Abstract
Amyloid deposits are often found in the bone marrow in patients with AL amyloidosis; we sought to determine whether this affects stem cell collection or engraftment following high dose melphalan and autologous stem cell transplantation (HDM/SCT). Data on 361 patients with AL amyloidosis who had Congo red staining of the pre-treatment bone marrow biopsy and underwent HDM/SCT from July 1994 to December 2011 were reviewed. Data were analyzed for stem cell yield, number of days of stem cell collection, neutrophil and platelet engraftment post SCT. Sixty-five % of patients (n=233) had bone marrow amyloid deposits. There were no significant differences in median number of stem cells collected, days to neutrophil or platelet engraftment between patients with and without bone marrow amyloid deposits. Thus, while amyloid involvement of the bone marrow is common, it does not negatively impact stem cell mobilization or neutrophil and platelet engraftment after HDM/SCT.
Keywords: Amyloidosis, light-chain, melphalan, stem cell transplantation, stem cell mobilization, stem cell collection, engraftment, bone marrow
Introduction
High-dose melphalan and autologous stem cell transplantation (HDM/SCT) is an important treatment modality for selected patients with AL amyloidosis1; however, typically less than half of newly diagnosed patients are eligible for this treatment2.
SCT is used successfully in treatment of multiple hematologic disorders and some solid tumors. A rare complication is primary graft failure, reported in 4.7% of patients undergoing SCT in a recent series of 300 patients3. The variables associated with favorable engraftment kinetics are the CD34+ stem cell dose, as established by multiple transplantation studies4-6. Prior studies have also demonstrated that extensive antecedent exposure to alkylating agents negatively impacts platelet engraftment6,7. In AL amyloidosis, a previous study showed that the important variables affecting stem cell engraftment were CD34+ stem cell dose, female gender, and prior alkylator therapy8.
Amyloid deposition in the bone marrow (BM) is common in patients with AL amyloidosis, having been documented in 60% of biopsies from a series of 100 patients9. Two distinct histologic patterns for bone marrow amyloid deposition exist – vascular and interstitial.
We report on the impact of amyloid deposits in the BM on stem cell mobilization and engraftment kinetics in patients with AL amyloidosis who underwent HDM/SCT.
Methods
A retrospective review of data from July 1994 to December 2011 was performed using the Boston University Amyloid Treatment and Research Program database. Patients with AL amyloidosis who underwent HDM/SCT at this institution and had documented Congo red staining performed on the initial BM biopsy were included. Patients who initiated stem cell mobilization but did not proceed to HDM either due to death or complications were excluded. Patients who completed high-dose melphalan but died prior to platelet or neutrophil engraftment were included for overall analysis, however, were excluded from the analysis of engraftment kinetics.
Data were collected on baseline demographics, laboratory characteristics, organ involvement and prior treatment. Baseline data were collected on quantitative serum free light chain assay and BM plasma cell percentage; the difference between the involved and uninvolved free light chain was calculated (dFLC). Data were collected and analyzed for stem cell collection yield, number of days of collection, neutrophil and platelet engraftment post SCT.
Amyloid deposits in BM biopsies stained with Congo red were graded as 0 (absent), 1+ (vascular only), 2+ (limited interstitial deposits, <2/hpf), and 3+ (extensive interstitial deposits, >2/hpf). Neutrophil engraftment was defined as an absolute neutrophil count of > 500 cells/μL for 2 consecutive days, and platelet engraftment was defined as a platelet count > 20,000/μL without platelet transfusion during the previous 48 hours.
Descriptive statistics were used to summarize patient characteristics. We compared groups using chi-sqaured tests for comparing proportions and t-tests for comparing means. A value of p ≤ 0.05 was considered statistically significant. Statistical analyses were conducted using SAS Version 9.2.
Results and Discussion
Patient Characteristics
A total of 361 patients with AL amyloidosis and documented Congo red staining of initial BM biopsy underwent HDM/SCT (Table 1a). The majority of patients, 233 (65%) had evidence of BM amyloid deposition; of these, 150 patients (64%) had vascular amyloid deposition only (1+), 27 patients had limited interstitial amyloid deposition (12%), and 56 patients (24%) had extensive interstitial amyloid deposition present (Figure 1). Combined, 83 patients (36%) had interstitial amyloid deposition. One hundred twenty eight patients (35%) had no amyloid deposition identified.
Table 1a.
Patient characteristics
| Amyloid deposits in bone marrow N=233 | Interstitial amyloid in bone marrow N=83 | No amyloid in bone marrow N=128 | Amyloid vs no amyloid, P | Interstitial amyloid vs no amyloid, P | |
|---|---|---|---|---|---|
| Age, median (range) (yr) | 56 (28 – 80) | 56 (28 – 71) | 57 (35 – 79) | 0.88 | 0.07 |
| Women, n (%) | 91 (39) | 34 (41) | 51 (40) | 0.88 | 0.87 |
| Clonality n, (%) | |||||
| Kappa | 51 (22) | 25 (30) | 20 (16) | 0.15 | 0.01 |
| Lambda | 182 (78) | 58 (70) | 108 (84) | 0.15 | 0.01 |
| Organ involvement, n (%) | |||||
| Renal | 221 (95) | 77 (93) | 95 (74) | <0.001 | <0.001 |
| Cardiac | 109 (47) | 34 (41) | 59 (46) | 0.90 | 0.46 |
| Hepatic | 77 (33) | 49 (59) | 20 (16) | <0.001 | <0.001 |
| Soft tissue | 50 (21) | 16 (19) | 39 (30) | 0.06 | 0.07 |
| GI | 53 (23) | 20 (24) | 18 (14) | 0.05 | 0.06 |
| Autonomic nervous | 68 (29) | 21 (25) | 21 (16) | 0.01 | 0.11 |
| Peripheral nervous | 25 (11) | 5 (6) | 13 (10) | 0.87 | 0.29 |
| Pulmonary | 14 (6) | 7 (8) | 6 (5) | 0.60 | 0.27 |
| >2 Organs involved | 116 (50) | 45 (54) | 41 (32) | 0.001 | 0.001 |
| Baseline laboratory values | |||||
| Serum creatinine, mg/dL | 1.1 (0.4 – 14.8) | 1.2 (0.5 – 11.7) | 0.9 (0.4 – 13.3) | 0.8 | 0.66 |
| 24 hour urine protein, mg | 5875 (<60-58212) | 5797 (<60-27456) | 3629 (<60-20493) | 0.09 | 0.004 |
| Bone marrow plasma cells | 5 (5 – 25) | 5 (5 – 25) | 10 (<5 – 30) | 0.06 | 0.28 |
| Prior treatment, n (%) | |||||
| Alkylator based treatments | 54 (23) | 21 (25) | 21 (16) | 0.06 | 0.049 |
| IMiD based treatments * | 3 (1) | 0 (0) | 6 (5) | 0.06 | 0.049 |
Figure.
Extensive interstitial amyloid deposition in a patient with AL amyloidosis, with almost total replacement of the marrow. Amyloid highlighted by PAS and Congo red stains.
Clonality was more frequently lambda than kappa for all groups; the group including all interstitial amyloid deposition had greater frequency of kappa predominance in 25 patients (30%) as compared with those without BM amyloid deposition in 20 (16%) (p = 0.01).
Organ involvement varied among the groups; for all patients with BM amyloid deposition present, coexistent renal involvement was present in 221 patients (95%), in comparison with those without BM amyloid deposition, where renal involvement was present in 95 patients (74%) (p<0.001). Multi-organ involvement (>2 organs involved), was common with amyloid BM deposition in 116 patients (50%), and occurred in greater frequencies in patients with interstitial BM amyloid (54%), as compared with 41 (32%) of those without BM amyloid deposition (p=0.001 for both comparisons).
Prior treatment before HDM/SCT was found in 54 (23%) of patients with BM amyloid deposition and in 21 (16%) of patients without and this was not a significant difference (p=0.06).
Stem Cell Mobilization, Collection, and Engraftment
G-CSF was used as a stem cell mobilization regimen at 10-16 mcg/kg/day for 3 to 4 days for all patients. The median number of stem cells collected for all patients with BM amyloid deposition (vascular and interstitial) was 6.8 x 106 CD 34+/kg (range, 0.2 – 31.4), and for patients with interstitial bone marrow amyloid, was 7.2 x 106 CD 34+/kg (range, 0.6 – 24.1) (Table 1b). For those patients without BM amyloid deposition, the median number of stem cells collected was 6.9 × 106 CD 34+/kg (range, 0.28 – 20.4); this was not significantly different from either all patients with amyloid or those with interstitial amyloid only (p=0.79). The mean number of collections required for all groups was 2.
Table 1b.
Stem cell collection and engraftment data
| Amyloid deposits in bone marrow N=233 | Interstitial amyloid in bone marrow N=83 | No amyloid deposits in bone marrow N=128 | Amyloid vs no amyloid, P | Interstitial amyloid vs no amyloid, P | |
|---|---|---|---|---|---|
| Median CD34+ cells collected, (range) (×106) | 6.8 (0.2 - 31.4) | 7.23 (0.6 - 24.1) | 6.9 (0.28 - 20.4) | 0.988 | 0.79 |
| Mean number of collections, n (range) | 2 (0.5 - 5) | 2 (1 - 4) | 2 (1 - 4) | 0.444 | 0.132 |
| Neutrophil engraftment, d (range) | 10 (5 - 16) | 10 (5 - 16) | 10 (8 - 17) | 0.691 | 0.213 |
| Platelet engraftment, d (range) | 13 (7 - 93) | 13 (7 - 32) | 12 (8 - 46) | 0.177 | 0.79 |
For all patients, 8 patients died before neutrophil engraftment, and 10 additional patients died before platelet engraftment. These patients were excluded from engraftment analyses. The median time to neutrophil engraftment for all patients with BM amyloid was 10 days (range, 5 – 16), and for patients with interstitial BM amyloid was 10 days (range, 5 – 16). The median time to neutrophil engraftment in patients without BM amyloid deposition was 10 days (range, 8 – 17). There were no significant differences between the groups (p = 0.691 and 0.213, respectively).
The median time to platelet engraftment in patients with BM amyloid deposition was 13 days (range, 7 – 93), and for patients with interstitial BM amyloid deposition was 13 days (range, 7 – 32). The median time to platelet engraftment for patients without BM amyloid deposition was 12 days (range, 8 – 46). There were no significant differences between these groups (p = 0.177 and 0.79, respectively).
Thirty-eight patients (11%) experienced mobilization failure, defined as stem cell collection of less than 2.5 x 106 CD34+/kg. However, these patients did proceed to HDM/SCT after undergoing bone marrow harvest. There were not a significantly different proportion of failures in all patients with amyloid deposition or among the subgroup with extensive amyloid deposition (p=0.15 and 1.0, respectively). No significant differences were observed in rates of bone marrow harvest among these groups (p=0.23 and 1.0). Notably, 22 of these patients (58%) were pretreated, the majority (95%) with oral melphalan.
In our series of 361 patients with AL amyloidosis who underwent HDM/SCT, BM amyloid deposition was relatively common, occurring in 65% of patients. Given how extensive amyloid BM deposition can be, this might theoretically impede stem cell collection and engraftment after HDM/SCT; nonetheless, whether amyloid deposition in the bone marrow was vascular, or more extensive interstitial deposition was present, it did not negatively impact stem cell mobilization, collection, or neutrophil and platelet engraftment kinetics. Indeed, our engraftment data are similar to that published previously on stem cell engraftment post transplant in these patients, but the numbers here are much larger and encompass more years of study8.
In keeping with a previous publication from our institution, kappa clonality was more commonly seen with BM amyloid deposition than in patients without deposition9. The association of amyloid BM deposition and greater renal, multi-organ involvement is of note and merits further investigation.
Acknowledgments
The authors acknowledge the participation of colleagues in the Amyloid Treatment and Research Program at Boston University School of Medicine and the Stem Cell Transplant Program at Boston Medical Center. The development of the Amyloid Repository and Database was supported by P01 HL68705 and by grants from the Gruss and Wildflower Foundations.
Footnotes
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Authorship Contribution:
AJC, DCS, MS and VS designed the study; AJC and VS analyzed the data and wrote the manuscript; DCS, MS, KQ, KTF critically reviewed the manuscript; JT and CO performed pathological analysis of the bone marrow specimens; GD performed statistical analysis; and all authors approved the final version of the manuscript
Conflicts of Interest: Authors declare no competing financial interests.
References
- 1.Cibeira MT, Sanchorawala V, Seldin DC, et al. Outcome of AL amyloidosis after high-dose melphalan and autologous stem cell transplantation: long-term results in a series of 421 patients. Blood. 118:4346–4352. doi: 10.1182/blood-2011-01-330738. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Skinner M, Sanchorawala V, Seldin DC, et al. High-dose melphalan and autologous stem-cell transplantation in patients with AL amyloidosis: an 8-year study. Ann Intern Med. 2004;140:85–93. doi: 10.7326/0003-4819-140-2-200401200-00008. [DOI] [PubMed] [Google Scholar]
- 3.Pottinger B, Walker M, Campbell M, Holyoake TL, Franklin IM, Cook G. The storage and re-infusion of autologous blood and BM as back-up following failed primary hematopoietic stem-cell transplantation: a survey of European practice. Cytotherapy. 2002;4:127–135. doi: 10.1080/146532402317381839. [DOI] [PubMed] [Google Scholar]
- 4.Faucher C, Le Corroller AG, Chabannon C, et al. Autologous transplantation of blood stem cells mobilized with filgrastim alone in 93 patients with malignancies: the number of CD34+ cells reinfused is the only factor predicting both granulocyte and platelet recovery. J Hematother. 1996;5:663–670. doi: 10.1089/scd.1.1996.5.663. [DOI] [PubMed] [Google Scholar]
- 5.Haas R, Mohle R, Fruhauf S, et al. Patient characteristics associated with successful mobilizing and autografting of peripheral blood progenitor cells in malignant lymphoma. Blood. 1994;83:3787–3794. [PubMed] [Google Scholar]
- 6.Tricot G, Jagannath S, Vesole D, et al. Peripheral blood stem cell transplants for multiple myeloma: identification of favorable variables for rapid engraftment in 225 patients. Blood. 1995;85:588–596. [PubMed] [Google Scholar]
- 7.Dreger P, Kloss M, Petersen B, et al. Autologous progenitor cell transplantation: prior exposure to stem cell-toxic drugs determines yield and engraftment of peripheral blood progenitor cell but not of bone marrow grafts. Blood. 1995;86:3970–3978. [PubMed] [Google Scholar]
- 8.Oran B, Malek K, Sanchorawala V, et al. Predictive factors for hematopoietic engraftment after autologous peripheral blood stem cell transplantation for AL amyloidosis. Bone Marrow Transplant. 2005;35:567–575. doi: 10.1038/sj.bmt.1704826. [DOI] [PubMed] [Google Scholar]
- 9.Swan N, Skinner M, O'Hara CJ. Bone marrow core biopsy specimens in AL (primary) amyloidosis. A morphologic and immunohistochemical study of 100 cases. Am J Clin Pathol. 2003;120:610–616. doi: 10.1309/PFUG-HBX0-TY20-E08U. [DOI] [PubMed] [Google Scholar]