The role of alveolar macrophages in Pneumocystis carinii degradation and clearance from the lung

Although studies indicate that alveolar macrophages participate in host defense against Pneumocystis carinii, their role in organism degradation and clearance from the lung has not yet been established. We, therefore, quantified the uptake and degradation of 35S-labeled P. carinii by cultured macrophages, demonstrating significant degradation of P. carinii over 6 h. We further evaluated the role of macrophages in elimination of P. carinii from the living host. Rats received either intratracheal PBS, liposomal PBS (L-PBS), or liposomal dichloromethylene diphosphonate (L-Cl2MDP), a preparation which leads to selective depletion of macrophages. Over 72 h, L-Cl2MDP-treated animals had loss of > 85% of their alveolar macrophages. In contrast, L-PBS-treated rats had cellular differentials identical to rats receiving PBS. Macrophage-depleted rats and controls were next inoculated with P. carinii and organism clearance was determined after 24 h. P. carinii elimination was evaluated with both cyst counts and an ELISA directed against glycoprotein A (gpA), the major antigen of P. carinii. Both assays indicated that macrophage-depleted rats had substantial inpairment of P. carinii clearance compared to L-PBS- or PBS-treated rats. These data provide the first direct evidence that macrophages mediate elimination of P. carinii from the living host.     

Granulomatous Pneumocystis carinii in AIDS patients

Seven cases of Pneumocystis carinii pneumonia with granulomatous reaction in patients infected with the human immunodeficiency virus are described. The patients were all adult men between the ages of 32 and 45 years, with different high-risk factors. Clinically, all the patients presented with a history of non-productive cough and shortness of breath. Two of the patients had a past history of pulmonary pneumocystosis. Radiologically, six patients had diffuse pulmonary infiltrates and one nodular pulmonary infiltrate. Transbronchial lung biopsies were obtained in four patients and open lung biopsies in three. All presented a predominant granulomatous reaction composed of epithelioid and multinucleated giant cells. Several other special stains to detect the presence of other microorganisms to account for the granulomatous reaction were negative.     

Reduced binding and phagocytosis of Pneumocystis carinii by alveolar macrophages from persons infected with HIV-1 correlates with mannose receptor downregulation

The macrophage mannose receptor, a pattern recognition molecule and component of innate immunity, mediates binding and phagocytosis of Pneumocystis carinii and likely represents an important clearance mechanism in the lungs of immunocompetent hosts. The purpose of this study was to examine the ability of alveolar macrophages from HIV-infected individuals to bind and phagocytose P. carinii, and to investigate the role of the macrophage mannose receptor in mediating this interaction. Compared with healthy individuals, alveolar macrophage phagocytosis of P. carinii from HIV+ persons was reduced up to 74% (P = 0.02), primarily reflecting a reduction in the number of organisms associated with each macrophage (P = 0.019). Furthermore, macrophages from HIV+ individuals demonstrated up to an 80% (P < 0.05) reduction in mannose receptor surface expression and endocytosis. Mannose receptor affinity was unaltered, and mRNA levels were modestly reduced (P < 0.05). Cells from HIV+ individuals with CD4(+) counts < 200 cells/mm3 (representing individuals at high clinical risk for P. carinii pneumonia) demonstrated the lowest levels of P. carinii phagocytosis and mannose receptor endocytosis. In vitro HIV infection of alveolar macrophages from healthy individuals reduced mannose receptor endocytosis to 53.2% (P < 0.05) and P. carinii binding and phagocytosis to 67.4% (P < 0.05) of control. Our studies suggest that HIV infection may alter innate immunity in the lungs, and that impaired alveolar macrophage mannose receptor-mediated binding and phagocytosis of P. carinii may contribute to the susceptibility of HIV-infected individuals to this opportunistic pulmonary pathogen.     

Pneumocystis carinii meningoradiculitis in a patient with AIDS

Pneumocystis carinii is a common opportunistic pathogen in patients infected with the human immunodeficiency virus (HIV). Pneumocystis carinii pneumonia is common, while extrapulmonary infections with Pneumocystis carinii have been reported sparingly. The clinical features are frequently nonspecific. The detection of Pneumocystis carinii in cerebrospinal fluid (CSF) has not been reported thus far. In this report, an unusual case of Pneumocystis carinii meningoradiculitis in an HIV-infected patient who had previously received primary prophylaxis with trimethoprim-sulfamethoxazole is presented.     

Uptake and metabolism of L-serine by Pneumocystis carinii carinii

Serine is an important amino acid that is utilized in the biosyntheses of proteins and lipids. It is directly incorporated into the head group of phosphatidylserine, which in turn can be converted to other phospholipids. Also, it is required for the formation of long chain bases, precursors of sphingolipids. Uptake and incorporation of radiolabeled serine into both lipids and acid-precipitable material were demonstrated in Pneumocystis carinii carinii organism preparations freshly isolated from infected rat lungs. Radioactivity in proteins was about double that observed in lipids. Liquid scintillation spectrometry of metabolically radiolabeled lipids separated by thin-layer chromatography showed 53% of the total radioactivity were in phosphatidylserine, 12% in phosphatidylethanolamine, 24% in ceramides, and 11% in long chain bases and other compounds. Four long chain bases were detected by thin-layer chromatography in hydrolyzed P. carinii ceramides metabolically labeled with radioactive serine. Phytosphingosine and dihydrosphingosine were tentatively identified by their migrations on thin-layer plates. Radiolabeled ethanolamine was incorporated into P. carinii phosphatidylethanolamine, but relatively low incorporation of radiolabeled choline into phosphatidylcholine occurred. The observations made in this study indicated that P. carinii has the biosynthetic capacity to metabolize phospholipid head groups and to de novo synthesize sphingolipids. L-Cycloserine and beta-Cl-D-alanine, inhibitors of long chain base synthesis, reduced the incorporation of serine into P. carinii long chain bases and ceramides, which supported the conclusion that the pathogen synthesizes sphingolipids.     

Mediastinal and hilar lymphadenopathy due to Pneumocystis carinii infection in AIDS patients: CT features

Smoking, alcohol, and familial background are considered major cofactors in the cause of oral cancer. The purpose of the present study was to determine the relationship between ethnic origin and oral cancer in the Israeli Jewish Population. Data were collected during the years 1970 to 1980 from 342 dental records of patients in Israeli hospitals. Results showed a male/female ratio of 2:1. Of 264 patients with clearly determined ethnic origin, 72% were Ashkenazi, 15% Sephardi, and 13% Eastern ethnic origin. The relative prevalence showed that the risk of the Ashkenazi group to develop oral cancer was at least twice as high as the other two ethnic groups. The increase in occurrence of oral cancer with age in each ethnic group was highly significant (p < 0.001). The most common type of malignancy was squamous cell carcinoma (95%) with 99% of this malignancy occurring in patients in their sixth and seventh decade. A significant (p < 0.02) relationship between site of involvement and ethnic origin was also noted. The tongue was the leading site in the Ashkenazi and Sephardi groups, whereas the lip and alveolar ridges were the most affected sites in the Eastern ethnic group.     

Clindamycin and primaquine therapy for mild-to-moderate episodes of Pneumocystis carinii pneumonia in patients with AIDS: AIDS Clinical Trials Group 044

The objective of this prospective, noncomparative study was to assess the safety and efficacy of clindamycin and primaquine therapy for mild-to-moderate pneumocystis pneumonia (defined as a difference of < 40 mm Hg between the alveolar and the arterial oxygen determinations) in patients with AIDS. In the first part of the study, 22 patients were treated with iv clindamycin (900 mg every 8 hours) for the first 10 days, and then their therapy was switched to oral clindamycin (450 mg every 6 hours) for an additional 11 days. In the second part of the study, 38 patients were treated entirely with oral clindamycin (600 mg every 8 hours). All patients were treated with oral primaquine base (30 mg once daily). Fifty-five (92%) of 60 patients responded to the study treatment. Forty-six (77%) of 60 patients completed a full course of therapy. Of the nine patients with treatment-limiting toxic effects, four had only a mild rash. This study indicates that the combination of clindamycin and primaquine is an effective and well-tolerated therapy for mild-to-moderate pneumocystis pneumonia in patients with AIDS. Entirely oral therapy appears to be as effective as initial therapy with iv clindamycin.     

Fulminant Pneumocystis carinii pneumonia in 4 patients with dermatomyositis

Between 1989 and 1996, 4 cases of Pneumocystis carinii pneumonia (PCP) were observed in patients seronegative for the human immunodeficiency virus who were receiving corticosteroid therapy for dermatomyositis in our institution. These cases were considered unusual in light of the short delay of their onset after initiation of immunosuppressive therapy and their fulminant course: 3 of these patients died of PCP occurring during the first month of treatment with prednisone. In all 4 patients lymphopenia was observed before the initiation of corticosteroid treatment and low CD4 and CD8 cell counts were evident at the time of PCP. These observations support the view of an increase in both the severity and incidence of PCP in patients without human immunodeficiency virus infection and question the need for a primary prophylaxis in patients with connective tissue diseases receiving high-dose corticosteroid therapy.     

Effects of phagocytosis of mineral dusts on elastase secretion by alveolar and peritoneal exudative macrophages

Peritoneal exudative and alveolar macrophages secrete a nonlysosomal neutral protease which hydrolyses particulate elastin suspended in agar. A variety of particles were administered to macrophages in culture to determine their effect on the secretion of this elastase. Among the particles were silica, two types of asbestos, and kaolinite--all minerals implicated in the production of lung diseases accompanied by reorganization of connective tissue. Peritoneal exudative macrophages increased their secretion of elastase in response to phagocytosis of all the pathogenic particles examined. The increase, however, was not as great as that observed with latex beads, the most inert particles. Although these same particle types were phagocytized by cultured alveolar macrophages, none of them augmented the elastase secretion of alveolar macrophages above the resting level, and many decreased it. The lessened stimulation of elastase secretion by peritoneal macrophages and the decrease in the resting level of elastase secretion of alveolar macrophages probably reflect the cytotoxicity of the particles.     

Atypical Pneumocystis carinii infection in AIDS: massive cervical lymphadenitis and fever of unknown origin

Pulmonary Pneumocystis carinii infections are relatively common in patients with the acquired immunodeficiency syndrome (AIDS). Extrapulmonary pneumocystis is a less common manifestation, particularly when it occurs without concurrent Pneumocystis carinii pneumonia. Disseminated pneumocystis is most commonly found in lymph nodes, the liver, and the spleen and may result in nonspecific debilitating illness, which is often overlooked in the absence of pulmonary symptoms. We present the case of an AIDS patient who had massive cervical pneumocystis lymphadenitis and minimal pulmonary infiltrates of undetermined etiology and a clinical picture of severe wasting and fever of unknown origin.     

A controlled trial of dapsone versus pyrimethamine-sulfadoxine for primary prophylaxis of Pneumocystis carinii pneumonia and toxoplasmosis in patients with AIDS

Pneumocystis carinii pneumonia (PCP) is the most common opportunistic human immunodeficiency virus (HIV)-related infection, occurring in 85% of HIV infected patients without prophylaxis. Preventive treatment is required when CD4 cell count falls below 200 cells per cubic millimeter. Cotrimoxazole has been shown to be highly effective but alternative drug regimens are often necessary because of the frequent drug hypersensitivity exhibited by HIV infected patients. The aim of this prospective, open, randomized, one-site study, involving HIV-infected patients with a CD4 cell count below 200/mm3, or a percentage under 20%, randomly assigned to receive either dapsone 50 mg daily or Fansidar one tablet weekly, was to compare the efficacy and safety of these drugs in the primary prophylaxis of PCP. Both dapsone and Fansidar appear to be safe and effective alternative agents for the prevention of PCP. Their role in Toxoplasma gondii prophylaxis requires further evaluation.     

The effect of endotoxin on in vivo rat alveolar macrophage phagocytosis

This study was performed to explore whether alveolar macrophage (AM) phagocytosis would be impaired during endotoxemia. Therefore, we characterized in vivo AM phagocytic function in rats following either intravenous (i.v.) or intratracheal (i.t.) administration of lipopolysaccharide (LPS). The i.v. administration of LPS to rats at dosages of 0, 1, 2, and 5 mg/kg showed that increasing LPS doses were significantly associated with increased AM phagocytosis of 198Au colloid (P < .01), decreased recovery of AMs in bronchoalveolar lavage (BAL) (P = .017), no significant differences in neutrophil recovery by lavage (P = .15), or in the concentration of albumin in BAL (P = .14). Across the dosages of LPS administered i.t. (i.e., 0, 1, 5, and 10 mg/kg), there was no difference in AM phagocytosis (P = .29), a significant decrease in AM recovery (P = .002), a significant increase in neutrophil number (P = .01), and little effect on the concentration of albumin (P = .06). Thus, we found that the administration of endotoxin to rats did not impair in vivo AM phagocytic function. In fact, our findings suggest that the i.v. administration of LPS may increase AM phagocytosis of 198Au.     

Diagnosis of pneumocystis carinii pneumonia in AIDS patients

BACKGROUND: Based on the changing disease pattern of human immunodeficiency virus (HIV) associated pulmonary complications we conducted a prospective study in order to compare the value of laboratory tests in patients with Pneumocystis (P.) carinii pneumonia (PCP) and other pulmonary complications and of different identification methods of P. carinii in bronchoalveolar lavage fluid (BALF) in PCP patients. PATIENTS AND METHODS: In 217 HIV-1-infected patients we evaluated the following parameters: platelets, serum lactat dehydrogenase (LDH), total serum protein (TP), hemoglobin (Hb), and CD4+ and CD8+ T-lymphocyte count. P. carinii was identified in BALF by May Grünwald Giemsa stain (MGG), direct immunofluorescence test (DIFT), and polymerase chain reaction (PCR). We correlated these parameters in patients with a presumptive diagnosis of PCP and compared them with those of patients suffering from other pulmonary complications. RESULTS: All patients underwent bronchoscopy. 55 patients (25.3%) had a presumptive diagnosis of PCP. The sensitivity values of MGG stain, DIFT, and PCR differed considerably (79.1%, 56.1%, and 65.9%, respectively), but specificity values did not (99.2%, 97.3%, and 98.2%, respectively) as well as accuracy values (93.8%, 86.2%, and 89.7%, respectively). The mean values of platelets, of LDH, and of total serum protein of PCP patients and those of patients with other pulmonary diseases differed statistically significant as well as the mean values of these parameters of PCP patients and those of patients with bacterial pneumonia. Logistic-regression analysis revealed the number of platelets and the amount of total serum protein as independent, significant prognostic factors. Moreover, each PCP patient had a CD4+ T-lymphocyte count of less than 200 cells/mm3 blood. The CD4/CD8 ratio of PCP patients was statistically significant lower than that of patients with bacterial pneumonia. CONCLUSIONS: A detection of P. carinii in BALF is inevitable for a definitive diagnosis of a PCP. The most efficient identification method in this case is the MGG stain. Platelets, total serum protein, and CD4+ T-lymphocyte count should be included into the criteria for the presumptive diagnosis of PCP.     

Radiographic findings in Pneumocystis carinii pneumonia and its complications in HIV patients

Despite their increasing representation in the population, little is known about the neuropsychological test performance of the oldest old, particularly those who live in residential settings. Limited published data and clinical experience suggest that this group is more likely to perform in the impaired range on standardized tests when cut-offs developed with younger groups are used. We examined the Dementia Rating Scale (DRS) performance of 82 nondemented nursing home residents, aged 80 to 99, with a mean education level of 11 years. Using published norms and cutoffs, a large percentage of this sample performed in the impaired range, particularly on the initiation and conceptualization subtests and on the total score. Education, but not age, was significantly related to performance in this sample. Percentages of patients misclassified were substantial in all groups, but were higher in those with less than 13 years of education. Using a lower total-score cutoff of 110 reduced the percentage of misclassifications markedly. We recommend the development and use of revised cutoff scores for the evaluation of very elderly nursing home residents.     

Pneumocystis carinii and parasitic infections in transplantation

Pneumocystis carinii remains an important pathogen in organ transplantation. New therapeutic options have been developed for the prevention and treatment of P. carinii pneumonia. Parasitic infections are recognized more frequently in potential organ donors or recipients as travel and technology for transplantation extend into endemic regions. Parasites important to transplantation are largely those that can replicate in humans and that cause infection, the intensity of which is regulated by immune mechanisms in the normal host. The spectrum of parasitic infections is likely to increase with improved diagnostic methods, expansion of intestinal transplantation, and xenotransplantation.     

Pneumocystis carinii infections in patients with neoplasms and AIDS--clinical-pathologic changes in the lungs

Administration of 0.5 or 1% lyophilized green tea (5 or 10 mg tea solids per ml, respectively) as the sole source of drinking fluid to female Long-Evans rats for 18 days stimulated liver microsomal glucuronidation of estrone, estradiol and 4-nitrophenol by 30-37%, 15-27% and 26-60%, respectively. Oral administration of 0.5% lyophilized green tea to female CD-1 mice for 18 days stimulated liver microsomal glucuronidation of estrone, estradiol and 4-nitrophenol by 33-37%, 12-22% and 172-191%, respectively. The in vitro addition of a green tea polyphenol mixture, a black tea polyphenol mixture or (-)-epigallocatechin gallate inhibited rat liver microsomal glucuronidation of estrone and estradiol in a concentration-dependent manner and their IC50 values for inhibition of estrogen metabolism were approximately 12.5, 50 and 10 microg/ml, respectively. Enzyme kinetic analysis indicates that the inhibition of estrone glucuronidation by 10 microM (-)-epigallocatechin gallate was competitive while inhibition by 50 microM (-)-epigallocatechin gallate was noncompetitive. Similarly, several flavonoids (naringenin, hesperetin, kaempferol, quercetin, rutin, flavone, alpha-naphthoflavone and beta-naphthoflavone) also inhibited rat liver microsomal glucuronidation of estrone and estradiol to varying degrees. Naringenin and hesperetin displayed the strongest inhibitory effects (IC50 value of approximately 25 microM). These two hydroxylated flavonoids had a competitive mechanism of enzyme inhibition for estrone glucuronidation at a 10 microM inhibitor concentration and a predominantly noncompetitive mechanism of inhibition at a 50 microM inhibitor concentration.     

DNA sequences identical to Pneumocystis carinii f. sp. carinii and Pneumocystis carinii f. sp. hominis in samples of air spora

Samples of ambient air collected with three different types of spore traps in a rural location were examined for the presence of Pneumocystis carinii by screening for P. carinii-specific DNA sequences by DNA amplification. Eleven spore trap samples were analyzed by nested PCR, using oligonucleotide primers designed for the gene encoding the mitochondrial large subunit rRNA of P. carinii f. sp. carinii and P. carinii f. sp. hominis. The samples were collected over a 3-year period during the months of May to September, with a range of sampling times from 9 to 240 h. One air sample from an animal facility housing P. carinii-infected rats was also examined. P. carinii-specific amplification products were obtained from samples from each of the spore traps. The amplification products from eight air samples were cloned and sequenced. The majority of the recombinants from each of these samples had sequences identical to those of P. carinii f. sp. carinii and P. carinii f. sp. hominis, and a number of clones had single-base differences. These data suggest that sequences identical to those of P. carinii f. sp. carinii and P. carinii f. sp. hominis can be detected in samples of air collected in a rural location and that P. carinii may be a component of the air spora of rural Oxfordshire.