathioprine, and rituximab. The therapy resulted in erythroid recovery in five out of six patients after a median of 13 months (range 3-16). The median number of transfused red blood cells (RBCs) was 36 U (range 8-57). With a median follow-up of 37 months, the 5-year probability of overall survival (OS) for the PRCA group was 66%. Major ABO mismatch may lead to delayed donor erythroid engraftment. It results in long-term transfusion dependence and, therefore, the risk of iron overload. The therapy is long lasting, but usually effective in majority of patients.