Augmented Immunosuppression Research Articles

Bronchiolitis obliterans: pathogenesis, prevention, and management.

Increasing early success-post lung transplant has been tempered by the long-term development of histologic bronchiolitis obliterans (OB) or of the progressive airway obstruction which is called bronchiolitis obliterans syndrome (BOS). Multiple lines of evidence suggest that OB/BOS is due to an injury directed against the epithelial cells in the airways of the donor lung by the immune system of the recipient. Acute rejection is the strongest risk factor for the subsequent development of this process. Efforts to prevent or minimize acute rejection may reduce the prevalence of OB/BOS. Results of treatment with augmented immunosuppression have been disappointing but the treatment of complicating infections in the allograft can be beneficial. Multicenter studies are needed to assess the efficacy of new immunosuppressive agents in preventing or treating OB/BOS.

Invasive aspergillosis in liver transplant recipients in the 1990s.

Invasive aspergillosis occurred in 26 liver transplant recipients since 1990 at five liver transplant centers. The median time to onset was 17 days after transplantation. Twenty-seven percent of the patients had undergone retransplantation. Invasive aspergillosis occurred significantly earlier after transplantation in smokers than in nonsmokers (P=0.017). Patients with late-onset aspergillosis (occurring after posttransplant day 90) were more likely to have had prior cytomegalovirus infection than those with early-onset aspergillosis (occurring within 90 days of transplantation) (67% vs. 10%, respectively, P=0.013). Only 8% of the patients had received additional corticosteroids or OKT3, which suggests that augmented immunosuppression may not be a relevant risk factor for invasive aspergillosis in the 1990s due to less frequent use of these agents. The median serum bilirubin level of the patients was 21.8 mg/dl, 85% of the patients had renal insufficiency, and 54% were on dialysis before the onset of invasive aspergillosis, which suggest that overall severity of illness, including poorly functioning hepatic allograft and renal failure may be the major determinants of disease occurrence. Overall mortality was 92% (24/26). No difference in mortality could be shown for the patients who received amphotericin B versus liposomal amphotericin B preparations (100% vs. 89%); however, the mean time to death after the initiation of therapy was 20 days in patients who received amphotericin B and 43 days in those who received liposomal amphotericin B preparations.

Stanford experience with obliterative bronchiolitis after lung and heart-lung transplantation

Obliterative bronchiolitis (OB) is the main chronic complication after heart-lung (HLTx) and lung transplantation (LTx), limiting the long-term success of both transplant procedures. Since 1981, 135 HLTxs and 61 isolated LTxs were performed in 184 patients at Stanford University. The overall prevalence of OB in patients surviving longer than 3 months postoperatively was 64% after HLTx and 68% after LTx. The actuarial freedom from OB was 72%, 51%, 44%, and 29% at 1, 2, 3, and 5 years, respectively, after HLTx and LTx. An analysis of potential risk factors revealed that the frequency and severity of acute rejection episodes (p < 0.001) and the appearance of lymphocytic bronchiolitis on biopsy (p < 0.05) were significantly associated with the development of OB. With regard to diagnosis of OB, pulmonary function tests show early reductions of the forced expiratory flow between 25% and 75% of the forced vital capacity with subsequent decreases in the forced expiratory volume in 1 second. The sensitivity of transbronchial biopsies has increased to 71% since 1993. Current treatment consists of augmented immunosuppression. Concurrent acute rejection episodes or active OB on biopsy have been treated aggressively with high-dose steroid pulses. Analysis of data from 73 patients with OB after HLTx and LTx revealed actuarial 1-, 3-, 5-, and 10-year survival of 89%, 71%, 44%, and 17% versus 86%, 77%, 63% and 56% in patients without OB (p < 0.05 by log-rank analysis). The main complication and cause of death in patients with OB was superimposed respiratory tract infection, which was treated aggressively. Early diagnosis of OB using pulmonary function tests or transbronchial biopsy is possible and important, because immediate treatment initiation has led to acceptable survival rates, with nearly 50% of affected patients still alive 5 years after transplantation. Current experimental research on OB suggests that immune injury is the main pathogenetic event of airway obliteration in animal models; rapamycin and leflunomide are new immunosuppressive agents that may have the potential to prevent and treat airway obliteration.

Bronchodilator Response at Low Lung Volumes Predicts Bronchiolitis Obliterans in Lung Transplant Recipients

Bronchiolitis obliterans syndrome (BOS) is the major obstacle to long-term lung allograft viability. The diagnosis often occurs after significant organ dysfunction is present, and BOS is often unresponsive to standard immunosuppressive agents. We have observed bronchodilator responses (BRs) at low lung volumes in many of our patients who have developed BOS. We therefore assessed whether BR could predict the development of BOS. We conducted a retrospective review of the clinical and pulmonary function laboratory records of 146 patients who underwent transplantation between March 1983 and November 1993. BR was defined as 25% or more increase in forced expiratory flow at 50% of vital capacity or 30% or more increase in forced expiratory flow at 75% of vital capacity. BOS was defined according to recently published FEV1 criteria. Bronchiolitis obliterans was defined histologically according to criteria of the Lung Rejection Study Group. Of the total population, 52 were excluded because of death or insufficient information. BRs of the small airways were seen in 31 patients (33%), 25 of whom developed BOS (83%). Approximately half of those with BR who developed BOS had evidence of acute rejection in the month prior to the onset of BR. Two thirds (four of six) of patients with BR not developing BOS had acute rejection in the previous month. The sensitivity of BR in predicting BOS was 51% with a specificity of 87%. The positive predictive value was 81%. BR appears to be useful as an early marker of BOS. The development of BR in selected patients should lead to closer monitoring and possibly a trial of augmented immunosuppression to arrest the establishment of BOS.

Obliterative bronchiolitis after lung and heart-lung transplantation: An analysis of risk factors and management

With a prevalence of 34% (55/162 at-risk recipients) and a mortality of 25% (14/55 affected recipients), obliterative bronchiolitis is the most significant long-term complication after pulmonary transplantation. Because of its importance, we examined donor-recipient characteristics and antecedent clinical events to identify factors associated with development of obliterative bronchiolitis, which might be eliminated or modified to decrease its prevalence. We also compared treatment outcome between recipients whose diagnosis was made early by surveillance transbronchial lung biopsy before symptoms or decline in pulmonary function were present versus recipients whose diagnosis was made later when symptoms or declines in pulmonary function were present. Postoperative airway ischemia, an episode of moderate or severe acute rejection (grade III/IV), three or more episodes of histologic grade II (or greater) acute rejection, and cytomegalovirus disease were risk factors for development of obliterative bronchiolitis. Recipients with obliterative bronchiolitis detected in the preclinical stage were significantly more likely to be in remission than recipients who had clinical disease at the time of diagnosis: 81% (13/15) versus 33% (13/40); p < 0.05). These results indicate that acute rejection is the most significant risk factor for development of obliterative bronchiolitis and that obliterative bronchiolitis responds to treatment with augmented immunosuppression when it is detected early by surveillance transbronchial biopsy.

Natural history of focal moderate cardiac allograft rejection. Is treatment warranted?

The rate of progression and potential long-term consequences of isolated foci of moderate acute rejection (FMR) on endomyocardial biopsy (EMB) have not been defined; therefore, whether FMR necessitates augmented immunosuppression remains controversial. At our institution, recipients with EMBs having FMR, defined as one or two isolated foci of cellular infiltrates with associated myocyte damage (International Society for Heart and Lung Transplantation [ISHLT] grade 2 and a subset of grade 3A), do not routinely receive intensified immunosuppression. Accordingly, to determine the outcome of untreated FMR, we reviewed 4398 EMBs (mean, 4.4 samples each) obtained after orthotopic heart transplantation in 208 consecutive recipients maintained on triple immunosuppressive therapy. The incidence of progression versus resolution of FMR, the time interval after transplantation when FMR was detected, and the relation of untreated FMR to recipient survival were analyzed. FMR categorized as one (n = 312) or two (n = 89) foci was present in 401 EMBs (9% of total) obtained 10 days to 7.5 years after transplantation from 149 recipients (72%). EMBs with FMR resolved without treatment in 341 of 401 (85%), and only 60 of 401 (15%) progressed to higher grade rejection. EMBs that progressed occurred 7.5 +/- 7.9 months (mean +/- SD) after transplantation compared with 14.0 +/- 16.5 months after transplantation for those that resolved (P < .005). Of the 60 EMBs that progressed, 55% occurred within the first 6 months, 78% within the first year, and 97% within the first 2 years after transplantation. EMBs with two foci of FMR were no more likely to progress than those with one focus. Thirty-nine recipients experienced one (n = 25), two (n = 9), three (n = 3), or four (n = 2) episodes of FMR that progressed. One or more episodes of FMR that did not progress occurred in 110 recipients. By Kaplan-Meier analysis, survival at 1 and 5 years was similar in recipients with and those without FMR progression. First, untreated FMR consisting of either one or two foci has a low rate of progression. Second, progression of FMR decreases with increasing postoperative interval and becomes rare after 2 years. Last, FMR progression did not identify recipients with decreased survival.

Parainfluenza and Influenza Virus Infections in Pediatric Organ Transplant Recipients

We retrospectively reviewed parainfluenza and influenza virus infections that occurred in pediatric organ transplant recipients at our hospital from January 1985 through September of 1992. Cultures of respiratory specimens revealed 45 infections in 42 transplant recipients (32 cases of parainfluenza and 13 cases of influenza virus infection). The following organs were transplanted: liver (28 patients), small bowel with and without liver (4), heart (3), lung with and without heart (5), and kidney (2). Clinical presentations of the patients and outcomes were similar regardless of the type of virus isolated or the type of organ transplanted. There were 20 cases in which patients had upper respiratory symptoms but did not require supplemental oxygen, nine cases in which patients required oxygen supplementation only, and eight cases in which the patients survived with mechanical ventilation. Eight patients died (five had parainfluenza, three had influenza virus infection); four children had serious concurrent infections (cytomegaloviral pneumonia in one patient, bacteremia in two, bacteremia and pneumonia in one). Factors associated with poor outcome for the entire group were age (increased morbidity and mortality if < 6 months old), augmentation of immunosuppression, and onset of infection within 1 month of transplantation. In this patient population, parainfluenza and influenza infections were important causes of morbidity and mortality.

Severe or multiple rejection episodes are associated with early recurrence of hepatitis C after orthotopic liver transplantation

Recurrent hepatitis C causes significant morbidity after liver transplantation. Because immunosuppression is associated with enhanced viral replication, we postulated that clinical recurrence of the disease may be associated with augmented immunosuppression for rejection. In 96 patients with hepatitis C who received liver transplants, we recorded the interval from transplantation to recurrence, the episodes of steroid-resistant rejection (SRR) requiring OKT3, the number of rejection episodes, and the use of OKT3 induction. Recurrence was diagnosed based on elevated transaminases and characteristic histology. Hepatitis C recurred in 43 of 96 patients. Fifteen of 21 patients (71.4%) who previously had SRR had recurrence, versus 28 of 75 patients (37.3%) who either had no SRR (72 patients) or had it after recurrence was diagnosed (3 patients) (P < .01). Mean time to recurrence was 127 +/- 31 days in the 15 patients who had had SRR versus 246 +/- 42 days in the other 28 patients (P = .02). Recurrence and number of rejection episodes were clearly associated: 6 of 33 patients (18.2%) with no rejection had recurrence (P < .05), versus 11 of 26 patients (42.3%) with one rejection episode (P < .05) and 26 of 37 (70.2%) with more than 1 episode (P < .05). OKT3 induction was used in 15 patients; 9 of 15 patients had recurrence (ns) at 337 +/- 95 days. Of 72 patients who initially received triple immunosuppression, 30 patients had recurrence at 186 +/- 25 days (P = .05). Nine patients received primary FK506; 4 had recurrence at 68 +/- 14 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Severe or multiple rejection episodes are associated with early recurrence of hepatitis C after orthotopic liver transplantation

Recurrent hepatitis C causes significant morbidity after liver transplantation. Because immunosuppression is associated with enhanced viral replication, we postulated that clinical recurrence of the disease may be associated with augmented immunosuppression for rejection. In 96 patients with hepatitis C who received liver transplants, we recorded the interval from transplantation to recurrence, the episodes of steroid-resistant rejection (SRR) requiring OKT3, the number of rejection episodes, and the use of OKT3 induction. Recurrence was diagnosed based on elevated transaminases and characteristic histology. Hepatitis C recurred in 43 of 96 patients. Fifteen of 21 patients (71.4%) who previously had SRR had recurrence, versus 28 of 75 patients (37.3%) who either had no SRR (72 patients) or had it after recurrence was diagnosed (3 patients) ( P <.01). Mean time to recurrence was 127 ± 31 days in the 15 patients who had had SRR versus 246 ± 42 days in the other 28 patients ( P = .02). Recurrence and number of rejection episodes were clearly associated: 6 of 33 patients (18.2%) with no rejection had recurrence ( P < .05), versus 11 of 26 patients (42.3%) with one rejection episode ( P < .05) and 26 of 37 (70.2%) with more than 1 episode ( P < .05). OKT3 induction was used in 15 patients; 9 of 15 patients had recurrence (ns) at 337 ± 95 days. Of 72 patients who initially received triple immunosuppression, 30 patients had recurrence at 186 ± 25 days ( P = .05). Nine patients received primary FK506; 4 had recurrence at 68 ± 14 days. SRR requiring OKT3 is associated with a higher incidence and earlier presentation of recurrent hepatitis C. Multiple rejection episodes are also associated with a higher recurrence rate. Induction immunotherapy, by reducing the rate of early rejection, may delay the clinical recurrence of hepatitis C.

EVALUATION OF SEQUENTIAL SERUM INTERLEUKIN-6 LEVELS IN LIVER ALLOGRAFT RECIPIENTS

Control serum levels of IL-6 measured by ELISA in 30 healthy blood donors or volunteers were 18±34 pg/ml (mean ± SD). Pretransplant serum levels of IL-6 in 169 adult candidates for liver transplantation were significantly higher than control in those with fulminant hepatitis (203±232 pg/ml), alcoholic cirrhosis (116±257 pg/ml), and hepatocellular carcinoma (82±105 pg/ml). With these data as background, plasma or serum levels of IL-6 were monitored in 24 adult patients after first OLT and correlated with the clinical courses and the histopathological diagnosis of rejection. Serum or plasma levels of IL-6 decreased after transplantation regardless of pretransplant value. Four patients with infection subsequently developed continuously high IL-6 values. In the 20 of 24 patients who did not have infection, significantly higher levels of IL-6 were consistently found 0–4 days before histopathological diagnosis of rejection (131±78 pg/ml) compared with significantly lower values in patients without rejection episodes (40±21 pg/ml). The elevations of IL-6 were spike shaped, did not correlate well with the histopathological grades of rejection, and were highly responsive to augmented immunosup-pression. These 20 cases were classified as: group 1, no spikes of IL-6 after liver transplantation; group 2, single spike of IL-6 after liver transplantation; and group 3, multiple spikes of IL-6 after liver transplantation. The combined early and late graft loss of each group was 0% (group 1), 25% (group 2), and 67% (group 3). We conclude that daily monitored serum or plasma IL-6 levels can be a good premonitor of liver allograft rejection and also a useful predictor of long-term graft outcome.

Evaluation of sequential serum interleukin-6 levels in liver allograft recipients.

Control serum levels of IL-6 measured by ELISA in 30 healthy blood donors or volunteers were 18 +/- 34 pg/ml (mean +/- SD). Pretransplant serum levels of IL-6 in 169 adult candidates for liver transplantation were significantly higher than control in those with fulminant hepatitis (203 +/- 232 pg/ml), alcoholic cirrhosis (116 +/- 257 pg/ml), and hepatocellular carcinoma (82 +/- 105 pg/ml). With these data as background, plasma or serum levels of IL-6 were monitored in 24 adult patients after first OLT and correlated with the clinical courses and the histopathological diagnosis of rejection. Serum or plasma levels of IL-6 decreased after transplantation regardless of pretransplant value. Four patients with infection subsequently developed continuously high IL-6 values. In the 20 of 24 patients who did not have infection, significantly higher levels of IL-6 were consistently found 0-4 days before histopathological diagnosis of rejection (131 +/- 78 pg/ml) compared with significantly lower values in patients without rejection episodes (40 +/- 21 pg/ml). The elevations of IL-6 were spike shaped, did not correlate well with the histopathological grades of rejection, and were highly responsive to augmented immunosuppression. These 20 cases were classified as: group 1, no spikes of IL-6 after liver transplantation; group 2, single spike of IL-6 after liver transplantation; and group 3, multiple spikes of IL-6 after liver transplantation. The combined early and late graft loss of each group was 0% (group 1), 25% (group 2), and 67% (group 3). We conclude that daily monitored serum or plasma IL-6 levels can be a good premonitor of liver allograft rejection and also a useful predictor of long-term graft outcome.

AIRWAY OBSTRUCTION AND BRONCHIOLITIS OBLITERANS AFTER LUNG TRANSPLANTATION

Bronchiolitis obliterans, defined histologically or clinically, is the most significant long-term cause of morbidity and mortality after lung transplantation. It shares many pathogenetic features with chronic allograft dysfunction that can occur in bone marrow, liver, heart, and kidney recipients. Lessons learned in the prevention and management of this disorder in lung recipients therefore should have application to the analogous process that develops in other organ allograft recipients. Because the lung is exposed to the external environment, it can be sampled repeatedly by techniques like bronchoalveolar lavage and transbronchial lung biopsy with little or no long-term adverse consequence to the allograft. Excellent pulmonary function tests also are available with which to assess the functional capacity of the allograft and to correlate with the results from immunologic testing. For these reasons, this disorder in lung recipients could serve as a model to determine the pathogenesis and treatment of the analogous disorder that may develop in other major organ recipients. Because this disorder most likely is immunologic in origin, advances in transplant immunology that create tolerance between the donor and recipient as well as efforts to prevent CMV infection and airway ischemic injury likely will be effective preventive measures. Although augmented immunosuppression appears to be of some benefit in treating bronchiolitis obliterans, it is far from optimal and new or better use of current immunosuppressive medications is warranted. Because the number of recipients at any one center is too few to critically assess the efficacy and safety of different immunosuppressive regimens, it is likely that collaboration between transplant centers will be necessary for success to be achieved.

Prolonged Survival After Heart-Lung Transplantation in Systemic Lupus Erythematosus

Patients with multisystem involvement of connective tissue disorders are generally excluded from consideration for heart-lung and lung transplantation because of profound donor organ shortages. A 23-year-old woman with systemic lupus erythematosus (SLE) was referred for evaluation of severe, progressive pulmonary hypertension. She underwent an uneventful heart-lung transplant and received cyclosporine A, azathioprine, and prednisone on a long-term basis. Bronchiolitis obliterans resulted in the development of moderate airflow obstruction 18 months after transplantation, but the process was stabilized with augmented immunosuppression consisting of high-dose parenterally administered corticosteroids, and subsequently a course of antithymocyte globulin. Four years after transplant, despite the persistence of reduced complement levels, the patient remains functionally well without clinical manifestations of SLE. This patient's long-term successful outcome indicates that connective tissue disorders such as SLE do not necessarily represent absolute contraindications to heart-lung and lung transplantation.

Surveillance for CMV infection in orthotopic liver transplant recipients.

Infection with cytomegalovirus is a major cause of morbidity and mortality following orthotopic liver transplantation. In order that preventive strategies may be devised, a detailed assessment of risk factors for infection and disease is required. We have prospectively assessed 46 orthotopic liver transplant recipients for CMV excretion from multiple sites in order to determine incidence of, and risk factors for, CMV infection and disease. Risk factors for posttransplant CMV infection were donor CMV seropositivity, an increased volume of peritransplant whole-blood transfusion and an increased dose of extra steroid therapy to treat rejection episodes. These findings implicate, respectively, transfer of virus with donor organ, transfer of virus with blood transfusion, and stimulation of reactivation of latent virus in recipients through augmented immunosuppression. The possible ways of preventing or ameliorating these effects are discussed.

Retransplantation following isolated lung transplantation.

The results of retransplantation for early allograft failure are discouraging. Fortunately, with recent technical advances and improved postoperative immunosuppression, airway complications have been significantly reduced. It is now unusual to see patients with airway complications following lung transplantation. This group of patients is not likely to represent a large population in need of retransplantation in the future. However, rejection-mediated OB remains a persistent problem seen in all transplant centers. The group of patients who deteriorate despite augmented immunosuppression will put increasing pressure on transplant programs to provide the only known solution for survival: retransplantation. In the Toronto experience, only 1 patient survived early retransplantation. Three of the 5 recipients retransplanted late in their course have survived and 2 are presently alive and well. Yet this is in sharp contrast to the current 80% 1-year survival for initial transplant recipients. As the demand for donor lungs increases with the growing need for first-time procedures, the use of donor lungs for retransplantation becomes a significant problem. The decision whether to allocate a donor lung (and commit significant hospital resources) to a retransplant recipient or to a first-time recipient is difficult. A patient with early graft failure has a dismal prognosis and a decision not to retransplant may be straightforward. However, the decision to retransplant a patient who has developed OB late following their initial transplant is much more difficult. It is still our responsibility to manage this limited resource and provide donor lungs to those who have the optimal chance of survival.

Application of echocardiographic color flow Doppler mitral regurgitation to the diagnosis of acute cardiac transplantation rejection.

Numerous noninvasive techniques have been examined for the detection of acute rejection following cardiac transplantation, but none has proven sufficiently sensitive to replace the endomyocardial biopsy. A prospective study was performed in 92 heart transplant patients in order to test the hypothesis that mitral regurgitant ratio by two-dimensional echocardiography with Doppler flow mapping could detect moderate or severe acute allograft rejection. There were 82 rejection episodes identified, of which 40% were associated with mitral regurgitation by echo-Doppler at the beginning of the episode. With augmentation of immunosuppression during a rejection episode, there was a progressive fall in the degree of mitral incompetence (P = 0.03). The sensitivity of color Doppler studies in identifying rejection was low (60% of all rejection episodes had no associated mitral incompetence at the beginning of the episode), but the likelihood of rejection progressively increased with higher degrees of mitral regurgitation (P less than 0.01), approaching 60% when the echo-Doppler regurgitant ratio exceeded 15%. Echo-Doppler studies do not provide sufficient sensitivity to be useful as a screening technique for acute cardiac rejection, but high or increasing echocardiographic mitral regurgitant ratio is predictive of acute rejection and should indicate prompt endomyocardial biopsy.

Cytomegalovirus infection in heart-lung transplant recipients: risk factors, clinical associations, and response to treatment.

The risk factors, clinical associations, and response to treatment of cytomegalovirus (CMV) pneumonia and infection were studied in 65 recipients of heart-lung transplantation. There were 29 episodes of CMV pneumonia in 22 patients. In 80% (20/25) of episodes of CMV pneumonia treated with intravenous ganciclovir, the histologic changes resolved and the patient survived. Among seronegative recipients, a seropositive donor was a significant risk factor for CMV pneumonia and infection in the first 90 days after heart-lung transplantation (P = .004 and .002, respectively). Among seropositive recipients, there was no additional risk associated with a sero-positive donor. Rates of CMV pneumonia and infection were significantly increased when treatment with augmented immunosuppression had been given in the preceding 30 days (P less than .001). A significant association was found between CMV pneumonia or infection and pulmonary bacterial infections occurring 30 days before or after such an episode (P less than .001).

The histological changes in transbronchial biopsy after treatment of acute lung rejection in heart‐lung transplants

Transbronchial lung biopsies taken during episodes of acute lung rejection in heart-lung transplant patients were examined histologically. When the diagnosis was confirmed by microscopy, the patients were treated with augmented immunosuppression by high-dose corticosteroids. A second biopsy was obtained an average of 23.5 days after commencement of treatment. These biopsies were examined to determine the histological changes caused by treatment. In most cases, there were both quantitative and morphological differences between the infiltrates in acute rejection and in the remaining perivascular infiltrates after treatment. In acute rejection, 26 of 28 biopsies contained perivascular lymphocytic infiltrates, lymphocytes being large and blast-like. Although 20 of 28 follow-up biopsies still contained perivascular infiltrates, they were smaller and the lymphocytes smaller in size. Half the biopsies in rejection contained neutrophils, but less than half contained eosinophils in the perivascular infiltrates. After treatment, all these cells were less numerous. Another feature of treated rejection was the presence of haemosiderin around vessels suggesting earlier acute vascular injury. However, haemosiderin persists long after the cellular infiltrate has disappeared and cannot be considered a reliable feature of recently treated acute lung rejection. The bronchiolar infiltrates showed a similar pattern of responses to the perivascular infiltrates.

HERPES SIMPLEX VIRUS INFECTION IN HEART-LUNG TRANSPLANT RECIPIENTS

We report our experience of herpes simplex virus infection in a series of 51 recipients of heart lung transplantation (HLT). Nine patients, all of whom were seropositive for the virus preoperatively, developed HSV infection. Seven episodes of culture-proved mucocutaneous HSV infection without evidence of pulmonary involvement occurred in four patients. Six episodes of HSV pneumonia were seen in a further five patients, one of whom died. Diagnosis of HSV pneumonia was by histological appearances on transbronchial biopsy, together with culture of lung tissue or bronchoalveolar lavage. Concomitant cytomegalovirus infection occurred in four patients. All patients who developed HSV pneumonia did so within the first two postoperative months; in four patients following augmented immunosuppression. We now suggest that HLT recipients who are HSV antibody-positive should receive prophylactic acyclovir for the first two months after surgery and at times of augmented immunosuppression.

Future prospects for adjunctive therapy

An increasingly large number of dietary components have been found to alter immune system function and, therefore, may be considered to have a pharmacologic effect (pharmacologic nutrition). Those dietary factors which have already been shown to influence outcome by producing a pharmacologic effect rather than correcting or preventing a simple deficiency include proteins (both type and amount), arginine, glutamine, omega-6 and omega-3 fatty acids, short-chain fatty acids, the metals iron and zinc, and the vitamins E, C, and A. Therapeutic outcome has already been influenced by dietary therapy (pharmacologic nutrition) in patients after burn injury or who have vascular diseases, and in experimental animals for the prevention of gut origin sepsis, the prevention and treatment of infection, prevention and development of secondary lesions in autoimmune diseases, augmentation of immunosuppression in transplantation, and in the treatment of cancer. Nutritional therapy using disease-specific formulations or supplements is an old idea now undergoing rapid evolution to increasing importance for successful therapeutic outcome.