Evaluation of alveolitis by studies of lung biopsies

CD4+ and CD8+ T lymphocytes in lung tissue of NSIP: correlation with T lymphocytes in BALF

BACKGROUND

Nonspecific interstitial pneumonia (NSIP) is characterized by the interstitial infiltration T lymphocytes (TLs). Bronchoalveolar lavage fluid (BALF) has been used to analyze the inflammatory cells infiltrating in lung. The controversy about whether the BALF cellular profile reflects T lymphocytes in lung tissue still persists. Some studies found a positive correlation of cell composition between BALF and lung tissue, but others gave opposite conclusion.

OBJECTIVE

To investigate CD4+ and CD8+ T lymphocytes distribution in lung tissue of NSIP and the relationship with T lymphocytes in bronchoalveolar lavage.

METHODS

Thirty-seven patients diagnosed as NSIP were included. The pathological and BALF date were reviewed. The characteristics of TLs infiltration in different lung regions were investigated.

RESULTS

The study included 28 women. The median age was 48 years. In lung tissue, CD4+ and CD8+ lymphocytes (counts/0.1mm2) were separately accounted in lymphoid follicle region (156.51 ± 90.70 vs 85.30 ± 43.75), small blood vessel region (66.58 ± 31.99 vs 58.43 ± 30.24), interstitial region (37.60 ± 19.40 vs 47.12 ± 33.42) and small airway region (26.59 ± 17.04 vs 40.18 ± 34.02). CD4+/CD8+ ratios in lymphoid follicle and small vessel > 1, in interstitium and small airway <1. The number of CD8+ lymphocytes in BALF was correlated with CD8+ lymphocytes around small airway (r = 0.360, p = 0.029) and in interstitial region (r = 0.451, p = 0.005). CD4+/CD8+ ratio in BALF was correlated with that in small airway region (r = 0.437, p = 0.007) and interstitial region (r = 0.468, p = 0.003).

CONCLUSIONS

In NSIP, T lymphocytes were distributed in different regions of lung tissue. The CD8+ T lymphocytes and CD4+/CD8+ ratio in BALF reflect those in interstitium regions and around small airway of the lung.

Influência do biofármaco DNA-hsp65 na lesão pulmonar induzida por bleomicina

OBJETIVO: Avaliar a influência do biofármaco DNA-hsp65 em um modelo de distúrbio fibrosante pulmonar experimental. MÉTODOS: Foram estudados 120 camundongos machos C57BL/6, divididos em quatro grupos: grupo SS, animais tratados com salina (placebo) e injetados com salina intratraqueal (IT); grupo SB, tratados com salina (placebo) e injetados com bleomicina IT; grupo PB, tratados com plasmídeo, sem gene bacteriano, e injetados com bleomicina IT; e grupo BB, tratados com DNA-hsp65 e injetados com bleomicina IT. A bleomicina foi injetada 15 dias após a última imunização, e os animais sacrificados seis semanas após o uso da droga IT. O pulmão esquerdo retirado foi utilizado para análise morfológica, e o pulmão direito para dosagens de hidroxiprolina. RESULTADOS: A proporção de camundongos que apresentaram morte não-programada depois de 48 h da injeção IT foi maior no grupo SB em comparação ao grupo SS (57,7% vs. 11,1%). A área percentual média de interstício septal foi maior nos grupos SB e PB (53,1 ± 8,6% e 53,6 ± 9,3%, respectivamente) em comparação aos grupos SS e BB (32,9 ± 2,7% e 34,3 ± 6,1%, respectivamente). Os grupos SB, PB e BB mostraram aumentos nos valores médios da área de interstício septal corada por picrosirius em comparação ao grupo SS (SS: 2,0 ± 1,4%; SB: 8,2 ± 4,9%; PB: 7,2 ± 4,2%; e BB:6,6±4,1%).O conteúdo pulmonar de hidroxiprolina no grupo SS foi inferior ao dos demais grupos (SS: 104,9 ± 20,9 pg/pulmão; SB: 160,4 ±47,8 pg/pulmão; PB:170,0 ± 72,0 pg/pulmão; e BB: 162,5 ± 39,7 pg/pulmão). CONCLUSÕES: A imunização com o biofármaco DNA-hsp65 interferiu na deposição de matriz não-colágena em um modelo de lesão pulmonar induzida por bleomicina.

Inflammatory Cell Phenotyping of the Pulmonary Interstitium in Idiopathic Interstitial Pneumonia

BACKGROUND

Several studies have implicated the role of inflammation in the pathogenesis of lung damage in idiopathic interstitial pneumonias (IIPs). Investigations of inflammatory cells in IIP have show that eosinophils, neutrophils and T cells may be associated with a poorer prognosis.

OBJECTIVES

The aim of our study was to map, by quantitative analysis, the number of inflammatory cells in the lung tissue of patients with non-specific interstitial pneumonia/non-specific interstitial pneumonia (NSIP/NSIP), acute interstitial pneumonia/diffuse alveolar damage (AIP/DAD) and idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) and to correlate them with lung function tests and survival.

METHODS

After immunohistochemical staining, we quantified the content of inflammatory cells [macrophages, neutrophils (elastase+), plasma cells, and CD3, CD4 and CD8 T lymphocytes (TLs)] in 20 NSIP, 20 DAD and 20 UIP surgical lung biopsies.

RESULTS

The total density of inflammatory cells was significantly increased in DAD and NSIP when compared to UIP (p = 0.04). TLs were increased in DAD and NSIP when compared to UlP lungs (p < 0.05). The density of inflammatory cells in UIP showed significant differences in normal, intervening and dense fibrosis areas (p < 0.05). The most numerous cells infiltrating the mural fibrosis and honeycombing areas were plasma cells, neutrophils (elastase+), CD20+, CD3+, CD4+ and CD8+ (p < 0.05). In UIP, CD3+ TLs were directly correlated with forced expiratory volume in 1 s/forced vital capacity ratio x 100 (p = 0.05). CD68+ cells presented a significant positive correlation with the forced expiratory volume in 1 s (p = 0.04); neutrophil (elastase+) cells significantly correlated with residual volume (p = 0.02), residual volume/total lung capacity (p = 0.04) and carbon monoxide transfer factor (p = 0.03). The most important predictor of survival in UIP was CD3+ TLs (p = 0.05).

CONCLUSION

The total density of inflammatory cells and lymphocytes presents a different distribution within the pulmonary parenchyma in AIP/DAD, NSIP/NSIP and IPF/UIP evolutionary adapted responses to injury. There is a localized distribution of inflammation in the normal, intervening and dense fibrosis areas of UIP for CD3+, associated with a lethal deterioration of the pulmonary function and poor survival. Our findings provide further evidence of the importance of inflammation in the pathophysiology of IIPs.

CD8+ T lymphocytes in lung tissue from patients with idiopathic pulmonary fibrosis

Background

Several studies have implicated a role of inflammation in the pathogenesis of lung damage in idiopathic pulmonary fibrosis (IPF). Parenchymal lung damage leads to defects in mechanics and gas exchange and clinically manifests with exertional dyspnea. Investigations of inflammatory cells in IPF have shown that eosinophils, neutrophils and CD₈₊ TLs may be associated with worse prognosis. We wished to investigate by quantitative immunohistochemistry infiltrating macrophages, neutrophils and T lymphocytes (TLs) subpopulations (CD₃₊, CD₄₊ and CD₈₊) in lung tissue of patients with IPF and their correlation with lung function indices and grade of dyspnoea.

Methods

Surgical biopsies of 12 patients with IPF were immunohistochemically stained with mouse monoclonal antibodies (anti-CD₆₈ for macrophages, anti-elastase for neutrophils, and anti-CD₃, anti-CD₄, anti-CD₈ for CD₃₊TLs, CD₄₊TLs, and CD₈₊TLs respectively). The number of positively stained cells was determined by observer-interactive computerized image analysis (SAMBA microscopic image processor). Cell numbers were expressed in percentage of immunopositive nuclear surface in relation to the total nuclear surface of infiltrative cells within the tissue (labeling Index). Correlations were performed between cell numbers and physiological indices [FEV₁, FVC, TLC, DLCO, PaO₂, PaCO₂ and P(A-a)O₂)] as well as dyspnoea scores assessed by the Medical Research Council (MRC) scale.

Results

Elastase positive cells accounted for the 7.04% ± 1.1 of total cells, CD₆₈₊ cells for the 16.6% ± 2, CD₃₊ TLs for the 28.8% ± 7, CD₄₊ TLs for the 14.5 ± 4 and CD₈₊ TLs for the 13.8 ± 4. CD₈₊TLs correlated inversely with FVC % predicted (r_s = -0.67, p = 0.01), TLC % predicted (r_s = -0.68, p = 0.01), DLCO % predicted (r_s = -0.61, p = 0.04), and PaO₂ (r_s = -0.60, p = 0.04). Positive correlations were found between CD₈₊TLs and P(A-a)O₂ (r_s = 0.65, p = 0.02) and CD₈₊TLs and MRC score (r_s = 0.63, p = 0.02). Additionally, CD₆₈₊ cells presented negative correlations with both FVC % predicted (r_s = -0.80, p = 0.002) and FEV₁ % predicted (r_s = -0.68, p = 0.01).

Conclusion

In UIP/IPF tissue infiltrating mononuclear cells and especially CD₈₊ TLs are associated with the grade of dyspnoea and functional parameters of disease severity implicating that they might play a role in its pathogenesis.

The Increase in Serum Soluble ST2 Protein Upon Acute Exacerbation of Idiopathic Pulmonary Fibrosis

BACKGROUND

The human ST2 gene can be specifically induced by growth stimulation in fibroblastic cells, and the soluble ST2 protein (ST2) is expressed preferentially in T-helper type 2 (Th2) cells. Furthermore, ST2 is induced by proinflammatory stimuli such as tumor necrosis factor-alpha and interleukin-1 beta. It has been reported that the inflammatory response in idiopathic pulmonary fibrosis (IPF) is thought to be associated with proinflammatory cytokines and Th2 immune response.

STUDY OBJECTIVE

The objective of this study was to evaluate the relevance of the serum ST2 levels in the pathogenesis of IPF.

DESIGN

Retrospective study.

SETTING

Inpatients in a college hospital.

PARTICIPANTS

Forty-nine patients with IPF admitted to our hospital 64 times: 36 patients were admitted once, 11 patients were admitted twice, and 2 patients were admitted three times. The participants also included 200 healthy control volunteers.

MEASUREMENTS AND RESULTS

Among 64 events in 49 patients with IPF, 50 of the events occurred in a stable state, and 14 events occurred during acute exacerbation. An acute exacerbation of IPF was defined as an accelerated phase of IPF. The serum ST2 levels were measured by enzyme-linked immunosorbent assay. The serum levels of ST2 in the stable state group did not differ from those in the healthy control group, while the serum levels of ST2 in the acute exacerbation group were significantly higher than those in the stable state group or the healthy control group (p < 0.001, acute exacerbation group vs stable state group or healthy control group; acute exacerbation group, 2.76 +/- 0.56 ng/mL; stable state group, 0.44 +/- 0.07 ng/mL; healthy control group, 0.42 +/- 0.03 ng/mL). Furthermore, serum ST2 statistically correlated with lactate dehydrogenase (r = 0.344, p = 0.005) and C-reactive protein (r = 0.496, p < 0.001), and inversely correlated with PaO(2) (r = - 0.356, p = 0.018) and the percentage of predicted vital capacity (r = - 0.346, p = 0.026).

CONCLUSIONS

These results suggest that ST2 protein may increase in the serum, reflecting severity in the inflammatory process and Th2 immune response in the IPF lung.

Phase I/II trial of autologous stem cell transplantation in systemic sclerosis: procedure related mortality and impact on skin disease

BACKGROUND

Systemic sclerosis (SSc, scleroderma) in either its diffuse or limited skin forms has a high mortality when vital organs are affected. No treatment has been shown to influence the outcome or significantly affect the skin score, though many forms of immunosuppression have been tried. Recent developments in haemopoietic stem cell transplantation (HSCT) have allowed the application of profound immunosuppression followed by HSCT, or rescue, to autoimmune diseases such as SSc.

METHODS

Results for 41 patients included in continuing multicentre open phase I/II studies using HSCT in the treatment of poor prognosis SSc are reported. Thirty seven patients had a predominantly diffuse skin form of the disease and four the limited form, with some clinical overlap. Median age was 41 years with a 5:1 female to male ratio. The skin score was >50% of maximum in 20/33 (61%) patients, with some lung disease attributable to SSc in 28/37 (76%), the forced vital capacity being <70% of the predicted value in 18/36 (50%). Pulmonary hypertension was described in 7/37 (19%) patients and renal disease in 5/37 (14%). The Scl-70 antibody was positive in 18/32 (56%) and the anticentromere antibody in 10% of evaluable patients. Peripheral blood stem cell mobilisation was performed with cyclophosphamide or granulocyte colony stimulating factor, alone or in combination. Thirty eight patients had ex vivo CD34 stem cell selection, with additional T cell depletion in seven. Seven conditioning regimens were used, but six of these used haemoimmunoablative doses of cyclophosphamide +/- anti-thymocyte globulin +/- total body irradiation. The median duration of follow up was 12 months (3-55).

RESULTS

An improvement in skin score of >25% after transplantation occurred in 20/29 (69%) evaluable patients, and deterioration in 2/29 (7%). Lung function did not change significantly after transplantation. One of five renal cases deteriorated but with no new occurrences of renal disease after HSCT, and the pulmonary hypertension did not progress in the evaluable cases. Disease progression was seen in 7/37 (19%) patients after HSCT with a median period of 67 (range 49-255) days. Eleven (27%) patients had died at census and seven (17%) deaths were considered to be related to the procedure (direct organ toxicity in four, haemorrhage in two, and infection/neutropenic fever in one). The cumulative probability of survival at one year was 73% (95% CI 58 to 88) by Kaplan-Meier analysis.

CONCLUSION

Despite a higher procedure related mortality rate from HSCT in SSc compared with patients with breast cancer and non-Hodgkin's lymphoma, the marked impact on skin score, a surrogate marker of mortality, the trend towards stabilisation of lung involvement, and lack of other treatment alternatives justify further carefully designed studies. If future trials incorporate inclusion and exclusion criteria based on this preliminary experience, the predicted procedure related mortality should be around 10%.

Bronchoalveolar lavage in children with chronic diffuse parenchymal lung disease

The aim of the present study was to compare cellular and noncellular components of bronchoalveolar lavage fluid (BAL) in a group of children with a diagnosis of chronic diffuse parenchymal lung disease (cDPLD) and a group of children without parenchymal lung disease undergoing BAL for various clinical indications (control group). We evaluated cellular and non-cellular components (total proteins, albumin, hyaluronic acid, and fibronectin) in BAL fluid from 14 children (7 boys and 7 girls; mean age 9.2 years, range 5 months to 18.4 years) fulfilling the clinical and radiological diagnosis of chronic cDPLD, and in 19 controls without evidence of lung disease. The 14 patients were assigned to two study groups: early-stage cDPLD (6 patients; age range 5 months to 5.2 years; duration of illness, 5-7 months) and long-standing cDPLD (8 patients; age range 9.6-18.4 years; duration of illness, 1.2-17.6 years). Ninety-three percent of the patients with cDPLD had at least two BAL constituents outside normal limits, with high numbers of cells, including all types of alveolar cells, but especially lymphocytes and foamy macrophages. These findings indicate a mixed, predominantly lymphocytic alveolitis. Our patients also had a significant increase in two noncellular BAL components, namely fibronectin and hyaluronic acid. BAL samples from children with long-standing cDPLD contained increased numbers of lymphocytes, whereas samples from children with early-stage cDPLD contained increased percentages and numbers of foamy macrophages and increased concentrations of fibronectin, hyaluronic acid, and albumin. In conclusion, we clearly identified an abnormal BAL profile in our group of cDPLD patients. Moreover, BAL findings differentiated younger cDPLD patients in the early stages of their illness from old patients with long-standing disease.

Secretion of stem cell factor by alveolar fibroblasts in interstitial lung diseases

Sarcoidosis (SA) and diffuse interstitial fibrosis (DIF) are characterized by alveolitis, mast cell hyperplasia and increased fibroblast proliferation. Stem cell factor (SCF) stimulates proliferation of hematopoietic progenitor cells involved in mast and stromal cell interaction. We assessed the role of SCF secreted by alveolar fibroblasts (AFb) in the development of fibrosis of DIF and SA in six patients with SA and six patients with DIF. Bronchoalveolar lavage (BAL) was performed by conventional methods. A total of 500 cells were differentially counted from Giemsa-stained cytopreps. AFb and supernatants were recovered from long-term cultures of BAL cells and from 24 h cultures of confluent AFb. Levels of SCF were measured by ELISA. Alpha actin content of AFb was characterized by immunohistochemistry. The expression of AFb mRNA for IL1-alpha and beta, TGF-beta, IFN-gamma, IL-2, IL-4, IL-5 and IL-6 was determined by RT-PCR. There was a lymphocytic predominance in the SA patients and an increase in neutrophils and eosinophils in DIF. SCF secreted by AFb from DIF was significantly higher than in SA. TNF + IL-1 significantly decreased the secretion of SCF by AFb. There was a positive correlation between SCF levels and the percentage eosinophils but not for metachromatic cells. Alpha-actin expression of AFb in DIF was significantly higher than in SA. Cytokine mRNA was extracted from AFb of two SA and two DIF patients. The profile showed that only in stimulated AFb isolated from the DIF patients can IL-5 transcripts be visualized. In conclusion, AFb can contribute to the onset of fibrosis by secreting SCF and IL-5 which, in turn, may recruit eosinophils.

Interstitial lung disease in systemic sclerosis: comparison of BALF lymphocyte phenotype and DLCO impairment

Patients with scleroderma (systemic sclerosis-SSc) frequently develop an interstitial lung disease. The role of lymphocytes in fibrosing alveolitis preceding lung fibrosis has been established. The purpose of this work was to evaluate cell profiles and lymphocyte phenotypes in the bronchoalveolar lavage (BAL) fluid and to correlate them with depression in lung function tests detected by depletion of diffusing capacity (DLCO). BAL was carried out in 25 untreated, non-smoking patients suffering from diffuse scleroderma and in 12 healthy non-smoking volunteers. For the analysis of lymphocyte sub-sets flow cytometry and monoclonal antibodies were used. The following cell sub-types were counted: T lymphocytes, B lymphocytes, helper lymphocytes, suppressor/cytotoxic lymphocytes, natural killer cells, cytotoxic T lymphocytes and activated T lymphocytes. The total cell count was higher in the group of patients with mild and moderate impairment in DLCO. The percentage of lymphocytes was greater in patients with DLCO lower than 65% of the predicted value since neutrophilia was found in patients with severe DLCO depletion, i.e. significant when compared with healthy subjects. The proportions of suppressor/cytotoxic lymphocytes and of activated T lymphocytes were higher in patients than in controls. The statistical analysis revealed significant differences between patients with moderate and mild changes in DLCO and the healthy volunteers. A decreased helper/suppressor ratio was noticed in these patients. We concluded that the BALF lymphocyte phenotype analysis may reflect the features of alveolitis in patients with SSc.

Detection of anti-cytokeratin 8 antibody in the serum of patients with cryptogenic fibrosing alveolitis and pulmonary fibrosis associated with collagen vascular disorders

BACKGROUND

It has been suggested that the humoral immune system plays a role in the pathogenesis of cryptogenic fibrosing alveolitis (CFA). Although circulating autoantibodies to lung protein(s) have been suggested, none of the lung proteins have been characterised. The purpose of this study was to determine the antigen to which the serum from patients with pulmonary fibrosis reacted.

METHODS

The anti-A549 cell antibody was characterised in a patient with CFA using Western immunoblotting and immunohistochemical staining of A549 cells. As we identified that one of the antibodies against A549 cells was anti-cytokeratin 8, the expression of mRNA of cytokeratin 8 in A549 cells was evaluated. In addition, we attempted to establish an enzyme linked immunosorbent assay to measure the levels of anti-cytokeratin 8 antibody in the serum of patients with CFA and pulmonary fibrosis associated with collagen vascular disorders (PF-CVD).

RESULTS

Initially two anti-A549 cell antibodies were detected in the serum of patients with pulmonary fibrosis, one of which was characterised as anticytokeratin 8 antibody by Western immunoblotting. We were able to establish an ELISA to measure anti-cytokeratin 8 antibody and found significantly higher levels in patients with CFA and PF-CVD than in normal volunteers, patients with sarcoidosis, pneumonia, and pulmonary emphysema.

CONCLUSIONS

One of the anti-A549 cell antibodies in the serum of patients with CFA was against cytokeratin 8. The serum levels of anti-cytokeratin 8 antibody were increased in patients with CFA and PF-CVD. These results suggest that anticytokeratin 8 antibody may be involved in the process of lung injury in pulmonary fibrosis.

Mast cells, eosinophils and fibrosis

We have presented results that increase our understanding of the roles MC and EOS play in modulating fibrotic processes. In vitro studies have provided clear-cut evidence for the direct involvement of these two inflammatory cells in enhancing proliferation, and either enhancing or decreasing collagen synthesis in human fibroblasts isolated from different anatomical locations. In addition, we have shown that MC and EOS interactions can also take part in modulating fibrosis. In vivo studies in murine and human cGVHD showed that MC activation is detrimental, and that MC stabilization therapy may be helpful in treating the fibrotic outcome of this disease. Much is still obscure. It is, for example, important to define the MC and EOS mediators involved in the modulation of fibroblast properties, and their pattern of influence, keeping in mind the ultimate goal of defining new therapeutic targets for the treatment of fibrotic diseases.

The immunological architecture of B-lymphocyte aggregates in cryptogenic fibrosing alveolitis

Cryptogenic fibrosing alveolitis (CFA) is believed to have a pathogenesis mediated by the cellular arm of the immune system. Previous studies have, however, indicated the presence of B-lymphocyte aggregates, as well as evidence of local immunoglobulin production and increased levels of B-cell growth factors. It has recently been shown that CFA is associated with the production of circulating IgG autoantibodies to antigen(s) associated with alveolar lining cells. This prompted an examination of the immunological architecture of the B-lymphocyte aggregates, in order to assess whether they might provide histological confirmation of a local humoral immune response in these patients. Thirty-eight consecutive open lung biopsy specimens were examined from patients with CFA and aggregates of B lymphocytes were identified in 37/38. In only five cases were germinal centres seen. The morphological appearances of the aggregates were reminiscent of those observed in mucosal associated lymphoid tissue (MALT). Using immunohistochemistry, despite the low frequency of true germinal centre formation, the B-lymphocyte aggregates were shown to contain the cellular micro-environment necessary for a humoral immune response. In addition, there was evidence of lymphocyte proliferation and activation within these aggregates. These results provide evidence of a local humoral immune response associated with B-lymphocyte aggregates in the lungs of patients with CFA.

A type 2 (Th2-like) pattern of immune response predominates in the pulmonary interstitium of patients with cryptogenic fibrosing alveolitis (CFA)

CFA is an inflammatory condition of the lungs resulting in scarring, pulmonary failure and death. The etiology of the disease is unknown, but the pathogenesis is believed to involve a persistent immunological reaction to unidentified antigen in the lung resulting in tissue damage. Recent advances in our understanding of the immune system have shown that different patterns of stimulatory cytokines are produced at sites of inflammation by a range of cell types. Patterns of cytokine reproduction by inflammatory cells are recognized to be associated with different patterns of immunological response, and these have been described as type 1 (or Th1-like) and type 2 (or Th2-like) on this basis. We have studied cytokine expression in the intestinal inflammatory cell infiltrate in lung tissue from patients with CFA using mRNA in situ hybridization and immunohistochemistry. Our results show that while there is evidence for both a type 1 (characterized by interferon-gamma (IFN-gamma) and type 2 (characterized by IL-4 and IL-5) response present in CFA, the type 2 (or Th2) pattern of cytokines appears to predominate. This would be consistent with a possible role for the humoral immune response in the pathogenesis of this condition. In addition, recent evidence suggests that IL-4 and IFN-gamma may be important regulatory factors for pulmonary fibroblasts. The relative paucity of IFN-gamma may contribute to the excessive fibroblast activation, deposition of collagen and scar formation that occurs in CFA.

Phenotypic and functional activation of alveolar macrophages, T lymphocytes and NK cells in patients with systemic sclerosis and primary Sjögren's syndrome

OBJECTIVES

Attempts to differentiate between the pathogenesis of the severe pulmonary manifestations observed in systemic sclerosis (SSc) and the mild form in primary Sjögren's syndrome (pSS) were performed by studying cell populations recovered during bronchoalveolar lavage (BAL).

METHODS AND RESULTS

Two-colour flow cytometric analysis of BAL fluid lymphocytes showed a similar degree of phenotypic activation (DR+) of CD4+ and CD8+ T lymphocyte subsets and CD16+ NK cells in patients with SSc (n = 13) and pSS (n = 11) groups and healthy controls (n = 11). Alveolar macrophages expressed the CD14 antigen at significantly increased densities in patients with SSc. Alveolar macrophage activation in SSc was also suggested by increased IL-6 concentrations in neat BAL fluid and increases in macrophage production of TNF alpha and EGF in vitro. SSc patients also had increased proportions of neutrophils and eosinophils in BAL fluid. No correlations were found between any cellular subsets or cytokine levels in BAL fluid and lung status at the time of lavage in SSc or pSS patients or the subsequent course of the pulmonary function in SSc patients.

CONCLUSION

It is concluded that the phenotypical activation of alveolar helper/inducer (DR+CD4+) and suppressor/cytotoxic (DR+CD8+) T lymphocytes and NK (DR+CD16+) cells is not a prerequisite for the development of lung fibrosis in SSc or bronchial hyper-responsiveness in pSS. Alveolar macrophage activation may contribute to the development of lung fibrosis in SSc.

Circulating antibodies to lung protein(s) in patients with cryptogenic fibrosing alveolitis

BACKGROUND

It has been hypothesised that cryptogenic fibrosing alveolitis has an immunological pathogenesis mediated by T lymphocytes. It is, however, recognised that patients may show dysregulation of the humoral immune system and that the presence of large numbers of B lymphocytes in open lung biopsies may be associated with a poor prognosis. Evidence of a role for the humoral immune system in the pathogenesis of cryptogenic fibrosing alveolitis has been suggested, but attempts to demonstrate circulating immunoglobulin to antigen within the lung have been inconclusive.

METHODS

Plasma samples from 22 patients with cryptogenic fibrosing alveolitis, 22 patients with sarcoidosis, and 17 healthy controls were screened by SDS-PAGE and Western blotting for the presence of autoantibodies to lung proteins derived from cryptogenic fibrosing alveolitis, sarcoid and control lung tissue, as well as four normal non-pulmonary tissues. Possible site(s) of target protein(s) within the lung tissue were identified by immunohistochemical examination using IgG purified from the plasma of six patients and two controls.

RESULTS

Eighteen of the plasma samples from patients with cryptogenic fibrosing alveolitis had reactive IgG to lung protein(s) in the 70-90 kDa molecular weight range compared with five of 18 plasma samples from patients with sarcoidosis and one of 17 controls. Plasma from patients with cryptogenic fibrosing alveolitis recognised antigen(s) of the same molecular weight in control and sarcoid lung tissue, but not non-pulmonary tissues, with a similar frequency. Immunohistochemical staining of cryptogenic fibrosing alveolitis biopsy material using IgG purified from plasma samples from patients with cryptogenic fibrosing alveolitis, but not control samples, revealed fine linear positivity in the lung parenchyma in a pattern suggestive of reaction with alveolar lining cells. The pattern was cytoplasmic/membranous and not nuclear.

CONCLUSIONS

Patients with cryptogenic fibrosing alveolitis have a high frequency of plasma IgG autoantibodies to protein(s) within lung tissue associated with alveolar lining cells. This is believed to be the site where immunological injury occurs in cryptogenic fibrosing alveolitis, but the significance of these antibodies to the aetiology and pathogenesis is as yet unclear.

New perspectives on basic mechanisms in lung disease. 1. Lung injury, inflammatory mediators, and fibroblast activation in fibrosing alveolitis

It is over 25 years since Scadding first defined the term fibrosing alveolitis. It has since been established that complex mechanisms underlie its pathogenesis, including epithelial and endothelial injury, vascular leakage, production of inflammatory cells and their mediators, and fibroblast activation. Only through a detailed knowledge of how these cellular and molecular events are interlinked will we learn how to combat this disease, which is notoriously resistant to present treatments. So far the only therapeutic advances have been refinements in immunosuppression, and even these treatments are frequently disappointing. We believe that future advances in treatment will come from the development of agents that protect endothelial and epithelial cells from further injury and agents that can inhibit release of inflammatory mediators. A better knowledge of the mechanisms of collagen gene activation and the biochemical pathways of collagen production may also allow the identification of vulnerable sites at which new treatments may be directed. A combined approach to modifying appropriate parts of both the inflammatory component and the fibroblast/collagen component should provide a new stimulus to research. Further epidemiological studies are also needed to identify the environmental causes of lung injury that initiate the cascade of events leading to interstitial fibrosis.

In vivo levels and in vitro production of interferon-gamma in fibrosing interstitial lung diseases

The in vivo role of interferons in the development of fibrosis is not fully understood but it is known that interferons can suppress fibroblast proliferation and collagen synthesis in vitro. We have recently demonstrated that in a group of patients with sarcoidosis having predominant pulmonary involvement, patients with the highest levels of circulating interferon-gamma (IFN-gamma) more frequently resolved on corticosteroids, suggesting that they had a less 'fibrotic' component to their disease. We now report that in two other diseases, where the tendency to develop pulmonary fibrosis is greater than in sarcoidosis, namely cryptogenic fibrosing alveolitis (CFA) and fibrosing alveolitis associated with the systemic connective tissue disease progressive systemic sclerosis (FA + PSS), very few patients have elevations in IFN-gamma in their serum. However, as in sarcoidosis, those with the highest levels responded to corticosteroids (P less than 0.05). Attempts to measure IFN-gamma levels in the lungs, using cell-free bronchoalveolar lavage (BAL) fluid supernatants, were negative in all the study groups, suggesting that these samples may be inadequate for such studies. To investigate whether there might be an intrinsic defect in T lymphocyte function associated with predisposition to fibrosing lung diseases, we then investigated the in vitro production of IFN-gamma by lymphocytes separated from the blood of 18 untreated patients (six with CFA, six with FA + PSS and six with sarcoidosis). IFN-gamma production was impaired in 10 (56%) (two with CFA, four with FA + PSS and four with sarcoidosis). A higher proportion of the fibrosing alveolitis patients (CFA or FA + PSS) with impaired IFN-gamma production have subsequently shown spontaneous lung functional deterioration. These findings suggest that impaired IFN-gamma release might be a potentiating factor in the pathogenesis of these fibrosing lung diseases.