Pulmonary infections in renal transplant recipients

Effects of Clarithromycin and Ketoconazole on FK506 Metabolism in Different CYP3A4 Genotype Recombinant Metabolic Enzyme Systems

OBJECTIVE

This study aimed to investigate the effects of clarithromycin and ketoconazole on the pharmacokinetic properties of tacrolimus in different CYP3A4 genotype recombinant metabolic enzyme systems, so as to understand the drug interactions and their mechanisms further.

METHOD

The experiment was divided into three groups: a blank control group, CYP3A4*1 group and CYP3A4*18 recombinant enzyme group. Each group was added with tacrolimus (FK506) of a series of concentrations. Then 1 umol/L clarithromycin or ketoconazole was added to the recombinant enzyme group and incubated in the NADPH system for 30 minutes to examine the effects of clarithromycin and ketoconazole on the metabolizing enzymes' activity of different genotypes. The remaining concentration of FK506 in the reaction system was determined using UPLC-MS/MS, and the enzyme kinetic parameters were calculated using the software.

RESULTS

The metabolism of CYP3A4*18 to FK506 was greater than that of CyP3А4*1B. Compared with the CYP3A4*1 group, the metabolic rate and clearance of FK506 in the CYP3A4*18 group significantly increased, with Km decreasing. Clarithromycin and ketoconazole inhibit the metabolism of FK506 by affecting the enzyme activity of CYP3A4*1B and CYP3A4*18B. After adding clarithromycin or ketoconazole, the metabolic rate of FK506 significantly decreased in CYP3A4*1 and CYP3A4*18, with Km increasing, Vmax and Clint decreasing.

CONCLUSION

Compared with CYP3A4*1, CYP3A4*18 has a greater metabolism of FK506, clarithromycin and ketoconazole can inhibit both the enzymatic activities of CYP3A4*1 and CYP3A4*18, consequently affecting the metabolism of FK506 and the inhibitory on CYP3A4*1 is stronger.

Pulmonary infections after renal transplantation: a prospective study from a tropical country

Pulmonary infection is a leading cause of morbidity and mortality in renal transplant recipients. In a prospective study, we characterized their epidemiology in a tropical country with high infectious disease burden. Adult renal transplant recipients presenting with pulmonary infections from 2015 to 2017 were evaluated using a specific diagnostic algorithm. 102 pulmonary infections occurred in 88 patients. 32.3% infections presented in the first year, 31.4% between 1 and 5, and 36.3% beyond 5 years after transplantation. Microbiological diagnosis was established in 69.6%, and 102 microorganisms were identified. Bacterial infection (29.4%) was most common followed by tuberculosis (23.5%), fungal (20.6%), Pneumocystis jiroveci (10.8%), viral (8.8%), and nocardial (6.9%) infections. Tuberculosis(TB) and bacterial infections presented throughout the post-transplant period, while Pneumocystis (72.7%), cytomegalovirus (87.5%) and nocardia (85.7%) predominantly presented after >12 months. Fungal infections had a bimodal presentation, between 2 and 6 months (33.3%) and after 12 months (66.7%). Four patients had multi-drug resistant(MDR) TB. In 16.7% cases, plain radiograph was normal and infection was diagnosed by a computed tomography imaging. Mortality due to pulmonary infections was 22.7%. On multivariate Cox regression analysis, use of ATG (HR-2.39, 95% CI: 1.20-4.78, P = 0.013), fungal infection (HR-2.14, 95% CI: 1.19-3.84, P = 0.011) and need for mechanical ventilation (9.68, 95% CI: 1.34-69.82, P = 0.024) were significant predictors of mortality in our patients. To conclude, community-acquired and endemic pulmonary infections predominate with no specific timeline and opportunistic infections usually present late. Nocardiosis and MDR-TB are emerging challenges.

Spectrum of Pulmonary Infections in Renal Transplant Recipients in the Tropics: A Single Center Study

BACKGROUND

Pulmonary infections have been implicated as the most common cause of infection related mortality in renal transplant recipients. An appropriate empirical treatment of post transplant pulmonary infections requires knowledge of the spectrum of the microorganisms involved in causing these infections. Besides this knowledge, an aggressive diagnostic approach including the use of invasive tests is often essential to make an early diagnosis for instituting timely and appropriate therapy. We carried out a prospective cohort study to analyze the spectrum of pulmonary infections in these patients and study the utility of bronchoalveolar lavage (BAL) in the diagnosis of the same.

METHODS

From September 2001 to December 2002, 428 patients were under follow up with the department. In all, 40 renal transplant recipients reported with 44 episodes of pulmonary infection during this study period. All patients underwent detailed and appropriate investigations including specific laboratory tests, sputum analysis, X-ray chest, CT and BAL. The spectrum of the causative organisms and the utility of BAL as compared to the other methods of diagnosis were studied and compared.

RESULTS

Out of the 44 episodes of pulmonary infection evaluated, single causative organism could be found in only 24 (54.5%) episodes and multiple etiologies were found in 15 (34.1%) episodes. No definitive cause could be found in 5 episodes. Out of 57 organisms isolated in the 44 episodes, 20 (45.4 %) were bacteria, 16 (36.3 %) each were M. tuberculosis and fungus, 3 were CMV infection and 2 were nocardia. BAL gave a diagnostic yield of 75.8% (25 out of 33 cases). Nine of forty patients died (mortality rate 22.5%) of which 6 deaths could be attributed directly to pulmonary infection. Out of these 9 patients who died, cause of pulmonary infection was bacterial in 5, fungal in 2 and CMV disease in 1. In one patient, organism could not be isolated.

CONCLUSIONS

Our study has shown that more than 1/3rd of pulmonary infections in renal transplant recipients can be attributed to multiple organisms. Bacterial infections were the commonest cause of post transplant pulmonary infection. Tuberculosis is common cause of pulmonary infection in these patients in our set up. Because of its high diagnostic yield, BAL should be considered in all patients with suspected pulmonary infections in the post transplant period.

The diagnosis of pneumonia in renal transplant recipients using invasive and noninvasive procedures

STUDY OBJECTIVES

We used invasive and noninvasive procedures to determine the causes of pneumonia in renal transplant recipients.

SUBJECTS AND METHODS

We retrospectively surveyed 565 renal transplant recipients (transplants received March 1984 to August 2001) to find those with pneumonia. Noninvasive diagnostic methods included serologic testing, and blood and sputum cultures with stains. Invasive procedures included fiberoptic bronchoscopy and percutaneous transthoracic procedures.

RESULTS

A total of 92 patients were enrolled. Of these, 71 patients had a definite etiologic diagnosis of pneumonia. The major infectious pathogens were bacterial (n = 21) and mixed bacterial infection (n = 10), Mycobacterium tuberculosis (TB) [n = 18], and fungi (n = 8). Noninvasive and invasive procedures led to the diagnosis of pneumonia in 31.5% (n = 29) and 45.6% (n = 42) of patients, respectively. Bronchoscopy was used in 64 patients, with a diagnostic yield of 38 cases (59.3%). Patients were 3.62 times more likely to contract pneumonia within 12 months of renal transplantation than they were > or =12 months thereafter (95% confidence interval, 1.33 to 9.84). Twenty-seven of the 92 patients (29.3%) died. The pneumonia mortality rate has dropped significantly since 1996 (41.8% vs 10.8%, p = 0.002).

CONCLUSION

Both invasive and noninvasive procedures are useful in the diagnosis of pneumonia, with declining mortality, in renal transplant recipients. Bacterial and mixed bacterial infection, TB, and fungal infection are the most common pathogens; cases are most likely to occur within 1 year after renal transplantation.

Lung nodular lesions in heart transplant recipients

To describe the characteristics and etiology of lung nodules after heart transplantation (HT). During a 6-year period 147 patients received HT and 130 survived more than 1 week. Nodular lesions were demonstrated after HT in 13 patients (10%). Median age was 53 years, and all patients were male. Nodules were detected 23 to 158 days after HT (median, 66 days). An etiologic diagnosis was made in all but 1 case: Aspergillus (5), Nocardia-Rhodococcus (4), and cytomegalovirus (CMV) (3). Previous severe infection was present in 50% of the patients and rejection in 33% (75% with nocardiosis). Initially all patients with Nocardia but only 1 patient with aspergillosis were asymptomatic. The most common symptoms were fever (67%) and cough (50%). Central nervous system (CNS) involvement appeared in only one Aspergillus-infected patient. An average of 1.8 diagnostic procedures per patient were performed. Median time to establish a diagnosis was 8 days (0 to 24). Median hospital stay was 36 days and reached 60 in patients with Aspergillus. No patient died, although aspergillosis, which must be suspected in the presence of dyspnea, pleuritic pain, and CNS symptoms, caused the highest morbidity. Overall diagnostic yield was 60% for transtracheal aspiration, 70% for bronchoalveolar lavage, and 75% for transthoracic aspiration. Ten percent of HT patients developed lung nodules that were mainly caused by Aspergillus, Nocardia, and CMV. The time of appearance and some clinical manifestations may suggest the etiology and may help in the empirical treatment.

Successful management of pulmonary tuberculosis in renal allograft recipients in a single center

BACKGROUND

Pulmonary infections, especially tuberculosis, are responsible for significant mortality and morbidity among renal transplant recipients in developing countries. Conventional diagnostic modalities are associated with a low yield, delaying specific therapy.

METHODS

All patients transplanted within a 1.5-year period were prospectively followed-up for one year. Patients were on a cyclosporine-based triple immunosuppressive regimen. None received isoniazid prophylaxis, and those transplanted in the last seven months of the study period received daily cotrimoxazole. Patients exhibiting unequivocal evidence of pulmonary infections underwent further evaluation. Search for offending organisms was made by sputum examination and bronchoalveolar lavage (BAL).

RESULTS

. Thirty-nine infection episodes were recorded in 34 patients. M. tuberculosis was isolated during 10 episodes, pyogenic bacteria and Pneumocystis carinii in 6 each, candida in 4, aspergillus in 3, cytomegalovirus (CMV) in 3, and nocardia and mucor in one episode each. More than one organism was isolated during five episodes. Bacterial pneumonia and tuberculosis were diagnosed in another seven and two patients, respectively, on the basis of a therapeutic response to specific chemotherapy. Over two thirds of the organisms were identified by examination of BAL fluid. BAL was useful in the diagnosis of tuberculosis and P. carinii pneumonia but was relatively insensitive for CMV and bacterial infections. An increased frequency of acute rejection and higher serum creatinine were factors that predisposed to infections. All patients with pulmonary tuberculosis made a full recovery.

CONCLUSIONS

Tuberculosis and P. carinii are the most common nonpyogenic infections in the first year after transplantation in developing countries. An aggressive search for tubercle bacilli should be made using bronchoscopy and examination of BAL fluid in patients not responding to a short trial of antibiotics. A four-drug regime without rifampicin given for 18 months is effective for pulmonary tuberculosis in patients on cyclosporine. We recommend routine prophylactic use of one single-strength tablet of cotrimoxazole daily for at least six months after transplantation.

Invasive aspergillosis in systemic lupus erythematosus

Invasive aspergillosis is seldomly described in systemic lupus erythematosus. We present two cases of aspergillosis and review 21 cases reported between 1957 and 1994. The typical clinical presentation is fever and cough in a hospitalized SLE patient previously treated with corticosteroids, immunosuppressors, and broad-spectrum antibiotics. Unlike aspergillosis in other conditions, granulocytopenia is uncommon. Chest radiographs show diffuse or patchy infiltration of lung fields. Diagnosis was suspected premortem in 2 patients. Aspergillus fumigatus was identified or isolated in sputum or parenchimal tissues in the majority of cases. Twenty-two patients died (95%). The finding of hyphae in the sputum of a systemic lupus erythematosus patient with a suggestive clinical picture should lead to bronchoscopy, bronchoalveolar lavage, and lung biopsy. Proof of diagnosis will come from the demonstration of hyphae in tissues and isolation of aspergillus from tissue cultures. Long-term therapy with amphotericin B alone or in combination with fluorocytosine or itraconazole may help improve survival.

Utility of bronchoalveolar lavage in assessing pneumonia in immunosuppressed renal transplant recipients

PURPOSE

To determine if initial results obtained from diagnostic bronchoalveolar lavage (BAL) in immunosuppressed renal transplant patients with pulmonary infiltrates, fever, or hypoxemia can affect therapeutic decisions, morbidity, and mortality.

DESIGN

A retrospective study of all BAL specimens obtained from renal transplant patients from January 1985 through June 1991. Initial results of Gram stain, cytology, cell differential count, and semi-quantitative bacterial cultures, all available within 24 hours of bronchoscopy, were compared with clinical outcomes and final diagnoses.

SETTING

University hospital nephrology-transplant/pulmonary service.

PATIENTS

Seventy renal transplant patients with a suspected pneumonia were stratified into 3 groups. A total of 48 patients underwent 58 bronchoscopies. Group 1 was comprised of 32 BALs that yielded 1 or more infectious organisms and was considered diagnostic. Group 2 (n = 26) were those BALs in which no organism was isolated and were thus nondiagnostic. Twenty-two additional immunosuppressed renal transplant recipients with pneumonia were considered by the admitting transplant nephrologist to have an uncomplicated community-acquired lung infection and thus were empirically treated and did not undergo BAL (Group 3).

METHODS

BAL fluid analysis included cell differential count, cytopathologic examination, and culture for mycobacteria, legionella, fungi, viruses, and bacteria using a semi-quantitative technique. Etiologic diagnosis and the time of onset of the infectious processes were recorded. Therapeutic outcome and mortality were determined for each group.

RESULTS

Thirty-nine etiologic organisms were found in 32 patients, with 6 patients having more than 1 infection. Twenty-two patients had 26 negative BALs, and 8 of these patients were clinically believed to have a volume overload state. Eight of 13 (61%) patients with bacterial pneumonia had BAL neutrophil counts greater than 20%, whereas 11 of 13 (84%) patients without bacterial pneumonia had neutrophil counts less than 20% (p < 0.05). Those patients with an infectious etiology remained in the hospital longer than patients without a specific etiologic organism identified (p < 0.02). Therapeutic decisions leading to the institution of specific antibiotics were more frequently made in patients with a diagnostic BAL (p < 0.0001). An overall 3-month mortality (16%) was low compared with the historical rate (30%).

CONCLUSION

BAL is a useful procedure in the diagnosis of an infectious process in immunosuppressed renal transplant patients where initial results can alter therapy in more than 70% of cases.

Anaesthesiological complications in renal transplantation: a retrospective study of 500 transplantations

This retrospective study consisted of 500 consecutive renal transplantations performed between September 1977 and September 1981. Preoperatively, congestive heart failure was registered in 262 cases (53.0%) and blood pressure disease in 352 cases (71.3%). The total number of patients with ischaemic heart disease was 22 (4.5%). General anaesthesia was given in 493 and regional anaesthesia in seven cases. In general anaesthesias, tubocurarine was the main relaxant and halothane the main inhalation agent used. Major complications during anaesthesia were blood pressure changes with a higher incidence of hypotension (49.6%) than hypertension (26.8%). Severe cardiac arrhythmias were rare and no intraoperative deaths occurred. One patient was successfully resuscitated in the ICU postoperatively, this being possibly related to hypoventilation caused by prolonged muscular relaxation. Other rare complications included one pneumothorax, one haemo- and hydrothorax, and two large haematomas all caused by preoperative central venous cannulation. In 69 cases (14.0%) additional neostigmine doses and in 34 cases (6.9%) naloxone was given at the end of anaesthesia. Pneumonia during the first postoperative week was recorded in 11 cases (2.2%), and occurred only in patients who received general anaesthesia. One of the three patients who died during the first week developed pneumonia postoperatively.

Infection in renal transplant recipients. Current approaches to diagnosis, therapy, and prevention

Despite dramatic improvements in patient and renal allograft survival, infections continue to be an important cause of post-transplantation morbidity and mortality. Most serious infections manifest clinically as febrile diseases, and immunosuppression-induced compromised cell-mediated immunity is the basis for the predominance of infections due to opportunistic intracellular microorganisms. Diagnostic evaluation is guided by the timing of fever after transplantation, epidemiologic factors, and evidence of specific organ system involvement. Although current therapy of bacterial and parasitic infections is usually effective, the management of deep-seated fungal infections remains highly unsatisfactory. Cytomegalovirus disease, the single most important infection in some transplant centers, frequently presents as a self-limited viral syndrome; however, multiple organs may be affected. New measures for the rapid diagnosis and treatment of this viral infection hold promise. A number of recommendations have been proposed to prevent infections in renal transplant recipients; however, continued progress will depend primarily upon further refinements in immunosuppressive therapy.

Comparison of biopsy-proven Pneumocystis carinii pneumonia in acquired immune deficiency syndrome patients and renal allograft recipients

Pneumonia unresponsive to antibacterial agents in patients with acquired immune deficiency syndrome (AIDS) has become a new indication for lung biopsy. In 14 patients, transbronchial or open-lung biopsy demonstrated Pneumocystis carinii. An additional 12 patients, who were immunosuppressed after renal transplantation, were seen with P. carinii pneumonia. The diagnosis was established by transbronchial biopsy in the majority of patients. All patients were treated initially with trimethoprim plus sulfamethoxazole. Pentamidine was added after diagnosis if improvement did not occur. Both groups demonstrated reversal in the T cell helper: suppressor ratio. We compared these two groups of immunocompromised patients with respect to clinical presentation, lung pathology, response to therapy, and survival. Patients with AIDS were seen with a two- to three-week prodrome of fever, lymphadenopathy, weight loss, and malaise followed by hypoxia and leukopenia within 12 hours. Transplant patients became acutely ill with fever and hypoxia within 24 to 36 hours. In both groups, chest roentgenogram showed bilateral diffuse infiltrates; sputum cultures were generally negative; and lung biopsy demonstrated Gomori-Jones periodic acid-methenamine-silver-positive P. carinii. Mortality was substantially higher in patients with AIDS (50% versus 8%). This difference may be explained by the fact that the T cell defect in AIDS has an infectious cause, while the defect in the renal allograft recipient is pharmacologically mediated.

Pneumonia in renal transplant patients

Between January 1976 and March 1982, 28 episodes of pneumonia occurred in 26 renal transplant patients. The overall mortality rate was 46%. Of the 16 patients with nosocomial pneumonia 9 (56%) died, whereas of the 12 patients with community-acquired pneumonia 4 (33%) died. In all 9 cases of unknown cause the response to empiric treatment was prompt, whereas in 4 of the 10 cases of monomicrobial pneumonia and 8 of the 9 cases of polymicrobial pneumonia the patient died. Cytomegalovirus was the sole cause of the pneumonia in two patients and a contributing cause, along with aerobic gram-negative bacteria, in another five, four of whom also had a fungal infection. Two patients, both of whom survived, had nosocomial Legionnaires' disease.

Radionuclide diagnosis of allograft rejection

Interaction with one or more anatomical and physiopathological characteristics of the rejecting renal allograft is suggested by those radioagents utilized specifically for the diagnosis of allograft rejection. Rejection, the most common cause of declining allograft function, is frequently mimicked clinically or masked by other immediate or long term post transplant complications. Understanding of the anatomical pathological features and kinetics of rejection and their modification by immunosuppressive maintenance and therapy are important for the proper clinical utilization of these radioagents. Furthermore, in selecting these radionuclides, one has to consider the comparative availability, preparatory and procedural simplicity, acquisition and display techniques and the possibility of timely report. The clinical utilities of radiofibrinogen, 99mTc sulfur colloid and gallium-67 in the diagnosis of allograft rejection have been evaluated to a variable extent in the past. The potential usefulness of the recently developed preparations of 111In labeled autologous leukocytes and platelets are presently under investigation.

Response of renal allograft recipients to pneumococcal vaccine

Antibody responses to pneumococcal polysaccharide vaccine were compared in a control group of 17 normal adults and in a group of 27 adult patients with stable renal function (serum creatinine 0.8--2.1 mg/dl) seven months to nine years following renal transplantation. Using the indirect hemagglutination technique, antibody titers to 13 of the 14 capsular antigens contained in the vaccine were determined for each patient just prior to and again three weeks following immunization. There was no significant difference between the two groups in the proportion of patients responding with a fourfold rise in titer to 12 of the 13 antigens tested. The response rate to antigen type 3 was reduced in the transplant group (p less than 0.05). Mean fold increase in indirect hemagglutination titers was likewise determined for each antigen, and a reduced response in the transplant group was noted only to antigen type 23 (p = 0.037). Immunosuppressed renal allograft recipients appear capable of mounting a nearly normal antibody response to pneumococcal vaccine.