Investigation of the simian polyomavirus SV40 as a potential causative agent of human neurological disorders in AIDS patients

Neurological diseases and a variety of neoplasms frequently occur in AIDS patients. Human JC and BK polyomaviruses have been associated with neurological disorders in such patients. SV40 polyomavirus sequences have been detected in human brain tumours, other neoplasms and normal tissues. JCV, BKV and SV40 DNA sequences were investigated in cerebrospinal fluid (CSF) samples from 12 AIDS patients affected by different neurological disorders, by PCR assay and filter hybridisation with specific internal oligoprobes, and DNA sequencing. Three of the 12 CSF samples were positive for JCV (one sample) or SV40 (one) DNA, or both (one). No sample was positive for BKV DNA. JCV- and SV40-specific genomic regions were confirmed by DNA sequencing. CSF samples from the two patients diagnosed clinically as having progressive multifocal leukoencephalopathy (PML) contained either JCV (one sample) or SV40 (one) DNA. The CSF found to contain both JCV and SV40 DNA originated from a patient with a cerebral mass lesion of unknown aetiology. These results suggest that SV40 may be involved in the aetiology of PML in AIDS patients, and raise the possibility that SV40 and JCV may act synergically in vivo to enhance their pathogenicity.

Evidence of cerebrospinal fluid free kappa light chains in AIDS patients with Toxoplasma gondii encephalitis

Cerebrospinal fluid (CSF) free light chains of kappa or lambda (FLC kappa/lambda) type were investigated by affinity mediated blotting technique (AMI) and ELISA in 28 patients of which nine with AIDS and Toxoplasma gondii encephalitis (AIDS, TE), 11 with AIDS with or without other CNS AIDS-related opportunistic infections (non-TE AIDS) and eight control patients with or without inflammatory neurological disorders (control group). CSF restricted oligoclonal FLC bands either of k or lambda isotype or both were found by AMI in 18 (90%) out of 20 AIDS patients, while a CSF pattern predominantly characterized by FkappaLC rather than FlambdaLC was observed in eight (88.8%) out of nine TE patients. No FLC components were detected in the matched sera of TE or non-TE AIDS patients or in the CSF and sera from control group. The anti-parasite-specific FkappaLC CSF/serum mean levels and the T. gondii-specific FkappaLC index values were found by ELISA to be significantly more elevated in TE patients when compared to non-TE AIDS or control group. These findings suggest that the increased production of T. gondii-specific FkappaLC could provide insights into pathogenesis of reactivated TE in immunocompromised patients and may have important diagnostic usefulness.

Evidence of increased carriage of Corynebacterium spp. in healthy individuals with low antibody titres against diphtheria toxoid

This study evaluated whether a correlation exists between carriage of corynebacteria and the lack of immunity to diphtheria toxoid. Samples of both nasal and pharyngeal secretions were taken from 500 apparently healthy subjects of both sexes and of all ages and inoculated onto Tinsdale's medium. A serum sample was also taken for ELISA test to determine the titre of diphtheria toxin antibodies. None of the subjects carried Corynebacterium diphtheriae. Ninety-three strains of Corynebacterium spp. were isolated from 93 subjects and 86 of these were classified to species or group level by biochemical tests. C. xerosis was the most common (25.8%) followed by C. pseudodiphthericum (16.1%), C. jeikeium and C. striatum (both 10.8%), and C. urealyticum (9.7%). Three other species accounted for approximately 20% of strains and seven were unclassified as biochemically atypical corynebacteria. Non-protective antibodies to diphtheria toxin were found in 80 of the 93 subjects and a strong statistical association was demonstrated between carriage of corynebacteria and non-protective levels of anti-toxin antibodies. The remaining 13 subjects had protective levels of antitoxin antibodies. In contrast, only 45 of the 407 non-colonized subjects had non-protective antitoxin titres. The prevalence of carriage increased with age among males as did the percentage of non-protected subjects. The prevalence of female carriers of corynebacteria was significantly lower. Serum samples from 12 subjects with different antibody titres to diphtheria toxoid reacted to varying degrees with whole-cell lysates of a number of species of corynebacteria. The results suggest that a causal relationship may exist between nasopharyngeal carriage of corynebacteria and a low anti-diphtheria toxin immune response.

Human auricolar myiasis caused by Wohlfartia magnifica (Schiner) (Diptera: Sarcophagidae): first case found in Sardinia

The authors report a case of myiasis of the middle ear caused by Wohlfartia magnifica Schiner (Diptera: Sarcophagidae). The entomological aspects, the clinical epidemiological characteristics and the therapeutic solutions of this disease are evaluated. In particular, they underline the rarity of myiasis both because of the aetiologic agent and the anatomical site. The therapeutic aspects are also reported and discussed.

Management of a case of chloroquine-resistant falciparum malaria in a pregnant woman with glucose-6-phosphate dehydrogenase (G6PD) deficiency

The available antimalarial drugs for the treatment of Plasmodium falciparum malaria during pregnancy are potentially toxic, especially in the presence of red blood cells (RBC) defects. We describe a case of chloroquine-resistant malaria by P. falciparum in a pregnant woman with glucose-6-phosphate dehydrogenase (G6PD) deficiency successfully treated with pyrimethamine followed by mefloquine administration. The susceptibility of P. falciparum to chloroquine and mefloquine was assessed by an in vitro test before treatment. Pyrimethamine and mefloquine were administered at the 18th and 22nd week of pregnancy, respectively. Mefloquine concentrations were monitored in the mother's blood at 2, 4, 8, 12, 24 and 48 hr after the administration to define effective blood-drug concentrations. Blood smear examination was negative after 48 hr post mefloquine treatment. No histologic lesions of the placenta were observed. The newborn presented normal clinical parameters. The administration of pyrimethamine prevented massive placental infection, thus permitting the fetus to achieve suitable gestational age for further treatment with mefloquine to eradicate P. falciparum malaria without deleterious effects to the newborn. Subsequent studies could contribute to define safe administration of mefloquine in G6PD-deficient pregnant woman.

Decreased production of local immunoglobulin A to Pneumocystis carinii in bronchoalveolar lavage fluid from human immunodeficiency virus-positive patients

An enzyme-linked immunosorbent assay and a Western blot analysis were developed to study the antibody response to Pneumocystis carinii in serum and bronchoalveolar lavage fluid from 27 human immunodeficiency virus 27 (HIV)-infected patients with P. carinii pneumonia (Pcp), 32 patients without Pcp, and 51 HIV-negative controls. Urea was used for the correct dilution of epithelial lining fluid, and albumin was used to evaluate transudation from plasma for the assessment of local production of antibodies to P. carinii. By contrast with those of immunoglobulin G (IgG), IgA responses to P. carinii were increased in serum from HIV-positive patients compared to negative controls. Local production of antibodies to P. carinii, especially IgA, was decreased in patients with Pcp. In a study of 10 patients of each group, IgG and IgA responses to gp116 from P. carinii were lower in patients with Pcp than in other groups. These results suggest that, in addition to alveolar macrophages, local antibodies may play a role in host defense against P. carinii.

Sterols of Pneumocystis carinii hominis organisms isolated from human lungs

The opportunistic pathogen Pneumocystis carinii causes pneumonia (P. carinii pneumonia, or PCP) in immunocompromised individuals such as AIDS patients. Rat-derived P. carinii carinii organisms have distinct sterols which are not synthesized by mammals and not found in other microbes infecting mammalian lungs. The dominant sterol present in the organism is cholesterol (which is believed to be scavenged from the host), but other sterols in P. carinii carinii have an alkyl group at C-24 of the sterol side chain (C(28) and C(29) 24-alkylsterols) and a double bond at C-7 of the nucleus. Recently, pneumocysterol (C(32)), which is essentially lanosterol with a C-24 ethylidene group, was detected in lipids extracted from a formalin-fixed human P. carinii-infected lung, and its structures were elucidated by gas-liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectrometry in conjunction with analyses of chemically synthesized authentic standards. The sterol composition of isolated P. carinii hominis organisms has yet to be reported. If P. carinii from animal models is to be used for identifying potential drug targets and for developing chemotherapeutic approaches to clear human infections, it is important to determine whether the 24-alkylsterols of organisms found in rats are also present in organisms in humans. In the present study, sterol analyses of P. carinii hominis organisms isolated from cryopreserved human P. carinii-infected lungs and from bronchoalveolar lavage fluid were performed. Several of the same distinct sterols (e.g., fungisterol and methylcholest-7-ene-3beta-ol) previously identified in P. carinii carinii were also present in organisms isolated from human specimens. Pneumocysterol was detected in only some of the samples.

Structural changes in rat Pneumocystis carinii surface antigens after terbinafine administration in experimental P. carinii pneumonia

Terbinafine is a synthetic antifungal agent which has recently been found to be highly effective against Pneumocystis carinii. This study evaluated the efficacy of terbinafine on rat P. carinii antigenic profile and the immune response by Western blot analysis, in comparison with atovaquone and co-trimoxazole in rats with pneumocystosis. Terbinafine was shown to target two specific major antigens, particularly those of 116 and 35-40 kDa. Antibodies reactive against these moieties were found in all rats treated with atovaquone and co-trimoxazole, but not in those treated with terbinafine. These surface antigen modifications could be related to disease severity and could provide additional information for monitoring the efficacy of this treatment.

Advanced laboratory techniques for diagnosing Toxoplasma gondii encephalitis in AIDS patients: significance of intrathecal production and comparison with PCR and ECL-western blotting

The polymerase chain reaction (PCR) for detection of cerebral spinal fluid (CSF) Toxoplasma gondii DNA was combined with the study of intrathecal antibody synthesis by antibody specific index calculation (ASI) and the detection of specific oligoclonal IgG bands (OCB) by affinity mediated immunoblotting (AMI) in 11 AIDS patients with T. gondii encephalitis (TE) and in 20 control patients with or without neurological disorders. Enhanced chemiluminescence (ECL) western-blot technique was employed to evaluate the antigenic specificity of CSF-IgG towards individual T. gondii antigens. PCR was positive in all TE patients which displayed brain-derived or blood-derived specific OCB, even when comparative ASI failed. Four TE patients had a unique anti-T. gondii OCB restricted to the CSF and a strong antibody response toward the 29 kDa band by ECL western blot. This response could be an important marker to discriminate TE from other opportunistic central nervous system (CNS) infections in the course of AIDS.

Use of PCR to detect mycoplasma DNA in respiratory tract specimens from adult HIV-positive patients

The polymerase chain reaction (PCR) was evaluated retrospectively for its ability to detect Ureaplasma urealyticum and Mycoplasma spp. in respiratory tract specimens obtained from adult patients with AIDS. Mycoplasma DNA was detected in specimens from 12 of 84 patients. Of the 107 specimens tested, 13 and seven positive PCR results were obtained with the genus- and species-specific oligonucleotide primers used, respectively, in two different steps. With the latter, one sample was positive for U. urealyticum plus M. hominis, another for M. fermentans plus M. salivarium, and five others were positive for M. salivarium. The unexpected detection of U. urealyticum DNA in respiratory secretions from an adult AIDS patient suggested that this urogenital mycoplasma could have a role in determining or exacerbating respiratory tract infections in the HIV-positive population, but that its low rate of isolation could be related to the frequent failure of methods used currently to detect mycoplasmas.

Detection of Pneumocystis carinii among children with chronic respiratory disorders in the absence of HIV infection and immunodeficiency

A nested polymerase chain reaction (PCR) assay was investigated for detection of Pneumocystis carinii in 96 respiratory tract specimens from 82 children, of whom 28 were immunocompetent but with chronic lung disorders (CLD), eight had AIDS and P. carinii pneumonia (PCP), 16 had AIDS but no respiratory symptoms, and 30 were healthy immunocompetent children. Gomori methenamine silver stain (GMS) and indirect immunofluorescence assay (IFA) were performed in parallel. Of 36 specimens from children with CLD, 12 were P. carinii PCR-positive compared to 10 positive by GMS-IFA. Of eight specimens from children with AIDS and PCP, seven were P. carinii-positive by PCR and six by GMS-IFA, and of 22 specimens from HIV-positive children without respiratory symptoms, two were positive by PCR and none by GMS-IFA. P. carinii DNA was also detected by PCR in blood samples from four children with P. carinii-positive nasopharyngeal aspirates. Specimens from healthy children were negative for P. carinii by both PCR and GMS-IFA. Of the seven children with CLD, who were P. carinii-positive, two had clinical and microbiological improvement with co-trimoxazole treatment, two improved initially but relapsed, and one had P. carinii cysts persistently in follow-up specimens despite co-trimoxazole treatment. These results suggest an association between P. carinii and exacerbations of CLD in childhood, in the absence of HIV infection or other immunodeficiency syndromes.

Cytomegalovirus in bronchoalveolar lavage specimens from patients with AIDS: comparison with antigenaemia and viraemia

Pulmonary infection with cytomegalovirus (CMV) is a well recognised complication of AIDS. It is often possible to detect CMV-infected cells in bronchoalveolar lavage (BAL) specimens with monoclonal antibodies, but the clinical significance of their presence remains unclear. To investigate this, 24 AIDS patients were tested for CMV antigenaemia and viraemia, in addition to CMV detection in BAL. CMV was detected in the BAL of nine patients (38%), five with clinical and laboratory evidence of pulmonary infection and four without pulmonary involvement. Blood samples positive for CMV antigen were observed in two patients with CMV-positive BAL specimens and, in both cases, antigenaemia resolved without therapy. No case of viraemia was detected. Pneumocystis carinii was detected concomitantly with CMV in the BAL of four of the patients with pulmonary involvement and in one without signs of pulmonary infection. These data suggest that CMV-positive BAL results are of limited significance in the diagnosis of CMV pneumonia in AIDS patients, unless associated with high levels of antigenaemia or viraemia and compatible clinical symptoms.

Employment of terbinafine against Pneumocystis carinii infection in rat models

The anti-Pneumocystis carinii response of terbinafine together with that of three other compounds, trimethoprim sulphamethoxazole (TMP-SMX), atovaquone (ATQ) and albendazole (ALB), has been investigated in immunosuppressed Sprague-Dawley rats with established pneumocystosis. Drugs were administered orally (terbinafine in dosages of 40 and 80 mg/kg per day, TMP 12.5 mg/kg per day plus SMX 62.5 mg/kg per day, ATQ 100 mg/kg per day and ALB 600 mg/kg per day) to six rat groups except one which served as a control. P. carinii pneumonia (PCP) was identified post-mortem in nine (90%) of the control rats which exhibited a marked P. carinii burden, and mean lung weights were higher with respect to the other treatment groups. During treatment, five rats in the control group died, whereas between 11 and 13 rats in all treatment groups survived. In the terbinafine groups (40 mg and 80 mg/kg per day), a mild P. carinii infection developed in three and two rats (27.2 and 18%), respectively, and almost the same infectivity score was obtained for those treated with 40 mg and 80 mg/kg per day. Histological changes in the lungs in animals receiving terbinafine treatment were minimal. Among the remaining compounds the rate of infection was seven (58.3%) for the ALB treatment group and five (45.4%) for the ATQ group (mean score 19.4 +/- 7.1 and 23 +/- 2.1, respectively). In the TMP-SMX treatment group, there were 13 surviving rats and P. carinii organisms were found in two (15.3%, mean infection score 8 +/- 1.1).

Production of plasminogen activator and plasminogen activator inhibitors by alveolar macrophages in control subjects and AIDS patients

OBJECTIVE

To reveal a possible impairment of the plasminogen activator system in the pulmonary infections of AIDS patients.

DESIGN

To test the plasminogen activator system functionality in alveolar macrophages and bronchoalveolar lavage fluid (BALF) in control subjects and AIDS patients. Procedures were designed to detect the presence of imbalance in plasminogen activator activity and to ascertain if this imbalance is due to a direct effect of the HIV virus on macrophages or to superimposed opportunistic infection.

METHODS

Alveolar macrophages obtained by bronchoalveolar lavage (BAL) were either lysed with Triton X-100 or cultured for 24 h. Plasminogen activators and plasminogen activator inhibitors (PAI) were measured by chromogenic substrate assay and binding to 125I-urokinase followed by 10% sodium dodecyl-sulphate polyacrylamide gel electrophoresis (SDS-PAGE), respectively.

RESULTS

Plasminogen activator activity in BALF and in alveolar macrophages from AIDS patients was decreased. This reduction was independent of the presence of an infectious pulmonary process. In contrast, free PAI was increased in AIDS patients with Pneumocystis carinii infection. This increase is possibly caused by a different glycosylated form of PAI-2.

CONCLUSIONS

Our data support the view that the pulmonary fibrogenic response is in part secondary to an imbalance within the plasminogen activator system and provide the basis for clarifying the role of these alterations in the pathophysiology of AIDS-related pulmonary infections.

Pneumocystis carinii pneumonia in preterm infants: report of two cases successfully diagnosed by non-bronchoscopic bronchoalveolar lavage

We present two cases of Pneumocystis carinii pneumonia in apparently immunocompetent preterm infants presenting with unexplained respiratory distress associated with a predominantly interstitial process on the chest radiograph. Definite diagnosis was promptly established on the detection of cyst forms in the lung fluid obtained by non-bronchoscopic bronchoalveolar lavage, and a favourable outcome was achieved.

Evidence of Pneumocystis carinii in cell line cultures infected with peripheral blood mononuclear cells isolated from AIDS patients with P. carinii pneumonia

The detection of Pneumocystis carinii was investigated in an in-vitro system consisting of a human lung epithelial cell line (A-549) inoculated with infected peripheral blood mononuclear cells (PMBC) from HIV-infected patients with proven or suspected P. carinii pneumonia (PCP), and from HIV-negative patients with other lung infections. Supernates from cultures were sampled daily and evaluated for the presence of P. carinii by Giemsa and immunofluorescence staining. P. carinii was isolated from 98 (95.1%) of 103 culture supernate samples from patients with proven pneumocystosis and 45 (66.1%) of 68 from patients with suspected PCP 40 or 72 h after PBMC inoculation. This system has been shown to support the growth of P. carinii but did not seem to be adequate for the production of large numbers of organisms, although long-term survival in vitro for up to 3 weeks was observed. Recovery of P. carinii from infected PBMC strongly supports previous observations about its ability to disseminate haematogenously and could represent a further advance in understanding the pathogenesis and diagnosis of PCP.

Diagnosis of Toxoplasma gondii infection in AIDS patients by a tissue-culture technique

Toxoplasma gondii infection was investigated in 14 AIDS patients with neurological involvement who showed clinical and computer tomographic scan signs suggestive of toxoplasmic encephalitis or extraneuronal localization suggestive of toxoplasmic infection. Blood, lung secretion (bronchoalveolar lavage and/or induced sputum sample) and cerebral spinal fluid (CSF) samples were cultured, and the results compared with the results of direct examination by Giemsa and by immunofluorescence of lung secretions and CSF. Toxoplasma gondii were observed directly in only four patients by immunofluorescence in bronchoalveolar lavage, induced sputum and CSF samples, and in three of these patients by Giemsa staining of bronchoalveolar lavage and CSF smears. In contrast, parasites were detected after 48 h in blood cultures from 11 of the 14 AIDS patients, in CSF cultures from eight of them and also in cultures of bronchoalveolar lavage and induced sputum from the six patients with respiratory and radiological features indicative of lung tissue damage. The findings indicate the value of tissue culture for diagnosis of toxoplasmosis as well as for monitoring the effects of treatment and also indicate that culture of induced sputum could be a powerful tool in establishing the incidence of pulmonary toxoplasmosis in AIDS patients.

Activity of terbinafine against Pneumocystis carinii in vitro and its efficacy in the treatment of experimental pneumonia

The antiprotozoan and antifungal agent, the terbinafine, was investigated for its potential activity against Pneumocystis carinii infection of the A549 cell line culture and on immunosuppressed Sprague Dawley rats in comparison with trimethoprim-sulphamethoxazole and pentamidine isethionate. Terbinafine suppressed P. carinii growth at doses up to 3 g/L within 24 h and it was able to inhibit cyst forms at 60 h post inoculation. With respect to trimethoprim-sulphamethoxazole and pentamidine isethionate P. carinii organisms decreased at the same time interval but cyst form elimination was less apparent than with terbinafine. The results of the in-vitro culture were consistent with the in-vivo observations. Of the 3 groups of rats tested, the occurrence of P. carinii pneumonia was documented in 18 (60%) of the control rats (group 3) which showed a high degree of P. carinii burden and a marked weight loss with respect to the beginning of the experiment. Among terbinafine treated rats (group 1), P. carinii pneumonia was present in one rat (3.3%), while no P. carinii infection occurred in the pentamidine isethionate and in trimethoprim-sulphamethoxazole treatment rat groups (group 2). All the agents investigated showed no particular signs of toxicity. These preliminary results suggest further explorations of the terbinafine in clinical trials for treatment and prophylaxis of P. carinii pneumonia.