title: Ultraviolet-A (UVA-1) radiation suppresses immunoglobulin production of activated B lymphocytes in vitro.
abstract: Previous studies have shown that low-dose ultraviolet-A (UVA-1) total body irradiations were capable of improving disease activity in patients with systemic lupus erythematosus (SLE). We hypothesized that UVA-1-induced suppression of immunoglobulin production by activated B cells in the dermal capillaries could be (partly) responsible for this effect. Our experiments with donor skin demonstrated that approximately 40% of UVA-1 could penetrate through the epidermis. Irradiation of peripheral blood mononuclear cells (PBMCs) with 2 J/cm(2) of UVA-1 resulted in 20% cell death. This toxic effect could be prevented totally by preincubation of the cell cultures with catalase. This indicates that the generation of hydrogen peroxide plays a role in UVA-1 cytotoxicity. T cells and B cells appeared to be less susceptible to UVA-1 cytotoxicity than monocytes. With the use of a CD40-CD40L B cell activation method we measured immunoglobulin production after various doses of UVA-1 irradiation (0-2 J/cm(2)). The doses of 2 J/cm(2) caused a significant decrease of IgM, IgG, IgA and IgE production under the conditions of interleukin (IL)-10 or IL-4 (IgE) stimulation. Although UVA-1 can cause apoptosis of B lymphocytes, we show that relatively low doses of UVA-1 radiation also affect the function of these cells. Both effects may be responsible for the observed improvement of disease activity in SLE patients.
authors.affiliation: Department of Dermatology, Leiden University Medical Center, Leiden, the Netherlands. M.C.A.Polderman@lumc.nl
authors.forename: M C A
authors.initials: MC
authors.lastname: Polderman
authors.forename: C
authors.initials: C
authors.lastname: van Kooten
authors.forename: N P M
authors.initials: NP
authors.lastname: Smit
authors.forename: S W A
authors.initials: SW
authors.lastname: Kamerling
authors.forename: S
authors.initials: S
authors.lastname: Pavel
mesh_terms: D001402:B-Lymphocytes / Q000378:metabolism / Q000528:radiation effects*; D002374:Catalase / Q000378:metabolism; D016923:Cell Death; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis*; D016753:Interleukin-10 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D008180:Lupus Erythematosus, Systemic / Q000532:radiotherapy; D008213:Lymphocyte Activation; D009000:Monocytes / Q000528:radiation effects; D012867:Skin / Q000276:immunology / Q000528:radiation effects*; D013601:T-Lymphocytes / Q000528:radiation effects; D046509:Tissue Culture Techniques; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D007136:Immunoglobulins; D016753:Interleukin-10; D015847:Interleukin-4; D002374:Catalase