Rapid immunodiagnosis of cytomegalovirus pneumonia by bronchoalveolar lavage using human and murine monoclonal antibodies

Immunological Detection and Characterization

Immunological methods have been used for viral diagnosis for more than 100 years. Although molecular methods are replacing many older methods of viral diagnosis, there is still a significant role for immunological methods to guide patient care and in the performance of epidemiologic studies. Identification of viral antigens in clinical samples can be accomplished rapidly through the use of point-of-care lateral immunoassays or through the use of more traditional immunofluorescence and enzyme immunoassays in the virology laboratory. Serological assays are also a valuable tool for the clinician and epidemiologist. Many of the available diagnostic assays have enzyme immunoassay formats, but functional assays such as hemagglutination-inhibition and neutralizing antibody tests are also available. In some instances, virus infection can be diagnosed with a single serum sample (e.g., HIV and hepatitis C virus infections) while in other instances paired sera are needed (e.g., those caused by common respiratory viruses). Point-of-care antibody assays are also available for testing blood and saliva samples for some viruses. An understanding of the principles of immunological detection methods is important in the application and interpretation of test results.

Cytomegalovirus pneumonia in patients with lymphoma

BACKGROUND

Even when treated with antiviral therapy, cytomegalovirus pneumonia (CMVp) is associated with high morbidity and mortality in immunocompromised patients. CMVp has been rarely reported in patients with lymphoma.

METHODS

The authors reviewed the records of patients treated at The University of Texas M. D. Anderson Cancer Center (Houston, TX) between 1997 and 2003. Collected information included demographics, use of chemotherapy, or corticosteroids, concomitant infections, and outcome.

RESULTS

Thirty-one patients with lymphoma with 36 episodes of CMVp were identified. The incidence of CMVp increased between 1997 and 2003 (0 of 1000 treated patients vs. 9 of 1000 treated patients; P = 0.07). Most episodes occurred in patients with non-Hodgkin lymphoma (89%). Most of the patients (92%) had received chemotherapy and corticosteroids (89%) before the onset of CMVp. Concomitant CMV antigenemia was detected in 11 (41%) of the 27 episodes in which testing was performed. In 19 episodes (53%), patients had coinfections within 90 days of the episode of CMVp. Coinfections were present at the onset of CMVp in 11 episodes (31%). The yield for CMV in bronchoalveolar lavage (BAL) specimens was higher with culture methods than with cytologic evaluation or immunohistochemical staining (P < 0.001). The number of CMV antigenemia tests performed increased fourfold over the study period. The CMV-attributed mortality rate was 30% (9 of 30 patients). Independent predictors of death by multivariate Cox regression analysis were high APACHE II score (> 16) at onset of CMVp (P = 0.02, hazards ratio [HR] = 15.5, 95% confidence interval [CI], 1.5-163.7), and development of toxicity to antivirals (P = 0.04, HR = 14.03, 95% CI, 1.2-169.1).

CONCLUSIONS

The incidence of CMVp in patients with lymphoma is increasing. CMV detection in BAL specimens was better with culture methods than with cytologic or immunohistochemical methods. High APACHE II score and development of antiviral toxicity were associated with a fatal outcome.

Diagnosis and treatment approaches of CMV infections in adult patients

BACKGROUND

Cytomegalovirus (CMV) infections are very common in the general population. Clinical CMV disease, particularly CMV pneumonitis, greatly impacts the morbidity and mortality of immunosuppressed patients.

OBJECTIVE

To present an overview of the basic aspects of the biology, epidemiology, and clinical features of CMV in relation to the available diagnostic and therapeutic approaches in adult patients.

METHODS

Review of the medical literature on cytomegalovirus infection and disease in adult hosts, with a focus on approaches to diagnosis and treatment of CMV respiratory disease in immunosuppressed hosts.

CONCLUSIONS

Cytomegalovirus infections are likely to remain a significant cause of morbidity and mortality among immunosuppressed patients. Important aspects of the biological events underlying the transition from infection to clinical disease remain unclear. Despite that, considerable progress has been made in the design of improved diagnostic techniques and the development of antiviral agents. Preventive and particularly preemptive therapeutic approaches demand further technical improvements in diagnostic testing. At present, the emphasis in the search for improved diagnostic testing rests on the development of quantitative methods for early detection of the increased viral replicative activity that presumably precedes the onset of CMV disease in infected individuals.

Quantitative evaluation of cytomegalovirus DNA in infantile hepatitis

We used a PCR method to develop a diagnostic assay for the detection of cytomegalovirus (CMV) DNA in infantile hepatitis, which has been suggested to be associated with CMV infection. CMV DNA was detected in 25 (58.1%) of 43 patients with elevated serum alanine aminotransferase (ALT) levels but no jaundice, and no hepatitis B or C as assessed by conventional PCR. None of the samples from 97 healthy infants tested positive for CMV DNA. We assayed CMV DNA quantitatively in blood using a real-time PCR system that allowed reproducible detection of at least 10 copies of CMV DNA. When 1 microg of DNA from each blood sample was used in this system, a good correlation was obtained between the calculated and measured copy numbers of CMV DNA. This system detected CMV DNA in 29 patients (67.4%) with liver dysfunction. Serial studies in patients with liver dysfunction revealed that CMV DNA copy number decreased, ultimately to below 10, as the ALT levels normalized. In contrast, no CMV DNA copies were detectable by the real-time system in any of the samples from control subjects. These results highlight the usefulness of detecting CMV DNA in the diagnosis of infantile hepatitis and indicate that the real-time quantitative PCR assay may be a valuable tool for monitoring CMV-associated infantile hepatitis.

Pulmonary cytomegalovirus infection in immunocompromised patients

BACKGROUND

Cytomegalovirus (CMV) infection and CMV disease are frequent complications in immunocompromised patients. In this study, the incidence of pulmonary CMV infection was analyzed in different groups of immunocompromised patients and the diagnostic value of immunostaining with anti-CMV antibodies in BAL cells was evaluated in regard to the diagnosis of CMV pneumonitis.

METHODS

Five hundred eighty consecutive BAL procedures were analyzed prospectively in 442 immunocompromised and 126 nonimmunocompromised control subjects. CMV culture in BAL fluid was performed by shell vial assay and immunostaining using three monoclonal anti-CMV antibodies.

RESULTS

The incidence of culture results positive for CMV in the BAL fluid varied from 20 to 30% in HIV-positive patients, in patients following stem cell or renal transplantation, and in patients with autoimmune disease or lung fibrosis treated with immunosuppressive agents. CMV was cultured from 4.4% of BALs in patients treated with high-dose chemotherapy and from 2.4% of control subjects. CMV disease developed in 37 patients; in 18 of these patients, CMV pneumonitis was present. The results of CMV immunostaining were positive in a total of 22 BALs, all in patients with CMV disease. The sensitivity, specificity, and positive and negative predictive values of positive CMV immunostaining results for the diagnosis of CMV pneumonitis were 88.9%, 98.6%, 72.7%, and 99.5%, respectively.

CONCLUSION

The incidence of pulmonary CMV infection is similar in different groups of immunocompromised patients except for patients following high-dose chemotherapy. CMV immunostaining in the BAL fluid is a very helpful method to diagnose CMV pneumonitis in these patients.

The use of flow cytometry for the detection of CMV-specific antigen (pp65) in leukocytes of kidney recipients

Flow cytometric assay (FCA) was used to detect a cytomegalovirus (CMV) specific antigen (pp65) in CMV-infected fibroblast cells and in leukocytes of kidney recipients. FCA distinguished clearly between the infected and non-infected fibroblast cells. Regarding transplant patients, the FCA was positive when the number of antigenemia assay (AA) positive cells was five or more per 5 x 10(4). Moreover, the percentage of antigenemia-positive cells by FCA correlated well with symptomatic CMV infections.

Simultaneous Ex Vivo Expansion of Cytomegalovirus and Epstein-Barr Virus–Specific Cytotoxic T Lymphocytes Using B-Lymphoblastoid Cell Lines Expressing Cytomegalovirus pp65

Cytomegalovirus (CMV) infection and Epstein-Barr virus (EBV)-induced lymphoproliferative disease are serious complications associated with allogeneic stem cell transplantation. Immunotherapy using ex vivo expanded, virus-specific cytotoxic T lymphocytes (CTL) has been explored and proven to be effective in therapeutic or prophylactic regimens for CMV and EBV infections. To generate CTL specific for both CMV and EBV, we engineered EBV-transformed B-lymphoblastoid cell lines (BLCL) to express CMV pp65 for use as antigen-presenting cells (APC). BLCL were transduced with a recombinant retrovirus encoding pp65, the immunodominant CMV polypeptide. Western blot analysis and immunocytochemistry confirmed the expression of pp65 in the transduced cells. Peripheral blood mononuclear cells (PBMC) from healthy CMV seropositive donors were stimulated with autologous pp65-expressing BLCL weekly for 3 weeks. Chromium release assays showed that the resulting CTL cultures possessed specific cytotoxicity against EBV and CMV. Recombinant vaccinia viruses encoding individual CMV peptides were used to demonstrate that this CMV-specific cytotoxicity was specific for pp65. Assays on CD4- and CD8-depleted CTL fractions indicated that CD8+ CTL mediated the pp65-specific cytotoxicity. These CMV/EBV-specific CTL recognized CMV- and EBV-infected targets sharing HLA class I antigens, but not HLA mismatched targets. Our results demonstrate that BLCL can be used as APC to stimulate expansion of EBV- and CMV-specific CTL simultaneously. These findings have potential implications for posttransplant CMV and EBV immunotherapy in recipients of allogeneic stem cell transplants.

Simultaneous Ex Vivo Expansion of Cytomegalovirus and Epstein-Barr Virus–Specific Cytotoxic T Lymphocytes Using B-Lymphoblastoid Cell Lines Expressing Cytomegalovirus pp65

Cytomegalovirus (CMV) infection and Epstein-Barr virus (EBV)-induced lymphoproliferative disease are serious complications associated with allogeneic stem cell transplantation. Immunotherapy using ex vivo expanded, virus-specific cytotoxic T lymphocytes (CTL) has been explored and proven to be effective in therapeutic or prophylactic regimens for CMV and EBV infections. To generate CTL specific for both CMV and EBV, we engineered EBV-transformed B-lymphoblastoid cell lines (BLCL) to express CMV pp65 for use as antigen-presenting cells (APC). BLCL were transduced with a recombinant retrovirus encoding pp65, the immunodominant CMV polypeptide. Western blot analysis and immunocytochemistry confirmed the expression of pp65 in the transduced cells. Peripheral blood mononuclear cells (PBMC) from healthy CMV seropositive donors were stimulated with autologous pp65-expressing BLCL weekly for 3 weeks. Chromium release assays showed that the resulting CTL cultures possessed specific cytotoxicity against EBV and CMV. Recombinant vaccinia viruses encoding individual CMV peptides were used to demonstrate that this CMV-specific cytotoxicity was specific for pp65. Assays on CD4- and CD8-depleted CTL fractions indicated that CD8+ CTL mediated the pp65-specific cytotoxicity. These CMV/EBV-specific CTL recognized CMV- and EBV-infected targets sharing HLA class I antigens, but not HLA mismatched targets. Our results demonstrate that BLCL can be used as APC to stimulate expansion of EBV- and CMV-specific CTL simultaneously. These findings have potential implications for posttransplant CMV and EBV immunotherapy in recipients of allogeneic stem cell transplants.

Quantitation of cytomegalovirus: methodologic aspects and clinical applications

Cytomegalovirus (CMV) is an important pathogen in transplant recipients and human immunodeficiency virus (HIV)-infected individuals. Major progress has been made in developing quantitative detection methods for CMV in recent years. Due to their high sensitivity, these assays can detect CMV early, and quantitation may be useful in predicting the patient's risk for disease and in monitoring the effect of antiviral therapy. This review discusses methodological aspects of currently used quantitative assays for CMV (i.e., viral culture techniques, antigen detection assays, DNA detection assays including PCR, branched-DNA assay, and the DNA hybrid capture assay) and addresses the correlation of systemic and site-specific CMV load and CMV disease in different populations of immunosuppressed patients as well as the response to antiviral treatment. To date, direct antigen detection and molecular techniques have largely replaced traditional culture-based techniques for CMV quantitation. In general, a high systemic CMV load is correlated with CMV disease. This correlation is strong in the HIV-infected population and in solid-organ transplant recipients but less clear in allogeneic marrow transplant recipients. Measuring the viral load at specific anatomic sites may be an alternative way to assess disease activity in situations where the systemic viral load correlates poorly with disease activity. A reduction of the systemic CMV load also correlates with a response to antiviral treatment, but more research is needed to evaluate the role of viral load as a surrogate marker for drug resistance. Due to the widespread use of quantitative CMV detection techniques to direct and monitor antiviral treatment, there is a great need for an assessment of the reproducibility of test results and better standardization of the assays.

Quantitative detection of human cytomegalovirus DNA in lung transplant recipients

Human cytomegalovirus (HCMV) disease remains a major cause of morbidity and mortality after lung transplantation. Currently, routine diagnostic tests for HCMV are inefficient and insensitive or nonspecific for HCMV disease. We describe an efficient, highly sensitive, quantitative polymerase chain reaction (PCR) assay for HCMV using competitive PCR and fluorescently labeled primers, and we have used this to measure HCMV DNA load in donor and recipient tissues of six lung transplant recipients at the time of transplantation, and 2 wk after transplantation when clinically stable. Total DNA yield was adequate for analysis in transbronchial biopsy, bronchoalveolar lavage, and peripheral blood leukocytes, but the endobronchial biopsy specimens did not consistently produce sufficient DNA for analysis. There was a large intersubject and intrasubject variability between tissues in HCMV DNA load, with a tendency for greater levels in lung tissue compared with BAL or peripheral blood cells. All six HCMV IgG seronegative donors or recipients were found to have HCMV DNA present. One of the three seronegative matched transplant recipients developed histopathologically proven HCMV disease, and HCMV DNA levels were shown to increase at that time point and subsequently decrease with ganciclovir treatment. This assay will allow prospective studies to confirm the predictive value of HCMV DNA load in donor and recipient tissues for HCMV disease.

Approach to the patient with pulmonary disease

The approach to the HIV-infected patient with pulmonary disease is summarized by the algorithms in Figures 3 and 4. These are not intended to be followed in a rigid step-wise fashion. Rather, the practitioner's knowledge of the patient with his or her accompanying medical risks influences the path taken, including the depth and the speed of the evaluation. For example, the patient with cough who is afebrile and breathing at 18 breaths a minute, with a normal chest radiograph and a CD4 count of 350 cells/mm3, is reasonably treated with a macrolide or cephalosporin for bacterial bronchitis and clinical follow-up while awaiting cultures (see Fig. 4). A febrile patient with a cough productive of thin mucus, but known to have a CD4 count of 60 cells/mm3 should be started on anti-PCP therapy while being evaluated for PCP with an induced sputum and if nondiagnostic, a bronchoscope despite a normal chest radiograph. Screening can be as simple as placing an oximeter on the patient's finger in the clinic. If the oxygen saturation of a patient with a normal chest radiograph is low, then the patient should be hospitalized and begun on treatment for PCP while diagnostic evaluation is initiated. If the oxygen saturation is normal, the patient can be exercised to elicit desaturation. If there is no desaturation, PCP is unlikely. If the results are equivocal (i.e., a decrease in saturation, but less than 3%), rest and exercise arterial blood gases can be performed, along with a Dlco-Gallium scanning can be done in patients known to have abnormal Dlco or those who cannot exercise. Patients with focal infiltrates who have acute onset of symptoms (see Fig. 4) commonly have bacterial infections, but the possibility of PCP or TB should not be dismissed. Induced sputum should be examined if TB or PCP is suspected. Patients who are severely ill might go quickly to bronchoscopy without awaiting improvement on empiric therapy. The patient with diffuse infiltrates (see Fig. 4) needs no screening because the presence of disease is apparent from the radiograph. The diagnostic part quickly leads to bronchoscopy for these patients and the initiation of therapy for PCP when suspected. In patients with known pulmonary KS, gallium scanning can be helpful to rule out acute infection, but bronchoscopy is warranted if the patient is severely ill, or at high risk for PCP. This approach should avoid unnecessary procedures in patients with simple bacterial infections, without missing opportunistic infections and tumors.

Viruses and other miscellaneous organisms

Pulmonary infections caused by several types of viruses and other miscellaneous organisms may cause disease in HIV infection. Evidence suggests that pulmonary conditions may result from infections of the lung by HIV itself. Other viruses, most commonly cytomegalovirus, may be primary perpetrators of pneumonitis or may contribute to diseases caused by coexisting infections. Although diagnosis and assessment of the clinical significance of these infections may be difficult, their recognition is of practical importance because potentially effective therapeutic agents are available for several of them. Miscellaneous infections such as pulmonary toxoplasmosis and pertussis are other uncommon but potentially treatable complications of HIV disease.

Role of bronchoalveolar lavage in hospitalized pediatric patients

Bronchoalveolar lavage (BAL) has been shown to be a rapid, relatively safe, and relatively noninvasive diagnostic procedure. Theoretically, BAL can be performed on all children hospitalized for pneumonia resistant to oral antibiotics, though practically and economically, this is not feasible. A 1-year retrospective review was conducted to define a cost-effective role for BAL in the management of hospitalized children with resistant pneumonia. The data revealed identification of at least one pathogen in 87% of sputum samples and in 95% of BAL specimens. Sputum samples provided the same information as the more invasive BAL technique in 60% of patients who had both sputum and BAL obtained for culture. Recommendations are made for the use of BAL as a diagnostic tool in the hospitalized child with resistant pneumonia.

Human cytomegalovirus-induced immunosuppression. Relationship to tumor necrosis factor-dependent release of arachidonic acid and prostaglandin E2 in human monocytes

Cytomegalovirus (CMV) has been associated with immunosuppression. Previously CMV was reported to interfere with signal transduction pathways in T cells. In this report the mechanisms underlying CMV-mediated immunosuppression were examined. Supernatants of CMV (Strains C-87, AD-169)-infected primary human monocyte (MO) cultures inhibited mitogenic T cell proliferative responses by > 95%. The inhibitory activity was observed 24 h through day 7 postinfection. The infection of MO was associated with a sustained elevation of intracellular levels of cAMP and the release of arachidonic acid (AA) and its metabolite PGE2 (activator of adenylate cyclase) in culture supernatants. The AA release was incidentally associated with TNF-alpha production. Monoclonal antibodies to TNF-alpha and pentoxyphylline (inhibitor of TNF synthesis) inhibited both AA and PGE2 release. The release of AA required protein synthesis and occurred under conditions consistent with the expression of CMV immediate early genes. Treatment of MO cultures at time of infection with 100 microM indomethacin or 1 microg of TNF-alpha mAb abolished the CMV-induced T cell inhibitory activity of the supernatants by 100%. These data suggest that TNF dependent release of AA and PGE2 contributes to CMV-induced immunosuppression.

The relationship between cytomegalovirus retrieved by bronchoalveolar lavage and mortality in patients with HIV

STUDY OBJECTIVE

To evaluate mortality over 6 months of patients with HIV with cytomegalovirus (CMV) cultured from bronchoalveolar lavage (BAL) compared with those without CMV and to assess the significance of CMV cytologic study, CD4+ counts, and coexistent Pneumocystis carinii pneumonia.

DESIGN

Retrospective evaluation of HIV-infected patients undergoing bronchoscopy with BAL. The 40 most recent HIV-positive patients undergoing bronchoscopy with BAL were included for each of three categories: CMV by cytologic study; CMV by culture only; and CMV absent. Patients for whom survival status at 6 months was unknown were excluded from analysis.

SETTING

University hospital, tertiary care center.

PATIENTS

Group 1 consisted of 36 patients with positive CMV culture and cytologic study and group 2 consisted of 38 patients with only a positive culture for CMV. Group 3 consisted of 40 patients with no evidence of CMV by BAL.

RESULTS

On comparison of the groups, there was no difference in 3-week survival (from date of bronchoscopy). There was a statistically significant increase in mortality in group 1 patients compared with group 3 patients at both 3 and 6 months. Between groups 2 and 3, there was a difference in mortality that approached but did not reach significance at 3 months but did at 6 months. The mortality in group 1 at 3 months = 28%, at 6 months = 47%, whereas mortality in group 2 at 3 months = 26% and at 6 months = 45%. Group 3 had a 3-month mortality of 10% and a 6-month mortality of 15%. While those patients with positive CMV cytologic study had lower mean CD4+ counts, within the group, CD4+ counts were no different between the 3-month survivors and nonsurvivors (survivors, CD4/mm3 median = 38 [0 to 141]; and nonsurvivors, CD4/mm3 median = 16 [3 to 224]). Coinfection with P carinii did not increase mortality at 3 months.

CONCLUSIONS

The CMV retrieved by BAL in HIV-infected patients was associated with significantly greater 3- and 6-month mortality. The CMV cytologic study did not predict a higher mortality and the difference in mortality between patients with and without CMV in BAL fluid was not directly attributed to lower CD4+ counts or P carinii coinfection.

Bronchoscopic diagnosis of pneumonia

Lower respiratory tract infections are characterized by significant morbidity and mortality but also by a relative inability to establish a specific etiologic agent on clinical grounds alone. With the recognized shortcomings of expectorated or aspirated secretions toward establishing an etiologic diagnosis, clinicians have increasingly used bronchoscopy to obtain diagnostic samples. A variety of specimen types may be obtained, including bronchial washes or brushes, protected specimen brushings, bronchoalveolar lavage, and transbronchial biopsies. Bronchoscopy has been applied in three primary clinical settings, including the immunocompromised host, especially human immunodeficiency virus-infected and organ transplant patients; ventilator-associated pneumonia; and severe, nonresolving community- or hospital-acquired pneumonia in nonventilated patients. In each clinical setting, and for each specimen type, specific laboratory protocols are required to provide maximal information. These protocols should provide for the use of a variety of rapid microscopic and quantitative culture techniques and the use of a variety of specific stains and selective culture to detect unusual organism groups.

Human monoclonal anti-cytomegalovirus (CMV) antibody (MSL 109): enhancement of in vitro foscarnet- and ganciclovir-induced inhibition of CMV replication

Human CMV causes a number of diseases that cause considerable morbidity and that can be life-threatening in immunocompromised patients, particularly those with AIDS. Ganciclovir (GCV) and Foscarnet (PFA) are currently the drugs of choice for management of CMV disease. Both are not without side effects and have a relatively narrow margin of safety. In this report the effects of a human IgG1 neutralizing monoclonal antibody MSL-109 (MSL, Sandoz Pharmaceuticals) on CMV replication was examined both alone or in combination with either GCV or PFA. Human embryonic lung fibroblasts were infected with CMV strain AD169 with a multiplicity of infection of 3 plaque forming units/cell for 1 h. Prior to infection the virus was incubated for 30 min at 37 degrees C with serial concentrations of the MSL Ab (0.1-3.0 micrograms/ml). Concentrations of GCV (0.3 to 30 microM) or PFA (50-400 microM) were added to CMV-infected cells that had been either previously incubated with MSL or not. Four days after infection CMV replication was measured by DNA/DNA probe hybridization using the Hybriwix system. MSL in combination with GCV had an additive effect that was observed at concentrations of GCV of 3-10 microM and MSL of 1-10 micrograms/ml. On the other hand, MSL (3-10 micrograms/ml) together with PFA (100-400 microM) produced a synergistic effect on CMV replication. The data suggest that MSL at doses achievable in humans, enhanced GCV- and PFA-induced antiviral effect in a dose-dependent manner and that the combination might be clinically useful in the treatment of CMV disease.

Cytomegalovirus DNA polymerase activity and an 80 kDa-associated polypeptide: a potential diagnostic tool for CMV disease

CMV has been reported to be associated with a DNA polymerase activity (DPA). In this communication its purification, characterization and potential diagnostic value were examined. CMV DNA polymerase was prepared from cell free supernatants of CMV (AD 169) infected cultures. Separation and purification of the enzyme was accomplished by column chromatography of the purified, lysed virus. CMV DPA was measured on an oligo (dT)-poly (dA) template primer. SDS-PAGE and western blot analysis under reducing conditions using an anti-CMV early antibody showed an 80 kDa protein band that was associated with the peak of polymerase activity. However, CMV isolates and CMV from urines from CMV retinitis patients immunoblotted by the same Ab revealed 140 kDa and 80 kDa bands under non-reducing and reducing conditions respectively, the latter was also associated with a 58 kDa band. The diagnostic value of the CMV associated DAP was tested using CMV positive urines. The latter demonstrated high PAA-sensitive DPA activity, compared to normal, HSV positive urines and urines from HBSAg positive patients. Taken collectively, these findings indicate the potential usefulness of CMV-associated DNA polymerase activity in the diagnosis and follow-up of patients with CMV-related illnesses.

Application of PCR to multiple specimen types for diagnosis of cytomegalovirus infection: comparison with cell culture and shell vial assay

Human cytomegalovirus (CMV) is a herpesvirus that is responsible for significant morbidity and mortality in congenitally infected infants and immunocompromised patients. Antiviral therapies are available, thus making timely diagnosis of significant importance to at-risk patients. A PCR system was devised. The newly devised system, unlike previously described systems, can be applied to a wide variety of specimen types in a clinical microbiology laboratory setting. Specimens from all sites routinely accepted for CMV culture were shown to be acceptable for CMV PCR. Sensitivity and specificity were established in comparison with those of both monolayer culture and shell vial assay (SVA). The sensitivity and specificity of PCR for detection of CMV in specimens exclusive of urine and blood were 97.5 (77 of 79 specimens) and 87.2% (41 of 47 specimens), respectively. The sensitivity and specificity of PCR for urine and blood specimens were 100 (10 of 10) and 95.7% (45 of 47) and 66.7 (4 of 6) and 78.8% (41 of 52), respectively. Discrepancies of positive PCR results with negative culture or SVA results occurred for specimens flanked chronologically by other culture- or SVA-positive specimens and were likely culture failures, increasing the specificity (100%) of PCR. Discrepancies of negative PCR results with positive culture or SVA results occurred in specimens with few cells or infectious foci by SVA or culture and may represent sampling variability associated with low virus titers.

Viral pneumonias. The increasing importance of a high index of suspicion

Viral pneumonias account for at least 17% of cases of community-acquired pneumonia in children and in adults. Although patients with viral pneumonia appear less ill clinically than those with bacterial pneumonia, viral pneumonias can be fatal. Antiviral therapy is available for pneumonias caused by respiratory syncytial virus, influenza A virus, and cytomegalovirus. Several vaccines are important tools for the prevention of influenza A and B pneumonia.

The diagnosis of Pneumocystis carinii pneumonia by cytologic evaluation of Papanicolaou and Leishman-stained bronchoalveolar specimens in patients with the acquired immunodeficiency syndrome

The presence of foamy alveolar casts or flocculent material in Papanicolaou and Leishman-stained smears of bronchoalveolar lavage (BAL) fluid is said to be indicative of infection with Pneumocystis carinii. We have investigated the sensitivity and specificity of this method of diagnosing pneumocystis pneumonia in patients with the acquired immunodeficiency syndrome (AIDS). Patients (n = 114) with diffuse lung infiltrates were submitted to fibreoptic bronchoscopy and BAL. Seventy of them were patients with AIDS. The other 44 individuals were not infected by the human immunodeficiency virus (HIV). Pneumocystis carinii organisms were identified on Grocott's methenamine silver (GMS)-stained BAL smears in 30 patients with AIDS. Flocculent material was present in the Papanicolaou and Leishman-stained smears from all of these cases. Conversely, P. carinii were not seen on GMS-stained smears in the remaining 84 individuals with or without AIDS. No flocculent material was observed in Papanicolaou or Leishman-stained smears in these 84 patients. We concluded that the presence of flocculent material in Papanicolaou or Leishman-stained smears of BAL fluid is indicative of P. carinii pneumonia in patients with AIDS.

Quantification of cytomegalovirus in bronchoalveolar lavage fluid after allogeneic marrow transplantation by centrifugation culture

A technique to quantify cytomegalovirus (CMV) by centrifugation culture of bronchoalveolar lavage fluid from marrow transplant recipients was developed. This technique was used to assess the CMV response to antiviral treatment and the relationship between viral load, asymptomatic excretion versus symptomatic infection, and prognosis. Relative to tube cell culture, centrifugation culture of bronchoalveolar lavage fluid was more sensitive than direct fluorescent-antibody staining. It was also a rapid, replicable method for detecting and measuring the amount of CMV. There was no significant difference between viral load at diagnosis and after 9 days of treatment with ganciclovir and intravenous immunoglobulin. Viral load was not predictive of outcome, and there was no difference in amount of virus between patients with asymptomatic CMV excretion and those with CMV pneumonia. The amount of CMV may not be as important as other factors (e.g., host immune response) in the pathogenesis of CMV pneumonia.

Cytomegalovirus and Pneumocystis carinii pneumonia in children with acquired immunodeficiency syndrome

To ascertain the effect of cytomegalovirus (CMV) infection on the course of Pneumocystis carinii pneumonia (PCP) in children with acquired immunodeficiency syndrome (AIDS), we reviewed the charts of all children with AIDS who also had a lung biopsy specimen or a bronchoalveolar lavage specimen cultured for CMV at the time PCP was diagnosed. The data indicate that children with AIDS and PCP whose cultures are positive for CMV do not have a poorer prognosis during a first episode of PCP compared with children whose cultures are negative for CMV.

Bronchoscopy with bronchoalveolar lavage in the evaluation of pulmonary complications of bone marrow transplantation in children

Pulmonary complications are a frequent cause of morbidity and mortality following bone marrow transplantation. We examined the results of flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) in 27 pediatric bone marrow transplant (BMT) recipients with 29 episodes of pulmonary complications. Bone marrow transplant was performed for a variety of malignancies and hematologic disorders. Median age of BMT was 10.3 years (range, 1.7-17.6 years). Median time of FB following BMT was 60 days (range, 11-1,026 days). Routine cytologic and culture techniques were utilized to detect malignant cells, viruses, fungi, bacteria, and protozoa. Positive results were found in 15 (52%) with cytomegalovirus (CMV), the most common positive finding. In 14 (48%) episodes the results were negative. Fourteen patients had follow-up autopsy or open lung biopsy (OLB). Based on autopsy/OLB results, there were two false negatives and no false positives, giving a diagnostic sensitivity of 75% and specificity of 100%. There was one possible complication of FB and BAL. Survival of both positive and negative patients was poor, only seven patients being alive 90 days post-FB with BAL. We conclude that FB with BAL is a safe and accurate procedure for the diagnosis of pulmonary complications of BMT.

Bilateral bronchoalveolar lavage in the diagnosis of opportunistic pulmonary infections

To further improve the diagnostic value of bronchoscopy in the immunosuppressed population presenting with diffuse pulmonary infiltrates, we prospectively investigated the utility of bilateral bronchoalveolar lavage (BAL). We performed 62 bronchoscopies on 52 immunosuppressed patients. Of the 52 patients, 33 had pulmonary infections. The yield for Pneumocystis carinii pneumonia on bilateral BAL was 94 percent (31/33), compared to the 84 percent (51/61) previously obtained with unilateral BAL in our institution. The recovery of P carinii was unilateral in four of five patients without AIDS and in four of 26 patients with AIDS. Transbronchial biopsy gave a yield of 85 percent (11/13). In ten patients with definitive cytomegalovirus (CMV) pneumonia, recovery of CMV by combined culture and cytology was 100 percent. Of nine bronchoscopies with positive cytology for CMV, five showed cytopathologic changes in the BAL from both sides and four in the BAL from one side only. No complications were seen in the 14 patients with thrombocytopenia or the five patients receiving mechanical ventilation. Our findings indicate that bilateral BAL significantly increases the yield for recovery of P carinii (p less than 0.02) and CMV (p less than 0.001) in immunosuppressed patients.

Successful management of CMV pneumonia in a mechanically ventilated patient

We report a case of severe respiratory failure due to cytomegalovirus pneumonitis in a patient who underwent an allogeneic bone marrow transplant, who was successfully treated with the combination of ganciclovir and high-dose intravenous immune globulin. We also reviewed the rationale for the use of combination therapy with an antiviral agent and immunotherapy. Because of the bone marrow toxicity of ganciclovir, an aggressive diagnostic approach, including bronchoalveolar lavage and open lung biopsy, may be necessary to establish a definitive diagnosis prior to institution of therapy.

Diagnosis of cytomegalovirus pneumonitis on bronchoalveolar lavage fluid: comparison of cytology, immunofluorescence, and in situ hybridization with viral isolation

Forty-three bronchoalveolar lavage (BAL) specimens from 40 immunocompromised patients were studied for the presence of cytomegalovirus (CMV) by rapid diagnostic methods. DNA in situ hybridization, cytology, and immunofluorescence were compared to conventional cell culture. Eleven (25%) of the 43 BAL samples grew CMV in culture. In situ hybridization detected 6 of these 11 for sensitivity, specificity, and predictive values of positive and negative of 55%, 94%, 75%, and 86%, respectively. Cytology had a sensitivity of 73% and specificity of 100%. Six Papanicolaou-stained cytospins were screened cytologically versus one hybridization cytospin, and the higher sensitivity of cytology may reflect this extensive sampling. The immunofluorescent method had a sensitivity equal to that of cytology (73%): however, the specificity (72%) was significantly less than that of either the probe or cytology. These data suggest that although in situ hybridization can be a rapid, useful method for detecting CMV in BAL specimens, cytology appears to be a more sensitive method.

The diagnostic yield of bronchoscopy

The endoscopic examination of the tracheobronchial tree is most helpful in the diagnosis and staging of bronchial carcinoma. Tumors that are endoscopically visible may be confirmed in more than 95% of the cases. In localized peripheral tumors, the diagnostic yield of bronchoscopy is significantly lower; for peripheral metastases, only about 10%. In diffuse interstitial pulmonary diseases other than malignancies, some infections, and histiocytosis X, bronchoscopy including transbronchial biopsy is less successful.

Central airway obstruction due to cytomegalovirus-induced necrotizing tracheitis in a patient with AIDS

Cytomegalovirus (CMV) infection in patients with the acquired immunodeficiency syndrome (AIDS) can present as either disseminated disease, pneumonitis, retinitis, gastroenteritis, neuropathy, or a subclinical infection. We report a patient whose initial manifestation of CMV infection was severe central airways obstruction due to necrotizing tracheitis. At bronchoscopy, the lesion appeared deeply ulcerated, distinctly different from previously described airway lesions in patients with AIDS. Mucosal biopsies showed characteristic intranuclear and intracytoplasmic inclusions and cultures yielded only CMV. The patient responded partially to ganciclovir, steroids, and antibiotics against suspected anaerobic superinfection but died as a result of central nervous system disease believed due to toxoplasmosis or lymphoma. CMV infection of the upper airway should be considered in the patient with AIDS presenting with atypical cough or stridor and ulcerated endobronchial lesions.

Detection of cytomegalovirus in bronchoalveolar lavage specimens. Spin amplification and staining with a monoclonal antibody to the early nuclear antigen for diagnosis of cytomegalovirus pneumonia

To diagnose cytomegalovirus pneumonia in a hetergeneous population of patients, three methods for detection of CMV in bronchoalveolar lavage specimens were compared as follow: (1) spin amplification followed by staining with a monoclonal antibody to the early nuclear antigen (EA-assay); (2) conventional tissue cell culture; and (3) cytology. Cell differentials were performed on most specimens. Cytomegalovirus was detected by one or more method in 55 BAL specimens from 39 patients. Cytomegalovirus (CMV) pneumonia was diagnosed by lung tissue (primarily autopsy) histologic findings and conventional culture results or the presence of CMV in extrapulmonary tissue, fulfillment of specific clinical and radiographic criteria plus failure to recover a pathogen other than CMV from a respiratory specimen. Probable CMV pneumonia was diagnosed if only the latter two criteria were met. The EA-assay was positive in all patients with proven or probable CMV pneumonia and in 92 percent of those without documented pneumonia. Cytologic findings were positive only in patients with CMV pneumonia but were negative in one-third of those patients. As a diagnostic test for CMV pneumonia, the EA-assay, conventional culture, and cytology had positive predictive values of 45, 57, and 100 percent, respectively. Lymphocyte percentages in BAL specimens from patients with CMV pneumonia were significantly decreased compared with those of patients without CMV pneumonia (p less than 0.005). Although the EA-assay should not be used alone as a diagnostic test for CMV pneumonia in our patient population, the combination of alveolar lymphopenia and a positive BAL CMV EA-assay was highly suggestive of disease.

Cytomegalovirus in the bronchoalveolar lavage fluid of patients with AIDS

This study investigated the significance of detecting cytomegalovirus in the bronchoalveolar lavage fluid of patients with human immunodeficiency virus infection. Bronchoscopy with BAL was performed on all patients. Lavage was examined for CMV by cytology, culture, and immunofluorescence. The lavage results were compared to clinical status at the time of bronchoscopy and the outcome of the respiratory event. Cytomegalovirus was detected in 51 percent of the BALs in the patients with HIV infection and 25 percent of the immunosuppressed patients without HIV. No association was found in the HIV infected patients between CMV and hypoxemia, abnormal chest roentgenogram, leukopenia, and increased mortality. As indicated by mortality, CMV did not significantly increase the severity of Pneumocystis carinii pneumonia. The study also suggested that CMV in BAL fluid reflected bronchopulmonary replication of the virus, and not contamination by virus in the blood. Cytomegalovirus does not appear to contribute directly to the pulmonary disease found in most patients with HIV infection.

[Pneumonia in immunocompromised patients: the value of non-biopsy bronchoscopic examination procedures in the diagnosis of pathogens]

Bronchoscopy was performed on 101 immunocompromised patients with fever and pulmonary infiltrates. Underlying diseases were mainly hematological malignancies. In 71% of cases, etiology of pneumonia was clarified by nonbioptic bronchoscopic methods (bronchoalveolar lavage, bronchial secretions, protected specimen brush). In 51% of cases, empirical antibiotic treatment was modified following bronchoscopy. In patients with early bronchoscopy a better prognosis regarding healing and survival was observed than in those cases, where bronchoscopy was performed later during pneumonia. Bronchoalveolar lavage was particularly suited for diagnosis of Pneumocystis carinii and pneumonia due to viruses or Legionella. Sensitivity and specificity of bronchoscopy were lower for diagnosis of mycotic pneumonia and of Gram-negative or Gram-positive bacteria.

Immunoserology of infectious diseases

The immune response to microorganisms not only participates in the elimination of unwanted organisms from the body, but also assists in diagnosis of infectious diseases. The nonspecific immune response is the first line of defense, assisting the body until the specific immune response can be mobilized to provide protective mechanisms. The specific immune response involves humoral or cell-mediated immunity or both, dependent on the nature of the organism and its site of sequestration. A variety of test systems have been developed to identify the causative organisms of infectious diseases. Test systems used in immunoserology have classically included methods of detecting antigen-antibody reactions which range from complement fixation to immunoassay methods. Relevant test systems for detecting antigens and antibodies are described. With numerous test systems available to detect antigens and antibodies, there can be confusion regarding selection of the appropriate system for each application. Methods for detecting antibody to verify immunity differ from immunologic methods to diagnose disease. Techniques to detect soluble antigens present in active infectious states may appear similar to those used to detect antibody, but their differences should be appreciated.

Cytomegalovirus necrotizing bronchiolitis with HIV infection

Cytomegalovirus (CMV) is frequently isolated from respiratory secretions of human immunodeficiency virus (HIV)-infected patients. Even in the presence of histopathologic evidence of CMV cytopathic abnormalities, the true clinical significance of CMV pneumonitis is not well established. Airways disease is increasingly recognized in HIV-infected patients, but its etiology is unclear. We describe an HIV-infected patient who presented with fever, wheeze, and micronodular interstitial infiltrates and developed severe hypercapnic and hypoxemic respiratory failure. Open lung biopsy showed necrotizing bronchiolitis with cytopathic changes characteristic of CMV infection; no other pathogens were isolated. He responded well to treatment with ganciclovir.

Comparative recovery of cytomegalovirus from saliva, mucolysed induced sputum, and bronchoalveolar lavage fluid from patients at risk for or with acquired immunodeficiency syndrome

The recovery rates of cytomegalovirus from mucolysed induced sputum samples and bronchoalveolar lavage fluid obtained from individuals at risk for or with acquired immunodeficiency syndrome were compared. It was demonstrated that cytomegalovirus could be reliably recovered from mucolysed induced sputum, and such recovery was highly predictive of recovery from bronchoalveolar lavage samples obtained from the same individual.

Rapid detection of cytomegalovirus in bronchoalveolar lavage specimens from marrow transplant patients: evaluation of a direct fluorescein-conjugated monoclonal antibody reagent

An FITC-conjugated monoclonal antibody reagent containing three CMV-specific monoclonal antibodies was evaluated for the rapid detection of CMV in bronchoalveolar lavage (BAL) cytospin preparations by direct IF (DFA). Eighty-six BAL samples from 72 marrow transplant patients were inoculated into both centrifugation and standard cell culture. CMV was detected in 49/86 (57%) BAL samples. DFA detected 37/46 (80%) samples which were positive in centrifugation culture. While DFA staining lacked the sensitivity (overall sensitivity 38/49, 78%) to replace either standard or centrifugation culture, the total laboratory time needed to complete the DFA was only 1.5 h and its concurrent use with centrifugation culture can provide rapid specific diagnosis of CMV pneumonia.