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The introduction of pediatric-inspired regimens in adult Philadelphia-negative acute lymphoblastic leukemia (Ph- ALL) has significantly improved patients' prognosis. Within the Campus ALL network, we analyzed the outcome of adult Ph- ALL patients treated according to the GIMEMA LAL1913 protocol outside the clinical trial to compare the real-life data with the study results. We included 421 consecutive patients; median age 42 years. The complete remission (CR) rate after the first course of chemotherapy was 94%, and measurable residual disease (MRD) negativity after the third course was achieved in 72% of patients. The 3-year overall survival (OS) and disease-free survival (DFS) were 67% and 57%, respectively. In a multivariate analysis, MRD positivity negatively influenced DFS. In a time-dependent analysis including only very high-risk (VHR) and MRD positive cases, transplanted (hematopoietic stem cell transplantation [HSCT]) patients had a significantly better DFS than non-HSCT patients (P=0.0017). During induction, grade ≥2 pegaspargase-related hepato-toxicity was observed in 25% of patients (vs. 12% in the GIMEMA LAL1913 trial, P=0.0003). In this large, real-life cohort of Ph- ALL, we confirmed the very high CR rate and a superimposable OS and DFS compared to the GIMEMA LAL1913 clinical trial (CR rate after C1, 94% vs. 85%, P=0.0004; 3-year OS, 67% vs. 67%, P=0.94; 3-year DFS, 57% vs. 63%, P=0.17). HSCT confirms its important role in VHR and MRD-positive patients. The rate of pegaspargase-related toxicity was significantly higher in the real-life setting, emphasizing the importance of dose adjustment in the presence of risk factors to avoid excessive toxicity.

The administration of TKIs after Allo-SCT in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) remains controversial, and the TKI approach (prophylactic, pre-emptive or salvage) is still heterogeneous in transplant centers. In this context, very little is known about the feasibility and safety of third-generation TKIs. In this paper, we analyze the efficacy and safety of ponatinib (PONA) administered after Allo-SCT to prevent cytologic relapse of Ph + ALL. This is a multicenter observational study including 48 patients (pts) with Ph + ALL (median age 49 years) who received PONA after Allo-SCT while in complete cytological remission (cCR); 26 (54%) had positive minimal residual disease (MRD pos) before Allo-SCT. PONA was administered after Allo-SCT prophylactically (starting with MRD neg) in 26 pts or pre-emptively (starting with MRD pos post-SCT and without hematological relapse) in 22 pts. Patients treated prophylactically with PONA started treatment earlier, at a median of 4.3 months (range 1.5-6) after Allo-SCT, than those treated pre-emptively, who started PONA at a median of 7.4 months (range 2-63) after Allo-SCT ( p = 0.01). The median starting dose of PONA was 30 mg/day (range 15-45). A dose reduction was required in 10/48 (21%) of cases, but a permanent discontinuation of PONA, due to toxicity, was required in only 5/48 pts (10.5%). No deaths due to PONA-related adverse events (AEs) were reported. The median follow-up time after Allo-SCT was 34 months (range 7.7-118). At the last follow-up, the median duration of PONA therapy was 22 months (range 2-100). The 5-year OS and RFS after Allo-SCT were 92% and 71%, respectively. The 5-year RFS after Allo-SCT of pts who received PONA prophylaxis was 95%, and it was 57% for those who received PONA pre-emptively (log-rank p = 0.02). In conclusion, this multicenter analysis of 48 patients with Ph + ALL undergoing Allo-SCT while in CcR, although with the caution of the retrospective data, supports the feasibility of PONA maintenance strategy after Allo-SCT with a low rate of discontinuations (10.5%) due to PONA-related AE.

Pediatric-inspired chemotherapy is the standard of care for younger adults with Philadelphia chromosome-negative acute lymphoblastic leukemia/lymphoma (Ph- ALL/LL). In LAL1913 trial, the Gruppo Italiano Malattie EMatologiche dell'Adulto added pegaspargase 2000 IU/m2 to courses 1, 2, 5, and 6 of an 8-block protocol for patients aged from 18 to 65 years, with dose reductions in patients aged >55 years. Responders were risk stratified for allogeneic hematopoietic cell transplantation (HCT) or maintenance per clinical characteristics and minimal residual disease (MRD). Of 203 study patients (median age, 39.8 years), 91% achieved a complete remission. The 3-year overall survival, event-free, and disease-free survival (DFS) rates were 66.7%, 57.7%, and 63.3%, respectively, fulfilling the primary study end point of a 2-year DFS >55%. Although based on the intention-to-treat, the DFS being 74% and 50% in the chemotherapy (n = 94) and HCT (n = 91) assignment cohorts, respectively, a time-dependent analysis proved the value of HCT in patients who were eligible (DFS HCT 70% vs no HCT 26%; P <.0001). In multivariate analysis, age and MRD were independent factors predicting DFS rates of 86% (age ≤ 40 and MRD-negative), 64%-65% (MRD-positive or age > 40) and 25% (age > 40 and MRD-positive); P < .0001. Grade ≥2 pegaspargase toxicity was mainly observed at course 1, contributing to induction death in 2 patients but was rare thereafter. This program improved outcomes of patients with Ph- ALL/LL aged up to 65 years in a multicenter national setting. This trial was registered at www.clinicaltrials.gov as #NCT02067143., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Within the Campus ALL network we analyzed the incidence, characteristics, treatment and outcome of a central nervous system (CNS) relapse in 1035 consecutive adult acute lymphoblastic leukemia (ALL) patients treated frontline with pediatric-inspired protocols between 2009 and 2020. Seventy-one patients (6.8%) experienced a CNS recurrence, more frequently in T- (28/278; 10%) than in B-ALL (43/757; 5.7%) (p = 0.017). An early CNS relapse-< 12 months from diagnosis-was observed in 41 patients. In multivariate analysis, risk factors for early CNS relapse included T-cell phenotype (p = <0.001), hyperleucocytosis >100 × 10 9 /L (p<0.001) and male gender (p = 0.015). Treatment was heterogeneous, including chemotherapy, radiotherapy, intrathecal therapy and novel agents. A complete remission (CR) was obtained in 39 patients (55%) with no differences among strategies. After CR, 26 patients underwent an allogenic transplant, with a significant overall survival benefit compared to non-transplanted patients (p = 0.012). After a median observation of 8 months from CNS relapse, 23 patients (32%) were alive. In multivariate analysis, the time to CNS relapse was the strongest predictor of a lower 2-year post-relapse survival (p<0.001). In conclusion, in adult ALL the outcome after a CNS relapse remains very poor. Effective CNS prophylaxis remains the best approach and allogenic transplant should be pursued when possible., (© 2022 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Tyrosine kinase inhibitors have improved survival for patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). However, prognosis for old or unfit patients remains poor. In the INCB84344-201 (formerly GIMEMA LAL 1811) prospective, multicenter, phase 2 trial, we tested the efficacy and safety of ponatinib plus prednisone in newly diagnosed patients with Ph+ ALL ≥60 years, or unfit for intensive chemotherapy and stem cell transplantation. Forty-four patients received oral ponatinib 45 mg/d for 48 weeks (core phase), with prednisone tapered to 60 mg/m2/d from days-14-29. Prophylactic intrathecal chemotherapy was administered monthly. Median age was 66.5 years (range, 26-85). The primary endpoint (complete hematologic response [CHR] at 24 weeks) was reached in 38/44 patients (86.4%); complete molecular response (CMR) in 18/44 patients (40.9%) at 24 weeks. 61.4% of patients completed the core phase. As of 24 April 2020, median event-free survival was 14.31 months (95% CI 9.30-22.31). Median overall survival and duration of CHR were not reached; median duration of CMR was 11.6 months. Most common treatment-emergent adverse events (TEAEs) were rash (36.4%), asthenia (22.7%), alanine transaminase increase (15.9%), erythema (15.9%), and γ-glutamyltransferase increase (15.9%). Cardiac and vascular TEAEs occurred in 29.5% (grade ≥3, 18.2%) and 27.3% (grade ≥3, 15.9%), respectively. Dose reductions, interruptions, and discontinuations due to TEAEs occurred in 43.2%, 43.2%, and 27.3% of patients, respectively; 5 patients had fatal TEAEs. Ponatinib and prednisone showed efficacy in unfit patients with Ph+ ALL; however, a lower ponatinib dose may be more appropriate in this population. This trial was registered at www.clinicaltrials.gov as #NCT01641107., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

In acute lymphoblastic leukemia, flow cytometry detects more accurately leukemic cells in patients' cerebrospinal fluid compared to conventional cytology. However, the clinical significance of flow cytometry positivity with a negative cytology - occult central nervous system disease - is not clear. In the framework of the national Campus ALL program, we retrospectively evaluated the incidence of occult central nervous system disease and its impact on outcome in 240 adult patients with newly diagnosed acute lymphoblastic leukemia. All cerebrospinal fluid samples were investigated by conventional cytology and flow cytometry. The presence of ≥10 phenotypically abnormal events, forming a cluster, was considered as flow cytometry positivity. No central nervous system involvement was documented in 179 patients, while 18 were positive by conventional morphology and 43 were occult central nervous system disease positive. The relapse rate was significantly lower in central nervous system disease negative patients and the disease-free and overall survival were significantly longer in central nervous system disease negative patients than in those with manifest or occult central nervous system disease positive. In multivariate analysis, the status of manifest and occult central nervous system disease positivity was independently associated with a worse overall survival. In conclusion, we demonstrate that in adult acute lymphoblastic leukemia patients at diagnosis flow cytometry can detect occult central nervous system disease at high sensitivity and that the status of occult central nervous system disease positivity is associated with an adverse outcome. (Clinicaltrials.gov NCT03803670).

The outcome of relapsed or refractory (R/R) T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/T-LBL) in adults is poor, with less than 20% of patients surviving at 5 years. Nelarabine is the only drug specifically approved for R/R T-ALL/T-LBL, but the information to support its use is based on limited available data. The aim of this observational phase four study was to provide recent additional data on the efficacy and safety of nelarabine in adults with R/R T-ALL/T-LBL and to evaluate the feasibility and outcome of allogeneic hematopoietic stem cell transplant (SCT) after salvage with nelarabine therapy. The primary endpoints were overall response rate (ORR) and overall survival (OS). Additional endpoints were safety, SCT rate and post-SCT OS. Between May 2007 and November 2018, 118 patients received nelarabine salvage therapy at 27 Italian hematology sites. The median age was 37 years (range 18-74 years), 73% were male, 77 had a diagnosis of T-ALL and 41 of T-LBL, and 65/118 (55%) had received more than two lines of therapy. The median number of nelarabine cycles was two (range 1-4); 43/118 (36%) patients had complete remission (CR), 16 had partial remission (14%) and 59 (50%) were refractory, with an ORR of 50%. The probability of OS, from the first dose of nelarabine, was 37% at 1 year with a median survival of 8 months. The OS at 1 year was significantly better for the 47 patients (40%) who underwent SCT after nelarabine salvage therapy (58% vs 22%, log-rank P < .001). The probability of OS at 2 and 5 years from SCT was 46% and 38%, respectively. Seventy-five patients (64%) experienced one or more drug-related adverse events (AE). Grade III-IV neurologic toxicities were observed in 9/118 (8%) of cases and thrombocytopenia or/and neutropenia (grade III-IV) were reported in 41% and 43% of cases, respectively. In conclusion, this is one of the largest cohorts of adult patients with R/R T-ALL/T-LBL treated in real life with nelarabine. Taking into account the poor prognosis of this patient population, nelarabine represents an effective option with an ORR of 50% and a CR rate of 36%. In addition, 40% of cases following nelarabine salvage therapy could undergo SCT with an expected OS at 2 and 5 years of 46% and 38%, respectively. The safety profile of nelarabine was acceptable with only 8% of cases showing grade III-IV neurological AE., (© 2020 Wiley Periodicals LLC.)

Background: Fertility and gonadal function represent one of the most important aspects for long-term lymphoma survivors., Aims: The aim of our study was to determine possible risk factors, such as age at treatment, chemotherapeutic regimen, protection with oral contraceptives (OCs), and gonadotropin-releasing hormone (GnRH) analogues in female patients treated for Hodgkin's lymphoma (HL) or non-Hodgkin lymphoma (NHL) at a reproductive age., Methods: Patients between the age of 16 and 50 years at the time of HL or NHL diagnosis were selected. Eligible patients were requested to respond to a questionnaire by phone interview about fertility, menstrual status, sexual aspects, and treatment with OCs or GnRH analogues during chemotherapy., Results: The resumption of menstrual activity was associated with the use of the OCs and GnRH analogues during chemotherapy (p = 0.008 and 0.034, respectively). At univariate analysis, the use of OCs during chemotherapy was associated with a lower risk of amenorrhea (prevalence ratio [PR] = 0.37; 95% CI 0.17-0.82). A higher age at the time of treatment correlated positively with therapy-induced amenorrhea, with a difference of 12.8 years between the mean age at diagnosis of the women with therapy-induced amenorrhea and those who resumed their menses. Amenorrhea was significantly higher in women receiving R-CHOP than in women treated with ABVD (PR = 6.00; 95% CI 2.32-15.54). Moreover, NHL had an infertility PR of 1.51 (95% CI 0.86-2.45) at multivariate analysis compared to HL., Conclusions: This study suggests a possible role of pharmacological prophylaxis with OCs and GnRH analogues., (© 2019 S. Karger AG, Basel.)

In the spectrum of diffuse large B-cell lymphomas (DLBCL), both T-cell/histiocyte-rich large B-cell lymphoma (TCHRBCL) and most lymphomatoid granulomatosis (LG) cases are characterized by the relative rarity of the neoplastic B-cell population, with respect to the overwhelming non-neoplastic counterpart of T cells or histiocytes. Here we report a case of aggressive B-cell lymphoma with unusual clinicopathological features partially overlapping these two entities. The patient was a previously healthy 55-year-old male, presenting with a computed tomography finding of a pelvic mass, inguinal lymphadenopathies, and pulmonary nodules. Two excisional lymph node biopsies resulted inconclusive for lymphoproliferative disease. Because of a colonic perforation, the patient underwent an urgent laparotomy, which disclosed a large pelvic abscess. The pathological examination of the surgical specimen could not discriminate between a primary aggressive B-cell lymphoproliferative disorder and an abnormal inflammatory hyper-reaction. The patient developed a septic state, not resolving until death, which occurred because of an abdominal hemorrhage. A second perimortem surgical specimen consisting of a nodal mass revealed a diagnosis of an Epstein-Barr virus-negative high-grade large B-cell lymphoma with massive necrosis, angiocentric pattern of growth, and prominent T-cell infiltrate. The unique clinicopathological features did not allow to classify this tumor within any of the recognized WHO entities, potentially representing a new clinicopathological variant of DLBCL in-between TCHRBCL and LG.

We prospectively evaluated 2 postconsolidation strategies, administered according to the mobilization outcome, in 72 acute myeloid leukemia (AML) fit elderly patients, achieving complete remission after the first high-dose cytarabine-based induction. Autologous stem cell transplantation (ASCT) was performed in patients collecting ≥3 × 10(6) CD34(+)/kg and low-dose gemtuzumab ozogamicin (GO) was performed in poor mobilizers (collecting <3 × 10(6) CD34(+)/kg). Fifty-five patients (76.3%) underwent peripheral blood stem cell (PBSC) mobilization, after first consolidation, and 24 of 55 (44%) collected >3 × 10(6) CD34(+) cells/kg. Among the 55 patients eligible for PBSC mobilization, 7 did not receive the planned treatment, 23 were allocated for ASCT, and 25 were allocated for GO on an intention-to-treat basis. With a median follow-up of 70 months (range, 24 to 124), 20 of 55 patients are alive, 18 of them in continuous complete remission. The 8-year overall survival (OS) and disease-free survival (DFS) are, respectively, 35.9% (95% confidence interval [CI] 24% to 49.8%) and 31.2% (95% CI, 21% to 43.8%), median OS and DFS were 22 and 16 months, respectively. In multivariate analysis, postconsolidation treatment and hyperleukocytosis (WBC > 50,000/μL) significantly predicted OS and DFS, whereas secondary AML was significantly associated with a higher relapse rate (83.4% versus 54% of de novo AML). Patients with hyperleukocytosis had 0% 3-year OS versus the 46% (at 8 years) in patients without hyperleukocytosis (P = .01); 57% of patients in the GO arm are alive at 8 years, compared with 25.4% of patients in the ASCT arm, who had an overall relative risk (RR) of death of 2.6 (95% CI, 1.2 to 5.8; P = .02). DFS at 8 years was 45.3% in patients receiving GO, compared with 26% in ASCT arm (RR, 2.1; 95% CI, 1 to 4.3; P = .05). Our study outlines low feasibility and efficacy of ASCT in elderly AML patients, whereas postconsolidation with GO appears safe and effective in this unfavorable setting. The study was registered at Umin Clinical Trial Registry (www.umin.ac.jp/ctr), number R000014052., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Telomere dysfunction might generate genomic instability leading to the progression of myelodysplastic syndromes (MDS) into acute myeloid leukemia (AML). We investigated telomere length (TL), telomerase activity (TA) and hTERT, c-myc, mad1, and p53 expression in the bone marrow of patients with MDS (n=109), AML (n=47) and in controls (n=24). TL was lower in MDS patients than in controls (p<0.001) and higher in L-MDS (low, intermediate-1 IPSS, p<0.01) respect H-MDS (high, intermediate-2 IPSS, p<0.01) patients. Mad-1 expression was higher in MDS patients than in controls (p<0.01), c-myc expression was highest in AML and in H-MDS patients. Our results show that the telomere dynamics might be useful for stratifying patients according to a risk scoring system., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Aberrant DNA methylation at CpG islands within promoters is increasingly recognised as a common event in human cancers and has been associated with the silencing of important tumour suppressor genes. Epigenetic therapy using hypomethylating agents has demonstrated clinical effectiveness; the drugs azacitidine and decitabine have been approved for the treatment of MDS., Method: We investigated the association between global DNA methylation and clinical outcome in MDS. We evaluated 134 MDS bone marrow trephine biopsies (BMTB) by immunohistochemistry and compared the results with those from an age-matched group of normal BMTB. Immunohistochemistry was performed on paraffin-embedded sections using the anti-5-methylcytosine (5mc) antibody., Results: Our results showed that the 5mc immunostaining score (M-score) of patients with MDS was higher than those of normal controls and that overall survival significantly correlated with global DNA methylation, age and IPSS score. Therefore, we found that patients with high levels of methylation had a shorter median overall survival (OS) compared with patients with lower levels. These immunohistochemistry results were confirmed by analysing global DNA methylation on LINE-1 sequences using the COBRA method and pyrosequencing., Conclusion: This study reports that global DNA methylation detected by immunohistochemistry predicts OS in MDS., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

To detect factors associated with quality of life (QOL) of patients with myelodysplastic syndrome (MDS) and to compare the MDS patients' self-assessed QOL with that perceived by their physicians. In an observational, non-interventional, prospective, multicentre study, QOL was evaluated in 148 patients with newly diagnosed low- and intermediate-risk IPSS MDS. QOL measures (QOL-E v.2, LASA and EQ-5D) and patient-related candidate determinants of QOL were assessed for up to 18 months. Patients' QOL scores were compared with those obtained by appointed hematologists' assessment and with ECOG performance status (PS). Fatigue was not prevalent at diagnosis, though physical QOL and energy levels were low. Transfusion-dependent patients had worse QOL scores. In multivariate analysis, Hb levels and comorbidities were a major determinant of QOL. Physicians' perception of patients' well-being correlated with patients' QOL. Physicians underestimated the impact of disturbances on patients' QOL, mainly in the MDS-specific components. ECOG PS did not discriminate patients according to QOL status. In conclusion, the association of anemia with QOL is confirmed, while co-morbidities emerge as an independent predictor of QOL in MDS. Fatigue is not a major concern. ECOG PS is not a valuable surrogate of patient's QOL, thus highlighting that physician's judgment of patient's well-being must not substitute patient-reported outcomes. Appropriate questionnaires should be used to assess MDS patients' QOL in order to improve communication and therapeutic choice.

Background: Elderly patients with diffuse large B-cell lymphoma (DLBCL) are a heterogeneous population; clinical trials have evaluated a minority of these patients., Patients and Methods: Ninety-one elderly patients with DLBCL received tailored treatment based on a comprehensive geriatric assessment (CGA). Three groups were identified: I, fit patients; II, patients with comorbidities; III, frail patients. Group I received 21-day cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP-21), group II received R-CHOP-21 with liposomal doxorubicin, and group III received 21-day cycles of reduced-dose CHOP. Fifty-four patients (59%) were allocated to group I, 22 (25%) were allocated to group II, and 15 (16%) were allocated to group III., Results: The complete response (CR) rates were 81.5% in group I, 64% in group II, and 60% in group III. With a median follow-up of 57 months, 42 patients are alive, with 41 in continuous CR: 31 patients (57%) in group I, seven patients (32%) in group II, and four patients (20%) in group III. The 5-year overall survival, event-free survival, and disease-free survival rates in all patients were 46%, 31%, and 41%, respectively. Multivariate analysis selected group I assignment as the main significant prognostic factor for outcome., Conclusions: This approach in an unselected population of elderly DLBCL patients shows that treatment tailored according to a CGA allows the evaluation of elderly patients who are currently excluded from clinical trials.

There are no reliable markers useful to predict the onset or the evolution of chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT), although several candidate biomarkers have been identified from limited hypothesis-driven studies. In this study we evaluated 14 patients who received a reduced intensity conditioning HSCT. Seven patients had cGVHD, whereas 7 never developed cGVHD during the period of observation. The expression of 114 cytokines in immunoselected cell populations was explored by microarray analysis and 11 cytokines were selected for further evaluation by real-time PCR. Differential gene expression measurements showed a significant up-regulation for INFγ (interferon, gamma) in CD8+ and for TNFSF3 (tumor necrosis factor superfamily, member 3) and for TNFSF10 (tumor necrosis factor superfamily, member 10) in CD14+ cell population when comparing cGVHD with control samples. The expression levels were significantly decreased for TNFSF10 in CD8+ cell population and for TNFSF12 (tumor necrosis factor superfamily, member 12) and for PDGFβ (platelet-derived growth factor, beta) in CD4+. Our data seem to suggest that different immune populations can play a role in cGVHD pathogenesis and the early detection of gene expression profile in these patients could be useful in the monitoring of GVHD. We hypothesized that PDGFβ down-regulation could represent a negative feedback to compensate for enhanced expression of its receptor recently reported., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Testing for viral BKV-DNA in urine is a non-invasive early detection and monitoring tool in the diagnostic of BKV-related pathologies: quantitative analysis by Real-Time PCR can provide useful information in addition to cytologic analysis, although our study suggests that high BKV viruria is not necessarily associated with kidney or bladder damage.

Extensive chronic graft-versus-host disease (ecGVHD) is characterized by fibrosis similar to that of patients with systemic sclerosis (scleroderma). Since stimulatory autoantibodies against the platelet-derived growth factor (PDGF) receptor (PDGFR) have been found in patients with scleroderma and are responsible for the activation of skin fibroblasts, we tested the hypothesis that these autoantibodies are also present in patients affected by ecGVHD. Serum from 39 patients subjected to allogeneic stem cell transplantation for hematologic malignancies (22 with ecGVHD and 17 without cGVHD) and 20 healthy controls was assayed for the presence of stimulatory autoantibodies to the PDGFR by incubating purified IgG with mouse-embryo fibroblasts lacking PDGFR alpha or beta chains or with the same cells expressing PDGFR alpha. Stimulatory antibodies to the PDGFR were found selectively in all patients with ecGVHD but in none of the patients without cGVHD. Higher levels were detected in patients with generalized skin involvement and/or lung fibrosis. Antibodies recognized native PDGFR, induced tyrosine phosphorylation, accumulation of reactive oxygen species (ROS), and stimulated type 1 collagen gene expression through the Ha-Ras-ERK1/2-ROS signaling pathway. The biologic activity of these autoantibodies suggests a role in the development of fibrosis and argues for a common pathogenetic trait in ecGVDH and scleroderma phenotypes.