Effect of photodynamic therapy on selected laboratory values of patients with nasopharyngeal carcinoma

Secure transplantation by tissue purging using photodynamic therapy to eradicate malignant cells

The field of photodynamic therapy (PDT) for treating various malignant neoplasms has been given researchers' attention due to its ability to be a selective and minimally invasive cancer therapy strategy. The possibility of tumor cell infection and hence high recurrence rates in cancer patients tends to restrict autologous transplantation. So, the photodynamic tissue purging process, which consists of selective photoinactivation of the malignant cells in the graft, is defined as a compromising strategy to purify contaminated tissues before transplantation. In this strategy, the direct malignant cells' death results from the reactive oxygen species (ROS) generation through the activation of a photosensitizer (PS) by light exposure in the presence of oxygen. Since new PS generations can effectively penetrate the tissue, PDT could be an ideal ex vivo tissue purging protocol that eradicates cancer cells derived from various malignancies. The challenge is that the applied pharmacologic ex vivo tissue purging should efficiently induce tumor cells with minor influence on normal tissue cells. This review aims to provide an overview of the current status of the most effective PDT strategies and PS development concerning their potential application in ex vivo purging before hematopoietic stem cell or ovarian tissue transplantation.

T-cell mediated anti-tumor immunity after photodynamic therapy: why does it not always work and how can we improve it?

Photodynamic therapy (PDT) uses the combination of non-toxic photosensitizers and harmless light to generate reactive oxygen species that destroy tumors by a combination of direct tumor cell killing, vascular shutdown, and activation of the immune system. It has been shown in some animal models that mice that have been cured of cancer by PDT, may exhibit resistance to rechallenge. The cured mice can also possess tumor specific T-cells that recognize defined tumor antigens, destroy tumor cells in vitro, and can be adoptively transferred to protect naïve mice from cancer. However, these beneficial outcomes are the exception rather than the rule. The reasons for this lack of consistency lie in the ability of many tumors to suppress the host immune system and to actively evade immune attack. The presence of an appropriate tumor rejection antigen in the particular tumor cell line is a requisite for T-cell mediated immunity. Regulatory T-cells (CD25+, Foxp3+) are potent inhibitors of anti-tumor immunity, and their removal by low dose cyclophosphamide can potentiate the PDT-induced immune response. Treatments that stimulate dendritic cells (DC) such as CpG oligonucleotide can overcome tumor-induced DC dysfunction and improve PDT outcome. Epigenetic reversal agents can increase tumor expression of MHC class I and also simultaneously increase expression of tumor antigens. A few clinical reports have shown that anti-tumor immunity can be generated by PDT in patients, and it is hoped that these combination approaches may increase tumor cures in patients.

Topical ALA-PDT modifies neutrophils' chemiluminescence, lymphocytes' interleukin-1beta secretion and serum level of transforming growth factor beta1 in patients with nonmelanoma skin malignancies A clinical study

BACKGROUND

Photodynamic therapy (PDT) has been recognized as a noninvasive therapeutic approach for the effective treatment of tumors. It has been shown in studies conducted on malignant cell lines and various animal tumor models, that the interaction of photosensitizing substances with light leads to the release of cytotoxic substances and stimulates the immune response.

PURPOSE

The aim of our study was to analyze the immune system response in patients undergoing photodynamic therapy due to basal cell carcinoma (BCC).

METHODS

Patients with skin malignancies have been treated by 10% delta-aminolevulinic acid (ALA) (Medac GmbH, Wedel, Germany) topically and light from a diode laser. Blood samples were obtained from each patient twice in the same day: before and 4h after photodynamic treatment procedure. In patients' serum the concentration of transforming growth factor beta1 (TGF-β1) was determined. Additionally the study has been conducted on lymphocytes and granulocytes from peripheral blood. In cell culture supernatants the concentration of interleukin 1beta (IL-1β), interleukin 2 (IL-2), interleukin 6 (IL-6), tumor necrosis factor alpha (TNFα), the percentile composition of patients' lymphocytes and the chemiluminescence of neutrophils have been measured.

RESULTS

We have observed a significant increase (p=0.015) in the intensity of the neutrophil chemiluminescence and significant diminution (p=0.006) of IL-1β concentration in supernatants. Similarly the serum level of TGF-β1 has been significantly decreased (p<0.001).

CONCLUSION

It is very likely that human immune system activity is modified by topical ALA-PDT and may potentially contribute to its final outcome.

On the role of sIL-2R measurements in rheumatoid arthritis and cancers

A soluble IL-2 receptor (sIL-2R) is a circulating form of a membrane receptor localized on lymphoid and some cancer cells. The biological function of sIL-2R has not been completely understood. Substantially, it seems to reflect T-lymphocyte activation in diseases of different pathology. Moreover, the soluble receptor has been considered, at least in part, responsible for unsuccessful immunotherapy with IL-2 in cancers. Several lines of evidence indicate sIL-2R measurements to be useful in determining disease progress and prognosis. This review summarizes current knowledge on the sIL-2R behavior in RA and solid cancers of varied etiology.