K. Spichty

HLA-specific antibodies are risk factors for lymphocytic bronchiolitis and chronic lung allograft dysfunction

Bronchiolitis obliterans syndrome (BOS) represents a major limitation in lung transplantation. While acute rejection is widely considered the most important risk factor for BOS, the impact of HLA‐specific antibodies is less understood. Of 51 lung recipients who were prospectively tested during a 4.2 ± 1.6‐year period, 14 patients developed HLA‐specific antibodies. A multi‐factorial analysis was performed to correlate the prevalence of BOS with HLA antibodies, persistent‐recurrent acute rejection (ACR‐PR), lymphocytic bronchiolitis, and HLA‐A, ‐B, and ‐DR mismatches. HLA‐specific antibodies were associated with ACR‐PR (10/14 vs. 11/37 with no antibodies, p < 0.05), lymphocytic bronchiolitis (8/14 vs. 10/37, p < 0.05), and BOS (10/14, vs. 9/37, p < 0.005). Other risk factors for BOS were: lymphocytic bronchiolitis (13/18 vs. 6/33 with no lymphocytic bronchiolitis, p < 0.0001), ACR‐PR (12/21 vs. 7/30 with no ACR‐PR, p < 0.05), and the number of HLA‐DR mismatches (1.7 ± 0.48 in BOS vs. 1.2 ± 0.63 without BOS, p < 0.05). The presence of antibodies exhibited a cumulative effect on BOS when it was associated with either lymphocytic bronchiolitis or ACR‐PR. The complex relationship between the development of HLA antibodies and acute and chronic lung allograft rejection determines the importance of post‐transplant screening for HLA‐specific antibodies as a prognostic element for lung allograft outcome.

Experience With Immune Monitoring in Lung Transplant Recipients: Correlation of Low Immune Function With Infection

Background. Lung transplants, in particular, have the highest rate of infections among solid organ transplant recipients. However, there is no existing objective measure to predict the development of infections. We report the correlation between Cylex ImmuKnow (ng/mL ATP) values and various infectious syndromes in a large prospective cohort of lung transplant recipients. Methods. We followed up 175 lung transplants that developed 129 infectious episodes. Multiple logistic regression analysis was performed; generalized estimating equations were used to determine the odds ratio for infections. Results. The median ImmuKnow values in cytomegalovirus disease (49.3 ng/mL ATP), viral infection (70 ng/mL ATP), and bacterial pneumonia (92 ng/mL ATP) were significantly different from stable state (174.8 ng/mL ATP). The median ImmuKnow values of fungal disease (85 ng/mL ATP) and tracheobronchitis (123 ng/mL ATP) had a tendency to be lower than stable state (P=0.10), whereas patients with fungal colonization had comparable ImmunKnow values (167 vs. 174.8 ng/mL ATP). Of the patients colonized with fungus who subsequently developed fungal disease within 100 days, the median value of ImmuKnow was significantly lower than in those who did not develop fungal disease (22.5 vs. 183.5 ng/mL ATP; P<0.0001). Generalized estimating equation regression analysis showed ImmuKnow values less than or equal to 100 ng/mL ATP to be an independent predictor of infections (odds ratio 2.81). Conclusions. Cylex ImmuKnow assay monitoring has the potential to identify the patients at risk of developing infection and those colonized with fungus that are at risk of developing disease.

Recovery of Functional Memory T Cells in Lung Transplant Recipients Following Induction Therapy with Alemtuzumab

Profound T‐cell depletion with the monoclonal antibody alemtuzumab facilitates reduced maintenance immunosuppression in abdominal and lung transplantation. While the phenotype of the post‐depletional T cells has been characterized, little is known about their function. In the present study, global and CMV‐specific T‐cell function was assessed longitudinally in 23 lung transplant (LTx) recipients using T‐cell assays (ImmuKnow® and T Cell Memory™ , Cylex, Columbia, MD) during the first year posttransplant after induction therapy. Recovery of mitogen responses were seen at 2 weeks posttransplantation (65%PHA; 58% Con A), despite the low number of circulating T cells (<2%). These responses declined at 4–5 months (24%PHA; 54% Con A) and were partially reconstituted by 9 months (46% PHA; 73% Con A). CMV‐specific responses recovered in 80% of R+ patients as early as 2 weeks posttransplant (n = 5) and 72% of patients had a memory response by 3 months (n = 11). In contrast, only 2 of 5 patients who did not exhibit memory responses pre‐transplant (R–) developed transient CMV‐specific T‐cell responses. Our results show that profound depletion of T cells induced by alemtuzumab spares the functional subset of CMV‐specific memory T cells. Conversely, CMV R– patients predepletion may require a prolonged period of prophylaxis.

Efficacy of inhaled cyclosporine in lung transplant recipients with refractory rejection: Correlation of intragraft cytokine gene expression with pulmonary function and histologic characteristics

BACKGROUND Refractory rejection is a major cause of morbidity and death among lung transplant recipients. Traditional rescue therapies have proved only modestly successful. We recently demonstrated the safety of inhaled cyclosporine for patients with end-stage chronic rejection; this trial was extended to patients with refractory acute rejection. The present study was to determine whether effective inhaled cyclosporine therapy was correlated with suppression of cytokine gene expression. METHODS Twelve lung transplant recipients were studied. Maintenance therapy, cyclosporine or FK 506, azathioprine, and prednisone, was continued, and inhaled cyclosporine at a dose of 300 mg/day was added. Pulmonary function testing and histologic characteristics from transbronchial biopsy specimens were used to assess efficacy of therapy. Bronchoalveolar lavage (BAL) and peripheral blood cells were analyzed for the presence of messenger RNA by using 32P-labeled primers of cytokines interleukin-2 (IL-2), IL-6, IL-10, and interferon-gamma (gamma) via reverse transcriptase-polymerase chain reaction. RESULTS Nine of 12 patients (five with acute rejection, four with chronic rejection) exhibited histologic resolution of rejection within 3 months of inhaled cyclosporine therapy. Pulmonary function (forced expiratory volume in 1 second) improved from pretherapy levels in the patients with acute rejection (p < 0.05). All of the nine histologic responders exhibited 4- to 150-fold decreases (p < 0.05) in IL-6 and interferon-gamma messenger RNA levels in the BAL, whereas the three patients who failed exhibited persistent or increased cytokine profiles. IL-2 and IL-10 in BAL and peripheral blood lymphocyte cytokines were not informative. CONCLUSIONS These results indicate that inhaled cyclosporine is effective therapy for refractory pulmonary rejection and that its mechanism of action is associated with suppression of proinflammatory cytokines IL-6 and interferon-gamma within the allograft.

Cytokine mRNA profiles in Epstein–Barr virus-associated post-transplant lymphoproliferative disorders

Cytokine mRNA patterns were analyzed in 11 post‐transplant lymphoproliferative disorder (PTLD) specimens using qualitative reverse‐transcriptase polymerase chain reaction (RT‐PCR). In each case, a pattern of IL2−, IFNΓ−, IL4+, IL10+ was seen. A similar pattern was observed in a spleen sample from 1 patient with contemporaneous PTLD elsewhere. Semiquantitative RT‐PCR for cytokine message was performed using RNA from bronchoalveolar lavage (BAL) specimens obtained from 2 patients with pulmonary PTLD. In both cases, IL4 message predominated. Reduction of message coincided with resolution of the tumors. The pattern differed from that seen in 1 patient with acute pulmonary rejection, in which RT‐PCR of BAL cells showed predominance of IL6 and IFNΓ. We conclude that at least some PTLDs exist within a T‐helper cell type 2 (Th2)‐like cytokine microenvironment. The presence of a similar mRNA pattern in an extratumoral specimen at the time of PTLD suggests that it may reflect a systemic phenomenon. Disappearance of this pattern following PTLD resolution indicates its dynamic nature and is consistent with the hypothesis that specific cytokines contribute to the development of PTLDs.

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.

Anti-Human Leukocyte Antigen Antibodies, Vascular C4d Deposition and Increased Soluble C4d in Broncho-Alveolar Lavage of Lung Allografts

Background. The hallmark of humoral rejection is the presence of subendothelial C4d in the allograft. A simultaneous determination of vascular C4d with soluble C4d in broncho-alveolar lavage fluid (BAL) and circulating anti-human leukocyte antigen (HLA) antibodies (HLA-Ab) has not been reported in lung transplantation. Methods. Forty-two consecutive lung-transplant patients were included in this cross-sectional study. The presence and specificity of HLA-Ab was determined at the same frequency with transbronchial biopsies. Soluble C4d levels were measured by enzyme-linked immunosorbent assay in all 42 patients. In a subgroup of 32 patients with available timely matched paraffin-embedded tissue sections, the vascular C4d deposition was also assessed. Results. The presence of HLA-Ab in 16 patients was associated with biopsy-proven acute rejection (10/16 vs. 3/16, P<0.01) and increased immunosuppression (13/16 vs. 4/16, P<0.005). Pulmonary function was also decreased in patients with HLA-Ab (mean forced expiratory volume in 1 second=49%) when compared with the control group (mean forced expiratory volume in 1 second=66%, P<0.05). Nine patients exhibited specific vascular C4d deposition and in eight of nine (89%) cases HLA-Ab were detected, versus 8 of 23 (35%) in C4d-negative patients (P<0.05). Soluble C4d in BAL was highly (>0.5 &mgr;g/mL) elevated in patients with HLA-Ab and vascular C4d and was moderately (0.2 &mgr;g/mL) increased in patients with antibodies but C4d-negative. In contrast, only a slight elevation of soluble C4d (<0.1 &mgr;g/mL) was detected in patients without HLA-specific antibodies. Conclusions. The association of HLA-specific antibodies with vascular C4d deposition and soluble C4d in BAL, in addition to the reduced pulmonary function, might constitute a diagnostic triad for antibody-mediated rejection in lung transplant patients.

Proliferation of cytomegalovirus-primed lymphocytes in bronchoalveolar lavages from lung transplant patients.

Previous reports have described an association between cytomegalovirus infection and increased donorspecific alloreactivity of bronchoalveolar lavage (BAL) lymphocytes in transplanted lungs and a higher risk of bronchiolitis obliterans due to chronic rejection. We have postulated that during infection, intragraft CMV-specific lymphocytes are activated and release lymphokines that augment cellular rejection. This study deals with an analysis of CMV antigen induced proliferation of 28 BAL lymphocyte and 27 peripheral blood lymphocytes samples from 17 lung transplant patients with or without CMV infection. Kinetic studies of lymphocyte proliferation have shown that CMV infection of the lung allograft is associated with an accelerated response of BAL lymphocytes but not PBL, following in vitro exposure to CMV antigen. These findings indicate an accumulation of primed CMV-specific lymphocytes within the lung allograft during CMV infection. Evidence has also been obtained that primed CMV-specific lymphocytes may persist for months in BAL. We conclude that the CMV antigen induced proliferation assay is useful for studies of CMV infection in transplant patients.

Mitogen responses of lymphocytes from lung transplant recipients : correlation with rejection and infection

&NA; Proliferative responses to nonspecific mitogens were analyzed for 119 bronchoalveolar lavages and 108 concurrent peripheral blood samples from 35 lung transplant patients. The patients were classified at each time as normal, rejecting, or infected on the basis of trans-bronchial biopsy, culture results, clinical signs, and pulmonary function. During rejection episodes the bronchoalveolar lavage responses to concanavalin A and phytohemagglutinin were significantly increased (P<0.004 and P<0.006, respectively). The differences were less pronounced when rejection occurred within 30 days after bolus immunosuppressive therapy, either as immunoprophylaxis or as treatment for a previous rejection episode, and were not significantly different from normal. Differences in response during rejection were limited to the graft; analysis of circulating T cells was not helpful (P=NS). In contrast, markedly depressed responses to Con A and PHA were seen during infection. Significant differences were observed both in the graft (P<0.007) and in circulating lymphocytes (P<0.02), suggesting that global depression of mitogen response is associated with immunocompromise. Sequential analysis of 6 patients showed that individual changes in mitogen response paralleled those seen in the population (P<0.046, normal vs. rejection and P<0.043 normal). These findings suggest that mitogen assays of bronchoalveolar lavage lymphocytes and, to a lesser extent, PBL, are clinically useful in assessing intragraft immunocompetence and in distinguishing rejection from infection in lung transplant patients.

Clinical Significance of Cytomegalovirus-Specific T Helper Responses and Cytokine Production in Lung Transplant Recipients

Cytomegalovirus (CMV) disease continues to be a major problem for lung transplant recipients. In CMV-seropositive individuals, we detected two types of CMV-specific responses: a self-restricted response stimulated by soluble CMV antigen (sCMV-Ag) and a non-self-restricted response induced by CMV-infected cells (cCMV-Ag). Lung transplant recipients who develop the CMV-specific self-restricted T helper response have a low risk of recurrent CMV disease. In contrast, during CMV disease, lung transplant recipients exhibit only the non-self-restricted T helper responses. We characterized the T cell activation and the kinetics of cytokine production of sorted CD4+ and CD8+ T cells from PBLs of CMV seropositive donors. The two types of CMV antigens induced cytokine production in both T cell subsets. We also performed competitive RT-PCR for Granzyme B (GB) in BAL cells of lung transplant recipients prior to, during and following CMV disease. CMV disease was associated with increase in GB gene expression when was accompanied by acute cellular rejection while it remained low in patients with CMV disease that did not have a complicated course. In summary, CMV-activated T cells within the allograft may produce inflammatory cytokines and effector molecules that may promote allograft rejection.