The effects of phototherapy on the numbers of circulating natural killer cells and T lymphocytes in psoriasis

Impact of ROS-Dependent Lipid Metabolism on Psoriasis Pathophysiology

Psoriasis is the most common autoimmune disease, yet its pathophysiology is not fully understood. It is now believed that psoriasis is caused by the increased activation of immune cells, especially Th1 lymphocytes. However, in psoriasis, immune cells interfere with the metabolism of keratinocytes, leading to their increased activation. Therefore, the pathophysiology of psoriasis is currently associated with the overproduction of ROS, which are involved in the activation of immune cells and keratinocytes as well as the modulation of various signaling pathways within them. Nevertheless, ROS modulate the immune system by also boosting the increasing generation of various lipid mediators, such as products of lipid peroxidation as well as endocannabinoids and prostaglandins. In psoriasis, the excessive generation of ROS and lipid mediators is observed in different immune cells, such as granulocytes, dendritic cells, and lymphocytes. All of the above may be activated by ROS and lipid mediators, which leads to inflammation. Nevertheless, ROS and lipid mediators regulate lymphocyte differentiation in favor of Th1 and may also interact directly with keratinocytes, which is also observed in psoriasis. Thus, the analysis of the influence of oxidative stress and its consequences for metabolic changes, including lipidomic ones, in psoriasis may be of diagnostic and therapeutic importance.

Disseminated Superficial Actinic Porokeratosis in a Patient with Psoriasis, after Long-Term Narrowband Ultraviolet B Phototherapy

Porokeratosis is a rare epidermal disorder characterized by annular or linear hyperkeratotic plaques with slightly raised thread-like borders, and in most cases, atrophic centers. Disseminated superficial porokeratosis and disseminated superficial actinic porokeratosis (DSAP), which primarily involve sun-exposed areas, are common types of porokeratoses. Histologically, a column of parakeratotic cells, a so-called cornoid lamella, is a hallmark of porokeratosis. Porokeratosis is considered to result from the inability to eliminate an abnormal keratinocyte clone induced by genetic factors and various stimuli, including sunlight, artificial ultraviolet light, viral infections, immunosuppressive conditions (hematologic malignancies, organ transplants, or autoimmune disease), and immunosuppressive therapies. Here, we report a 59-year-old Korean woman with DSAP that developed after narrowband ultraviolet B (NB-UVB) therapy for psoriasis. Our case emphasizes the occurrence of DSAP due to NB-UVB that is able to induce local immunosuppression at the irradiated site; the pathogenesis of DSAP remains unclear.

Effect of phototherapy on B and T lymphocytes in Egyptian infants suffering from neonatal jaundice

BACKGROUND

Neonatal jaundice is one of the most common problems that affect newborn infants, and phototherapy is usually used for treatment.

OBJECTIVES

Evaluation of the effect of phototherapy on neonatal immune system through measuring the percentage of B and T lymphocytes and determining the frequency of development of infections and need for hospitalisation during the first six months of life.

METHODS

A prospective cohort study was conducted on 50 full term new-borns; 25 with indirect hyperbilirubinaemia and treated with conventional phototherapy and 25 healthy matched neonates as untreated controls. The percentages of CD19+, CD4+ and CD8+ lymphocytes were measured by flow cytometry before phototherapy and 72h after exposure. Follow-up of the study group for the occurrence of infections for a period of six months after phototherapy.

RESULTS

The study showed a significant difference in CD19+ lymphocytes percentage between patients before phototherapy and controls (P value<0.01), also a significant correlation between serum levels of total bilirubin in patients and CD19+ lymphocytes percentage (P value<0.05). There was no significant difference between the percentages of CD19+, CD4+ and CD8+ lymphocytes in patients before or after 72h of exposure to phototherapy (P value>0.05). Also, there was no correlation between the percentages of CD19+, CD4+ and CD8+ lymphocytes after 72h of exposure to phototherapy and the occurrence of infections (Gastrointestinal tract and Respiratory tract infection) after six months of follow-up (P value>0.05). More studies are needed with larger number of patients to determine the effect of phototherapy on immune system.

Neonates with sickle cell disease are vulnerable to blue light phototherapy-induced oxidative stress and proinflammatory cytokine elevations

Sickle cell disease is a frequent genetic anomaly characterized by altered molecular structure of hemoglobin resulting into crescent-like deformation of the red blood corpuscles. Neonatal jaundice is a frequent co-morbidity in sickle cell disease. Phototherapy induces isomerization of bilirubin rendering it extractable through urine and hence it is used as a routine treatment of neonatal jaundice. An exposure to light phototherapy as a treatment of neonatal jaundice induces oxidative stress. It is hypothesized that such exposure of neonates with sickle cell disease to the blue light phototherapy as a treatment of neonatal jaundice induces severe oxidative stress and increases the levels of proinflammatory cytokines. This hypothesis is supported with two case studies of sickle cell disease suffering neonates who were exposed to blue light phototherapy to treat jaundice. In both these cases, exposure to phototherapy induced oxidative stress (increased lipid peroxidation and superoxide dismutase, slight change in activity of catalase and GSH) and elevated the levels of proinflammatory cytokine (TNFα, IL-1, and IL-6) in the sickle cell disease suffering neonates. These observations warrant further investigations to determine the consequences and clinical significance of the blue phototherapy-induced oxidative and proinflammatory stress in Sickle cell disease suffering neonates exposed to phototherapy as a treatment of jaundice.

The effect of phototherapy on systemic inflammatory process in patients with plaque psoriasis

Psoriasis is a common, chronic immune-mediated inflammatory disease. The inflammatory process in psoriasis has systemic effects and may influence the development of psoriatic comorbidities. The systemic action of phototherapy in patients with psoriasis has been so far poorly elucidated. We aimed to investigate the expression of genes encoding selected psoriasis-related cytokines in peripheral blood mononuclear cells (PBMCs) isolated from patients with psoriasis before and after treatment with phototherapy. 17 patients with mild to moderate plaque psoriasis were treated with narrow band-UVB (NB-UVB), 8 patients with moderate to severe plaque psoriasis with bath-psoralen-ultraviolet A therapy (PUVA). PBMCs were isolated by Ficoll gradient density centrifugation. Expression of genes encoding TNF-α, IL-17A, IL-6, IL-1 β, INF-γ, and IL-10 in PBMCs of patients with psoriasis before and after phototherapy was analyzed with quantitative RT-PCR. Treatment with NB-UVB therapy led to a significant decrease in IL-17A, TNF-α, and IL-6 mRNA levels in PBMCs (p=0.003; p=0.042; p=0.019, respectively). Following treatment with bath-PUVA therapy, we observed a significant decrease in TNF-α and IL-6 mRNA levels in PBMCs (p=0.031, p=0.035, respectively). Treatment with phototherapy in patients with psoriasis may affect systemic inflammation by downregulation of the expression of genes encoding proinflammatory cytokines in PBMCs, implicated in the development of psoriasis and psoriatic comorbidities.

Phototherapy and photochemotherapy for psoriasis

Phototherapy is a first-line option for the treatment of moderate to severe psoriasis. Systematic reviews indicate near comparable efficacy of the different forms of phototherapy. Localized phototherapy can be an adjunctive treatment of recalcitrant plaques during systemic treatment of psoriasis. More than 200 psoralen-UV-A therapy treatment sessions is associated with an increased risk of keratinocytic cancers, whereas no increased risk has been demonstrated for narrow-band UV-B therapy. The mechanism of action of phototherapy in psoriasis is via inhibition of keratinocyte proliferation; induction of apoptosis in keratinocytes, dendritic, and T cells; and inhibition of Th1 and Th17 pathways, but activation of Th2.

The side effects of phototherapy for neonatal jaundice: what do we know? What should we do?

Neonatal phototherapy (NNPT), a noninvasive, easily available therapy, has been widely used for the treatment of neonatal jaundice for more than half a century. Its efficiency in decreasing plasma bilirubin concentration is well documented, and NNPT leads to greatly reduced exchange transfusion rates for neonates with hyperbilirubinemia. It is generally accepted that the side effects of NNPT are not serious and seem to be well controlled. This review will focus on these possible side effects as well as the approaches to minimize them.