Comparison of chronic graft-versus-host disease after transplantation of peripheral blood stem cells versus bone marrow in allogeneic recipients: long-term follow-up of a randomized trial

Peripheral blood stem cell transplantation (PBSCT) has emerged as an alternative to bone marrow transplantation (BMT) for treatment of malignant diseases. Nearly all studies have indicated faster engraftment and earlier hematopoietic recovery with PBSCT than with BMT.1-5 In some studies, the incidence of clinical extensive chronic graft-versus-host disease (GVHD) in allogeneic recipients was higher with PBSCT than with BMT,6-9 but others have not confirmed these findings.1 2 

Although the incidence of clinical extensive chronic GVHD has been evaluated in many studies comparing PBSCT to BMT, information describing the clinical features and clinical course of chronic GVHD after PBSCT has not been reported. We have now carried out a detailed retrospective review of results from a randomized prospective study1 comparing PBSCT and BMT to determine whether the clinical characteristics of chronic GVHD after PBSCT might be distinct from those that occur after BMT.

We previously reported outcomes among 172 patients randomized to receive either bone marrow (BM) or peripheral blood stem cell (PBSC) transplantations from an HLA-identical sibling for treatment of hematologic malignancy. All patients received their transplants at the Fred Hutchinson Cancer Research Center, at the City of Hope Medical Center, or at Stanford University Hospital between March 1996 and July 1999.1 Seventy-one of the 126 patients who were alive and free of malignancy at 100 days after the transplantation were included in the current study because they have developed extensive chronic GVHD after BMT (n = 32) or after PBSCT (n = 39). Information was retrieved by reviewing long-term follow-up medical records. Patients and donors signed forms approved by the Institutional Review Board documenting informed consent to participate in the clinical trials. Analysis was carried out as of October 31, 2001.

The pretransplantation conditioning regimen varied according to the underlying disease.1 Patients with chronic myeloid leukemia (CML) in chronic phase received busulfan and cyclophosphamide. Patients with acute leukemia or lymphoma received regimens of cyclophosphamide and fractionated total body irradiation. Patients with multiple myeloma or myelodysplastic syndrome received regimens of busulfan and total body irradiation. All patients received methotrexate plus cyclosporine for prevention of acute GVHD.10 

Marrow was collected from the donor according to standard procedures. PBSC donors were treated with granulocyte colony-stimulating factor (G-CSF) at a dose of 16 μg/kg per day by subcutaneous injection from day −5 to day −1. Mononuclear cells were collected by apheresis with a COBE Spectra machine (Gambro BCT, Lakewood, CO) on the day before the transplantation and on the day of the transplantation according to standard procedures.

Patients were evaluated for chronic GVHD between 80 and 100 days after the transplantation,11,12 at 1 year after the transplantation, whenever clinically indicated to establish the diagnosis of chronic GVHD, and at 9 to 12 months after initiation of treatment to assess response. The diagnosis and grading of chronic GVHD were established according to clinical and pathologic criteria.13 14 

Patients in both transplant groups received systemic immunosuppressive treatment according to available protocols or standard treatment guidelines for extensive chronic GVHD. Medications administered for control of chronic GVHD were continued for at least 9 months unless changes in therapy were clinically indicated. Protocol guidelines for starting secondary treatment of chronic GVHD included (1) progression of disease manifestations after at least 2 weeks of therapy, (2) no improvement after at least 1 month of therapy, (3) improvement with persistent disease after 9 to 12 months of therapy, or (4) recurrence of disease manifestations after discontinuation of immunosuppressive treatment.

One patient with extensive chronic GVHD had been originally assigned to receive PBSCs but received BM because consent was withdrawn after the result of randomization was disclosed. Results for this patient were analyzed according to the treatment actually given.

Treatments for chronic GVHD were counted from the start of initial therapy until the date of last contact. Changes in treatment were counted at the time of initiation of a new therapy, when the dose of steroids was increased to 1 mg/kg or more every other day, or when systemic immunosuppressive treatment was reinstituted for exacerbation of chronic GVHD after discontinuation of therapy. Topical steroid therapy was counted as a separate treatment only when used to control chronic GVHD involving at least 2 sites (mouth and vagina) or when administered to control progression of pre-existing manifestations or development of new manifestations during systemic immunosuppressive treatment.

The χ² or Fisher exact test was used to evaluate the significance of differences in proportions, and Wilcoxon rank sum tests were used to compare continuously valued outcomes and to evaluate the significance of differences in distributions among ordered categories.15 The Kaplan-Meier method was used to estimate overall and disease-free survival. Cumulative incidences and standard errors were estimated according to Andersen et al.16Comparisons between survival curves and cumulative incidence curves are based on likelihood ratio statistics from proportional hazards regression models.

Clinical extensive chronic GVHD developed in 39 of 63 PBSC recipients and in 32 of 63 BM recipients who were alive and free of malignancy at day 100 after the transplantation procedure. The cumulative incidence of clinical extensive chronic GVHD was 63% (95% CI, 51%-76%) at 3 years after PBSCT and 52% (95% CI, 39%-65%) after BMT (P = .33). The median follow up is 41 months (range, 26-63 months) for BM recipients and 40 months (range, 25-62 months) for PBSC recipients. Characteristics of patients who developed extensive chronic GVHD after PBSCT (n = 39) and after BMT (n = 32) were similar (Table 1).

Characteristics of chronic GVHD after PBSCT were similar to those observed after BMT. Similarities included the proportion of patients with a prior history of acute GVHD, the time and the type of onset of the disease, the prevalence of thrombocytopenia (< 100 × 10⁹/L), the extent of skin involvement, and the types of immunosuppressive treatment being given when chronic GVHD was diagnosed (Table 2). The proportion of patients with high-risk features of chronic GVHD was 59% for the BMT group and 38% for the PBSCT group (P = .08).

The prevalence of organ involvement at the initial diagnosis of clinical extensive chronic GVHD was similar in the 2 groups (data not shown). Skin, mouth, liver, and eyes were the sites most frequently affected by chronic GVHD during the course of the disease (Figure1). Skin involvement was more frequent in PBSC recipients than in BM recipients (P = .02). Involvement of the vagina and vulva was observed in 7 of 15 female PBSC recipients compared to 1 of 10 female BM recipients (P = .05). The prevalence of organ involvement was otherwise similar in the 2 groups (Figure 1). The incidence rates of bronchiolitis obliterans, scleroderma, joint contractures, myofascitis, esophageal strictures, and keratitis were similar in the 2 groups (Table 3).

The most common initial treatment for chronic GVHD in both arms was prednisone plus cyclosporine or tacrolimus (Table4). One patient in the BMT group received interferon as part of a clinical trial to prevent recurrent CML. This patient did not receive any treatment for control of chronic GVHD, and manifestations of chronic GVHD resolved after discontinuation of treatment with interferon. One PBSC recipient was treated with topical glucocorticoids for control of chronic GVHD limited to the mouth and vagina. Mycophenolate mofetil (MMF) alone was given as initial therapy for chronic GVHD of the skin and oral cavity in one PBSC recipient who declined glucocorticoid therapy and in whom cyclosporine blood levels could not be measured under the care of the referring physician. Seven patients were treated with cyclosporine alone (6 PBSC recipients and 1 BM recipient) after they declined combination treatment with prednisone. None of these patients had high-risk features at the onset of extensive chronic GVHD (ie, platelet count < 100 × 10⁹/L, progressive onset, or rash involving > 50% of body surface area [BSA]). Neither of the 2 BM recipients treated initially with prednisone alone had high-risk features of chronic GVHD (Table 2). Two PBSC recipients were treated initially with MMF and prednisone because of cyclosporine toxicity.

Although the power to detect differences is limited by the small number of patients, the number of agents used for initial treatment was similar between the 2 transplant arms (P = .28, rank sum test). The proportions of patients treated initially with a single drug as opposed to 2 or more drugs were also similar between PBSCT and BMT (P = .37).

The numbers of successive treatments needed to control chronic GVHD were higher in PBSC recipients than in BM recipients (P = .03; Table 5). In keeping with this finding, the duration of glucocorticoid treatment was longer in PBSC recipients than in BM recipients (P = .03; Figure 2). The duration of immunosuppressive treatment was similar in the 2 transplant arms (P = .08; Figure 3). Because higher numbers of treatments might simply reflect longer survival in PBSC recipients compared to the BM recipients, we analyzed the proportions of patients who received less than or equal to 1 versus more than 1 cycle of treatment for control of chronic GVHD. The proportion of patients receiving more than one treatment was higher in the PBSCT group than in the BMT group (P = .04). The average duration of treatment cycles was similar in the 2 groups. All patients in both groups receiving more than one cycle had progression of chronic GVHD in a previously involved site, development of chronic GVHD in a new site, or unimproved chronic GVHD as a reason for starting secondary treatment (Table 6). These findings suggest that chronic GVHD is less responsive to treatment when it occurs after PBSCT as compared to BMT.

Survival at 3 years after the diagnosis of chronic GVHD was 76% (95% CI, 53%-98%) for PBSC recipients and 70% (95% CI, 51%-88%) for BM recipients. Clinical performance of all surviving patients according to the transplant arm is shown in Table7. The estimated relapse-free survival at 3 years after the diagnosis of chronic GVHD was 68% (95% CI, 42%-94%) for PBSC recipients and 61% (95% CI, 41%-80%) for BM recipients (P = .08; Figure 3). In the PBSCT group, deaths were caused by recurrent malignancy (n = 3), Aspergilluspneumonia (n = 1), and cytomegalovirus pneumonia (n = 1). In the BMT group, deaths were caused by recurrent malignancy (n = 3), cytomegalovirus pneumonia (n = 1), herpes simplex encephalitis (n = 1), idiopathic interstitial pneumonia (n = 1), and myocardial infarction (n = 1).

Results of this study suggest that chronic GVHD may be more difficult to control when it occurs after PBSCT as compared to BMT. This conclusion is supported by the greater numbers of treatments given to PBSC recipients and by the longer duration of glucocorticoid treatment in PBSC recipients. These findings could indicate either that the agents currently used for treatment of chronic GVHD are less effective in PBSC recipients or that the manifestations of the disease are more severe in PBSC recipients as compared to BM recipients. We found no evidence to suggest that PBSCT was associated with more severe chronic GVHD, because the incidence rates of complications caused by chronic GVHD and the proportions of patients with risk factors associated with poor outcome were not significantly different in the 2 groups, although there was a trend suggesting higher risk for BM recipients. Further assessment of this question will have to await the development and validation of scales for measuring the severity of chronic GVHD.

In a prospective, nonrandomized study of 168 PBSC recipients, Przepiorka et al21 reported that a platelet count of less than 100 × 10⁹/L had an adverse impact on overall mortality and relapse-free survival in patients with chronic GVHD. In our study, the incidence of chronic GVHD and the distribution of high-risk features, including thrombocytopenia, were similar among BM and PBSC recipients (Table 2) and thus could not explain the findings of more protracted chronic GVHD in the PBSCT group.

The requirement for increased therapy in patients with chronic GVHD after PBSCT as compared to BMT is difficult to explain. In the era before G-CSF, the incidence of chronic GVHD was higher in patients treated with donor “buffy coat” after BMT compared to BMT alone.17 In that study, chronic GVHD appeared to be less severe and more responsive to treatment than progressive-onset chronic GVHD after BMT alone.

The administration of G-CSF has been shown to favor the development of a type 2-cytokine profile in T-helper cells, with characteristic production of interleukin 4 (IL-4), IL-5, and IL-10 as opposed to IL-2 and interferon γ.18 Although these differences might contribute to the increased incidence of chronic GVHD after PBSCT as compared to BMT, they do not readily explain the differences in response to treatment. Experiments in mice have suggested that abnormal selection of T cells in the thymus may contribute to the pathogenesis of chronic GVHD. Failure of negative selection in the thymus may allow the development of T cells that recognize recipient or donor-derived antigens, leading to clinical manifestations that frequently mimic those of autoimmune diseases.19 It is possible that PBSCT causes more thymic damage than BMT, simply as a result of differences in the number of T cells in the graft. On the other hand, the increased incidence of chronic GVHD after PBSCT has been associated with higher numbers of CD34 cells in the graft and not with the numbers of CD3 or CD14 cells.20 These analyses did not evaluate associations between the numbers of CD34, CD3, or CD14 cells and the response of chronic GVHD during treatment. We found no association between the numbers of CD34, CD3, or CD14 cells and the numbers of treatments given for control of GVHD (data not shown).

Results of a recent meta-analysis showed that chronic GVHD occurs more frequently after PBSCT as compared to BMT, with a trend toward a protective effect of PBSCT in preventing relapse.9Although the power to detect differences may be compromised by the relatively small numbers of patients in our study, we did not find any difference between the rates of extensive chronic GVHD between PBSCT and BMT, but we found that chronic GVHD may be more protracted after PBSCT than after BMT. Assessment of the overall benefits of PBSCT compared to BMT will require continued long-term evaluation of quality of life and follow-up of morbidity associated with chronic GVHD in long-term survivors.

We thank Judy Campbell, RN; and Carina Moravec, ARNP, for outstanding assistance in the management of patients with chronic GVHD; and Chris Davis and the Long-Term Follow-Up staff at the Fred Hutchinson Cancer Research Center and the data managers at City of Hope and Stanford University for assistance in data collection.