Extracorporeal photopheresis (ECP), a modality that exposes isolated leukocytes to the photosensitizer 8-methoxypsoralen (8-MOP) and ultraviolet-A (UV-A) light, is used to treat conditions such as cutaneous T-cell lymphoma and graft-versus-host disease. However, the current procedure of ECP has limited selectivity and efficiency; and produces only partial response in the majority of treated patients. Additionally, the treatment is expensive and time-consuming, so the improvement for this modality is needed. In this study, we used the concept of photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA), a precursor of an endogenously synthesized photosensitizer protoporphyrin IX (PpIX) in combination with blue light to explore the possibility of targeting activated human blood T cells ex vivo. With various T-cell activation protocols, a high ALA-induced PpIX production took place in activated CD3⁺, CD4⁺CD25⁺, and CD8⁺ T cell populations with their subsequent killing after blue light exposure. By contrast, resting T cells were much less damaged by the treatment. The selective and effective killing effect on the activated cells was also seen after co-cultivating activated and resting T cells. Under our clinically relevant experimental conditions, ALA-PDT killed activated T cells more selectively and efficiently than 8-MOP/UV-A. Monocyte-derived dendritic cells (DCs) were not affected by the treatment. Incubation of ALA-PDT damaged T cells with autologous DCs induced a downregulation of the co-stimulatory molecules CD80/CD86 and also upregulation of interleukin 10 (IL-10) and indoleamine 2,3-dioxygenase expression, two immunosuppressive factors that may account for the generation of tolerogenic DCs. Overall, the data support the potential use of ALA-PDT strategy for improving ECP by selective and effective killing of activated T cells and induction of immune tolerance.

Photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA), a precursor to the potent photosensitizer, protoporphyrin IX (PpIX), is an established modality for several malignant and premalignant diseases. This treatment is based on the light-activated PpIX in targeted lesions. Although numerous studies have confirmed the necrosis and apoptosis involved in the mechanism of action of this modality, little information is available for the change of exosome levels after treatment. We report from the first study on the effects of ALA-PDT on cytokines and exosomes of human healthy peripheral blood mononuclear cells (PBMCs). The treatment reduced the cytokines and exosomes studied, although there was variation among individual PBMC samples. This reduction is consistent with PDT-mediated survivals of subsets of PBMCs. More specifically, the ALA-PDT treatment apparently decreased all pro-inflammatory cytokines included, suggesting that this treatment may provide a strong anti-inflammatory effect. In addition, the treatment has decreased the levels of different types of exosomes, the HLA-DRDPDQ exosome in particular, which plays an important role in the rejection of organ transplantation as well as autoimmune diseases. These results may suggest future therapeutic strategies of ALA-PDT.

Background/Objectives: With the increasing prevalence of Crohn’s disease (CD), treatment options for patients who fail conventional and advanced therapy are highly needed. Therefore, we explored the safety and efficacy of extracorporeal photopheresis (ECP) using 5-aminolevulinic acid (ALA) and blue light (405 nm). Methods: Patients with active CD who failed or were intolerant to biological therapy were eligible. Mononuclear cells (90 mL) were collected from each patient using a Spectra Optia^® apheresis system and diluted with 100 mL of 0.9% sodium chloride in a collection bag. The cells were incubated with ALA at a concentration of 3 millimolar (mM) for 60 min ex vivo and illumination with an LED blue light (405 nm) source (BLUE-PIT^®) before reinfusion to the patient. Recording of vital signs and adverse events were regularly performed. At week 13, we assessed the patients with colonoscopy, the Harvey Bradshaw Index (HBI), the Inflammatory Bowel disease Health Related Quality of Life Questionnaire, and the measurement of serum C-reactive protein and fecal calprotectin (FC) levels. Biopsies of the intestines were taken for immunohistochemistry. Results: Seven patients were included. Four patients completed the treatments, with a total of 24 treatments. Three of the four patients achieved a favorable response, including a lower HBI, lower FC levels, and/or endoscopic improvement. No significant adverse events were observed. The remaining three patients received only one, three, or five treatments due to technical difficulties, medical reasons, or the withdrawal of informed consent. Conclusions: ALA-based ECP appears safe and seems to give some clinical improvement for the patients with active CD who failed to respond to conventional and advanced therapies.

Activin A is a member of the TGF-β superfamily and activates the transcription factors SMAD2/3 through the ALK4 type 1 receptor. Activin A has also been shown to activate SMAD1/5/8 through mutated variants of the type 1 receptor ALK2. Interestingly, we here show that both activin A and activin B could activate SMAD1/5/8 through endogenous wild type ALK2 in multiple myeloma cells. Knockdown of the type 2 receptor BMPR2 strongly potentiated activin A- and activin B-induced SMAD1/5/8 activation and subsequent cell death. Furthermore, activity of BMP6, BMP7 or BMP9, which also signal via ALK2, was potentiated by BMPR2 knockdown. Similar results were seen in HepG2 liver carcinoma cells. We propose that BMPR2 inhibited ALK2-mediated signaling by preventing ALK2 from oligomerizing with the type 2 receptors ACVR2A and ACVR2B, necessary for ALK2 activation by activins and several BMPs in these cells. In conclusion, BMPR2 could be explored as a possible target for therapy in patients with multiple myeloma. Summary Statement: The activation of SMAD1/5/8 via endogenous wild type ALK2 by activin A, activin B, and certain BMPs was enhanced when BMPR2 levels were knocked down.

Background/Objectives: With the increasing prevalence of Crohn’s disease (CD), treatment op-tions for patients who fail conventional and advanced therapy are highly needed. Therefore, we explored the safety and efficacy of extracorporeal photopheresis (ECP) using 5-aminolevulinic acid (ALA) and blue light (405 nm). Methods: Patients with active CD who failed or were intolerant to biological therapy were eligi-ble. Mononuclear cells (90 mL) were collected from each patient using a Spectra Optia® apheresis system and diluted with 100 mL of 0.9% sodium chloride in a collection bag. The cells were in-cubated with ALA at a concentration of 3 millimolar (mM) for 60 minutes ex vivo and illumina-tion with a LED blue-light (405 nm) source (BLUE-PIT®) before reinfusion to the patient. Vital signs and adverse events were regularly performed. At week 13 we assessed the patients with colonoscopy, the Harvey Bradshaw Index (HBI), the Inflammatory Bowel disease Health Related Quality of Life Questionnaire, and measurement of serum C-reactive protein, and fecal calprotec-tin (FC) levels. Biopsies of the intestines were taken for immunohistochemistry. Results: Seven patients were included. Four patients completed, with in total 24 treatments. Three of the four achieved a response, including lower HBI, FC and/or endoscopic improvement. No significant adverse events were observed. The remaining three patients received only one, three or five treatments due to technical difficulties, medical reasons, or the withdrawal of informed con-sent. Conclusion: ALA-based ECP appears safe and seem to give some clinical improvement for the patients with active CD who failed to respond to conventional and advanced therapies.