Chronic Mucoid Research Articles

Polyguluronate simulations shed light onto the therapeutic action of OligoG CF-5/20

Chronic mucoid P. aeruginosa cystic fibrosis (CF) lung infections are associated with the development of a biofilm composed of anionic acetylated exopolysaccharide (EPS) alginate, electrostatically stabilised by extracellular Ca2+ ions. OligoG CF-5/20, a low molecular weight guluronate rich oligomer, is emerging as a novel therapeutic capable of disrupting mature P. aeruginosa biofilms. However, its method of therapeutic action on the mucoid biofilm EPS is not definitively known at a molecular level. This work, utilising molecular dynamics (MD) and Density-Functional Theory (DFT), has revealed that OligoG CF-5/20 interaction with the EPS is facilitated solely through bridging Ca2+ ions, which are not liberated from their native EPS binding sites upon OligoG CF-5/20 dispersal, suggesting that OligoG CF-5/20 does not cause disruptions to mature P. aeruginosa biofilms through breaking EPS-Ca2+-EPS ionic cross-links. Rather it is likely that the therapeutic activity arises from sequestering free Ca2+ ions and preventing further Ca2+ induced EPS aggregation.

Cation complexation by mucoid Pseudomonas aeruginosa extracellular polysaccharide.

Mucoid Pseudomonas aeruginosa is a prevalent cystic fibrosis (CF) lung colonizer, producing an extracellular matrix (ECM) composed predominantly of the extracellular polysaccharide (EPS) alginate. The ECM limits antimicrobial penetration and, consequently, CF sufferers are prone to chronic mucoid P. aeruginosa lung infections. Interactions between cations with elevated concentrations in the CF lung and the anionic EPS, enhance the structural rigidity of the biofilm and exacerbates virulence. In this work, two large mucoid P. aeruginosa EPS models, based on β-D-mannuronate (M) and β-D-mannuronate-α-L-guluronate systems (M-G), and encompassing thermodynamically stable acetylation configurations–a structural motif unique to mucoid P. aeruginosa–were created. Using highly accurate first principles calculations, stable coordination environments adopted by the cations have been identified and thermodynamic stability quantified. These models show the weak cross-linking capability of Na+ and Mg2+ ions relative to Ca2+ ions and indicate a preference for cation binding within M-G blocks due to the smaller torsional rearrangements needed to reveal stable binding sites. The geometry of the chelation site influences the stability of the resulting complexes more than electrostatic interactions, and the results show nuanced chemical insight into previous experimental observations.

Biofilm inhibitory effect of alginate lyases on mucoid P. aeruginosa from a cystic fibrosis patient

Chronic mucoid Pseudomonas aeruginosa infections are a major scourge in cystic fibrosis patients. Mucoid P. aeruginosa displays structured alginate-rich biofilms that are resistant to antibiotics. Here, we have assessed the efficacy of a panel of alginate lyases in combating mucoid P. aeruginosa biofilms in cystic fibrosis. Albeit we could not demonstrate alginate degradation by alginate lyases in sputum, we demonstrate that the endotypic alginate lyases, CaAly (from Cellulophaga algicola) and VspAlyVI (from Vibrio sp. QY101) and the exotypic alginate lyases, FspAlyFRB (from Falsirhodobacterium sp. alg1), and SA1-IV (from Sphingomonas sp. A1), indeed inhibit biofilm formation by a mucoid P. aeruginosa strain isolated from the sputum of a cystic fibrosis patient with comparative effect to that of the glycoside hydrolase PslG, a promising candidate for biofilm treatment. We believe that these enzymes should be explored for in vivo efficacy in future studies.

Remodeling of O Antigen in Mucoid Pseudomonas aeruginosa via Transcriptional Repression of wzz2.

Pseudomonas aeruginosa is an opportunistic pathogen that causes chronic lung infections in people with cystic fibrosis (CF). Chronic P. aeruginosa isolates generally do not express O antigen and often have a mucoid phenotype, which is characterized by the overproduction of the exopolysaccharide alginate. Therefore, O antigen expression and the mucoid phenotype may be coordinately regulated upon chronic adaption to the CF lung. Here we demonstrate that PDO300, a mucoid strain derived from the nonmucoid laboratory isolate PAO1, does not produce very long O antigen due to decreased expression of Wzz2, the very long O antigen chain length control protein, and that mucoid clinical isolates express reduced levels of Wzz2 compared to nonmucoid isolates. Further, we show that forcing the expression of very long O antigen by PDO300, by providing wzz2 in trans, does not alter alginate production, suggesting that sugar precursors are not limited between the two biosynthesis pathways. Moreover, we confirm that AmrZ, a transcription factor highly expressed in mucoid strains, is a negative regulator of wzz2 promoter activity and very long O antigen expression. These experiments identify the first transcriptional regulator of O antigen chain length in P. aeruginosa and support a model where transition to a chronic mucoid phenotype is correlated with downregulation of very long O antigen through decreased Wzz2 production.IMPORTANCE Detection of mucoid Pseudomonas aeruginosa, characterized by the overproduction of alginate, is correlated with the establishment of a chronic pulmonary infection and disease progression in people with cystic fibrosis (CF). In addition to the overproduction of alginate, loss of O antigen lipopolysaccharide production is also selected for in chronic infection isolates. In this study, we have identified the regulatory network that inversely regulates O antigen and alginate production. Understanding the regulation of these chronic phenotypes will elucidate mechanisms that are important for the establishment of a long-term P. aeruginosa lung infection and ultimately provide an opportunity for intervention. Preventing P. aeruginosa from chronically adapting to the CF lung environment could provide a better outcome for people who are infected.

The Q359K/T360K mutation causes cystic fibrosis in Georgian Jews

BackgroundThe Q359K/T360K mutation, described in Jewish CF patients of Georgian decent, is of questionable clinical significance. MethodsClinical records of patients with the Q359K/T360K mutation from three CF centers were studied for phenotypic expression and putative mechanism of dysfunction. Computer models of mutant CFTR were constructed. ResultsNine patients (4 homozygous) of Georgian Jewish origin were included. Age at diagnosis was 9.4 (0.25–38.2) years, median (range). Sweat chloride was 106 ± 13 meq/L, mean ± SD. Nasal Potential Difference performed in three, was abnormal. All had pulmonary symptoms since early childhood and bronchiectasis. Median FEV1 was 88 (40–121)%. Five had chronic mucoid P. aeruginosa. Homozygous patients were pancreatic insufficient. Enzyme supplementation was initiated at 3.8 (1–14.7) years, median (range). Structural models hint at possible interference of this mutation with transmembrane chloride transport. ConclusionIn our cohort, the Q359K/T360K mutation resulted in a severe CF phenotype, although with residual early CFTR function. The CFTR2 database should consider defining this mutation as CF-causing.

Recurrent bronchopneumonia in a young Beagle dog with situs inversus and suspected Kartagener's syndrome

This case report describes suspected Kartagener's syndrome in a 2-year-old intact male Beagle with a history of recurrent pneumonia and chronic rhinitis. Several febrile respiratory tract infections occurred during his first year. Chronic sneezing and mucoid nasal discharge prompted evaluation for allergies at 18 months of age. Pneumonia was diagnosed by several clinics in the 2 months prior to presentation. Clinical suspicion of Kartagener's syndrome prompted radiographic confirmation of situs inversus, with probable ciliary dyskinesia. This case illustrates that recurrent pneumonia and chronic rhinitis in an otherwise healthy young animal should prompt evaluation for underlying structural or immunological deficits.

Occult traumatic nasolacrimal duct obstruction causing anophthalmic socket contraction presenting 20 years later

Abstract Purpose To highlight undiagnosed nasolacrimal duct obstruction as a cause of multiple problems related to conjunctival cicatrisation of the anophthalmic socket and the importance of early diagnosis and treatment in their prevention. Methods Case report with high resolution digital clinical photography. Results We present a 43 year old Asian gentleman, who sustained penetrating trauma to the right globe and midface in 1984. At the time, he underwent primary repair of the globe, followed by enucleation. Over the next ten years, he suffered myriad problems with recurrent entropion and trichiasis of upper and lower lids, a dry socket with an uncomfortable artificial eye and chronic mucoid discharge. Twenty years later his initial diagnosis was revisited. On examination, he had a contracted socket with mucosal keratinisation, cicatricial entropion of the eyelids, forniceal shortening and mucoid discharge. There was also nasolacrimal duct obstruction with an occult mucoceole. He underwent external dacrocystorhinostomy with correction of the entropions and anophthalmic socket refashioning. He remains symptom free twelve months following surgery. Conclusion Contracted anophthalmic sockets can occur spontaneously or secondarily to a disease process. These may lead to changes in tear composition and have pro‐inflammatory effects on the ocular surface. We hypothesise that the chronic toxic tear film secondary to the mucocoele led to chronic conjunctivitis with cicatrisation over time and multiple structural lid & socket problems that ensued. This case highlights the importance of looking for occult causes of chronic cicatrisation in the anophthalmic socket.

Predictors of mucoid Pseudomonas colonization in cystic fibrosis patients

Chronic mucoid Pseudomonas aeruginosa within the airway in cystic fibrosis (CF) patients can determine prognosis. Understanding the risk factors of mucoid P. aeruginosa acquisition may change how we deliver care. This study aims to evaluate whether presence of risk factors reported to predict disease severity including gender, CFTR genotype, bacterial organisms in airway cultures, and serum levels of vitamins A and E, albumin, C-reactive protein, alpha 1-antitrypsin, and immunoglobulins increased the risk of mucoid P. aeruginosa acquisition. Primary endpoint was age at first transition from negative to positive culture for mucoid P. aeruginosa. Cox proportional hazards regression with time-dependent covariates examined development of mucoid P. aeruginosa infection and its association with longitudinally measured serum biomarkers, pulmonary function, and culture results for other organisms. Median ages at CF diagnosis and at first culture were 0.55 and 5.7 years, respectively. Median number of cultures/patient was 17. Of the 323 subjects, 150 developed mucoid P. aeruginosa during a median 8.1 years' follow-up. In multivariate analysis, gender (relative hazard [RH] 0.55 for male vs. female, P = 0.001), number of DF508 alleles (RH 1.66 for 1 or 2 vs. 0, P = 0.04), FEV(1) % (RH 1.16 for 10% decrease, P = 0.008), and most recent Staphylococcus aureus status (RH 0.24 for positive vs. negative, P < 0.0001) remained statistically significant. Female gender, number of DF508 alleles, decreased lung function, and lack of S. aureus on recent sputum culture are important risk factors for early detection of mucoid P. aeruginosa.

Occult traumatic nasolacrimal duct obstruction causing anophthalmic socket contraction presenting 20 years later: a case report

Purpose: To highlight undiagnosed nasolacrimal duct obstruction as a cause of multiple problems related to the anophthalmic socket and the importance of early diagnosis and treatment in their prevention. Methods: Case report with high resolution digital clinical photography. Results: A 43-year-old Asian gentleman sustained penetrating trauma to the right globe and midface in 1984. At the time, he underwent primary repair of the globe, followed by enucleation. Over the next ten years, he suffered a myriad of problems with recurrent entropion and trichiasis of upper and lower lids, a dry socket with an uncomfortable artificial eye and chronic mucoid discharge. Twenty years later he had a contracted socket with mucosal keratinization, cicatricial entropion of the eyelids, forniceal shortening and mucoid discharge. There was also nasolacrimal duct obstruction with an occult mucoceole. He underwent external dacrocystorhinostomy with correction of the entropions and anophthalmic socket refashioning. He remains symptom free twelve months following surgery. Conclusion: Contracted anophthalmic sockets can occur spontaneously or secondarily to a disease process. These may lead to changes in tear composition and have pro-inflammatory effects on the ocular surface. We hyphothesize that the chronic toxic tear film secondary to the mucocoele led to chronic conjunctivitis with cicatrisation over time and multiple structural lid & socket problems that ensued. This case highlights the importance of looking for occult causes of chronic cicatrization in the anophthalmic socket.

Cystic Fibrosis Mutations with Widely Variable Phenotype: The D1152H Example

D1152H is a type IV cystic fibrosis transmembrane regulator (CFTR) mutation associated with abnormal chloride gating. Although comprising 5-6% of mutations on genetic screening, clinical reports of cystic fibrosis (CF) are rare, suggesting that the disease is mild, atypical, or even absent. We describe our experience, which contrasts with this assumption, in a retrospective case series encompassing 91 CF patients (74 Jewish) aged 8 months to 56 years, from 2000-2005. Nine patients of varied Jewish ethnic origins were homozygous (2 patients) or compound heterozygous for D1152H with 11 of 182 potential alleles (6%). Five were diagnosed at age 33-49 years. Of 4 infants, 1 was diagnosed by prenatal screening, 1 had a prenatal dilated bowel, and 1 had pulmonary symptoms. Sweat chloride was 28-120 meq/l. Three adults had chronic mucoid Pseudomonas aeruginosa in sputum, and a forced expired volume in 1 sec (FEV1) of 20-55%. One was on bilevel positive airway pressure (BIPAP) ventilation. The infants had pulmonary symptoms that responded well to therapy. All 9 patients had good nutrition, 6 were pancreatic-sufficient, and 3 adults had subclinical pancreatic insufficiency. Three adults had recurrent pancreatitis. None had a bowel obstruction. Two of 3 adult males were fertile. Although asymptomatic at times, the D1152H mutation is associated with a broad clinical spectrum. This information is crucial for genetic counseling. Lung disease may be evident from infancy, and is severe in some adults, although all have outlived the median life expectancy of CF. Hopefully, with early diagnosis and therapy, prognosis can be good. A multicenter study of this mutation is warranted.

Endemic hyperdigoxinemia-related cardiovascular and endocrine mucopolysaccharidoses syndrome

Objective: South India is a geoendemic zone for endomyocardial fibrosis, chronic calcific pancreatitis, multinodular goitre and mucoid vasculopathy, suggesting a common etiological factor underlying all these disorders. The study deals with the role of digoxin (endogenous/exogenous), magnesium status and glycosaminoglycan metabolism in the pathogenesis of these disorders. Methods: The following parameters were evaluated in endomyocardial fibrosis, chronic calcific pancreatitis, multinodular goitre and mucoid vasculopathy: serum digoxin, magnesium and glycosaminoglycans, tissue glycosaminoglycans, RBC membrane Na + -K + ATPase activity. Results: Elevated levels of tissue and serum glycosaminoglycans have been demonstrated in these disorders. There are also elevated levels of an endogenous membrane Na + -K + ATPase inhibitor, digoxin as well as low serum magnesium and reduced RBC membrane Na + -K + ATPase activity in all these disorders. Low HDL cholesterol and elevated triglyceride levels characteristic of insulin resistance are seen in all these disorders. Conclusion: Membrane Na + -K + ATPase inhibition can lead to magnesium depletion and magnesium deficiency and is associated with increased tissue glycosaminoglycan synthesis and fibrosis. Digoxin and hypomagnesemia has been associated with the insulin resistance state. Insulin resistance state and hyperinsulinism can lead to increased tissue glycosaminoglycan synthesis. This diverse spectrum of disorders may be a manifestation of hypomagnesemia- and hyperdigoxinemia-related hyperinsulinism/insulin resistance state and upregulated glycosaminoglycan synthesis.

Defining tympanostomy tube plugs.

To define the composition of tympanostomy tube plugs because selecting or developing effective solvents depends on such knowledge. Prospective, in vitro laboratory study. Luminal contents of 105 plugged, microscopically removed tympanostomy tubes were expressed, pooled, acid hydrolyzed, and passed through a high-performance liquid chromatography column. Retention times were compared with high-performance liquid chromatography standards to develop free amino acid and monosaccharide profiles. Cerumen, blood, and chronic mucoid effusion (collected during myringotomy) were pooled and subjected to the same analysis. The elution profiles of each substance were compared to determine which substance most closely matched the plugs. High-performance liquid chromatography amino acid and monosaccharide analysis demonstrated greatest similarity between tympanostomy tube plugs and mucoid effusion. Tympanostomy tube plug composition is more similar to mucoid effusion than to blood or cerumen. Solvents to open plugged tympanostomy tubes should be directed against the components of mucoid effusion.

Therapeutic trial in the first three Asian cases of ethylmalonic encephalopathy: Response to riboflavin

Three Korean girls with ethylmalonic encephalopathy, the first Asian cases, were identified. In all three cases, we observed slight improvement in motor functions, cognitive behaviours and chronic mucoid diarrhoea after treatment with riboflavin and/or coenzyme Q10 treatment. The precise pathogenesis of ethylmalonic encephalopathy has not been fully elucidated, but riboflavin treatment may be helpful.

Soluble l-selectin and interleukin-8 in otitis media with effusion

Objective: adhesion of leukocytes to vascular endothelium and their invasion into local tissues are important steps in inflammation. l-selectin plays a crucial role in leukocyte rolling and adhesion on endothelial cell surface. Interleukin-8 (IL-8) is a potent chemotactic substance toward neutrophils and lymphocytes-T and mediate their migration to local inflammation. The levels of soluble l-selectin (s l-selectin) and IL-8 were measured in middle ear effusions (MEE) from children with otitis media (OM) to estimate their role in pathogenesis of inflammation in middle ear. Methods: MEE were collected from 113 ears of 62 children during routine myringotomy. The entire specimen was diluted with phosphate-buffered saline (PBS) to 2 ml and centrifugated at 1500 rpm for 15 min to separate cellular components. Supernatants of MEE were stored frozen at −20°C for s l-selectin and at −80°C for IL-8 assessment. The concentration of s l-selectin and IL-8 were estimated with ELISA and compared with total protein concentration measured by Bradford assay. Results: MEEs from children with chronic mucous otitis media contained significantly higher mean concentrations of IL-8 559.4 pg/mg total protein (TP) (±535.6) in comparison with normal serum 17.79 pg/mg TP (±10.9), serous OM 40.3 pg/mg TP (±28.1) and purulent OM 104.4 pg/mg TP (±128.6). High concentration of IL-8 was found in MEE from the children with early recurrence of OMS. The levels of s l-selectin were higher in purulent effusions 77.2 ng/mg TP (±67.4) than those of chronic mucoid 27.6 ng/mg TP (±36.7) and serous OM 26.3 ng/mg TP (±27.1). Conclusion: the results support a hypothesis that IL-8 can be responsible for prolongation of inflammatory process in middle ear, therefore long-term treatment and observation of children with the high levels of IL-8 in MEE may be necessary. Elevated level of s l-selectin in acute OM suggests the involvement of l-selectin in the acute phase of OM.

Riboflavin responsive ethylmalonic encephalopathy in two Korean sibs

Ethylmalonic encephalopathy is a complex organic aciduria characterized by ethylmalonic aciduria, lactic acidemia with developmental delay, acrocyanosis, petechia and chronic mucoid diarrhea. Since 1994, less than 30 patients have been reported and the underlying metabolic defect is unknown.We report 2 affected sibs with typical clinical and biochemical phenotypes, and brain MRI findings. Patient I is a 5 years old girl who presents with developmental delay, spastic quadriplegia, and chronic diarrhea. She was hospitalized several times due to chronic diarrhea and pneumonia in the early infancy. She developed frequent skin petechiae on compression sites and cyanosis on the lower extremities. Brain MRI taken at the age of 25 months was suggestive of hypoxic ischemic encepahlopathy and no further evaluation was undertaken. Patient 2, her younger sister, is a 34 months old girl who presents with a similar clinical course but had no evaluation until recently when she developed respiratory difficulty due to pneumonia which required hospitalization. She was able to control her head at 4 months of age and crawl at 9 months of age but never sit, stand or talk. Her spastic quadriplegia became worse after this episode and she is almost wheel chair bound. Brain MRI showed multifocal nodular T2 high signals in both basal ganglia with enhancement, patchy T2 high signals in both periventricular white matter, centrum semiovale, and cerebellum. Muscle biopsy showed diffuse atrophy but no evidence of mitocnondrial disorder. Organic acid and acylglycine profiles showed markedly elevated excretion of ethylmalonic acid (134 mmol/mol creatinine: controls: <18), isobutyrylglycine, butyrylglycine, methylbutyrylglycine, and isovalerylglycine were also elevated. Serum lactate was 3.2 mmol/L (control: 0.7-2.0). 100 mg/kg/day oral carnitine supplementation for 2 months had no visible effect. However, they became significantly more active and alert on riboflavin treatment (100 mg/day). Patient 1 rolled over and was socially more active with laughing and sounds. In patient 2, motor improvement was not significant but she became more alert and socially active. Notably, the chronic mucoid diarrhea subsided considerably in both children, but petechiae were unaffected.Our observations suggest that some cases with ethylmalonic encephalopathy could be responsive to riboflavin. In vitro evaluation of fatty acid and branched chain amino acid metabolism is in progress.

Assessment of mucociliary transport in patients with chronic mucoid rhinitis.

Chronic rhinitis is the manifestation of a heterogeneous group of disease entities and often proves difficult to manage successfully. We present the investigations of the mucociliary system in 40 patients with mucoid rhinorrhoea as their principal symptom of whom 20 had pan respiratory disease. The saccharin clearance time (SCT) was measured and classified as normal if it was below 20 min. Objective measurement of clearance was made using 99mTechnetium-labelled human serum albumin (99mTc-HSA). We have standardized our method using a micrometer syringe driver to produce a droplet of consistent size (droplet size, 0.01 ml, SD 0.0002 ml) that reduces the dose of radiation. The movement of the droplet was measured over 20 min (RLT). The mean, maximum rate and percentage moved were calculated. Patients were divided into those who had chest disease (20) and those without and a chi 2-test was performed for the mean RLT time between the two groups. There was a strong correlation between mean and maximum rates (r = 0.91). One patient has a normal SCT and normal RLT. Patients with chest disease had a significantly lower mean RLT (P > 0.01). Assuming that RLT is the standard investigation, six patients were normal but had an abnormal SCT, this is a false positive error of 15%. The false negative error was 4/40 (10%). The association between sinus and chest disease with abnormal mucociliary clearance is stressed.

Long term follow up of changes in FEV1 and treatment intensity during Pseudomonas aeruginosacolonisation in patients with cystic fibrosis

BACKGROUNDColonisation with Pseudomonas aeruginosa (PA) is a striking feature of lung involvement in cystic fibrosis. To identify the clinical consequences of the different steps of colonisation with PA under a...

Intraoperative diagnosis of primary ciliary dyskinesia

Primary ciliary dyskinesia refers to clinical disease attributable to congenitally abnormal or absent ciliary motility. Diagnosis typically requires electron microscopy to document aberrant axoneme ultrastructure. Electron microscopy, however, remains inaccurate and inconvenient as a screening test for symptomatic individuals. To avoid delays in diagnosis and to ensure adequacy of the tissue sample, we recommend a tracheal biopsy with an intraoperative histologic examination of ciliary motion. This study included patients evaluated at our institution for recurrent or chronic upper respiratory conditions characterized by chronic sinusitis, chronic mucoid otitis, and chronic bronchitis. A tracheal mucosa biopsy sample was obtained from each patient and was immediately examined in the operating room using light microscopy. If the magnified image demonstrated normal ciliary motility, primary ciliary dyskinesia was excluded and electron microscopy was not ordered. In the absence of normal ciliary motility, the specimen was placed in glutaraldehyde and ultrastructural axoneme morphology was evaluated. In the last 5 years, we have evaluated ciliary motility in 20 patients. Three patients had abnormal ciliary motility identified by light microscopy, and primary ciliary dyskinesia was confirmed histologically in each patient. In the remaining 17 patients, normal ciliary motility was observed, obviating the need for electron microscopy. We advocate intraoperative microscopic study of ciliary motility as a rapid, simple, accurate, and inexpensive technique to screen patients for primary ciliary dyskinesia. (Otolaryngol Head Neck Surg 1997;116:64-7.)

Sigmoidoscopy in children with chronic mucoid diarrhoea in rural St. Lucia

Sixty-nine per cent of a group of children with chronic mucoid diarrhoea who would not normally be seen in a tertiary health care facility had endoscopically demonstrable abnormality in the distal bowel, especially in the distal rectum. Sigmoidoscopy and punch biopsy of the rectum are safe procedures which can be undertaken in primary health care facilities. The inclusion of such investigations will facilitate the elucidation of the aetiology of chronic mucoid diarrhoea.

Middle ear mucosa in chronic effusions.

Biopsies of the middle ear mucosa were performed in 11 patients receiving their first ventilation tubes and in 5 patients who were admitted for reinsertion of tubes for chronic mucoid effusion. All patients had had the disease for at least 6 months. Mucosubstances were seen in the form of a mucus blanket, and as positive staining in the apical parts of the epithelial cells. Goblet cells varied greatly in frequency and larger subepithelial glands were present in cases of longer duration and intermittent discharge. In the majority of specimens, mononuclear cells were frequent in the propria, forming lymphocyte follicles in some cases. One-third of the specimens showed distinct fibrotic changes, and only a few inflammatory cells were present. Thus, mucosal response consisted of immune cells and could be due to chronic irritation, caused by bacteria and their immune complexes. Polymorphonuclear leukocytes were not present except in the effusion itself, a circumstance which points to infection as the causative factor. Pronounced proprial changes may indicate irreversibility of the disease.