Histologically atypical Pneumocystis carinii pneumonia

Exoantigens of Paracoccidioides spp. Promote Proliferation and Modulation of Human and Mouse Pulmonary Fibroblasts

Paracoccidioidomycosis (PCM) is a systemic granulomatous fungal infection caused by thermally dimorphic fungi of the genus Paracoccidioides. Endemic in Latin America, PCM presents with high incidence in Brazil, Colombia, and Venezuela, especially among rural workers. The main clinical types are acute/subacute (AF) form and chronic form (CF). Even after effective antifungal treatment, patients with CF usually present sequelae, such as pulmonary fibrosis. In general, pulmonary fibrosis is associated with dysregulation wound healing and abnormal fibroblast activation. Although fibrogenesis is recognized as an early process in PCM, its mechanisms remain unknown. In the current study, we addressed the role of Paracoccidioides spp. exoantigens in pulmonary fibroblast proliferation and responsiveness. Human pulmonary fibroblasts (MRC-5) and pulmonary fibroblasts isolated from BALB/c mice were cultivated with 2.5, 5, 10, 100, and 250 µg/ml of exoantigens produced from P. brasiliensis (Pb18 and Pb326) and P. lutzii (Pb01, Pb8334, and Pb66) isolates. Purified gp43, the immunodominant protein of P. brasiliensis exoantigens, was also evaluated at concentrations of 5 and 10 µg/ml. After 24 h, proliferation and production of cytokines and growth factors by pulmonary fibroblasts were evaluated. Each exoantigen concentration promoted a different level of interference of the pulmonary fibroblasts. In general, exoantigens induced significant proliferation of both murine and human pulmonary fibroblasts (p < 0.05). All concentrations of exoantigens promoted decreased levels of IL-6 (p < 0.05) and VEGF (p < 0.05) in murine fibroblasts. Interestingly, decreased levels of bFGF (p < 0.05) and increased levels of TGF-β1 (p < 0.05) and pro-collagen I (p < 0.05) were observed in human fibroblasts. The gp43 protein induced increased TGF-β1 production by human cells (p = 0.02). In conclusion, our findings showed for the first time that components of P. brasiliensis and P. lutzii interfered in fibrogenesis by directly acting on the biology of pulmonary fibroblasts.

Organizing pneumonia as a manifestation of Pneumocystis jiroveci immune reconstitution syndrome in HIV-positive patients: report of 2 cases

Organizing pneumonia (OP) is a nonspecific response to various forms of lung injury. Although patients with human immunodeficiency virus (HIV) infection tend to develop several respiratory disorders, especially infections and malignances, the association of HIV infection and OP is unusual. Pneumocystis jiroveci infection is also rarely associated with OP. We describe the radiologic findings in 2 HIV-positive patients who shortly after introduction of highly active antiretroviral therapy, presented with clinical and radiologic deterioration, despite elevation of the CD4 cell count and viral load decrease. In both patients, clinical and radiologic features were consistent with OP and lung biopsy revealed OP associated with P. jiroveci infection. These findings are consistent with immune reconstitution syndrome due to P. jiroveci.

[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.

Pneumocystis carinii pneumonia with an atypical granulomatous response in a patient with chronic lymphocytic leukemia

We have recently seen a patient who developed Pneumocystis carinii pneumonia (PCP) in the course of treatment for chronic lymphocytic leukemia (CLL). This case showed uncommon pathological findings with extensive formation of granulomatous lesions. Despite advanced CLL associated with poor B-cell function, she responded well to anti-PCP treatment. In contrast to B-cell function, the T-cell functions were well preserved in vitro, and the numbers of peripheral CD4- and CD8-positive cells were normal, and T-cell functions were normal. These findings suggest that the production of granulomatous lesions to PCP may have been associated with the patients' immune status, and that it may constitute a good indicator in PCP infection in patients with underlying hematological malignancy.

Bronchiolitis obliterans organizing pneumonia associated with Pneumocystis carinii infection in a liver transplant patient receiving tacrolimus

We report on a case of bronchiolitis obliterans organizing pneumonia (BOOP) associated with Pneumocystis carinii pneumonia (PCP) after liver transplantation and tacrolimus based immunosuppression. Radiologically, bilateral diffuse interstitial shadowing and patchy alveolar infiltrates developed after switching the patient from cyclosporin A to tacrolimus for persistent rejection. Bronchoalveolar lavage (BAL) fluid showed inflammatory cells but no pathogenic organisms. Open lung biopsy revealed BOOP with granulomatous PCP. Thus, even in the case of negative BAL the possibility of an atypical P. carinii infection has to be considered for differential diagnosis of pneumonia in immunocompromised patients after organ transplantation. The combination of BOOP with PCP after liver transplantation and tacrolimus medication has not been reported previously.

HIV-associated respiratory diseases

The lungs of individuals infected with HIV are often affected by opportunistic infections and tumours; over two-thirds of patients have at least one respiratory episode during the course of their disease. Despite the availability of effective prophylaxis, infection with the fungus Pneumocystis carinii remains a common cause of respiratory disease. Bacterial infections, which occur more frequently in HIV-infected persons than in the general population, and tuberculosis are increasing causes of morbidity and mortality. Kaposi's sarcoma, the commonest HIV-associated malignancy, may affect the lungs in addition to the skin. Pulmonary involvement by non-Hodgkin lymphoma is common in those with disseminated disease.

Interstitial pneumonitis in patients infected with the human immunodeficiency virus

BACKGROUND

A study was performed to identify the clinical, radiographic, and histopathological features of interstitial pneumonitis in patients infected with the human immunodeficiency virus.

METHODS

A retrospective review was made of the case notes, chest radiographs, and histopathological results of seven HIV-1 antibody positive patients with symptomatic diffuse pulmonary disease and a pathological diagnosis of non-specific interstitial pneumonitis.

RESULTS

All patients had dyspnoea, with or without cough, and chest radiographs showing diffuse infiltrates. The arterial oxygen tension ranged widely from 5.9 to 13.1 kPa. The initial clinical diagnosis was Pneumocystis carinii pneumonia in most cases. The pathological diagnosis was made by transbronchial biopsy in one case and by open lung biopsy in six cases. The interstitial pneumonitis consisted of a patchy lymphocytic infiltrate composed of B cells in focal aggregates and T cells in a more diffuse distribution. The T cell population was a mixture of CD4+ and CD8+ cells. The histological findings contrast with the more extensive infiltrate of predominantly CD8+ lymphocytes seen in HIV-associated lymphocytic interstitial pneumonitis which occurs mainly in children. The condition ran a subacute course. Three patients spontaneously improved and three improved with steroid therapy. Long term survival was less than three years, the prognosis being determined by other infective or neoplastic complications.

CONCLUSIONS

Non-specific interstitial pneumonitis usually presents with an illness resembling Pneumocystis carinii pneumonia but occurs when the CD4 and total lymphocyte counts are still preserved. The pneumonitis resolves spontaneously or responds to steroids, and does not itself lead directly to the patient's death. It does, however, appear to mark a downturn in the course of HIV infection.

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.

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

Three HIV positive subjects presented with symptoms and radiographic changes suggestive of Pneumocystis carinii pneumonia. Methenamine silver staining of bronchoscopic alveolar lavage (BAL) fluid was negative (from one sample in one patient and two samples in the other two patients). Open lung biopsy was performed because of uncertain clinical progress and diagnosis; all three patients were found to have multiple pulmonary granulomata encasing numerous P carinii organisms. DNA amplification, using P carinii specific oligonucleotides, was performed on stored bronchoscopic BAL samples. P carinii specific amplification product was detected by ethidium bromide staining after electrophoretic separation on agarose gel in one case, and by the more sensitive technique of oligohybridisation in all three cases. In granulomatous P carinii pneumonia organisms are rarely identified in bronchoscopic alveolar lavage samples using histochemical staining, but are detectable by DNA amplification, although not at levels which can be readily distinguished from low, subclinical infection.