Immunophenotyping of lymphocytes in bronchoalveolar lavage fluid. A new flow cytometric method vs standard immunoperoxidase technique

[Which technique should be used in the phenotyping of lymphocytic alveolitis: Immunocytochemistry or flow cytometry]

BACKGROUND

Diffuse interstitial pneumonias are considered as a group of multiple affections characterized by challenging diagnoses because of the lack of specific clinical signs. Radiologic investigations highlight the diagnoses in most of the cases but bronchoalveolar lavage plays a key role in the diagnostic diagram. We aim to compare the immunocytochemical technique and the flow cytometry in the phenotyping of lymphocytic alveolitis.

METHODS

We described a series of 32 lymphocytic alveolitis, which were analyzed using immunocytochemistry and flow cytometry.

RESULTS

We found a good reproducibility between the immunocytochemistry performed on smears and cytoblocks (kappa=0.7) and a poor reproducibility between immunocytochemistry and flow cytometry (kappa=0.35).

CONCLUSION

Our study emphasized on the poor reproducibility between immunocytochemistry and flow cytometry. Further studies about the reliability of both techniques are needed especially in discordant cases.

Nationwide epidemiological survey of chronic hypersensitivity pneumonitis in Japan

BACKGROUND

In 1999, a Japanese epidemiological survey of chronic hypersensitivity pneumonitis (HP) showed that summer-type HP was the most prevalent variant of the disease. The number of reported cases of chronic HP has recently been increasing, and the clinical features of the disease seem to have changed. We conducted another nationwide epidemiological survey of chronic HP in Japan to determine better estimates of the frequency and clinical features of the disease.

METHODS

A questionnaire was sent to qualified hospitals throughout Japan, and data on cases of chronic HP diagnosed between 2000 and 2009 were collected.

RESULTS

In total, 222 cases of chronic HP from 22 hospitals were studied. Disease subtypes included bird-related HP (n=134), summer-type HP (n=33), home-related HP (n=25), farmer's lung (n=4), isocyanate-induced HP (n=3), and other types (n=23). The median proportion of lymphocytes in bronchoalveolar lavage fluid was high (24.5%). The primary findings of computed tomography of the chest were ground-glass attenuation and interlobular septal thickening. Centrilobular fibrosis was the major pathological finding on examination of surgical lung biopsy specimens from 93 patients. The median survival time was 83 months.

CONCLUSIONS

The proportion of bird-related HP was higher than that in the previous epidemiological survey, and the proportions of isocyanate-induced HP and farmer's lung were lower. A crucial step in diagnosing chronic HP is to thoroughly explore the possibility of antigen exposure.

Bronchoalveolar lavage quality influences the T4/T8 ratio in sarcoidosis

BACKGROUND

Sarcoidosis is characterised by a T-lymphocytic alveolitis with a typically increased T4/T8 ratio. The diagnostic value of this ratio is under debate.

AIM OF THE WORK

We prospectively evaluated the influence of BAL pre-lavage and the impact of bronchial contamination on BAL differential cell count in 108 BAL specimens obtained from patients with histologically confirmed sarcoidosis.

METHODS

BAL was performed by instilling 150-300 ml normal saline either in the middle lobe or the lingula. Fifty-one patients (47%) underwent additional pre-lavage with 50 ml normal saline. Bronchial contamination was assessed by semi-quantitative analysis of mucus, ciliated and squamous cells in the untreated BAL recovery.

RESULTS

Pre-lavage did neither influence the lavage cellularity nor extend of contamination of the BAL. Content of mucus and ciliated cells, indicating bronchial contamination, showed a high correlation (Kendal's tau=0.61). Presence of either mucus or ciliated cells in the BAL recovery was associated with a significant lower T4/T8 ratio (mucus: 4.9 vs. 8.0, p=0.009; ciliated cells: 4.1 vs. 7.4, p=0.001). Squamous cells in the BAL recovery representing oropharyngeal contamination did not significantly influence the T4/T8 ratio (7.7 vs. 5.6, p=0.10).

CONCLUSION

Bronchial contamination of BAL as determined by the presence of mucus and ciliated cells in the recovery decreases the T4/T8 ratio of BAL in sarcoidosis.

Extrinsic allergic alveolitis: comparative study of the bronchoalveolar lavage profiles and radiological presentation

INTRODUCTION

Extrinsic allergic alveolitis (EAA) is an immunologically mediated interstitial lung disease. The abnormalities in the bronchoalveolar lavage (BAL) fluid cell counts are almost always seen in patients with EAA according to the stage of the disease. The aim of this retrospective study was to find out how the BAL lymphocyte count, percentage of lymphocytes expressing HLA-DR, CD4/CD8 T cell ratio in BAL fluid, and the concentration of immunoglobulin G in serum correspond to the inflammatory activity of the disease.

METHODS

The study included 14 patients with EAA. BAL fluid samples were obtained and processed for cytological and cytometric analysis. Immunoglobulin G serum concentrations were measured. High resolution computed tomography (HRCT) scoring system modified by Gay was used for establishing the alveolar and interstitial score in each patient.

CONCLUSIONS

It was found that subjects with normal value of CD4/CD8 ratio in BAL fluid had higher interstitial HRCT score. Clinical presentation, continuous exposure to the causative antigens, and BAL lymphocyte count positively correlated with the alveolar HRCT score. It is proposed that the increased BAL lymphocyte count could be the predictor of the inflammatory activity of the disease, especially in people with lasting exposure to the offending antigen.

Prognostic value of neutrophils and NK cells in bronchoalveolar lavage of sarcoidosis

BACKGROUND

Not all the patients with sarcoidosis need pharmacological therapy, and the decision to start therapy is based mainly on clinical conditions. The aim of this study was to evaluate the prognostic value of the leukocyte and lymphocyte subpopulations in the bronchoalveolar lavage fluid from these patients.

METHODS

Thirty-three nonsmoking patients with sarcoidosis were included and classified based on the presence of Löfgren's syndrome (n = 11), the radiological stage (12 at Stage I, 17 at Stage II, and 4 at Stage III), and their follow-up. Differential leukocyte subsets and the lymphocyte subpopulations were determined by flow cytometry.

RESULTS

The percentage of neutrophils was lower in patients with Löfgren's syndrome (P = 0.038) and in patients at Stage I (P = 0.002). Patients with a poor outcome had a higher percentage of neutrophils (P = 0.004) and NK cells (P = 0.023) than those with a stable disease. Finally, a higher percentage of NK cells was found in those patients who needed a steroid treatment (P = 0.012).

CONCLUSIONS

Increased percentages of neutrophils and NK cells in the bronchoalveolar lavage fluid from patients with sarcoidosis are associated with a poor outcome and a higher probability to need steroids treatment. The percentage of neutrophils was also lower in patients with Löfgren's syndrome.

A comparison of flow cytometry and immunohistochemistry in human colorectal cancers

In human colorectal cancer it has been reported that some tumours lack the HLA-ABC antigens. This has been interpreted as reflecting tumour escape from the immune system. Earlier data have been obtained by immunohistochemistry. In this study, we compared the expression of HLA-ABC, HLA-DR, CD80 (B7-1) and CD54 (ICAM-1) in 20 tumours using both a conventional immunohistochemistry two-layer technique and multiparameter flow cytometry, gating on an epithelial cell marker. Colorectal cancer tissue used in flow cytometry was dissociated with collagenase, deoxyribonuclease and hyaluronidase. The intensity of expression of HLA-ABC, HLA-DR and CD80 was unaffected by the enzymes, but CD54 was decreased by 30%. The reproducibility of flow cytometry was good. Microscopy of sections revealed that about 5% of each tumour sample consisted of normal epithelium, but even after correction for this, flow cytometry was superior to immunohistochemistry in 33 out of 80 cases, and showed that tumours described as HLA-ABC negative by immunohistochemistry were in fact weakly positive for HLA-ABC. We conclude that flow cytometry and immunohistochemistry are complementary, and that flow cytometry is superior to immunohistochemistry for detecting antigens/epitopes present in low amounts.

Automatic leukocyte differentiation in bronchoalveolar lavage fluids of guinea pigs and brown-Norway rats

Asthma is considered to be a chronic inflammatory response of the airways characterized by a leukocyte infiltration into the lungs. Whereas lymphocytes and macrophages are involved in the initiation and propagation of inflammation, both neutrophils and in particular eosinophils are considered to play major effector roles. Therefore, allergic animal models in various species have been established to assess leukocyte infiltration by bronchoalveolar lavage (BAL) of antigen-sensitized and antigen-challenged animals as an inflammatory parameter in asthma pharmacology. Differential leukocyte counts in BAL fluids are routinely assessed by visual microscopic analysis of stained slides after cytocentrifugation. This procedure is very time-consuming, and the underlying standard morphological criteria may vary between different observers. In the present paper, we propose an alternative automatic method for leukocyte differentiation in BAL fluids from ovalbumin-treated guinea pigs and Brown-Norway rats using Cobas Helios 5Diff from Hoffmann-La Roche. BAL samples are directly applied to the analyzer and are automatically mixed with "Eosinofix," which stabilizes leukocyte membranes and specifically stains eosinophils. By a combination of electric (resistance) and optical (light scatter) analysis, the lymphocytes, monocytes/macrophages, neutrophils, and eosinophils are discriminated and the total leukocyte numbers are obtained. For both animal species we found high correlations for all leukocyte populations by comparing the results obtained with Cobas Helios 5Diff and conventional microscopic analysis. The major advantage of the automatic method is the much lower (about one-third) time requirement.