Treated Cytomegalovirus Pneumonia Is Not Associated with Bronchiolitis Obliterans Syndrome Michael Tamm, Christina L. Aboyoun, Prashant N. Chhajed, Stephen Rainer, Monique A. Malouf, and Allan R. Glanville The Lung Transplant Unit, St. Vincent’s Hospital, Sydney, Australia
The association of cytomegalovirus (CMV) infection with the development of bronchiolitis obliterans syndrome (BOS) is unclear. We studied 341 lung transplant recipients to assess whether histopathologically diagnosed CMV pneumonia treated with ganciclovir was a risk factor for development of BOS and patient survival. We also analyzed the relationship between CMV donor/recipient serologic status and BOS plus the temporal association between acute rejection and CMV pneumonia. Freedom from BOS for patients with (n ⫽ 151) and without (n ⫽ 190) CMV pneumonia was 83 and 90% (1 year), 52 and 56% (3 years), and 29 and 38% (5 years), respectively (p ⫽ 0.2660). Cumulative survival of patients with and without CMV pneumonia was 90 and 93% (1 year), 70 and 74% (3 years), and 58 and 63% (5 years), respectively (p ⫽ 0.1811). There were no significant differences in either development of BOS or patient survival with any combination of donor/recipient serostatus for CMV. Acute rejection occurred in the month preceding CMV pneumonia in 62 of 193 (32%) cases. Histopathologically confirmed CMV pneumonia treated with ganciclovir is not a risk factor for BOS or patient survival, nor is any particular CMV serologic donor/ recipient group. CMV pneumonia often follows acute rejection, perhaps as a result of augmented immunosuppression. Keywords: bronchiolitis obliterans syndrome; cytomegalovirus; lung transplant
Obliterative bronchiolitis (OB) is the major factor limiting patient survival after lung transplantation (1). OB is characterized by progressive, irreversible narrowing of the bronchiolar lumen by concentric or eccentric submucosal granulation tissue progressing to fibrosis that may completely occlude the lumen. Histologic confirmation of OB is difficult because transbronchial biopsy (TBB) has a low diagnostic sensitivity for OB (2–4). Hence, a clinical description of OB, termed bronchiolitis obliterans syndrome (BOS), has been widely accepted as a surrogate marker for OB (5). BOS is defined by pulmonary function changes rather than histology, using FEV1 as the primary parameter to connote graft deterioration secondary to persistent airflow obstruction. Acute rejection, lymphocytic bronchitis/bronchiolitis, cytomegalovirus (CMV) pneumonia, and medication noncompliance are considered “probable” risk factors for BOS (5). CMV infection (without pneumonia), organizing pneumonia, bacterial/fungal/non-CMV viral infection, older donor age, longer graft ischemic time, and donor antigen-specific reactivity are considered “potential” risk factors for BOS (5). CMV infection and disease have also been associated with chronic graft rejection in vitro in a rat model (6).
(Received in original form October 14, 2003; accepted in final form July 28, 2004) C.L.A. and P.N.C. contributed equally to this article. Correspondence and requests for reprints should be addressed to Prashant N. Chhajed, D.N.B., M.D., F.C.C.P., Division of Respiratory Medicine and Pulmonary Cell Research, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. E-mail:
[email protected] Am J Respir Crit Care Med Vol 170. pp 1120–1123, 2004 Originally Published in Press as DOI: 10.1164/rccm.200310-1405OC on August 5, 2004 Internet address: www.atsjournals.org
OB is considered to be an immune-mediated process that affects the entire epithelium of the pulmonary allograft, the effects of which, for geometric reasons, are centered on the small airways (7, 8). The association of CMV infection and/or disease with the development of BOS remains unclear. In an earlier study, we reported that a new diagnosis of CMV pneumonitis was made in 33 of 173 (19%) follow-up biopsies performed within 45 days of acute rejection in 99 patients (9). We therefore reasoned that the association of CMV infection with chronic rejection described in previous studies might be due to the fact that patients treated for rejection experienced CMV disease subsequently due to the augmented immunosuppression. To test this hypothesis, we analyzed the time course of acute rejection and CMV pneumonia in our whole population of 341 evaluable patients. We also assessed whether histopathologically confirmed CMV pneumonia treated with ganciclovir or the CMV donor/recipient serologic status were risk factors for the development of BOS and patient survival after lung transplantation. This paper was presented at the Annual American Thoracic Society Meeting in Orlando in May 2004 and published in abstract form in the AJRCCM.
METHODS Between 1987 and 2001, 374 patients underwent lung or heart-lung transplantation at St.Vincent’s. Twenty-three of 374 (6%) patients surviving ⭐ 30 days were excluded from analysis because they were not evaluable for the diagnosis of BOS. Of the remaining 351 patients (167 males, 184 females), 61 were heart-lung transplant recipients, 170 bilateral lung transplant, and 120 single lung transplant recipients. The mean age was 41 years (range 12–62). Data were not available on two lung transplant recipients who were followed up at an interstate hospital. Hence, they and eight patients who did not undergo transbronchial biopsy (TBB) were also excluded from analysis. In total, 341 lung transplant recipients were included in the study. All patients were followed up for at least 6 months. The development of CMV pneumonia diagnosed on TBB and the onset of BOS were assessed. TBB was performed as described elsewhere (4). TBB was graded according to standardized nomenclature described by the Lung Rejection Study Group of the International Society for Heart and Lung Transplantation (10). CMV pneumonia was defined by the presence on TBB of typical inclusion bodies with cytopathic effect. Freedom from BOS and BOS were defined according to the updated recommendations of the International Society for Heart and Lung Transplantation (5). CMV and rejection were diagnosed only when there was unequivocal evidence of the histology meeting the International Society for Heart and Lung Transplantation criteria with tight perivascular infiltrates away from areas where there was a CMV cytopathic effect or in the case of sparse CMV inclusion bodies plus typical histology for rejection. Episodes of treated acute rejection and histopathologically diagnosed CMV pneumonia occurring within 3 months of each other were identified and analyzed to define a potential temporal association. CMV serologic status was established in all donors as well as in recipients. CMV-seronegative patients transplanted with a graft from a CMVseropositive donor received antiviral prophylaxis with intravenous ganciclovir (5 mg/kg 3 times/week) for a total of 10 weeks. After transplantation, all patients received triple drug immunosuppressive therapy with cyclosporine A or tacrolimus, azathioprine or mycophenolate mofetil, and prednisolone. Patients transplanted before
Tamm, Aboyoun, Chhajed, et al.: Cytomegalovirus and BOS
1995 also received induction therapy with antilymphocyte globulin. Acute rejection was treated with intravenous methyl prednisolone (12.5 mg/kg/day) for 3 days followed by an oral taper of prednisolone starting at 1 mg/kg/day and reducing by 5 mg every second day to 0.2 mg/kg/day. CMV pneumonia was treated with intravenous ganciclovir (5 mg/kg, 2 times/day for 14–21 days and then with/without 10 mg/kg/day, 3 times/week for the next 14 days). TBBs were performed for surveillance, symptoms or as a follow-up for acute rejection or CMV pneumonia, as described earlier. (3, 9) Pulmonary function tests were performed as defined by the guidelines of the American Thoracic Society (11). Actuarial freedom from BOS and survival in relation to CMV pneumonia and CMV serologic status were calculated using the Cox-Mantel log-rank test. The Fishers exact test was used to compare the incidence of CMV pneumonia in patients transplanted before and after 1995. For all tests, a p value of less than 0.05 was considered significant.
RESULTS CMV Pneumonia: Survival and Freedom from BOS
The cumulative survival of patients with CMV pneumonia (n ⫽ 151) and those without CMV pneumonia (n ⫽ 190) was 90 and 93% (1 year), 70 and 74% (3 years), and 58 and 63% (5 years), respectively (p ⫽ 0.1811) (Figure 1). Freedom from BOS for patients with and without CMV pneumonia was 83 and 90% (1 year), 52 and 56% (3 years), and 29 and 38% (5 years), respectively (p ⫽ 0.2660) (Figure 2). CMV Serogroups: Survival and Freedom from BOS
The number of patients in the CMV serogroups was, donor positive and recipient positive (D⫹R⫹) (n ⫽ 166), donor positive and recipient negative (D⫹R⫺) (n ⫽ 35), donor negative and recipient positive (D⫺R⫹) (n ⫽ 80), and donor negative and recipient negative (D⫺R⫺) (n ⫽ 60). The cumulative 1-, 3-, and 5-year survival for the D⫹R⫹ serogroup was 92, 73, and 63%; for the D⫹R⫺ serogroup, 90, 76 and 65%; for the D⫺R⫹ serogroup, 87, 65, and 47%; and for the D⫺R⫺ serogroup 100, 74, and 60%, respectively (p ⫽ 0.7752) (Figure 3). Freedom from BOS at 1, 3, and 5 years for the D⫹R⫹ serogroup was 87, 54, and 31%; for the D⫹R⫺ serogroup, 86, 55, and 36%; for the D⫺R⫹ serogroup, 89, 59, and 39%; and for the D⫺R⫺ serogroup, 86, 47, and 37%, respectively (p ⫽ 0.9989) (Figure 4).
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Figure 2. Freedom from bronchiolitis obliterans syndrome (BOS) in patients with and without CMV pneumonitis.
rejection (⭓ A2) on only 6 of 193 (3%) and 15 of 193 (8%) occasions within 1 and 3 months, respectively. There were 17 of 193 (9%) episodes of concomitant CMV pneumonia and acute rejection (⭓ A2). There were 108 of 193 (56%) and 63 of 193 (33%) cases of CMV pneumonia that were not temporally related to rejection within 1 and 3 months of each other, respectively. There was no significant difference in the rate of CMV pneumonia in patients transplanted until 1995 (60 of 151, 40%) and those from 1995 onwards (66 of 190, 35%) (Fishers exact test, p ⫽ 0.37).
DISCUSSION
CMV pneumonia was diagnosed on 193 occasions in 151 patients. Acute rejection (⭓ A2 [graded as described in the Lung Rejection Study Group of the International Society for Heart and Lung Transplantation]) preceded CMV pneumonia on 62 of 193 (32%) and 98 of 193 (51%) occasions within 1 and 3 months of each other, respectively. CMV pneumonia preceded acute
CMV causes significant morbidity and mortality in lung transplant recipients (12–14). CMV infection and disease are considered “probable” risk factors for the development of BOS (5). However, there is conflicting opinion in the literature regarding the true role of CMV in the development of BOS. Some reports, particularly those incorporating patients transplanted before the widespread prophylactic and therapeutic use of ganciclovir, consider CMV pneumonia and CMV sero-status risk factors for BOS (8, 13–21), whereas other studies have found no evidence of an increased risk (12, 22, 23). In a study of 32 lung transplant recipients, CMV pneumonia was significantly higher in the OB patient population compared with the non-OB group, and in most cases it preceded or was diagnosed concurrently with OB or acute rejection (16). Another study of 128 patients reported a significant association between CMV pneumonia and chronic rejection (8). An analysis of 132 consecutive lung allograft recipients revealed CMV pneumonia and late acute rejection as predictors of BOS (17). Both CMV infection and CMV pneumonia within 6 months after transplantation have been associated as risk factors for BOS onset (18). In another study of 46 lung transplant recipients, there was no association between CMV in-
Figure 1. Cumulative survival in patients with and without cytomegalovirus (CMV) pneumonitis.
Figure 3. Cumulative survival in various CMV serogroup combinations.
Temporal Association between CMV Pneumonia and Acute Rejection
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Figure 4. Freedom from survival in various CMV serogroup combinations.
fection and OB; however, D⫹R⫺ patients had a higher morbidity and a trend toward lower survival (12). Husain and colleagues reported no difference in histologically proven CMV pneumonia in patients with and without BOS (42 and 31%, respectively) (22). A lack of uniformity in diagnostic precision and variances in therapeutic strategies may have contributed to the differing outcomes reported in the literature to date. Histopathologic diagnosis of CMV pneumonia is the gold standard because it minimizes data pollution by reducing false positives, which may be contributed by other diagnostic modalities, such as molecular methods. Molecular methods have an excellent sensitivity for detection of CMV infection, but are less specific in regard to CMV disease (CMV pneumonitis). A recent study in 259 lung transplant recipients reporting respiratory viral infections as distinct risk factors for BOS and death also defined CMV pneumonitis purely on a histologic basis (24). This report also did not find a significant association between CMV pneumonia and BOS. We are confident that our surveillance and clinical biopsy program is very unlikely to have missed significant CMV pneumonia. We have also published the largest series of transbronchial lung biopsies in lung transplant recipients with the best reported rate of obtaining adequate lung tissue for histopathologic evaluation (3). Therefore, we believe that there is unlikely to be misidentification of CMV pneumonia in the non-CMV group. Our study provides results from a standard treatment regime based on a firm histopathologic diagnosis with histologic follow-up to confirm resolution of CMV pneumonia (9). Animal studies of OB have described an association of experimental CMV infection with the development of OB favoring the hypothesis that CMV infection triggers chronic rejection and subsequent BOS. To clarify whether BOS is associated with CMV infection, we applied strict criteria to analyze a large patient group in which lung transplant recipients with one or more episodes of histologically documented CMV pneumonia treated with ganciclovir were compared with recipients who had not had CMV pneumonia on TBB. We found no significant association between CMV pneumonia and the subsequent development of BOS or survival. The large number of lung transplant recipients in both groups (151 and 190, respectively), provides a persuasive argument that CMV pneumonia is not a risk factor for BOS. CMV-seropositive donors have been reported to confer an increased risk of clinical CMV disease in the lung transplant recipient. (13, 14, 19, 20). In a multiple variable analysis, acute rejection and CMV matching were the only two independent risk factors associated with BOS onset (18). With serogroup D⫺R⫺ as baseline, the hazard ratio for serogroup D⫹R⫺ was 3.41, for D⫺R⫹ 2.29, and for D⫹R⫹ 1.67 (18). However, the chronologic sequencing of rejection and CMV pneumonia was not examined, and not all patients received ganciclovir prophylaxis and therapy.
In our study, there was no significant association between CMV serologic matching and BOS or survival. BOS developed in a similar percentage of CMV seronegative lung transplant recipients of seronegative donors and the seropositive group, further supporting the hypothesis that with current diagnostic and therapeutic modalities there is no association of CMV with BOS. Our findings concur with a recent study that showed the CMV status of either the donor or recipient did not influence the development of BOS (25). The recent International Society for Heart and Lung Transplantation registry report has shown serogroup D⫹R⫺ to be a significant risk factor for mortality within 1 year, however, in our study there was no significant association between any serogroup combination and 1-, 3-, and 5-year mortality (1). In the current analysis, we found that almost one-third of CMV pneumonia cases were preceded by treated acute rejection in the previous month. Half of all episodes of CMV pneumonia occurred within 3 months of acute rejection. These findings lend support to the hypothesis that augmented immunosuppression, especially steroid pulses administered for the treatment of acute rejection, is a risk factor for the development of CMV pneumonia. Similar findings have been reported in renal transplant recipients in whom acute rejection preceded CMV infection (26). Furthermore, CMV infection after transplant was not found to be a risk factor for acute graft rejection or chronic graft dysfunction (26). We do not routinely offer ganciclovir prophylaxis while treating acute rejection. However, as the risk for CMV pneumonitis after treatment for rejection is high, as already documented in a follow-up transbronchial biopsy paper, ganciclovir prophylaxis can be considered in patients with recurrent rejection who have evidence of CMV disease (9). In a recent publication, high-dose intravenous ganciclovir, three times a week, seems to be an efficient, safe, and easy way to prevent CMV disease in renal transplant patients treated with antilymphocyte globulins for steroid-resistant acute rejection (27). In summary, our data clearly show that histopathologically diagnosed CMV pneumonia treated with intravenous ganciclovir is not a risk factor for BOS or patient survival; nor is any particular CMV serologic donor/recipient group. Furthermore, CMV pneumonia often follows acute rejection, perhaps as a result of augmented immunosuppression. We speculate that this previously underemphasized coupling may have confounded previous assessments of CMV as a risk factor for BOS. Conflict of Interest Statement : M.T. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; C.L.A. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; P.N.C. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; S.R. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; M.A.M. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; A.R.G. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript. Acknowledgment : The authors thank Jakob Passweg, Division of Hematology, University Hospital Basel, Switzerland, for the statistical advice.
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