Granulomatous Pneumocystis carinii pneumonia: DNA amplification studies on bronchoscopic alveolar lavage samples

Pneumocystis Pneumonia Presenting as an Enlarging Solitary Pulmonary Nodule

Pneumocystis pneumonia is a life threatening infection that usually presents with diffuse bilateral ground-glass infiltrates in immunocompromised patients. We report a case of a single nodular granulomatous Pneumocystis pneumonia in a male with diffuse large B-cell lymphoma after R-CHOP therapy. He presented with symptoms of productive cough, dyspnea, and right-sided pleuritic chest pain that failed to resolve despite treatment with multiple antibiotics. Chest X-ray revealed right lower lobe atelectasis and CT of chest showed development of 2 cm nodular opacity with ground-glass opacities. Patient underwent bronchoscopy and biopsy that revealed granulomatous inflammation in a background of organizing pneumonia pattern with negative cultures. Respiratory symptoms resolved but the solitary nodular opacity increased in size prompting a surgical wedge resection which revealed granulomatous Pneumocystis pneumonia infection. This case is the third documented report of Pneumocystis pneumonia infection within a solitary pulmonary nodule in an individual with hematologic neoplasm. Although Pneumocystis pneumonia most commonly occurs in patients with HIV/acquired immunodeficiency syndrome and with diffuse infiltrates, the diagnosis should not be overlooked when only a solitary nodule is present.

The role of a nested polymerase chain reaction in the diagnosis of Pneumocystis carinii pneumonia

Aim-To compare the techniques and results of a nested PCR and an immunofluorescence assay (IFA) for the detection of Pneumocystis carinii infection; to consider the role of the nested PCR in the diagnosis of P carinii pneumonia (PCP).Methods-Serial dilutions of two known P carinii positive samples were tested by IFA and PCR to determine their relative sensitivities. Seventy eight respiratory samples (15 from 11 patients with HIV infection/acquired immunodeficiency syndrome (AIDS) and 63 from 42 patients with other forms of immunodeficiency) were tested using both assays, and the costs and technical requirements of each assay were assessed.Results-The PCR had a greater relative sensitivity over the IFA of 2 x 10(1) to 2 x 10(3) fold in a postmortem lung sample and 2 x 10(5) to 2 x 10(6) fold in a bronchoalveolar lavage sample from a patient with PCP. P carinii was detected in all 15 samples from the patients with HIV/AIDS by both IFA and PCR. Of the 63 samples from the patients with immunodeficiencies other than HIV/AIDS, the PCR was more sensitive than IFA.Conclusions-The nested PCR is a more sensitive assay than the IFA. It may be useful in the diagnosis of PCP in patients with immunodeficiencies other than HIV/AIDS. Similarly, PCR may be of benefit for this patient group as less invasive specimens are needed. PCR has an increasing role to play in the diagnosis of PCP in the routine laboratory.

Pneumocystis jirovecii genotypes and granulomatous pneumocystosis

This study describes the initial data concerning molecular typing of Pneumocystis jirovecii in a patient having developed granulomatous Pneumocystis pneumonia (PCP). Three types, B(1)a(3), B(1)a(4), B(1)b(2), were identified. All three had been described in reports concerning patients with common diffuse alveolar PCP. The present data show that identical microorganisms can be involved in both granulomatous PCP and diffuse alveolar PCP and that the pathogenesis of the granulomatous response to P. jirovecii may more likely be related to host factors.

[Granulomatous pneumocystis pneumonia]

INTRODUCTION

Granulomatous pneumocystis pneumonia (PCP) is a rarity whose presentation may be misleading.

CASE REPORT

We report the case of a patient suffering from chronic lymphatic leukaemia presenting with acute respiratory insufficiency, with a fatal outcome, due to granulomatous PCP. Broncho-alveolar lavage (BAL) remained negative and the diagnosis could only be made later by open lung biopsy.

CONCLUSION

Although infrequent, granulomatous PCP should be recognised because in this situation the standard investigation (BAL) may be negative. New, more sensitive, methods of investigation such as the polymerase chain reaction (PCR) may permit earlier diagnosis.

Diagnosis of Pneumocystis carinii pneumonia: immunofluorescence staining, simple PCR or nPCR

OBJECTIVES

to compare immunofluorescence (IF) test, routinely used in the department for the detection of Pnemocystis carinni with simple polymerase chain reaction (PCR) and nested PCR (nPCR) METHODS: Bronchoalveolar lavage (BAL) and induced sputum (IS) specimens from HIV-positive (39), lung transplant ssart transplant (2), and one each from non-Hodgkin's lymphoma, drug addict and a premature baby were screened by IF test, simple PCR and nPCR for the presence of P.carinii.

RESULTS

of the 46 specimens tested, two (4.3%) were positive by IF, 11 (23.9%) by simple PCR and 21 (45.6%) by nPCR. Both simple and nPCR amplified those found positive by IF test. Analysis of the clinical data revealed both IF positive, 10 of the simple PCR and 15 of the nPCR group were strongly suspected of P. carinii pneumonia (PCP). Two specimens, one from a patient where chest X-ray was suggestive of PCP and the other where post-mortem histology revealed the presence of PCP, were negative by IF test.

CONCLUSION

simple PCR detection may be considered for patients where PCP is suggestive clinically and the specimen is negative by IF test.

Molecular methods for epidemiological and diagnostic studies of fungal infections

Over the past two decades there has been a remarkable increase in the incidence of invasive fungal infections. Molecular methods, such as karyotyping, restriction analysis and polymerase chain reaction (PCR), have now been applied to improve our current understanding of the epidemiology of these fungal infections. For example, investigations on nosocomial outbreaks of fungal infections have been greatly facilitated by molecular methods. In addition, the ability to diagnose and identify deep-seated mycoses may be enhanced by the use of molecular techniques. In the near future it is possible that PCR-based methods will supplement, or perhaps even replace, traditional methods for detection of Candida albicans blood stream infections, invasive aspergillosis and Pneumocystis carinii pneumonia. This review examines the progress of molecular biology into the clinical arena of fungal epidemiology, laboratory identification and diagnosis.

Genetic heterogeneity in Pneumocystis carinii: an introduction

Molecular techniques have played an important role in demonstrating a high level of heterogeneity among the different types of organisms which are collectively known as Pneumocystis carinii. Genetic heterogeneity has been observed in Pneumocystis organisms isolated from different host species, suggesting that Pneumocystis infection is host-species specific. On the basis of this genetic divergence a provisional trinomial nomenclature has been adopted, in which different types of Pneumocystis organisms are designated a 'special form'. Multiple special forms of Pneumocystis have been detected in some host species, for example in infected rat and ferret lungs, but not in human lungs. Lower levels of genetic heterogeneity have been observed within each Pneumocystis special form, and in particular in human-derived Pneumocystis. Analysis of the genetic heterogeneity of populations of Pneumocystis is contributing to the understanding of the epidemiology and pathophysiology of this infection.

Detection of Pneumocystis carinii by DNA amplification in human immunodeficiency virus-positive patients

The opportunistic pathogen Pneumocystis carinii (PC) is a frequent cause of a life-threatening pneumonia in human immunodeficiency virus (HIV)-infected individuals and in other immunocompromised hosts. Specimens obtained from 128 bronchoalveolar lavage (BAL) fluid samples from 123 HIV-positive patients with pulmonary disease and undergoing a diagnostic bronchoscopy were evaluated to detect this organism. We have developed a rapid DNA extraction procedure for nested polymerase chain reaction (PCR) using two sets of primers (pAZ102-E, pAZ102-H and P1 = 5'-CTAGGATATAGCTGGTTTTC-3' and P2 = 5'-TCGACTATCTAGCTTATCGC-3'). The results were compared using cytological techniques (direct wet mount, Giemsa, toluidine blue O) and related to the clinical follow-up of patients. The nested PCR had a 91% sensitivity and a 93% specificity. The effect of chemoprophylaxis and the evaluation of the follow-up of patients are discussed. Nested PCR may represent an important additional tool, along with current cytological methods, for the detection of P. carinii; however, at present it cannot replace routine microbiological methods more simple and less expensive.

PCR detection of Pneumocystis carinii in bronchoalveolar lavage specimens: analysis of sensitivity and specificity

Although PCR detection of Pneumocystis carinii DNA has been described, little is known about the sensitivity or specificity of the assay in routine laboratory practice. We had the unique opportunity to use a bronchoalveolar lavage (BAL) specimen bank with samples for which the direct examination results for P. carinii were known. DNA purified from 129 selected specimens was amplified by using the primers described previously (A. E. Wakefield, F. J. Pixley, S. Banerji, K. Sinclair, R. F. Miller, E. R. Moton, and J. M. Hopkin, Mol. Biochem. Parasitol. 43:69-76, 1990). Of the 129 specimens, 37 were positive for P. carinii by direct examination. All 37 specimens were positive for P. carinii by PCR, yielding a 100% sensitivity and 100% negative predictive value for the assay. An additional 23 specimens were repeatedly positive for P. carinii by PCR but were not positive by direct examination. Review of the patient charts for these specimens with discordant results demonstrated that five of the patients were actually positive for P. carinii, as determined by either biopsy or examination of repeat or prior BAL specimens. A response to empiric therapy for P. carinii pneumonia was seen in an additional two patients. Of the remaining specimens, 8 produced no significant isolates other than P. carinii, while 12 contained culture-confirmed significant respiratory pathogens in addition to P. carinii (two fungal, nine bacterial, and one viral pathogen). Cytomegalovirus, which was of unknown significance, was isolated from 16 additional specimens. Overall, the specificity of the PCR assay was 79.3% compared to the results of direct examination. We hypothesized that the apparently poor specificity of the PCR assay was due to the increased sensitivity of the assay compared to that of direct examination. The sensitivity of the PCR assay was therefore assessed with BAL specimens containing P. carinii cysts. Serial dilutions of this preparation were evaluated by direct examination and PCR. PCR was found to be 100-fold more sensitive than direct examination, which detected one to two cysts per amplification. No false-positive results were detected in controls containing no DNA or by using target DNA from various fungal, viral, or bacterial respiratory pathogens. We conclude that PCR detection of P. carinii in BAL specimens is very sensitive and should be considered for patients whose specimens do not yield a diagnosis. The increased sensitivity of the PCR assay may help to identify those patients with low-titer infections who might benefit from directed antibiotic therapy for P. carinii and would otherwise be missed by direct examination alone.

Lung lymphocytes: origin, biological functions, and laboratory techniques for their study in immune-mediated pulmonary disorders

Different types of immunocompetent cells, including T lymphocytes and alveolar macrophages, account for pulmonary host defense. Taking advantage of the availability of the monoclonal antibody technique, cell culture facilities, pure recombinant cytokines, and molecular probes for their genes, in the last few years it has been possible to keenly study the different steps that lead to the compartmentalization of immune response in human lung. Furthermore, the immunological analysis of cells retrieved from bronchoalveolar lavage (BAL) allowed recognition of the importance of immune mechanisms in the evolution of immune-mediated pulmonary disorders. The purpose of this review is to summarize recent advances on the immunologic characterization of lung lymphocytes in health and disease. Following a brief description of the pathways through which the pulmonary lymphoid system contributes to removing potentially harmful inhaled antigenic materials, available laboratory techniques to evaluate the lymphoid component of the pulmonary immune system and their byproducts are discussed. These techniques cover methods for preparing lymphocytes from the BAL fluid and for characterizing lung lymphocytes both in cell suspensions and pulmonary tissue biopsies. Other sections of this review describe the techniques for measuring the immunologic effector functions of lung lymphocytes. We also provide the reader with a flavor of the molecular biology methods used to characterize lymphocytes in the pulmonary microenvironment. The final sections of the review article highlight the pathogenetic role envisaged for lymphoid cells in pulmonary disease states and emphasize the importance of the BAL analysis in the clinical management of the most relevant immune-mediated lung disease.

Open lung biopsy for investigation of acute respiratory episodes in patients with HIV infection and AIDS

BACKGROUND

Open lung biopsy (OLB) is rarely necessary for investigation of HIV positive patients with acute respiratory episodes because of the high yield from fibreoptic bronchoscopy with bronchoalveolar lavage (BAL).

METHODS

A retrospective review of OLB in HIV positive patients admitted to a specialist inpatient unit with acute respiratory symptoms was carried out in order to define clinical indications, diagnostic yield, impact on management, complications and outcome.

RESULTS

OLB was performed in 23 patients; 21 had undergone one or more bronchoscopies with BAL (5 also had negative results from transbronchial biopsy). Indications for OLB were: Group A, 15 patients thought clinically to have pneumocystis pneumonia but not responding to treatment; Group B, 4 patients with focal chest radiographic abnormalities; Group C, 4 patients with diffuse radiographic abnormalities and miscellaneous conditions. Preoperative PaO2 (on air) ranged from 4.4 to 14.5 (mean = 9.5) kPa. The results of OLB were in Group A 5 patients had non specific interstitial pneumonitis (NIP), 1 also had Kaposi's sarcoma, 4 had pneumocystis pneumonia (1 also had bronchiolitis obliterans organising pneumonia [BOOP]), 3 had Kaposi's sarcoma and 1 had BOOP and emphysema, 1 had pulmonary infarction and no infection and 1 had normal lung tissue. In Group B diagnoses were NIP, B cell lymphoma, occult alveolar haemorrhage and Pseudomonas aeruginosa pneumonia with BOOP; In Group C 2 patients had NIP and 2 had pneumocystis pneumonia (1 also had cytomegalovirus pneumonitis). All patients survived surgery and none required mechanical ventilation. OLB results significantly affected management; in Group A inappropriate treatment was discontinued in 11 patients found not to have pneumocystis pneumonia, and alternative therapy was begun in the 4 with pneumocystis and in Groups B and C 6 patients began specific therapy; unnecessary therapy was avoided in one and antimicrobial treatment was modified in one.

CONCLUSIONS

Open lung biopsy in HIV positive patients with focal and diffuse radiographic abnormalities has a high diagnostic yield and low morbidity. This investigation should be considered in those with acute respiratory episodes and negative results from bronchoscopic investigations or who have contra-indications to this procedure.

Rapid simple and nested polymerase chain reaction for the diagnosis of Pneumocystis carinii pneumonia

We have developed a rapid and easy extraction procedure for polymerase chain reaction (PCR) protocols. Using this simplified step, we evaluated the sensitivity and the specificity of a simple PCR using the primers of Wakefield et al, and of a nested PCR, using new internal primers selected by us, in a total of 89 bronochoalveolar lavage (BAL) fluid samples from 43 immunosuppressed patients. In 13 patients, Pneumocystis carinii pneumonia (PCP) was diagnosed by immunofluorescent antibody (IFA) staining performed on BAL cells cytospun on microscope slides. In seven of these patients we attempted to estimate the post-treatment persistence of P. carinii in BAL, by PCR. After a rapid 2-h extraction procedure, simple and nested PCR were positive in all cases of PCP. SImple and nested PCR both had a 100% sensitivity and a 98 and 84% specificity respectively, compared to IFA. After completion of treatment, BAL liquids from asymptomatic patients were no longer positive by both PCR techniques, whereas the BAL fluid of a patient who was still symptomatic was positive by simple and nested PCR. In follow-up BAL fluids of patients with proven PCP, persistence of P. carinii was detected for a longer period by nested PCR than by simple PCR. Simple PCR is a very rapid and sensitive assay for the diagnosis of PCP in BAL fluid and gives clear-cut results in the case of doubtful IFA staining results. Nested PCR seems to improve the sensitivity of the detection of P. carinii in BAL fluid, but the clinical relevance of a positive result remains to be investigated..