A clinical assessment of fluorescence polarisation changes in lymphocytes stimulated by phytohaemagglutinin (PHA) in malignant and benign diseases

The induction of apoptosis by methotrexate in activated lymphocytes as indicated by fluorescence hyperpolarization: a possible model for predicting methotrexate therapy for rheumatoid arthritis patients

The objectives of this study were to test the in vitro response of healthy non-activated, activated, and rheumatoid arthritis (RA) lymphocytes to methotrexate (MTX), and design an in vitro model for predicting the efficiency of MTX treatment for RA patients. Considering the RA profile of clonal-expanded CD4(+) T cells, phytohemagglutinin-activated mononuclear cells taken from healthy donors were incubated with different concentrations of MTX. The MTX-immunosuppressive effect was tested by fluorescence intensity measurements, including PI assay and annexin V assay. For simple detection, we used the Individual Cell Scanner (IC-S), which enables the measurement of early events in individual cells. Healthy mononuclear cells (MNC), and MNC derived from RA patients, were tested by the IC-S while utilizing fluorescence polarization (FP) measurements of fluorescein diacetate (FDA) as an established marker of activation or suppression. In healthy activated MNC, we found that MTX, through its early incubation period, interferes with the activation signal obtained by PHA and exerts an apoptotic signal, which is noted by increases in the FP. Comparing our model to six long-standing RA patients and five newly-diagnosed patients revealed significant differences in the FP measurements, including fluorescence depolarization as an early established measurement of lymphocyte activation, and hyperpolarization as a measurement of an early immunosuppressive effect. We conclude that MTX, an effective therapy for RA patients, could easily be tested by fluorescence polarization measurements of FDA before (or during) clinical use in order to predict its efficiency on a specific RA patient. Moreover, the FP measurements can be used for the diagnosis, and making timing and dosage decisions.

Tumour specificity of the SCM test for cancer diagnosis

Phytohaemagglutinin (PHA), a well-known mitogen, and encephalitogenic factor (EF) are recognized by lymphocytes of patients with different malignant diseases as non-specific antigens. Utilizing these two antigens, the SCM (structuredness of the cytoplasmatic matrix) test offers a means of discrimination between malignant and non-malignant diseases. The SCM test can also be used as a specificity test since lymphocytes from donors with a given malignant disease react exclusively with the tumour-associated antigen (TAA) of that disease. Results from 73 donors (15 healthy patients, 38 patients with different types of malignant disorders and 20 patients with autoimmune diseases) indicate the predictive value of the test. First, the non-specific test was applied in order to establish whether the patients suffered from an active malignant disease. The lymphocytes of those patients which were found to suffer from an active malignant disorder were then exposed to different types of tumour tissues. Twenty-five out of the 38 patients with malignant disorders were found by the SCM test to have an active disease. The lymphocytes of 24 out of these 25 patients showed a positive reaction when exposed to tumour tissue of the same type of cancer of which they were found to suffer by other clinical tests, and displayed no reaction with any other tumour tissues for which they were tested. One patient, with an inconclusive value of the SCM test, showed no reaction with any type of tumour to which he was exposed. The remaining 13 patients, who were diagnosed by the test as non-cancerous, did not show any clinical evidence of malignancy at the time of the test, after their tumours had been excised. Eighteen out of 20 patients with autoimmune diseases showed negative results when tested by the general test and by the various specificity tests.

Fluorescence polarization assay by flow cytometry

Fluorescence polarization measurement on cell suspensions provides a highly sensitive means for detecting subtle changes in the cells, such as occur early after lymphocyte activation or on malignant transformation. We review here the principles of fluorescence polarization, its measurement by a commercially available flow cytometer and application of such assays especially in cellular immunology.