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.

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-, IFN gamma-, 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 IFN gamma. 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 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.

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.

Interleukin 6 and interferon-gamma gene expression in lung transplant recipients with refractory acute cellular rejection: implications for monitoring and inhibition by treatment with aerosolized cyclosporine.

BACKGROUND: The purpose of this study was to correlate cytokine gene expression from bronchoalveolar lavage (BAL) cells and peripheral blood lymphocytes (PBL) with graft histology in recipients with persistent acute rejection treated with aerosolized cyclosporine (ACsA). METHODS: We measured mRNA for interleukin (IL) 6, interferon (IFN)-gamma, and IL-10 in recipients (1) without rejection (n=13), (2) with acute rejection that responded to pulsed methylprednisolone (n=7), and (3) with "refractory" acute rejection that failed to respond to conventional immunosuppression (n=17). In the latter group, ACsA was initiated. RESULTS: BAL cell IL-6 and IFN-gamma were highest in recipients with refractory rejection compared with recipients with steroid-responsive rejection and recipients with no rejection. Improvement in rejection histology occurred in 15 of 17 recipients who were treated with ACsA. IL-6 and IFN-gamma mRNA levels from BAL cells decreased during treatment with ACsA (median IL-6:actin ratio: before treatment, 0.40 vs. after treatment, 0.003, P=0.001; IFN-gamma:actin ratio: before treatment, 0.32 vs. after treatment, 0.04, P=0.001). PBL IL-6 and IFN-gamma mRNA expression also decreased during ACsA treatment after 180 days. Expression of IL-10 mRNA from BAL and PBL did not change during ACsA treatment (0.0 vs. 0.03 and 0.0 vs. 0.02, respectively). CONCLUSIONS: IL-6 and IFN-gamma mRNA expression from BAL cells was highest in those recipients with refractory histologic acute rejection. ACsA was associated with decreased IFN-gamma and IL-6 gene expression in BAL cells and PBL.

Interferon-alpha affects the immune response in post-transplant lymphoproliferative disorder.

Post-transplant lymphoproliferative disorder (PTLD) is associated with Epstein-Barr virus (EBV) and characterized by fever, lymphadenopathy, and graft dysfunction. We describe the clinical course of an EBV seronegative 11-yr-old boy who underwent double lung transplantation and subsequently developed PTLD in the graft. A reduction in immunosuppression and the addition of acyclovir did not result in improvement. Treatment with interferon-alpha (IFN-alpha), however, led to dramatic clinical, radiographic, and histologic improvement. Semiquantitative measurements of cytokine mRNA in his bronchoalveolar lavage cells prior to therapy with IFN-alpha revealed high levels of IL-4 and IL-10 mRNA, which decreased significantly with treatment. We speculate that the beneficial effect of IFN-alpha in the treatment of PTLD is directly related to the inhibition of type 2 helper (Th2-like) T-cells.

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.

Monitoring of acute lung rejection and infection by bronchoalveolar lavage and plasma levels of hyaluronic acid in clinical lung transplantation.

Local immunological injury caused by acute lung rejection leads to fibroblast proliferation. Hyaluronate is a product of activated fibroblasts and possibly an indicator of fibroblast proliferation. One hundred thirty-six bronchoalveolar lavage and plasma hyaluronate assays were performed in 57 lung transplant recipients. Pulmonary endothelial cell function was assessed by measuring bronchoalveolar lavage levels of purine nucleoside phosphorylase. Presence of acute cellular rejection was monitored by transbronchial biopsy histologic evaluation and was classified as minimal to mild (acute rejection I, II) and moderate to severe (acute rejection III, IV). Infection was confirmed by bronchoalveolar lavage culture and antibiotic sensitivity. Bronchoalveolar lavage hyaluronate levels in clinically stable recipients were 33.5 +/- 4.69 micrograms/L and were significantly higher than with clinically stable recipients (p = 0.0001), infection (p = 0.008), or mild rejection (p = 0.001). Levels were highest in recipients with diffuse alveolar damage (392.4 +/- 60.6 micrograms/L). Diffuse alveolar damage also resulted in significant elevations of plasma HA as compared with stable recipients (p = 0.001) and mild rejection. We conclude that clinically significant injury to the allograft from rejection or diffuse alveolar damage can be assessed by bronchoalveolar lavage hyaluronate assays and suggest that the source of hyaluronate in these instances are activated fibroblasts.

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

Previous reports have described an association between cytomegalovirus infection and increased donor-specific 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.

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 less than 0.004 and P less than 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 less than 0.007) and in circulating lymphocytes (P less than 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 less than 0.046, normal vs. rejection and P less than 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.

Diet-induced reduction in serum lipoproteins stimulates cell proliferation in weanling rats.

Male weanling Wistar rats were fed a 4% cholestyramine diet and used as a model to demonstrate that a reduction in serum low density lipoproteins stimulates de novo cholesterogenesis leading to DNA synthesis and cell proliferation. Feeding this diet resulted in a decrease in serum very low density lipoproteins and low density lipoproteins, an increase in high density lipoproteins and an increase in de novo cholesterogenesis in liver, thymus, spleen, pancreas, kidney and lung. DNA synthesis increased only in the thymus and spleen. Histological examination of spleen, thymus and lymph nodes showed an increased number of immature cells and enhanced mitotic activity. These results suggest that a marked reduction in serum low density lipoproteins stimulates de novo cholesterogenesis, leading to enhanced DNA synthesis and cell proliferation.