Wayne F. Grgurich

Tacrolimus Dosing in Adult Lung Transplant Patients Is Related to Cytochrome P4503A5 Gene Polymorphism

Tacrolimus is a potent immunosuppressive agent used in lung transplantation and is a substrate for both P‐glycoprotein (P‐gp, encoded by the gene MDR1) and cytochrome (CYP) P4503A. A previous study by the authors identified a correlation between the tacrolimus blood level per dose with CYP3A5 and MDR1 gene polymorphisms in pediatric heart transplant patients. The objective of this study was to confirm the influence of these polymorphisms on tacrolimus dosing in adult lung transplant patients. Adult lung transplant patients who had been followed for at least 1 year after lung transplantation were studied. Tacrolimus blood level (ng/mL) per dose (mg/day) at 1, 3, 6, 9, and 12 months after transplantation was calculated as [L/D]. DNA was extracted from blood. MDR1 3435 CC, CT, and TT; MDR1 2677 GG, GT, and TT; and CYP3A5*1 (expressor) and *3 (nonexpressor) genotypes were determined by PCR amplification, direct sequencing, and sequence evaluation. Eightythree patients were studied. At 1, 3, 6, 9, and 12 months after the transplant, a significant difference in [L/D] was found between the CYP3A5 expressor versus nonexpressor genotypes (mean ± SD of 1.49 ± 0.88 vs. 3.11 ± 4.27, p = 0.01; 1.23 ± 0.82 vs. 3.44 ± 8.97, p = 0.05; 1.32 ± 0.96 vs. 3.81 ± 6.66, p = 0.005; 0.95 ±1.19 vs. 3.74 ±5.98, p = 0.0015; and 0.45 ± 0.2 vs. 3.76 ± 6.75, p = 0.0001, respectively). MDR1 G2677T and C3435T genotypes had only minimal effects on [L/D] at 1 and 3 months after transplantation. This study confirms the relationship of CYP3A5 polymorphisms to tacrolimus dosing in organ transplant patients. CYP3A5 expressor genotypes required a larger tacrolimus dose to achieve the same blood levels than the CYP3A5 nonexpressors at all time points during the first posttransplant year. This was not uniformly true for MDR1. The authors therefore conclude that tacrolimus dosing in adult lung transplant patients is associated with CYP3A5 gene polymorphisms.

Aerosol cyclosporin therapy in lung transplant recipients with bronchiolitis obliterans

The majority of patients who develop bronchiolitis obliterans, after lung transplantation, die within 2–3 yrs after onset since treatment with conventional immunosuppression is typically ineffective. A case/control study was conducted in lung transplant recipients with biopsy-documented bronchiolitis obliterans to determine whether aerosol cyclosporin use contributed to increased survival. The cases comprised 39 transplant recipients who received open-label aerosol cyclosporin treatment in addition to conventional immunosuppression. The controls were transplant recipients treated with conventional immunosuppression alone. There were 51 controls from the University of Pittsburgh Medical Center and 100 from a large multicentric database (Novartis Lung Transplant Database). Forced expiratory volume in one second expressed as a percentage of the predicted value was an independent predictor of survival in all patients with bronchiolitis obliterans. Cox proportional-hazards analysis revealed a survival advantage for aerosol cyclosporin cases compared to the Pittsburgh control group. A survival advantage was also seen when comparing study cases to multicentric controls. Aerosol cyclosporin, given with conventional immunosuppression to lung transplant recipients with bronchiolitis obliterans, provides a survival advantage over conventional therapy alone.

Interleukin-10 production genotype protects against acute persistent rejection after lung transplantation

BACKGROUND Our previous studies demonstrated that cytokine gene polymorphisms are related to acute rejection in pediatric heart transplantation; a decreased tumor necrosis factor (TNF)-alpha production genotype combined with an increased or intermediate interleukin (IL)-10 production genotype was associated with the smallest incidence of acute rejection. The objective of this study was to determine whether cytokine genotypes TNF-alpha, IL-10, IL-6, interferon-gamma, and transforming growth factor beta were associated with acute persistent rejection after lung transplantation. METHODS Cytokine genotyping was performed in 119 adult lung transplantation recipients who underwent surveillance transbronchial biopsies during their first year after transplantation. We categorized recipients with acute persistent rejection if they had 2 consecutive biopsy specimens at >/=Grade A2 despite anti-rejection treatment. We performed cytokine genotyping using the polymerase chain reaction-sequence specific primers technique, with a commercially available kit. RESULTS We analyzed the IL-10 genotype in 116 patients. For the increased IL-10 production genotype, 7 of 20 patients (35%) were persistent rejecters. In comparison, 57 of 96 patients (59%) with intermediate or decreased IL-10 production genotype had acute persistent rejection (p = 0.046). For IL-10 haplotypes associated with intermediate IL-10 production, 30 of 45 patients with GCC/ACC haplotype (67%) had acute persistent rejection compared with 10 of 22 patients with GCC/ATA (45%). In the patients with intermediate IL-10 production, 17 of 22 (77%) with IL-10 GCC/ACC and IL-6 G/C had acute persistent rejection, whereas only 2 of 7 patients (29%) with IL-10 GCC/ATA and IL-6 G/G had acute persistent rejection (p = 0.018). CONCLUSIONS In lung transplant recipients, the increased IL-10 production genotype protects against acute persistent rejection when compared with the intermediate or decreased IL-10 production genotypes. The intermediate IL-10 production genotype in lung transplant recipients can be differentiated into 2 haplotype responses, with the GCC/ACC haplotype associated more with acute persistent rejection. In lung transplant recipients, the immunomodulatory effects of IL-6 are differentiated in the G/C and G/G alleles in conjunction with IL-10 haplotypes, with G/C being associated with more acute persistent rejection in conjunction with the IL-10 GCC/ACC haplotype. Future pharmacogenomic models may incorporate these associations with acute persistent rejection in lung transplant recipients to formulate individualized therapeutic regimens.

Endobronchial metallic stent placement for airway complications after lung transplantation: Longitudinal results

BACKGROUND In lung transplant recipients, bronchial stenosis (SB) and bronchomalacia (MB) result in obstructive airway disease and allograft dysfunction due to pulmonary infection. We hypothesized that endobronchial metallic stent placement for SB and MB would result in long-term improvement in respiratory function and rates of pulmonary infection. METHODS We studied symptomatic lung transplant recipients with bronchoscopic evidence of proximal airway complications (SB or MB) and a synchronous decline in forced expiratory volume in 1 second (FEV1) of at least 10% in the 6-month period before intervention. Stent placement was the primary intervention for SB and all focal MB lesions and for recurrent or refractory SB lesions failing a single initial attempt at balloon dilation. FEV1 and rates of pulmonary infection were assessed in the 12-month interval before and after stent placement. Spirometric evaluation was performed at 3-month intervals and compared with spirometry at the time of stent placement. The rates of pulmonary infection, determined by the number of antibiotics prescribed, was determined before and after endobronchial correction. RESULTS Thirty recipients underwent a total of 75 procedures (50 stent insertions and 25 balloon dilations). FEV1 improved significantly after stent placement compared with base line (1.29 +/- 0.43 L) as follows: 3 months, 1.45 +/- 0.50 L, p = 0.014; 6 months, 1.59 +/- 0.57 L, p = 0.002; 12 months 1.59 +/- 0.53 L, p = 0.006. The infection rate decreased from the 12-month period preceding stent insertion to the corresponding period after stent insertion (6.97/100 days +/- 6.33 versus 5.74/100 days +/- 7.76, p = 0.018). Recurrent SB occurred in 17.3%. No life-threatening complications occurred after stent placement and no deaths were attributed to stent malfunction or malposition. CONCLUSIONS In lung transplant recipients with SB and MB, maintenance of airway patency by stent placement is safe and resulted in improvements in lung function and reduced pulmonary infection rates for up to 1 year after their insertion.

Outcomes of Lung Volume Reduction Surgery Followed by Lung Transplantation: A Matched Cohort Study

BACKGROUND Lung volume reduction surgery (LVRS) has been demonstrated to provide symptomatic relief and to improve lung function in patients with end-stage emphysema. The goal of this study was to assess the additional morbidity associated with lung transplantation after LVRS for end-stage emphysema with regard to immediate postoperative outcomes, longitudinal spirometry, and survival rates compared to an age-, gender-, procedure-matched, and transplant time-matched cohort that had lung transplantation alone. METHODS We compared the postoperative and long-term outcomes of a sequential procedure cohort to a matched cohort to assess the possible added post-transplant morbidity. RESULTS Fifteen patients who underwent sequential LVRS (including 11 unilateral LVRS, 4 bilateral LVRS) and lung transplantation (ipsilateral in 7 and contralateral in 8) on average 28.1 +/- 17.2 months (median, 27.4 months; range, 3.7 to 61.7 months) later were assessed. No significant differences were noted in pretransplant demographics, post-transplant variables, longitudinal spirometric indices, or survival. A trend toward a lower pretransplant arterial carbon dioxide tension was apparent in the sequential procedure cohort. Group analysis revealed a significant increase in the number of patients requiring transfusion and in the total number of units transfused in patients undergoing ispsilateral transplantation after LVRS; a significant increase in the length of intensive care unit stay; and a trend toward an increase in the duration of hospital stay in patients undergoing lung transplantation within 18 months of LVRS. CONCLUSIONS In appropriate candidates, LVRS bridged the time to transplantation by an average of 28.1 +/- 17.2 months (median, 27.4 months; range, 3.7 to 61.7 months) without significantly increasing post-transplant morbidity or mortality. Furthermore, bilateral LVRS bridged the time to transplantation to a greater extent than unilateral LVRS (34.9 +/- 29.8 months; median, 32.1 months versus 25.4 +/- 16.3 months; median, 22.3 months; p = 0.23).

CLINICAL SIGNIFICANCE OF CMV-SPECIFIC T HELPER RESPONSES IN LUNG TRANSPLANT RECIPIENTS

BACKGROUND Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant patients who generate an inefficient immune response to control this viral infection. Both T helper and cytotoxic T cells are thought to play an important role in prevention and control of CMV disease. We investigated the clinical significance of CMV-specific memory responses in lung transplant recipients. METHOD Peripheral blood samples (140) were collected from 99 lung transplant recipients. Patients were grouped according to their pre-transplant CMV serological status as recipient/donor (R-/D+, 25 patients), 28 R+/D+ patients, 35 R+/D- patients and 11 R-/D- patients. Memory responses to CMV whole antigen, 5 CMV proteins, and tetanus toxoid (TT) were measured in a 6-day proliferative assay. Results were expressed as the stimulation index (SI = experimental cpm/background cpm), and were considered positive if the SI was >3 and the cpm values were over 1,000. RESULTS The frequency of positive CMV memory responses was similar in three groups: 64% for R-/D+, 63% for R+/D+ and 56% for R+/D- except for R-/D- (21%). The memory response to TT was similar for all four groups (70% of samples were positive). The level of responsiveness to individual CMV proteins was much higher in R+/D+ group (65%) than the other two groups (35% for R+/D-, and 31% for R-/D+). We determined the temporal relationship between the presence of CMV-specific memory responses and the diagnosis of CMV disease. In the R-/D+ group, 16 of 17 patients who had CMV disease eventually developed CMV-specific memory. In those patients (n = 3) who failed to develop CMV-specific T helper response for a prolonged time, all had recurrent CMV disease. In the R+/D+ group, 4 of 8 patients with CMV disease exhibited CMV-specific memory responses. Three of 4 patients in whom we observed a persistent absence of CMV-specific memory had multiple episodes of CMV pneumonitis. In the R+/D- group, only one of 4 patients with CMV disease had suppressed CMV-specific memory response after first episode of CMV pneumonitis and had recurrent disease. CONCLUSION In lung transplant recipients, the loss or persistent lack of CMV-specific memory following infection was associated with chronic CMV disease. These data suggest that monitoring T helper memory responses following primary CMV infection or after augmented immunosuppression for treatment of rejection may identify those patients at risk for morbidity associated with recurrent CMV disease.