Inflammasome-Independent Role for NLRP3 in Controlling Innate Antihelminth Immunity and Tissue Repair in the Lung

Alternatively activated macrophages are essential effector cells during type 2 immunity and tissue repair following helminth infections. We previously showed that Ym1, an alternative activation marker, can drive innate IL-1R-dependent neutrophil recruitment during infection with the lung-migrating nematode, Nippostrongylus brasiliensis, suggesting a potential role for the inflammasome in the IL-1-mediated innate response to infection. Although inflammasome proteins such as NLRP3 have important proinflammatory functions in macrophages, their role during type 2 responses and repair are less defined. We therefore infected Nlrp3 -/- mice with N. brasiliensis Unexpectedly, compared with wild-type (WT) mice, infected Nlrp3 -/- mice had increased neutrophilia and eosinophilia, correlating with enhanced worm killing but at the expense of increased tissue damage and delayed lung repair. Transcriptional profiling showed that infected Nlrp3 -/- mice exhibited elevated type 2 gene expression compared with WT mice. Notably, inflammasome activation was not evident early postinfection with N. brasiliensis, and in contrast to Nlrp3 -/- mice, antihelminth responses were unaffected in caspase-1/11-deficient or WT mice treated with the NLRP3-specific inhibitor MCC950. Together these data suggest that NLRP3 has a role in constraining lung neutrophilia, helminth killing, and type 2 immune responses in an inflammasome-independent manner.

Bronchodilator Reversibility Occurring during the Acute Phase of Paragonimiasis westermani Infection

A 43-year-old woman was referred to our hospital with peripheral blood hypereosinophilia and abnormal chest X-ray findings. Her pleural effusion revealed hypereosinophilia and a low glucose level. She was diagnosed with pulmonary paragonimiasis based on an elevated antibody level of Paragonimiasis westermani. Although she had no medical history of allergic disorders, a pulmonary function test revealed bronchodilator reversibility. After praziquantel therapy, her symptoms, hypereosinophilia in peripheral blood, and pleural effusion were improved. A repeated pulmonary function test after praziquantel therapy showed a negative bronchodilator response. Pulmonary paragonimiasis may induce bronchodilator reversibility during the acute phase of infection.

[Evaluation of exercise tolerance in patients treated with praziquantel for chronic schistosomiasis with no signs of cardiopulmonary impairment]

OBJECTIVE

The purpose of this study was to evaluate whether a progressive cycle ergometer test (PCET) can detect minimal functional abnormalities that might indicate compromise of the pulmonary vascular bed in patients treated with praziquantel for chronic schistosomiasis who have no clinical signs of cardiopulmonary impairment.

PATIENTS AND METHOD

We studied 9 patients (whose mean (SD) age was 38 (18) years and 10 control subjects aged 32 (14) years. Both groups were evaluated by spirometry and a PCET to determine maximum oxygen consumption, heart rate, minute ventilation and gas exchange. Echocardiograms were used to rule out the presence of associated heart disease.

RESULTS

Lung function was similar among patients and controls. Slight decreases in maximum oxygen consumption and heart rate reserve were observed with effort during the PCET, with normal respiratory response. No echocardiographic abnormalities that might indicate the presence of pulmonary vascular occlusive disease were observed.

CONCLUSIONS

The results showed that the resting lung function is normal in these patients. However, there was a slight decrease in exercise tolerance, probably related to physical detraining. The data obtained during exercise indicated that pulmonary vascular occlusive disease is unlikely in these patients. Abnormalities may appear in later stages of the disease or in patients who do not receive early medical treatment.

[Pulmonary trichomoniasis: diagnosis based on identification of irritation in bronchoalveolar lavage]

Bronchopulmonary infections caused by trichomonads have been reported mainly in patients with pre-existing pulmonary or debilitating disease (e.g. bronchial carcinoma, lung abscess, bronchiectasis). Pulmonary trichomoniasis is most often due to infection with Trichomonas tenax, usually regarded as a harmless commensal of the human mouth, and may rarely be caused by other trichomonas species. A 45 year old female presented with a dry cough, exertional dyspnoea and malaise. These symptoms persisted for 6 months regardless of anti-inflammatory and anti-obstructive inhalative therapy. Sarcoidosis of the lungs, diagnosed 20 years prior, had been asymptomatic since and there was no coexistent disease. Laboratory data revealed increased ACE-levels (90 IE/ml) and lung function showed bronchial hyperreactivity on histamine challenge. No other abnormalities were found (chest x-ray, bronchoscopy, lung function test, blood count and serum calcium). The diagnosis was based on the cytological identification of numerous trophozoites of T. tenax in the bronchoalveolar lavage. Therapy with oral metronidazol for 40 days led to complete recovery from symptoms and normalisation of ACE serum levels. The patient has remained well for 12 months since. The pathogenicity of oral trichomonads in the non-immunocompromised host remains uncertain. Our patient had no known medical risk factors by comparison with published cases. The case illustrates the clinical relevance of pulmonary trichomoniasis in an otherwise healthy person.

A lung nematode in Canadian Arctic muskoxen. Standard radiographic and computed tomographic imaging

Medical imaging was used before death to follow the development of U. pallikuukensis infection in muskoxen and postmortem to investigate the distribution and characteristics of parasite-associated pulmonary cysts. In two experimentally infected animals, lesions were not visible radiographically until days 178 and 191 PI, 3 months after the parasites became patent. Serial radiographs taken throughout the period of patency of one animal showed an initial increase in lesion size by day 415 PI, but by day 789 PI, lesions had stabilized or decreased in size. Although all lesions detected postmortem were not visible radiographically during life, the radiographs did provide an indication of the relative severity of infection. In contrast to other parasitic pneumonias, there was no evidence of pulmonary disease outside of the discrete parasitic cysts. Radiographs of lungs postmortem proved to be an effective tool for locating parasitic cysts in a lightly infected muskox and demonstrated a bronchovascular cyst distribution. Postmortem CT provided a more rapid and detailed assessment of the number, size, and distribution of cysts in the lungs of one muskox.

Impaired pulmonary gas exchange in ewes naturally infected by small lungworms

Respiratory rate and blood gases were studied in 2 groups of ewes: the ewes in group 1 (9 ewes) acted as uninfected controls and those in group 2 (6 ewes) were infected with small lungworms (Muellerius, Cystocaulus, Protostrongylus and < 1% Neostrongylus). The respiratory rate was higher in infected (49 +/- 19 breath min-1) than in uninfected ewes. (20 +/- 3 breath min-1); it was strongly reduced after treatment (49 vs 22) in infected ewes. The partial carbon dioxide arterial tension (PCO2), total CO2 and HCO3- were higher (respectively 77 vs 39 mmHg, 38 vs 23 mmol-1 and 35 vs 23 mmol-1) in infected compared with uninfected ewes, whereas arterial pH (7.2 vs 7.4) and partial oxygen tension PO2 were lower (41 vs 81 mmHg) in infected ewes. Group 2 was treated with fenbendazole (at 15 mg kg-1 bodyweight) to eliminate small lungworms, and the respiratory rate and blood gases were measured 3 weeks after treatment. The values after treatment were similar to those in uninfected ewes. It is concluded that heavy infections by small lungworms in ewes impairs gas exchange, but that gas exchange improves rapidly after treatment.

[Pulmonary toxoplasmosis in patients with human immunodeficiency virus infection. 21 cases]

OBJECTIVES

Assess expression of pulmonary toxoplasmosis, the second most frequent localization after brain, in patients infected with the human immunodeficiency virus (HIV).

METHODS

Twenty-one HIV-infected patients (18M, 3F) were admitted for pulmonary toxoplasmosis between September 1987 and February 1995. Mode of HIV transmission was unprotected homosexual sexual activity (n = 16), intravenous drug abuse (n = 3) and transfusion (n = 2).

RESULTS

Isolated pulmonary toxoplasmosis was found in 11 patients. In 10 patients pulmonary toxoplasmosis was associated with cerebral (n = 4), bone marrow (n = 2), ocular (n = 1) and multifocal (n = 3) localizations. Seven patients were admitted for acute pulmonary distress. Fever (reported for 20 patients) and nonproductive cough (reported for 16 patients) were the most common clinical symptoms. Chest roentgenogram revealed bilateral pulmonary infiltrates in 16 (76%) patients. Mean absolute CD4 count was 25 +/- 57 (range 0-110). Serologic evidence of past infection was observed in 18 patients. Serology tests were not done for two patients and negative for one. Two patients presented co-infection with Pneumocystis carinii. Fourteen patients had elevated serum lactic dehydrogenase (LDH) concentration. Among those, 4 patients whose LDH concentration was elevated more than ten fold died of respiratory distress. Patients received pyrimethamine and sulfadiazine (n = 13) or clindamycin (n = 8). Seven patients died during the first month after diagnosis was made. For the other patients, mean survival was 8 months. No relapse of toxoplasmosis was observed. All the patients took a secondary prophylaxis.

CONCLUSION

No difference between patient with isolated pulmonary toxoplasmosis and patients with associated extra-pulmonary localization was noted for clinical, biological, radiological presentations and outcome.

[Parasitic invasions and bronchial obstruction]

The course and outcomes of bronchial obstruction were reviewed for clonorchiasis, metagonimosis, lambliasis. Bronchial obstruction is shown to run more aggressive course in Trematoda infestation with further transformation into bronchial asthma despite dehelminthization. In lambliasis current antiparasitic therapy is able to abolish the obstruction. In combination of lambliasis with bronchial asthma it is feasible to achieve a persistent remission of bronchial asthma.

Intestinal and extraintestinal cryptosporidiosis in AIDS patients

In a prospective study in AIDS patients with chronic diarrhea, the overall prevalence of intestinal cryptosporidiosis was 15.6% (43/275). The prevalence was higher in homosexual patients (33.3%) than in intravenous drug abusers (10.6%) (p < 0.001). Extraintestinal infection was present in 30% (13/43) of the patients with known intestinal cryptosporidiosis. Eight of the 13 (61.5%) patients with extraintestinal cryptosporidiosis had Cryptosporidium in the bile and 7 of 13 (16.28%) had it in the sputum. Of the seven patients with Cryptosporidium in the sputum, four had respiratory symptoms and an abnormal chest radiograph, although another pulmonary pathogen was isolated simultaneously. Two other patients from whom Cryptosporidium was the sole respiratory pathogen isolated had no respiratory symptoms and normal chest radiographs. The seventh patient had pulmonary symptoms, interstitial infiltrate on chest radiograph and excessive activity on a pulmonary Gallium scan; Cryptosporidium was the only organism detected in induced sputum and bronchoalveolar lavage specimens. The mean CD4+ lymphocyte count in patients with extraintestinal cryptosporidiosis was 55 cells/mm3.

Interaction of filarial proteins on growth regulation of normal lung epithelial cells in vitro

An in vitro model to examine the effects of filarial proteins on lung epithelial cells has been developed. Several of these proteins appear in circulation of infected individuals. A close association between tropical pulmonary eosinophilia (TPE) and filariasis has been reported by several workers. [3H]-thymidine studies do indicate that when optimum concentration of these filarial proteins were added to lung cultures in proliferating and basal/maintenance media a further increase in growth stimulation was observed early in culture. However, on longer exposures and at higher concentrations an inhibitory effect with distinct morphological changes were noted. The dual role of these proteins on lung epithelial cells in vitro may highlight the possibility of a direct interaction of these proteins with lung cells during disease also contributing to tissue damage.

Dose-dependent pathophysiological changes in cattle experimentally infected Dictyocaulus viviparus

In two trials five calves were each experimentally infected on three consecutive days with a total number of either 30 Dictyocaulus viviparus larvae per kg body weight (trial A) or 3 larvae/kg body weight (trial B). Five calves served as non-infected controls. Infected cattle in trial A developed severe clinical signs of dictyocaulosis and one calf died 37 days post infection (p.i.), whereas all cattle in trial B remained clinically healthy. Weight gains in both trials were not statistically different. Haemoglobin concentrations, packed cell volume (PCV), number of erythrocytes and leucocytes, blood pH and albumin concentrations were in the physiological range in all groups. Infected cattle in trial A showed increases in respiratory rates, body temperature, serum protein concentrations, and blood eosinophil counts and decreases in oxygen partial pressure. Infected cattle in trial B showed increased blood eosinophil counts. Antibody formation in infected cattle of both trials showed a similar pattern. Excretion of larvae from infected cattle reflected the different infection doses. Microbiological examinations showed an increase of facultatively pathogenic bacteria in the lung fluid.

Blood gas analysis in dogs with pulmonary heartworm disease

Blood gases were analyzed in dogs with pulmonary heartworm (HW) disease. The arterial oxygen tension (PaO2) in dogs with mild signs of dirofilariasis (mildly affected group, n = 48, 85.7 +/- 8.2 mmHg) and in dogs with signs of right heart failure (severely affected group, n = 13, 76.4 +/- 11.6 mmHg) was lower (p < 0.01) than in dogs without HW infection (HW-free group, n = 19, 91.5 +/- 7.3 mmHg). Only 2 dogs in the severely affected group had a PaO2 less than 60 mmHg. The arterial carbon dioxide tension (PaCO2, p < 0.01) and mixed venous O2 (p < 0.01) and CO2 (p < 0.01) tensions were lower, and alveolar-arterial oxygen difference (AaDO2, p < 0.01) was greater in the severely affected group than in the HW-free and mildly affected groups. Arterial pH and bicarbonate (HCO3-) concentrations were lower (p < 0.01) in both affected groups than in the HW-free groups. The anion gap level was not different among the 3 groups. Serum lactic acid level in the severely affected group was higher (p < 0.01) than in the HW-free and mildly affected groups. However, a slightly higher serum lactic acid concentration was found only in 2 dogs of the severely affected group (3.84 mmol/l and 3.82 mmol/l). The PaO2 (r = -0.62) and AaDO2 (r = 0.66) correlated significantly (p < 0.01) with mean pulmonary arterial pressure. One week after HW removal, blood gases, pH and HCO3- concentration remained unchanged in the mildly affected group. In the severely affected group, blood gas values were the same, but pH and HCO3- concentration improved slightly.

[Pulmonary involvement in malaria (review)]

Pulmonary involvement occurs in 3 to 10% of the cases of Plasmodium falciparum malaria and represents the most serious complication of this infection, with a lethality of about 70%. The understanding of its pathogenesis is still very fragmentary, however it is recognized that activation of the immune system by antigens released by the parasite plays an important role in the induction and worsening of lung damage. Capillary endothelial cells, which control the flux of fluids to the interstitial space, appear to be the most involved structure. These cells are activated by cytokines, produced by lymphocytes and macrophages during the immune response, and express receptors and molecules of adhesion, allowing for sequestration of parasitized erythrocytes and adherence of cells, which will produce locally inflammatory mediators. The inflammatory reaction and lesion of endothelial cells that ensue, together with the hemodynamic alterations induced by the capillary blockade due to the sequestration of parasitized erythrocytes and leukocytes, cause alterations of the vascular permeability and transfer of liquid to intertitial space and alveoles. Severe cases are clinically expressed by a picture of Adult Respiratory Distress Syndrome. The clinical manifestations of pulmonary involvement may start suddenly at any time during the course of malaria, even after disappearance of circulating parasites. The inducing factors are unknown. Hyperparasitemia, renal failure and pregnancy are predisposing factors. The prognosis will depend on how fast the diagnosis is established and convenient treatment initiated. If parasites are present they shall be treated with schizonticidal drugs, hemodynamic parameters continuously evaluated, preferably through a Swam-Ganz catheter. Appropriate oxygen supply and fluid balance have to be warranted. Other complications of malaria, frequently associated to the pulmonary involvement, need special attention and proper treatment. A better understanding of the pathogenesis of lung damage associated to malaria will certainly help to improve treatment and reduce morbidity and mortality.

Relationship between cytologic changes in bronchoalveolar lavage fluid and weight gain in calves with gastrointestinal nematodes and lungworms

Two of three groups of 10 calves each were infected with either 100,000 infective larvae (L3) of Ostertagia spp. and 100,000 L3 of Cooperia spp. or with 4000 L3 of Dictyocaulus viviparus, respectively, at the age of 14 weeks. The third group was not infected. After treatment with an anthelminthic five calves from each group were challenged with either 100,000 L3 of Ostertagia spp. and 100,000 L3 of Cooperia spp. or 4000 L3 of Dictyocaulus at the age of 20 weeks. The calves were 25 weeks old when slaughtered. Total and differential cell counts were determined in bronchoalveolar lavage fluid and showed that neutrophils were the most frequent and eosinophils the least frequent cell present. There was a significant negative relationship between eosinophil levels and weight gain of the calves.

Longitudinal study of the effects of lungworm infection on bovine pulmonary function

Clinical and physiologic investigations were done weekly in 5 nonsedated Friesian calves before, during, and after an induced infection with Dictyocaulus viviparus infective larvae. Clinical, hematologic, serologic, and parasitologic findings were all compatible with the classic picture of moderate subacute verminous bronchitis. Most pulmonary function values revealed significant (P less than or equal to 0.05) changes in the 2nd or 3rd week after inoculation and maximal changes at 5 weeks after inoculation. Most marked changes included a decrease in tidal volume, dynamic lung compliance, and arterial oxygen tension, and an increase in minute ventilation, minute viscous work of breathing, and alveolar-arterial oxygen difference. Minute ventilation, dynamic lung compliance, minute viscous work of breathing, and PaO2 revealed the most homogeneous change. Conversely, maximal change of intrapleural pressure, total pulmonary resistance, and viscous work of breathing had higher variability from week to week.

Physiological effects of experimental verminous bronchitis in Friesian calves

Pulmonary function values were measured in five Friesian calves of five months of age during the patent phase of an experimental moderate lungworm infection and were compared with the pulmonary function values recorded in four control animals. All the nine calves were free of any previous challenge with Dictyocaulus viviparus and were submitted to the same standardized conditions of body conformation, housing, feeding and procedures for pulmonary function testing. A significant increase of respiratory rate, minute ventilation, total pulmonary resistance and power of breathing and a significant decrease of tidal volume, dynamic lung compliance and PaO2 were observed in the infested animals. The absolute intrapleural pressure values were also significantly more negative. The conclusions of the statistical analysis were almost identical when predicted instead of measured pulmonary function values were used in the control group. The clinical, functional and pathological findings in the infested animals were all consistent with the picture of a lower airway obstructive disease.

Pulmonary function studies in acute pulmonary histoplasmosis

We performed follow-up pulmonary function studies on three patients with acute pulmonary histoplasmosis over a period of several months, and found that the disease is benign and usually responds well to treatment or is self-limiting. There are four major changes in lung function, namely a restrictive defect, an impairment of diffusing capacity, stiff lung, and obstruction in small airways. These changes usually lead to disturbance of ventilation-perfusion ratios and impaired gas transport across alveolar capillary membranes, resulting in arterial hypoxemia. There is also hypocapnia from alveolar hyperventilation commonly found in restrictive and stiff lung syndrome.

Advances in pathophysiology of schistosomiasis japonica: a review

Schistosomiasis is a chronic granulomatous disease caused by a delayed type of hypersensitivity reaction to eggs deposited or trapped in the tissues. Granuloma formation, depending on extent, if in the liver will lead to portal hypertension while if in the lungs, will lead to pulmonary hypertension and cor pulmonale.

Pulmonary function in tropical eosinophilia before and after treatment with diethylcarbamazine

Spirometric and lung volume measurements were carried out before and after treatment with diethylcarbamazine in 19 patients with tropical eosinophilia. The total lung capacity and vital capacity returned to or nearly to normal while the FEV1 and PEFR, though improved, tended to remain below normal, indicating some residual airways obstruction especially in patients whose treatment began more than one month from the onset of symptoms. The time taken for the pulmonary function to return to normal with treatment was found to be much longer than for the clinical and haematological response.