Quantitative computerized image analysis of immunostained lymphocytes. A methodological approach

Semi-automatic counting of connexin 32s immunolocalized in cultured fetal rat hepatocytes using image processing

Connexin 32s (Cx32s) were immunolocalized in fetal rat hepatocytes and their distribution was determined qualitatively. We used image analysis using a quantitative index (QI) of Cx32 (QI Cx32) defined as the area of Cx32s/number of cells in cultured fetal rat hepatocytes. Hepatocytes from livers of fetal rats were separated by collagenase digestion and low centrifugation on gestational day 17. Cells were cultured for 3 days in dexamethasone (DEX)-supplemented medium (Dex0). The medium was replaced with fresh medium and cells were continuously cultured for 3 days with DEX or epidermal growth factor supplemented medium (Dex3 or EGF3). After culture termination, cells were fixed and stained using the fluorescein-labeled antibody method for Cx32s and diaminophenylindole staining for nuclei. Thirty pairs of histological images for Cx32s and nuclei, 180 images in total, were obtained from each condition. The QI Cx32 significantly increased from 284.1 ± 102.0 (mean and SD, n=26) of Dex0 to 428.9 ± 101.0 of Dex3 (n=28) (P<0.05, Kruskal-Wallis test, then Steel-Dwass test). The increase of QI Cx32 was compatible with the morphological observations. The image analysis processing time after preparation for 180 images was reduced from 8h needed for manual operations to 1 min using ImageJ software with our macro routine.

Reproducibility of immunostaining quantification and description of a new digital image processing procedure for quantitative evaluation of immunohistochemistry in pathology

Quantification of immunostaining is a widely used technique in pathology. Nonetheless, techniques that rely on human vision are prone to inter- and intraobserver variability, and they are tedious and time consuming. Digital image analysis (DIA), now available in a variety of platforms, improves quantification performance: however, the stability of these different DIA systems is largely unknown. Here, we describe a method to measure the reproducibility of DIA systems. In addition, we describe a new image-processing strategy for quantitative evaluation of immunostained tissue sections using DAB/hematoxylin-stained slides. This approach is based on image subtraction, using a blue low pass filter in the optical train, followed by digital contrast and brightness enhancement. Results showed that our DIA system yields stable counts, and that this method can be used to evaluate the performance of DIA systems. The new image-processing approach creates an image that aids both human visual observation and DIA systems in assessing immunostained slides, delivers a quantitative performance similar to that of bright field imaging, gives thresholds with smaller ranges, and allows the segmentation of strongly immunostained areas, all resulting in a higher probability of representing specific staining. We believe that our approach offers important advantages to immunostaining quantification in pathology.

“Virtual flow cytometry” of immunostained lymphocytes on microscopic tissue slides:iHCFlow™ tissue cytometry

BACKGROUND

A method and approach is developed for fully automated measurements of immunostained lymphocytes in tissue sections by means of digital color microscopy and patent pending advanced cell analysis. The validation data for population statistic measurements of immunostained lymphocytes in tissue sections using tissue cytometry (TC) is presented. The report is the first to describe the conversion of immunohistochemistry (IHC) data to a flow cytometry-like two parameter dot-plot display, hence the technique is also a virtual flow cytometry. We believe this approach is a paradigm shift, as well as novel, and called the system iHCFlow TC. Seven issues related to technical obstacles to virtual flow cytometry (FC) are identified.

DESIGN

Segmentation of a 512 x 474 RGB image and tabular display of statistical results table took 12-15 s using proprietary developed algorithms. We used a panel of seven antibodies for validation on 14 cases of mantle cell lymphoma giving percentage positive, total lymphocytes, and staining density. A total of 2,027 image frames with 810,800 cell objects (COBs) were evaluated. Antibodies to CD3, CD4, CD8, Bcl-1, Ki-67, CD20, CD5 were subjected to virtual FC on tissue. The results of TC were compared with manual counts of expert observers and with the results of flow cytometric immunophenotyping of the same specimen.

RESULTS

The correlation coefficient and 95% confidence interval by linear regression analysis yielded a high concordance between manual human results (M), FC results, and TC results per antibody, (r = 0.9365 M vs. TC, r= 0.9537 FC vs. TC). The technical issues were resolved and the solutions and results were evaluated and presented.

CONCLUSION

These results suggest the new technology of TC by iHCFlow could be a clinically valid surrogate for both M and FC analysis when only tissue IHC is available for diagnosis and prognosis. The application for cancer diagnosis, monitoring, and prognosis is for objective, rapid, automated counting of immunostained cells in tissues with percentage results. We report a new paradigm in TC that converts IHC staining of lymphocytes to automated results and a flow cytometry-like report. The dot plot histogram display is familiar, intuitive, informative, and provides the pathologists with an automated tool to rapidly characterize the staining and size distribution of the immunoreactive as well as the negative cell population in the tissue. This systems tool is a major improvement over existing ones and satisfies fully the criteria to perform Cytomics (Ecker and Tarnok, Cytometry A 2005;65:1; Ecker and Steiner, Cytometry A 2004;59:182-190; Ecker et al., Cytometry A 2004;59:172-181).

Computerized image analysis as a tool to quantify infiltrating leukocytes: a comparison between high- and low-magnification images

The purpose of the present study was to establish a rapid and reproducible method for quantification of tissue-infiltrating leukocytes using computerized image analysis. To achieve this, the staining procedure, the image acquisition, and the image analysis method were optimized. Because of the adaptive features of the human eye, computerized image analysis is more sensitive to variations in staining compared with manual image analysis. To minimize variations in staining, an automated immunostainer was used. With a digital scanner camera, low-magnification images could be sampled at high resolution, thus making it possible to analyze larger tissue sections. Image analysis was performed by color thresholding of the digital images based on values of hue, saturation, and intensity color mode, which we consider superior to the red, green, and blue color mode for analysis of most histological stains. To evaluate the method, we compared computerized analysis of images with a x100 or a x12.5 magnification to assess leukocytes infiltrating rat brain tumors after peripheral immunizations with tumor cells genetically modified to express rat interferon-gamma (IFN-gamma) or medium controls. The results generated by both methods correlated well and did not show any significant differences. The method allows efficient and reproducible processing of large tissue sections that is less time-consuming than conventional methods and can be performed with standard equipment and software.(J Histochem Cytochem 49:1073-1079, 2001)

Effects of topical budesonide treatment on glucocorticoid receptor mRNA down-regulation and cytokine patterns in nasal polyps

The effects of a topically applied corticosteroid, budesonide, on the expression of glucocorticoid receptor (GR) mRNA and regulation of pro-inflammatory cytokine patterns in patients with nasal polyps were evaluated. All patients were eligible for surgical polypectomy, and a majority of them had been treated with nasal steroids. Patients were given 400 microg b.i.d. (group A, n = 11), 200 microg b.i.d. (group B, n = 10), or no treatment (group C, n = 15) during two months before polypectomy. Morning serum cortisol was analyzed on the day of surgery. Surgically removed polyps were taken for analysis of GR mRNA expression by solution hybridization. Remaining tissue was cryostat-sectioned, whereafter quantification of the cytokines interleukin 1beta, interleukin 2, interleukin 4, interleukin 5, interleukin 6, interleukin 10, tumor necrosis factor alpha, and interferon gamma was made by immunohistochemistry and digitized image analysis. No significant differences among the three groups were found for any of the parameters investigated.

CONCLUSION

nasal polyps do not respond with down-regulation of GR mRNA or cytokines following topical corticosteroid treatment. The proposed corticosteroid resistance may be inherent, or induced by a change of local tissue bioavailability.

Changes in F-actin labeling in the outer hair cell and the Deiters cell in the chinchilla cochlea following noise exposure

It has been found that 'conditioning' noise exposures can render the inner ear more resistant to traumatic noise exposures. To explore the possible mechanisms underlying this phenomenon, filamentous actin (F-actin), labeled by rhodamine-phalloidin, was examined in the chinchilla cochlea using confocal fluorescence microscopy. The conditioning noise was 0.5 kHz octave band noise (OBN) at 90 dB SPL for 6 h/day and the high-level noise was the same noise but at 105 dB SPL for 4 h. A variety of pathological changes were found in the chinchilla cochlea after exposure to noise. Subjects exposed to conditioning noise (1 day or 10 days) and only high-level noise showed an increase in F-actin labeling than unexposed controls. By contrast, subjects who had 5 days quiet after the 10-day conditioning exposure exhibited a decrease in F-actin labeling. Interestingly, subjects exposed to high-level noise with prior 10-day conditioning exposure also showed a decrease in F-actin labeling in the cuticular plate and the stereocilia. The F-actin decreases in the stereocilia and the cuticular plates may decrease the mechanical rigidity of the organ of Corti. A more pliable organ of Corti may have reduced the possibility of fracture or ripping of cell junctions during the motion of the basilar membrane induced by acoustic overstimulation.

Bcl-2 immunoreactivity in salivary gland neoplasms is unrelated to the expression of mRNA for natural killer cell stimulatory cytokines interleukin (IL)-2 and IL-12

Certain cytokines are involved in the generation of natural killer (NK) cells and participate in the regulation of the proto-oncogene bcl-2. We aimed to study the mRNA expression of interleukin (IL)-2, IL-4 and IL-5, the composition of the tumour infiltrating lymphocytes (TIL), and the expression of bcl-2 in 14 benign and malignant human parotid tumours. T IL were predominantly composed of T lymphocytes and NK cells. We found evidence for the homing of T cells, and for generation of NK cells in the vicinity of the tumours. mRNA for IL-2 and IL-12, were identified but IL-4 mRNA was not found. The cytokine profiles and the composition of TIL of the two tumour categories were indistinguishable, suggesting that these host-response variables do not explain the differences in biological behaviour of these particular tumours. The results support a shift towards Th 1 (T helper 1) cells and interferon-gamma production, and that IL-12 also in vivo may play an important role in the regulatory interaction between innate resistance and adaptive immunity in tumour diseases. Most infiltrating lymphocytes showed strong expression of bcl-2; an interesting observation with regard to lymphocytic apoptosis in neoplastic diseases. The immunoreactivity for the bcl-2 protein varied considerably between and within tumours, and almost all benign tumours showed strong bcl-2 positively whereas several of the malignant tumours showed weak or absent staining. The variable expression of bcl-2 protein suggests a different susceptibility of tumour cells to apoptosis. The results also indicate that bcl-2 cannot pla a major role as protective agent in the specific apoptotic pathway induced by NK cells.