Pulmonary function measures predict mortality differently in IPF versus combined pulmonary fibrosis and emphysema.

The composite physiologic index (CPI) was derived to represent the extent of fibrosis on high-resolution computed tomography (HRCT), adjusting for emphysema in patients with idiopathic pulmonary fibrosis (IPF). We hypothesised that longitudinal change in CPI would better predict mortality than forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC) or diffusing capacity of the lung for carbon monoxide (D(L,CO)) in all patients with IPF, and especially in those with combined pulmonary fibrosis and emphysema (CPFE). Cox proportional hazard models were performed on pulmonary function data from IPF patients at baseline (n = 321), 6 months (n = 211) and 12 months (n = 144). Presence of CPFE was determined by HRCT. A five-point increase in CPI over 12 months predicted subsequent mortality (HR 2.1, p = 0.004). At 12 months, a 10% relative decline in FVC, a 15% relative decline in D(L,CO) or an absolute increase in CPI of five points all discriminated median survival by 2.1 to 2.2 yrs versus patients with lesser change. Half our cohort had CPFE. In patients with moderate/severe emphysema, only a 10% decline in FEV(1) predicted mortality (HR 3.7, p = 0.046). In IPF, a five-point increase in CPI over 12 months predicts mortality similarly to relative declines of 10% in FVC or 15% in D(L,CO). For CPFE patients, change in FEV(1) was the best predictor of mortality.

Sex differences in physiological progression of idiopathic pulmonary fibrosis.

In idiopathic pulmonary fibrosis, incidence is higher in males, and females may have better survival. The aim of the present study was to determine whether the rate of increase in desaturation during serial 6-min walk testing would be greater, and survival worse, for males versus females. Serial changes in the percentage of maximum desaturation area (DA) over 1 yr were estimated using mixed models in 215 patients. DA was defined as the total area above the curve created using desaturation percentage values observed during each minute of the 6-min walk test. Multivariate Cox regression assessed survival differences. Adjusting for baseline DA, 6-min walk distance, change in 6-min walk distance over time and smoking history, the percentage of maximum DA increased by an average of 2.83 and 1.37% per month for males and females, respectively. Females demonstrated better survival overall, which was more pronounced in patients who did not desaturate below 88% on ambulation at baseline and after additionally adjusting for 6-month relative changes in DA and forced vital capacity. These data suggest that differences in disease progression contribute to, but do not completely explain, better survival of females with idiopathic pulmonary fibrosis.

Urokinase is required for the pulmonary inflammatory response to Cryptococcus neoformans. A murine transgenic model.

Urokinase (uPA) is hypothesized to provide proteolytic activity enabling inflammatory cells to traverse tissues during recruitment, and it is implicated as a cytokine modulator. Definitive evaluation of these hypotheses in vivo has previously been impossible because uPA could not completely and irreversibly be eliminated. This limitation has been overcome through the development of uPA-deficient transgenic mice (uPA-/-). Using these mice, we evaluated the importance of uPA in the pulmonary inflammatory response to Cryptococcus neoformans (strain 52D). C. neoformans was inoculated into uPA-/- and control mice (uPA+/+), and cell recruitment to the lungs was quantitated. The number of CFU in lung, spleen and brain was determined to assess clearance, and survival curves were generated. By day 21 after inoculation, uPA-/- mice had markedly fewer pulmonary inflammatory (CD45+), CD4+, and CD11b/CD18+ cells compared with uPA+/+ controls (P<0.0007); pulmonary CFUs in the uPA-/- mice continued to increase, whereas CFUs diminished in uPA+/+ mice(P<0.005). In survival studies, only 3/19 uPA+/+ mice died, whereas 15/19 uPA-/- mice died (p<0.001). We have demonstrated that uPA is required for a pulmonary inflammatory response to C. neoformans. Lack of uPA results in inadequate cellular recruitment, uncontrolled infection, and death.

Interleukin-8 gene expression by a pulmonary epithelial cell line. A model for cytokine networks in the lung.

Cellular constituents of the alveolar-capillary wall may be key participants in the recruitment of polymorphonuclear leukocytes to the lung through the generation of the novel neutrophil chemotactic peptide interleukin-8 (IL-8). This interaction appears to occur via the ability of human alveolar macrophage (AM)-derived monokines, tumor necrosis factor (TNF), and interleukin-1 (IL-1) to induce gene expression of IL-8 from pulmonary type II-like epithelial cells (A549). Northern blot analysis demonstrated that steady-state IL-8 mRNA expression, by either TNF- or IL-1 beta-treated A549 cells, occurred in both a dose- and time-dependent fashion. Similarly, extracellular antigenic IL-8, as assessed by specific ELISA, was expressed from TNF- or IL-1 beta-stimulated epithelial cells in a time-dependent fashion with maximal IL-8 antigen detected at 24 h poststimulation. Immunohistochemical staining utilizing rabbit anti-human IL-8 antibody identified immunoreactive, cell-associated IL-8 antigen as early as 8 h post-TNF or IL-1 beta stimulation. A549-generated neutrophil chemotactic bioactivity paralleled IL-8 steady-state mRNA levels. Signal specificity was demonstrated in this system as IL-8 mRNA or protein expression by lipopolysaccharide (LPS)-treated A549 cells was not different from unstimulated cells. Although LPS did not serve as a direct stimulus for the production of IL-8 by type II-like epithelial cells, the condition media from LPS-challenged AM induced a significant expression of IL-8 mRNA by the A549 cells. 24-h conditioned media from LPS-treated cells was as potent as either IL-1 beta or TNF in generating steady-state IL-8 mRNA by A549 cells. Preincubation of LPS-treated AM-conditioned media with anti-human TNF or IL-1 beta neutralizing antibodies resulted in significant abrogation of IL-8 gene expression by A549 pulmonary epithelial cells. These findings demonstrate potential cell-to-cell communication circuits that may be important between AMs and pulmonary epithelial cells during the recruitment phase of acute lung inflammation.

Focal interstitial CC chemokine receptor 7 (CCR7) expression in idiopathic interstitial pneumonia.

BACKGROUND/AIMS: Idiopathic interstitial pneumonias (IIPs) are a diverse grouping of chronic pulmonary diseases characterised by varying degrees of pulmonary fibrosis. The triggers of the fibroproliferative process in IIP remain enigmatic but recent attention has been directed towards chemokine involvement in this process. METHODS: The expression of two chemokine receptors, CCR7 and CXCR4, and their respective ligands, CCL19, CCL21, and CXCL12, were examined in surgical lung biopsies (SLBs) from patients with IIP. Transcript and protein expression of these receptors and their ligands was compared with that detected in histologically normal margin SLBs. RESULTS: CCR7 and CXCR4 were detected by gene array and real time polymerase chain reaction analysis and CCR7, but not CXCR4, expression was significantly raised in usual interstitial pneumonia (UIP) relative to biopsies from patients diagnosed with non-specific interstitial pneumonia (NSIP) or respiratory bronchiolitis/interstitial lung disease (RBILD). CCR7 protein was expressed in interstitial areas of all upper and lower lobe UIP SLBs analysed. CCR7 expression was present in 50% of NSIP SLBs, and CCR7 was restricted to blood vessels and mononuclear cells in 75% of RBILD SLBs. Immune cell specific CXCR4 expression was seen in IIP and normal margin biopsies. CCR7 positive areas in UIP biopsies were concomitantly positive for CD45 (the leucocyte common antigen) but CCR7 positive areas in all IIP SLBs lacked the haemopoietic stem cell antigen CD34, collagen 1, and alpha smooth muscle actin. CONCLUSION: This molecular and immunohistochemical analysis showed that IIPs are associated with abnormal CCR7 transcript and protein expression.

Human natural killer cells enhance a mixed leukocyte reaction.

Natural killer cells (NK) have been reported to down-regulate the initiation of T cell responses in animal models. In the current study, highly purified CD16+ human NK cells were obtained by cell sorting and their effect on the stimulation of allogeneic T cells (MLR) determined. NK cells did not directly stimulate T cell proliferation. However, when added to a population of loosely adherent mononuclear cells (LAM), NK enhanced the ability of these accessory cells to stimulate T proliferation. This effect was not reproduced by the addition of sorted CD5 + T cells, sorted CD16- cells, or control lymphocytes to the MLR. The effect of NK on the MLR was not restricted by class II antigens and was similar to the effect of adding IL-1 to MLR cultures. These results demonstrate that human NK cells are capable of enhancing a T cell response.

Mononuclear cells from human lung parenchyma support antigen-induced T lymphocyte proliferation.

We have previously demonstrated that there is a subpopulation of loosely adherent pulmonary mononuclear cells that can be isolated from minced and enzyme-digested lung tissue with a potent capacity to stimulate allogeneic T lymphocyte proliferation. We now demonstrate that these cells are also capable of stimulating an autologous mixed leukocyte reaction (AMLR) and presenting antigen to autologous T lymphocytes. These loosely adherent mononuclear cells (LAM) were more effective than either alveolar macrophages or monocytes as antigen-presenting cells. Depletion of phagocytic or Fc receptor-positive cells from the LAM population enhanced the stimulation of an reaction AMLR while preserving antigen-induced T lymphocyte proliferation. These results indicate that there are nonphagocytic, Fc receptor-negative accessory cells in human lung parenchyma capable of activating resting T cells in an AMLR and supporting antigen-specific T lymphocyte proliferation. The identity of these cells is uncertain, but the data strongly suggest that the cell is not a classical monocyte-derived macrophage. These antigen-presenting cells may be critical in the initiation of immune responses within the lung.

Separation of potent and poorly functional human lung accessory cells based on autofluorescence.

Human alveolar macrophages obtained by bronchoalveolar lavage are usually poor accessory cells in in vitro lymphoproliferation assays. However, we recently described a subpopulation of pulmonary mononuclear cells, obtained from minced and enzyme-digested lung, which were potent stimulators of allogeneic T-lymphocyte proliferation. These cells were enriched in loosely adherent mononuclear cell (LAM) fractions, but further study of these accessory cells was hampered by the heterogeneous nature of LAM. It was observed that in the majority of lung tissue sections, most alveolar macrophages were autofluorescent, whereas most interstitial HLA-DR positive cells were not. Therefore autofluorescence was utilized to fractionate LAM in an attempt to remove alveolar macrophages and selectively purify interstitial accessory cells. LAM were separated by flow cytometry using forward and side scatter to exclude lymphocytes, and red autofluorescence to obtain brightly autofluorescent (A pos) and relatively nonautofluorescent (A neg) mononuclear cells. Although both populations contained over 80% HLA-DR positive cells, A pos cells were poor accessory cells, whereas A neg cells were extremely potent stimulators of a mixed leukocyte reaction at all stimulator ratios tested. When A pos cells were added to A neg cells, T-cell proliferation was markedly suppressed in the majority of experiments. Morphologically, A pos cells appeared similar to classical alveolar macrophages with 95% of the cells being large and intensely nonspecific esterase positive. In contrast, the majority of A neg were smaller, B-cell antigen-negative, nonspecific esterase negative, and had a distinctive morphology on Wright-stained smears. We conclude that fractionation of LAM based on autofluorescence is a powerful tool to isolate and characterize lung mononuclear cells that act either as stimulators or as suppressors of immune responses in the lung.

Natural and perturbed distributions of Langerhans cells: responses to ultraviolet light, heterotopic skin grafting, and dinitrofluorobenzene sensitization.

Epidermal Langerhans cells exhibit many features of macrophages/monocytes. Both bear surface receptors for the Fc portion of immunoglobulin molecules and the C3b complement component. Both take up, process, and present antigens to reactive lymphocytes in an effective fashion, and they display on their cell surfaces the alloantigenic determinants encoded by the I region of the major histocompatibility complex. In view of these facts, we explored the extent to which cutaneous sites with unusual immunologic attributes might correspondingly have maldistributions or decreased surface densities of Langerhans cells. Common body sites such as the ear, back, and abdominal wall skin in hamsters, mice, and guinea pigs had regularly distributed ATPase-positive Langerhans cells in surface densities between 500 and 1,500 cells/mm2. In contrast, hamster cheek pouch epithelium had fewer than 200 Langerhans cells/mm2 and murine tail skin exhibited both a decreased density and an unusual gridlike distribution of the cells. Langerhans cells were never demonstrated in corneal epithelium. Perturbation of body wall skin with ultraviolet light and with dinitrofluorobenzene temporarily depleted the skin of ATPase-positive Langerhans cells. Heterotopic grafts of hamster cheek pouch and murine tail skin tended to accumulate Langerhans cells and to become more like body wall skin. The concordance of Langerhans cell aberrations and unusual immunologic features of corneal cheek pouches and tail skins suggests the possibility that intentional perturbations of surface Langerhans cells, as with UVL, might achieve unusual immunologic reactions within normal body wall skin.

Langerhans cells: sentinels of skin associated lymphoid tissue.

Langerhans-cell-enriched epidermal cell preparations, when pulsed with antigen, can induce proliferative responses, in immune T cells, that are of the same magnitude as those induced by antigen-pulsed macrophages. Additionally, these cells bear surface receptors for Fc and C3b and display on their cell surface determinants encoded by genes of the I region of the major histocompatibility complex. Histological studies have implicated Langerhans cells in cell-mediated immune responses such as delayed contact hypersensitivity to 2,4-dinitro-1-fluorobenzene (DNFB). Langerhans cells play an important role in the induction of contact sensitivity. When murine epidermis that is naturally or artificially depleted of Langerhans cells is painted with DNFB, no sensitization occurs. More importantly, animals whose initial exposure to DNFB occurs through skin deficient in Langerhans cells are unable subsequently to mount effective hypersensitivity responses to this agent. We there believe that Langerhans cells function as peripheral antigen-presenting cells and that in their absence the host responds to antigen challenge by becoming specifically unresponsive.

Unusual numbers and distribution of Langerhans cells in skin with unique immunologic properties.

Epidermal Langerhans cells resemble macrophages/monocytes in several remarkable ways: both bear surface receptors for the Fc portion of immunoglobulin molecules and for the C3b complement component. They take up, process and present antigen to reactive lymphocytes in an extremely effective fashion. They display on their cell surfaces the alloantigenic determinants encoded by genes of the I region of the major histocompatibility complex. Using ATPase activity, Langerhans cell surface densities are abnormal in 3 cutaneous sites which exhibit unique immunologic properties: markedly reduced numbers in hamster cheek pouch; reduced numbers and uneven distributions in murine tail skin; no Langerhans cells occur within corneal epithelium. As a functional expression of the absence of Langerhans cells from murine corneas, allografts prepared from corneal epithelium fail to sensitize recipients to Ia antigens encoded by I region genes of the donor. Corneal grafts disparate from their hosts at only I region loci are accepted for at least 45 days. The absence of Langerhans cells from cornea may account in part for its property as an immunologically privileged tissue. Subthreshold numbers of Langerhans cells in cheek pouch epithelium may contribute significantly to the observations that the hamster cheek pouch is an immunologically privileged site. We infer that skin deficient in Langerhans cells may be consequently deficient in alloantigenicity. Equally important, Langerhans cell-poor skin may be lacking in certain essential functions relating to the induction and expression of immune reactivity.

Androstenedione metabolism in human alveolar macrophages.

The metabolism of [3H]androstenedione by human alveolar macrophages was investigated. Alveolar macrophages were obtained by bronchopulmonary lavage by use of a heparinized saline solution devoid of Ca++ and Mg++. After purification, the macrophages were incubated at 37 C in RPMI-1640 medium that contained glucose and [1,2,6,7-3H]androstenedione under various experimental conditions. Control incubations were conducted without macrophages. After incubation, 14C-labeled steroids that corresponded to the metabolites were added as internal recovery standards. The metabolites were characterized by chromatography and crystallization to constant 3H to 14C ratios. Human alveolar macrophages convert [3H]androstenedione to 5 alpha-androstane-3,17-dione, testosterone, 5 alpha-dihydrotestosterone, androsterone, and isoandrosterone. Unidentified polar metabolites also were formed. Therefore, the following enzymes are present in these cells: 5 alpha-reductase, 17 beta-hydroxysteroid dehydrogenase, 3 alpha-hydroxysteroid dehydrogenase, 3 beta-hydroxysteroid dehydrogenase, and unknown hydroxylase(s). The rates of formation of the principal metabolites, 5 alpha-androstanedione and testosterone, remained linear up to 4 h of incubation and with macrophage number up to 1.5 X 10(7) cells/ml. These findings suggest that alveolar macrophages may be involved in the peripheral metabolism of androstenedione to potent androgens in man. It is possible that androgens, formed from blood-borne androstenedione within alveolar macrophages, may modulate phagocytic and other activities in these cells.

Pulmonary host defenses and oropharyngeal pathogens.

The lower respiratory tract is repetitively inoculated with oropharyngeal bacteria and yet pneumonia is an infrequent event. Efficient mechanisms of antibacterial defense are present in the respiratory tract that eliminate microbes before their presence or multiplication leads to disease in the majority of instances. Resident pulmonary defenses consist of aerodynamic defenses, the mucociliary apparatus, alveolar macrophages, complement, and surfactant. These resident defenses can be augmented by the development of an inflammatory response or the development of specific immunity. Significant species variability exists in the efficiency and mechanisms of clearance for oropharyngeal organisms. Streptococci are cleared promptly, Branhamella catarrhalis is cleared slowly, whereas non-typable Haemophilus influenzae multiply before being cleared. A dual phagocytic system of alveolar macrophages and recruited polymorphonuclear leukocytes is required for clearance of most oropharyngeal microbes. Systemic immunization can significantly enhance clearance of non-typable H. influenzae, suggesting immunoprophylaxis might be possible for this organism.

Steroids in idiopathic pulmonary fibrosis: a prospective assessment of adverse reactions, response to therapy, and survival.

PURPOSE: We evaluated the risk and potential benefit of high-dose corticosteroid therapy in patients with idiopathic pulmonary fibrosis. SUBJECTS AND METHODS: We prospectively studied 41 patients with previously untreated, biopsy-proven idiopathic pulmonary fibrosis. Before treatment, we calculated clinical, radiographic, and physiologic severity-of-illness scores for each patient. We scored high-resolution computerized tomographic (CT) scans for ground glass and interstitial opacity. We determined the extent of cellular infiltration, interstitial fibrosis, desquamation, and granulation in open lung biopsy samples. Patients were monitored monthly for steroid-related side effects, response to therapy at 3 months, and mortality. RESULTS: All patients experienced at least one steroid-induced side effect. Eleven (27%) patients were nonresponders, 11 (27%) were responders, and 19 (46%) remained stable. Of the 19 patients who died during a mean (+/- SD) follow-up of 3.3 +/- 2.3 years, 8 (42%) lost weight during the initial 3 months of steroid therapy; only 3 (14%) of the 22 patients still living (P = 0.08) experienced weight loss. In a multivariate analysis, greater fibrosis (hazard ratio [HR] = 1.4 per unit increase; 95% confidence interval [CI]: 1.0 to 1.9; P = 0.03) and cellularity (RR = 1.9 per unit increase; 95% CI: 1.3 to 2.8; 3, P <0.001) in the biopsy sample and whether a patient was classified as a responder (RR = 0.4 versus nonresponder; 95% CI: 0.2 to 1.0; P = 0.05) or stable (RR = 0.2 versus nonresponder; 95% CI: 0.1 to 0.6, P <0.001) after steroid therapy were associated with mortality. CONCLUSION: Corticosteroid treatment for idiopathic pulmonary fibrosis is associated with substantial morbidity. Patients who remain stable or respond to corticosteroid therapy have better survival than those who fail to respond. Whether this difference reflects an effect of treatment or less severe disease can be determined only in a randomized trial.

Mononuclear cells in exudative malignant pleural effusions. Characterization of pleural phagocytic cells.

The aims of this study were to develop a methodology for the isolation of highly enriched mononuclear phagocyte populations from exudative malignant pleural effusions (EMPE) and to characterize the phenotype and functional properties of these cells. Pleural effusion mononuclear cells (PEMC) were isolated by Ficoll centrifugation of EMPE and transudative pleural effusions and allowed to adhere to plastic for 1 h to obtain a pleural effusion mononuclear adherent cell (PEMAC) fraction. Only 66.0 +/- 4.2 percent of PEMAC ingested latex particles, indicating that a significant proportion of PEMAC were not phagocytic cells. Latex-positive PEMAC had the morphologic appearance of macrophages and stained positive (97.3 +/- 4.3 percent) with the anti-CD68 monoclonal antibody (MoAb), specific for macrophages. Conversely, latex-negative PEMAC (34.0 +/- 4.1 percent of PEMAC) did not react with the anti-CD68 MoAb and stained with anti-CD3 (34.7 +/- 10.7 percent) and anticytokeratin (50.5 +/- 16.4 percent) MoAbs, indicating that T cells and mesothelial cells were present in the PEMAC fraction. To improve the purification of pleural macrophages, PEMAC were cultured for an additional 18 h and the cells that remained adherent after this period constituted the firmly adherent mononuclear cell (FAMC) fraction. Nearly 90 percent of FAMC ingested latex particles and were CD68-positive. Virtually all FAMC were CD3-negative and cytokeratin-negative. Similar percentages of FAMC from EMPE and transudative effusions expressed the monocyte-lineage markers CD11b and CD14, suggesting that the proportion of monocyte-like mononuclear phagocytes in the pleural space is not increased during local tumor-associated inflammatory responses. The FAMC from EMPE (1) expressed HLA-DR antigens, (2) released interleukin 1 (IL-1) beta and tumor necrosis factor (TNF) alpha, and (3) stimulated allogeneic T-lymphocyte proliferation. The results of this study suggest that pleural mononuclear phagocytes may be involved in tumor-associated inflammatory reactions in the pleural compartment by stimulating the proliferation of other inflammatory cells and by releasing inflammatory cytokines.

Cyclophosphamide in the treatment of idiopathic pulmonary fibrosis: a prospective study in patients who failed to respond to corticosteroids.

STUDY OBJECTIVES: To prospectively examine the role of cyclophosphamide in patients with idiopathic pulmonary fibrosis that is unresponsive to or intolerant of high-dose steroid treatment. DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Nineteen patients with biopsy specimen-proven usual interstitial pneumonia who failed to respond (n = 16) or experienced adverse effects (n = 3) from corticosteroid treatment (1 mg/kg/d for 3 months). INTERVENTION: Steroid therapy was tapered quickly, and oral cyclophosphamide, 2 mg/kg/d, was prescribed (mean duration of treatment, 6.0 +/- 0.9 months). MEASUREMENTS AND RESULTS: In 10 patients, response to therapy was determined by pretreatment and posttreatment clinical (dyspnea), radiographic (chest radiograph), and physiologic (pulmonary function, including exercise saturation) scores (CRP). Response was defined as a > 10-point drop in CRP; stable as +/- 10-point change in CRP; and nonresponders as > 10-point rise in CRP. In nine patients, physiologic criteria were used to assess response; significant changes in pulmonary function were defined as follows: total lung capacity, +/- 10% of baseline value; FVC, +/- 10% of baseline value, diffusion capacity of the lung for carbon monoxide, +/- 20% of baseline value; and resting pulse oximetry, +/- 4% of baseline value. Patients who died while receiving or shortly after discontinuing cyclophosphamide were classified as nonresponders (n = 2). Among 19 patients treated with cyclophosphamide, only 1 patient demonstrated sustained response; 7 patients remained stable and 11 deteriorated while receiving the drug. Toxicity associated with cyclophosphamide was substantial; more than two thirds of the patients developed drug-related adverse effects, and almost half discontinued the drug prematurely due to side effects. In the remaining patients, cyclophosphamide therapy was discontinued due to lack of improvement or progressive deterioration. CONCLUSIONS: Cyclophosphamide therapy is of limited efficacy in patients with idiopathic pulmonary fibrosis who fail to respond or who experience adverse effects from corticosteroid treatment, and adverse effects often complicate its use.

The role of methotrexate in the management of steroid-dependent asthma.

Severe asthma often requires high-dose corticosteroid therapy. However, steroid therapy is fraught with many side effects. There are conflicting reports in the literature regarding the role of methotrexate in reducing the steroid requirements of these patients. This study examined the role of low-dose methotrexate in the management of steroid-dependent asthma. Eleven subjects with stable steroid-dependent asthma were enrolled in a placebo-controlled double-blind crossover trial. Patients received methotrexate, 15 mg/wk, or placebo each for two 12-week periods. There was significant improvement of pulmonary function and reduction of prednisone requirement in both placebo and methotrexate treatment periods. However, methotrexate was not superior to placebo. Only 3 of 11 patients responded to methotrexate. Although low-dose methotrexate therapy may have a role in a small select group of steroid-dependent asthmatics, it provided no additional benefit overall.

Augmented pulmonary IL-4 and IL-13 receptor subunit expression in idiopathic interstitial pneumonia.

BACKGROUND: Some idiopathic interstitial pneumonias (IIPs) are characterised by fibroproliferation and deposition of extracellular matrix. Because efficacious treatment options are limited, research has been directed towards understanding the cytokine networks that may affect fibroblast activation and, hence, the progression of certain IIPs. AIMS: To examine the expression of interleukin 4 (IL-4), IL-13, and their corresponding receptor subunits in the various forms of IIP and normal patient groups. METHODS: Molecular and immunohistochemical analysis of IL-4, interferon gamma (IFNgamma), IL-13, IL-4 receptor (IL-R), and IL-13 receptor subunits in surgical lung biopsies (SLBs) from 39 patients (21 usual interstitial pneumonia (UIP), six non-specific interstitial pneumonia (NSIP), eight respiratory bronchiolitic interstitial lung disease (RBILD), and five normal controls). RESULTS: Molecular analysis demonstrated that IL-13Ralpha2, IL-13Ralpha1, and IL-4Ralpha were present in a greater proportion of upper and lower lobe biopsies from patients with UIP than patients with NSIP and RBILD. Immunohistochemical analysis of patients with UIP, NSIP, and RBILD revealed interstitial staining for all three receptor subunits, whereas such staining was only seen in mononuclear cells present in normal SLBs. Fibroblastic foci in patients with UIP strongly stained for IL-4Ralpha and IL-13Ralpha2. Localised expression of IL-4Ralpha was also seen in SLBs from patients with NSIP but not in other groups. CONCLUSION: Some histological subtypes of IIP are associated with increased pulmonary expression of receptor subunits responsive to IL-4 and IL-13. These findings may be of particular importance in understanding the pathogenesis of IIP and, more importantly, may provide important novel therapeutic targets.

Influence of sample number and biopsy site on the histologic diagnosis of diffuse lung disease.

BACKGROUND: Although open biopsy is considered the optimal method for obtaining lung tissue for the diagnosis of diffuse infiltrative pulmonary disorders, there are no universally established guidelines concerning biopsy site selection and the ideal number of tissue samples. Relatively few investigations have been devoted to the influence exerted by the site and number of biopsy samples on the histologic diagnosis. METHODS: Seventy-seven open biopsy samples obtained from different lobes of 28 patients with idiopathic pulmonary fibrosis were analyzed. The histopathologic features were evaluated semiquantitatively and the results from each sample compared with those of the other samples obtained from each patient. RESULTS: Statistically significant differences in histopathologic features were not observed between samples. CONCLUSIONS: A single generous (2 cm or greater diameter) sample, obtained from a representative region of the radiographically most involved lobe, will suffice for diagnostic and evaluation purposes.

Nosocomial pneumonia.

Nosocomial pneumonias are a particularly problematic group of infections. The pathogenesis of these pneumonias, including mechanisms of colonization and pulmonary defense mechanisms, is discussed. An approach to the hospitalized patient with fever and infiltrates, based on the clinical setting, the nature of the host defense defect, the radiographic findings, and the results of invasive diagnostic procedures, is presented. Antimicrobial agents available to treat patients with nosocomial pneumonia are reviewed.