Cytomegalovirus the predominant cause of pneumonia in renal transplant patients. A two-year study of pneumonia in renal transplant recipients with evaluation of fiberoptic bronchoscopy

The role of Th17 cells in viral infections

The present review provides an overview of recent advances regarding the function of Th17 cells and their produced cytokines in the progression of viral diseases. Viral infections alone do not lead to virus-induced malignancies, as both genetic and host safety factors are also involved in the occurrence of malignancies. Acquired immune responses, through the differentiation of Th17 cells, form the novel components of the Th17 cell pathway when reacting with viral infections all the way from the beginning to its final stages. As a result, instead of inducing the right immune responses, these events lead to the suppression of the immune system. In fact, the responses from Th17 cells during persistent viral infections causes chronic inflammation through the production of IL-17 and other cytokines which provide a favorable environment for tumor growth and its development. Additionally, during the past decade, these cells have been understood to be involved in tumor progression and metastasis. However, further research is required to understand Th17 cells' immune mechanisms in the vast variety of viral diseases. This review aims to determine the roles and effects of the immune system, especially Th17 cells, in the progression of viral diseases; which can be highly beneficial for the diagnosis and treatment of these infections.

IL-23 plasma level is strongly associated with CMV status and reactivation of CMV in renal transplant recipients

Background

Cytomegalovirus seropositivity is an independent risk factor for atherosclerosis in patients with ESRD. Donor CMV seropositivity is associated with higher graft loss. Dendritic cells, macrophages and Th17 lymphocytes are defined as producers of IL-23. IL-23 is thought to be involved in the promotion of Th17 cell polarization. Latent CMV-induced Th17 might be involved in the pathogenesis of CMV infection in patients with ESRD. We aimed to evaluate associations of Th17-dependent cytokines with ESRD, CMV status and post-transplant outcome in kidney transplantation.

Results

IL-21 plasma levels were similar in patients and healthy controls (p = 0.47), whereas IL-9 (p = 0.02) and IL-23 (p < 0.0001) levels were significantly higher in ESRD patients. CMV-seronegative (p = 0.002) and –seropositive (p < 0.001) patients had significantly higher IL-23 plasma levels than controls. CMV-seropositive patients showed excessively higher IL-23 (p < 0.001) plasma levels than CMV-seronegative patients. Patients with post-transplant CMV reactivation had higher IL-23 plasma levels than patients without CMV reactivation (p = 0.025).

Conclusions

Our results indicate that latent CMV induces IL-23. IL-23 might be an inflammatory mediator of latent CMV infection in patients with ESRD and predisposes patients for post-transplant CMV reactivation.

Fatal case of Aspergillus coinfection in a renal transplant recipient suffering from cytomegalovirus pneumonitis (Case Report)

Cytomegalovirus (CMV) disease is common in postrenal transplant recipients, and may predispose the patients to secondary bacterial or fungal infections. However, simultaneous coinfection is rare and often makes diagnosis difficult. We report a case of CMV pneumonitis in a renal transplant recipient presenting with elevated CMV pp65 antigen level and abnormal chest radiograph. Despite potent and broad-spectrum antimicrobial therapy, his condition deteriorated rapidly - he soon went into respiratory failure, septic shock and died several days later. Transbronchial biopsy and bronchoalveolar lavage obtained before the patient's death showed evidence of invasive pulmonary aspergillosis with concomitant CMV pneumonitis. High index of suspicion and early and empirical initiation of antifungal therapy may be necessary for successful management of fulminant pneumonia in solid organ transplant recipients.

Cytomegalovirus Pneumonia in Transplant Recipients

The incidence of cytomegalovirus CMV pneumonia has been reduced by routine antiviral prophylaxis in susceptible populations. Many of the complications of this infection are caused by indirect effects of the virus, including acute and chronic graft rejection, graft-versus-host disease, and superinfection by other viruses, bacteria and fungi. Distinction must be made between viral secretion and invasion. Invasive procedures are often required for the optimal management of such infections. The use of sensitive and quantitative assays have greatly improved the outcomes of CMV infection.

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.

Pneumonia due to viral and atypical organisms and their sequelae

Most children presenting with pneumonia in the industrialised world will have a viral or 'atypical' organism. The clinical features of these 'atypical' pneumonias may be indistinguishable from bacterial pneumonia. New diagnostic techniques such as the polymerase chain reaction may help in diagnosis and choice of treatment, where appropriate. The pathological and clinical features of infection with each agent are discussed, together with their sequelae.

Diagnostic yield of bronchoalveolar lavage following renal transplantation

Organ transplant recipients are at high risk of infectious pulmonary complications. In this retrospective study, the diagnostic yield of bronchoalveolar lavage (BAL) was evaluated in renal transplant recipients. The results were analysed in special regard to the clinical presentation of pulmonary infections and the possible impact of new immunosuppressive agents. Over a 5-year period 91 BAL were performed in 71 renal transplant recipients. Microorganisms were isolated from 69% of BAL (63/91): bacteria 32%; cytomegalovirus (CMV) 27%; Pneumocystis carinii (PC) 22%; other viruses 9% (HSV; EBV, RSV, adenovirus, HHV8); Aspergillus fumigatus 1%. Total cell counts and neutrophil counts in BAL were significantly elevated in bacterial infection, whereas BAL positive for PC showed eosinophilia (P<0.05). There was no association between clinical symptoms and the radiological pattern of infiltrates and the type of infection. Immunosuppression containing tacrolimus or mycophenolate mofetil was associated with a significantly higher percentage of PC and CMV infections compared to cyclosporin-based immunosuppression (65% vs. 30%, P<0.005). A considerable number of PC and CMV infections occurred beyond 6 months after transplantation. In conclusion, BAL has a high diagnostic yield in renal transplant recipients. Infection with CMV and PC should also be considered beyond 6 months after transplantation, and prophylaxis for opportunistic infections should be given if the immunosuppression is intensified.

Infections After Organ Transplantation

Over the last ten to fifteen years medical and surgical advances have led to lower rates of infection and infection-related mortality in transplant recipients. Despite these advances, the process whereby one diagnoses and manages infectious problems in transplant patients has become increasingly complex. Evaluation of transplant patients with infections requires a good understanding of the intricacies of modern immunosuppressive therapy and both the typical and atypical clinical manifestations of many conventional and opportunistic pathogens. In particular, it is incumbent upon the clinicians caring for transplant patients to be familiar with the biology of cytomegalovirus and other herpes viruses, and of the prophylactic strategies that have evolved to lessen the burden of disease from these agents. Thorough knowledge is also required of common fungal pathogens and the viruses that cause chronic hepatitis. Transplant patients also should always be evaluated in the temporal context of their transplant operation, because different diseases are prevalent at different times after transplantation. Since immunosuppressive drugs modify the clinical presentation of infections is important to maintain clinical vigilance and attend to even minor new symptoms. This chapter is designed to provide a relatively concise overview of transplant infections for intensivists or other clinicians who encounter transplant patients in their practice. The references encompass much of the classic transplant infectious disease literature; they are included, not only for citation, but as a bibliography for further study.

Prognostic significance of pathological chest radiography in transplant patients affected by cytomegalovirus and/or pneumocystis carinii

PURPOSE

In order to evaluate the prognostic significance of chest film findings in connection with cytomegalovirus (CMV) and/or pneumocystis carinii infection (PC), a retrospective review was made of the pulmonary charts of 274 recipients of kidney and/or pancreatic grafts transplanted between April 1987 and December 1990.

MATERIAL, METHODS AND RESULTS

Positive laboratory findings for CMV and/or PC were seen in 92 patients. In 77 patients only CMV was found, 13 patients had both CMV and PC, and 2 patients had only PC. In 57 patients a chest examination was performed. The films were reviewed by 2 radiologists independently. In 32 patients normal chest film findings were seen, while 25 patients demonstrated pathological changes. Of the patients with pathological changes 3 had only pleuritis while the remaining 22 demonstrated parenchymal infiltrations. No deaths occurred among patients infected with CMV and/or PC, when the chest film findings were normal or pleuritis only was seen, but there were 9 deaths in the group of patients with parenchymal infiltrations. Of the patients who died, 2 had only CMV, 5 had both CMV and PC, and 2 had only PC. The overall mortality, regardless of radiological findings, did not exceed 3% in patients with CMV only, but increased to 38% in patients with both CMV and PC. In patients with parenchymal infiltrations the corresponding mortality figures were increased to 18% and 56%, respectively.

CONCLUSION

We conclude that a radiologically verified pneumonia related to the infectious agent influences the prognosis, and that CMV pneumonia has a better prognosis than PC pneumonia.

Diagnosis of pulmonary infections in immunocompromised patients by fiber-optic bronchoscopy with bronchoalveolar lavage and serology

Fiber-optic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) were performed on 67 occasions in 57 immunocompromised patients with symptoms consistent with pulmonary infection. Diagnosis was achieved more often in renal transplant patients than in patients with hematological malignancies (85% versus 28%). Culture (bacteria, virus, fungi), staining and microscopy (bacteria, fungi, Pneumocystis carinii (PC)) and antigen detection by indirect immunofluorescence (cytomegalovirus (CMV), respiratory viruses, PC, Legionella) were used for diagnosis. On 20 occasions transbronchial biopsies with histopathologic examination were performed. In addition, serology comprising the herpes group (HHV-6) and respiratory viruses was done. A microbial diagnosis was obtained on 45% of occasions. The most common pathogens found were CMV (31%) and PC (25%). On 22 (33%) occasions a rapid diagnosis of 1 or more microbial agents was obtained within 24 h by conventional staining or indirect immunofluorescence. The clinical relevance of findings of CMV, HHV-6, and Epstein-Barr virus in BAL by polymerase chain detection on 18, 6 and 3 occasions is discussed. On 4 occasions pathogenic bacteria were found. It was not possible to relate findings of coagulase-negative staphylococci, alpha-streptococci and Candida albicans to the pulmonary infection.

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.

Use of indium 111-labeled white blood cell scan in the diagnosis of cytomegalovirus pneumonia in a renal transplant recipient with a normal chest roentgenogram

Opportunistic infections are common in patients after renal transplantation. This report describes a case of cytomegalovirus pneumonia in a renal transplant recipient with a normal chest roentgenogram and normal arterial oxygenation. An abnormal 111In-white blood cell scan led to the discovery of a pulmonary source of his recurrent fevers.

New approaches to the diagnosis, prevention, and treatment of cytomegalovirus infection after transplantation

Infection occurring after solid organ transplantation continues to exert a considerable detrimental effect upon patient and allograft survival. While the search for better targeted immunosuppressive regimens continues, we must seek to improve our ability to both diagnose and treat those infections that do occur after transplantation. Viral infections in general, and cytomegalovirus (CMV) infections in particular, represent an area in which substantial progress is being made. Improvement in diagnostic modalities has allowed more rapid and precise identification of CMV infection and disease, and the use of antiviral agents that possess activity against CMV has allowed both prophylaxis and treatment of this frequently life-threatening disease. The prophylactic use of presently available agents in combination and the development of less toxic, more potent anti-CMV agents should serve to further lessen the impact of CMV disease upon the field of solid organ transplantation.

Fiberoptic bronchoscopy and sputum examination for diagnosis of pulmonary disease in AIDS patients in Stockholm

For diagnosing pulmonary disease on 82 occasions in 68 patients (64 males) aged 39 (23-73) years infected with HIV-1 we used flexible fiberoptic bronchoscopy (FFB) with bronchoalveolar lavage (BAL) or washing with or without transbronchial lung biopsy (TBB) and brushing. A clinical diagnosis of lower respiratory tract disease was obtained in 68/82 episodes (83%). An etiological diagnosis was reached by FFB in 59/82 episodes (72%). Pneumocystis carinii (PC), the dominating pathogen causing pneumonia in 54/82 episodes (66%), was detected by FFB in 51/54 (94%). In spite of being isolated in bronchoscopy material in 36/82 episodes (44%) cytomegalovirus (CMV) seemed to be the cause of pneumonia only in 2/36 (5%) episodes. Except PC and CMV, only bacteria (including mycobacteria) were found as infectious etiological agents. Kaposi's sarcoma and pulmonary edema were diagnosed in one patient each. For detection of PC in 37 episodes we compared staining of BAL fluid with indirect immunofluorescence (IF) using monoclonal antibodies (MoAB) with staining of BAL material by silver methenamine (Grocott). Staining with IF MoAB alone of BAL fluid only seemed to be even more sensitive than silver methenamine staining of BAL, TBB and brushing material. When using IF MoAB staining of BAL fluid, TBB and brushing added nothing to the result, except in the patient with Kaposi's sarcoma, diagnosed by TBB. Sputum investigation using IF MoAB for detection was increasingly adopted during the study time. It was very useful (sensitivity approximately 74%) and reduced the number of required FFBs.