Effect of centrifugal enhancement of infectivity on the rapid detection of human cytomegalovirus in cell culture by immunofluorescence using a monoclonal antibody to an immediate early nuclear antigen

A prospective study of a quantitative PCR ELISA assay for the diagnosis of CMV pneumonia in lung and heart-transplant recipients

BACKGROUND

Qualitative polymerase chain reaction (PCR) for the identification of cytomegalovirus (CMV) infection has a low predictive value for the identification of CMV pneumonia. This study prospectively evaluated the application of a quantitative PCR Enzyme-Linked Immuno-Sorbent Assay (ELISA) assay in 9 lung- and 18 heart-transplant recipients who did not receive ganciclovir prophylaxis.

METHODS

DNA was collected from peripheral blood polymorphonuclear leucocytes (PMNL) posttransplantation. Oligonucleotide primers for the glycoprotein B gene (149 bp) were used in a PCR ELISA assay using an internal standard for quantitation. CMV disease was defined as histological evidence of end organ damage.

RESULTS

The median level CMV genome equivalents in patients with CMV disease was 2665/2 x 10(5) PMNL (range 1,200 to 61,606) compared to 100 x 10(5) PMNL (range 20 to 855) with infection but no CMV disease (p = 0.036). All patients with CMV disease had genome equivalents levels of >1200/2 x 10(5) PMNL. A cut-off level of 1,200 PMNL had a positive predictive value for CMV disease of 100% and a negative predictive value of 100%. The first detection of levels of CMV genome equivalents above a level of 1200/2 x 10(5) PMNL was at a median of 58 days (range 47 to 147) posttransplant.

CONCLUSIONS

Quantitative PCR assays for the diagnosis of CMV infection may predict patients at risk of CMV disease and thereby direct preemptive treatment to high-risk patients.

Preemptive treatment for the prevention of cytomegalovirus disease: in lung and heart transplant recipients

BACKGROUND

Rapid quantifiable diagnostic techniques for the diagnosis of cytomegalovirus (CMV) infection may predict patients at risk of CMV pneumonitis and allow preemptive antiviral treatment.

METHODS

Using CMV antigenemia as a prospective surveillance technique for CMV infection, we compared the outcome of preemptive treatment (PT) with ganciclovir, 10 mg/kg/day for 21 days directed by "high levels" of CMV antigenemia (PT group, n= 19), with the outcome in a group of historical controls (n=18) treated with ganciclovir when CMV illness occurred. Greater than 50 antigen-positive cells per 2 x 10(5) polymorphonuclear leukocytes was considered to be high-level antigenemia.

RESULTS

Nine of the 18 controls developed high-level CMV antigenemia at a median of 33 days (range: 13-65 days) and 5 of the 9 developed CMV disease. Ten of the 19 PT group had high levels of CMV antigenemia detected at a median of 47 days (range: 20-63 days) and were given ganciclovir; none developed CMV disease. There was a significantly lower incidence of CMV disease in the PT group in comparison to controls (0 of 19 vs. 5 of 18: P=0.019).

CONCLUSION

We have reduced the incidence of CMV disease using preemptive treatment, and because of a 100% negative predictive value, we omitted unnecessary antiviral prophylaxis for many at-risk patients.

Successful diagnosis and management of cytomegalovirus carditis

Cytomegalovirus (CMV)-associated carditis in the immunosuppressed patient carries a 60% mortality. Underlying pathogenesis is poorly understood but may involve either direct viral invasion or autoimmune cardiac damage triggered in response to the infection. Specific anti-cytomegalovirus therapy and/or anti-inflammatory drugs have been shown to benefit in cases where an early diagnosis was established. We report an unusual case of endo-pericarditis which was temporally related to acute cytomegalovirus infection diagnosed by the immediate early antigen detection in cell culture on whole blood.

Pulmonary interstitial fibrosis and haemosiderin-laden macrophages: late following heart transplantation

Impairment of pulmonary diffusion is recognized following heart transplantation. This study was undertaken to determine the histopathological basis for the defect in pulmonary physiology. Heart transplant recipients (HTR) entered into a prospective study of post-transplant pulmonary physiology were asked to undergo bronchoscopy, bronchoalveolar lavage (BAL) and transbronchial biopsy (n = 18) in the presence of impaired gas transfer. Transbronchial biopsies were examined under light microscopy and demonstrated focal interstitial fibrosis in 12 patients, cytomegalovirus disease in four patients and Pneumocystis carinii pneumonia in three patients. Bronchoalveolar lavage differential counts were normal in HTR but BAL macrophages contained haemosiderin. The histological features of interstitial fibrosis may underlie the fall in gas transfer seen following heart transplantation. The presence of haemosiderin-laden macrophages late following heart transplantation suggests a capillary leak syndrome.

Comparative study of three PCR assays with antigenaemia and serology for the diagnosis of HCMV infection in thoracic transplant recipients

Three PCR assays were evaluated for the detection of human cytomegalovirus (HCMV) infection in heart and lung transplant recipients in comparison with HCMV antigenaemia and serology assay. Polymorphonuclear leucocyte (PMNL) samples taken at regular intervals after transplantation were tested for HCMV DNA using primer sets homologous to the glycoprotein B (gp58), major immediate early (IE1), and structural phosphoprotein (pp150) regions. The detection of HCMV infection at various times after transplantation showed all three primer sets to have a sensitivity of 100% and a specificity of 92.3% for the detection of HCMV infection although overall the gp58 primer set was found to be significantly more frequently associated with a positive PCR result than the IE1 (P = 0.0228) and pp150 (P = 0.0015) primer sets. The positive PCR result had a positive predictive value of 27.8% for HCMV disease. Detection of HCMV infection was first by the PCR assay, and significantly before the HCMV antigenaemia assay. Of nine patients who received antiviral therapy while PCR positive, only one patient cleared HCMV DNA from PMNLs during treatment but became positive again 17 days later. Quantitative PCR methodologies may improve the predictive value of PCR for HCMV disease and its value for monitoring antiviral therapy.

Detection of human cytomegalovirus antigenaemia: a rapid diagnostic technique for predicting cytomegalovirus infection/pneumonitis in lung and heart transplant recipients

BACKGROUND

New rapid diagnostic techniques offer the opportunity of early diagnosis of human cytomegalovirus (CMV) infection in immunocompromised patients at risk of developing CMV disease. The use of human CMV antigenaemia as a predictor of clinical CMV infection and disease in lung and heart transplant recipients was studied prospectively.

METHODS

Twenty three heart and nine lung transplant recipients who survived 40 days were observed by standard CMV surveillance with serological testing, culture, and by sequential testing for CMV antigenaemia. CMV antigenaemia testing is a rapid and quantifiable technique in which a viral lower matrix protein is detected in cytospin preparations of peripheral blood polymorphonuclear leucocytes (PMNLs) by immunofluorescent staining.

RESULTS

Eleven patients developed CMV infection and five developed CMV disease (four pneumonitis, one duodenitis). These clinical events occurred at a median of 65 days following transplantation. CMV antigenaemia occurred in 17 patients at a median of 35 days following transplantation. Detection of CMV antigenaemia had a sensitivity of 100%, a specificity of 93.7%, and a positive predictive value of 94.1% for CMV related illness. CMV antigenaemia was positive at a significant interval before the clinical event. High levels of CMV antigenaemia (> 50 CMV antigen positive cells/2 x 10(5) PMNLs) occurred in 11 patients and five of these developed disease. CMV antigenaemia of > 50 CMV antigen positive cells/2 x 10(5) PMNLs had a positive predictive value of 45.5% for disease but a negative predictive value of 100%. Patients with disease had higher levels of antigenaemia than those without disease.

CONCLUSIONS

CMV antigenaemia is a rapid diagnostic technique which can identify patients likely to develop CMV disease, potentially allowing early treatment.

Computer network for a diagnostic virology laboratory

A data base for a large diagnostic virology laboratory is described. The system uses a network of personal computers. It allows the entry, long-term storage, and subsequent retrieval of specimen and patient records (comprising personal identifiers and specimen and result information), and hard-copy results reporting. Sited entirely within the laboratory, the network is not connected to a modem. Within the laboratory there is restricted access to human immunodeficiency virus test results to guarantee patient confidentiality. Retention of a hard-copy of specimen request cards ensures the availability of the original clinical information. The data base is copied on a second file server to facilitate searches, and daily streaming onto magnetic tape provides system protection in the event of hard disc failure. Matching of old and new patient records is done by surname, date of birth, and sex, and therefore duplicate records accumulate when patient names are misspelt on specimen request forms. The system requires further development to speed searches of the data base and to achieve automatic generation of laboratory worksheets. Future goals are the replacement of hard-copy records of clinical information and hard-copy reporting with on-line access to hospital data bases and on-line requesting by and reporting to the clinician.

Fatal congenital cytomegalovirus infection acquired by an intra-uterine transfusion

A case of congenital cytomegalovirus infection acquired by intra-uterine blood transfusion and complicated by the nephrotic syndrome is described. Experience with the use of the antiviral agent ganciclovir is reported.

Sensitive non-isotopic DNA hybridisation assay or immediate-early antigen detection for rapid identification of human cytomegalovirus in urine

A sensitive non-radioactive DNA hybridisation assay employing digoxigenin-labelled probes was compared with immediate-early antigen detection and conventional virus isolation for the identification of human cytomegalovirus (HCMV) in 249 urine samples. Of 44 specimens yielding HCMV by virus isolation, more were positive by DNA hybridisation (32; 73%) than by immediate-early antigen detection (25; 52%) (P = 0.05). The specificity of the hybridisation assay in 45 apparently falsely positive specimens was supported by detection of HCMV DNA in 40 of these specimens using the polymerase chain reaction. Many urine specimens may thus contain large amounts of non-viable virus or free viral DNA. Evaluation of various protocols for the extraction and denaturation of virus DNA prior to hybridisation showed that proteinase K digestion with phenol/chloroform extraction was the most sensitive and reliable procedure. We conclude that the non-radioactive DNA hybridisation assay described is a potentially valuable routine diagnostic test.

Diagnosis of cytomegalovirus infection in cyclosporin-treated renal allograft recipients

The relative merits of antibody response and virus shedding as markers of cytomegalovirus (CMV) infection among cyclosporin-treated renal allograft recipients were analysed. CMV-specific antibody was assayed by IgG-specific radioimmunosorbent test (RIST) and by complement fixation test (CFT). CMV shedding was assayed by virus isolation and by the rapid test immediate early nuclear antigen detection (IENAD). RIST and CFT detected seroconversion in similar numbers of patients, but the former test was the more sensitive when CMV antibody was sought in pretransplant sera to differentiate primary from recurrent infection. IENAD detected or excluded CMV shedding for more urine specimens than virus isolation (462/515 [90%] vs. 366/515 [71%]), but the reverse applied to saliva specimens (33/57 [58%] vs. 54/57 [95%]). The high specificity of IENAD allowed positive results by IENAD to be accepted when virus isolation failed to provide a result. IENAD was, however, less sensitive than virus isolation even when specimens yielding CMV by IENAD, but no result by virus isolation, were included in the analysis (27/44 [61%] vs. 38/44 [86%]). Assays of both antibody response and virus shedding were required to maximise the diagnosis of recurrent CMV infections, but the former assay detected all primary CMV infections. The diagnostic implications of these results are discussed.

Virus infections in bone marrow transplant recipients: a three year prospective study

Over three years 81 consecutive bone marrow transplant recipients (32 allogeneic and 49 autologous) who received prophylaxis with acyclovir, were studied for symptomatic virus infection. Thirty nine infections were documented in a total of 28 patients. Thirty two infections were mild, five were moderately severe, and two were severe. Cytomegalovirus infection occurred in only six allogeneic recipients. Herpes simplex virus and varicella zoster virus infections occurred infrequently. Seven patients who were considered at the time of death to have died due to an infectious cause were studied virologically at necropsy. In only one patient was a virus infection thought to have been the cause of death. Prophylaxis with acyclovir may have influenced the rate and clinical prominence of herpes virus infections. In this study viruses were considered to have had a relatively minor role in causing morbidity and mortality.

Multisite evaluation of a monoclonal antibody reagent (Syva) for rapid diagnosis of cytomegalovirus in the shell vial assay

A pre-cytopathic effect (CPE) monoclonal antibody reagent (Syva Co., Palo Alto, Calif.) was evaluated in four laboratories for the rapid detection of cytomegalovirus (CMV) in shell vial cell cultures at 16 to 24 h and 40 to 48 h postinoculation. Results were compared with those obtained by inoculation of the specimen into conventional tube cell cultures that were examined for the presence of typical CMV CPE and subsequently tested by reaction with the monoclonal antibody reagent in an indirect immunofluorescence test. Of 937 specimens, CMV was positive in 184 (20%). CMV was detected twice as frequently in shell vials only (n = 29) as in conventional tube cell cultures (n = 14). Pre-CPE shell vial assay was 91% sensitive (range, 84 to 98%) and 96% specific (range, 93 to 98%) compared with the detection of CPE in conventional tube cell cultures. Overall, 137 of 166 (83%) and 143 of 166 (86%) of the CMV strains were detected at 16 to 24 h and 40 to 48 h postinoculation, respectively. The Syva reagent produced sensitive and specific results for the rapid detection of CMV infection in shell vial cell cultures and reliably confirmed the presence of the virus as detected by CPE in conventional tube cell cultures.

Comparison of dot-blot DNA hybridisation and immediate early nuclear antigen production in cell culture for the rapid detection of human cytomegalovirus in urine

The sensitivity and specificity of four modes of two assays, immediate early nuclear antigen detection in cell culture (IENAD) at 24 and 48 h post-infection (p.i.) by immunofluorescence using a murine monoclonal antibody, and dot-blot DNA hybridisation with overnight or prolonged autoradiography using the 32P-labelled HindIII J fragment of human cytomegalovirus (HCMV) DNA as probe, were compared for the rapid detection of HCMV in urine. The sensitivity of IENAD was enhanced by low-speed centrifugation at the time of inoculation. DNA hybridisation with overnight autoradiography was significantly less sensitive than IENAD at 24 h p.i. (P less than 0.001), and even with prolonged autoradiography the hybridisation assay was slower and significantly less sensitive than IENAD at 48 h p.i. (P less than 0.02). The specificity of the two assays was virtually 100%. The sensitivity of DNA hybridisation was thus clearly inferior to that of IENAD.