title: Effects of low-level laser irradiation on human blood lymphocytes in vitro.
abstract: Low-level laser irradiation (LLLI) has various effects on cultured human lymphocytes in vitro, but little is known about such effects in whole blood. This study investigated whether LLLI affected lymphocyte count in human whole blood in vitro. A total number of 130 blood samples were collected from apparently healthy adult patients through venipuncture into tubes containing EDTA. Each sample was divided into two equal aliquots to be used as a non-irradiated control sample and an irradiated sample. The irradiated aliquot was subjected to laser wavelengths of 405, 589, and 780 nm with different fluences of 36, 54, 72, and 90 J/cm2, at a fixed irradiance of 30 mW/cm2. A paired student t test was used to compare between non-irradiated and irradiated samples. The lymphocyte counts were measured using a computerized hematology analyzer and showed a significant (P < 0.02) maximum increase (1.6%) at a fluence of 72 J/cm2when compared with non-irradiated samples. This increase in lymphocyte count upon irradiation was confirmed by flow cytometry. At a wavelength of 589 nm and fluence of 72 J/cm2, irradiation of whole blood samples showed a significant increase in CD45 lymphocytes and natural killer (NK) (CD16, CD56) cells, but no significant changes in CD3 T lymphocytes, T-suppressor (CD3, CD8) cells, T-helper (CD3, CD4) cells, and CD19 B lymphocytes when compared with their non-irradiated counterparts. Our results clearly demonstrate that NK cell count is altered by irradiation, which ultimately affects the whole lymphocyte count significantly.
authors.affiliation: School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia. laser_mu@yahoo.com.|Department of Physiology, College of Medicine, Al-Mustansiriya University, Baghdad, Iraq. laser_mu@yahoo.com.
authors.forename: Mustafa S
authors.initials: MS
authors.lastname: Al Musawi
authors.affiliation: School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia.
authors.forename: M S
authors.initials: MS
authors.lastname: Jaafar
authors.affiliation: Department of Physiology, College of Medicine, Al-Mustansiriya University, Baghdad, Iraq.
authors.forename: B
authors.initials: B
authors.lastname: Al-Gailani
authors.affiliation: School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia.
authors.forename: Naser M
authors.initials: NM
authors.lastname: Ahmed
authors.affiliation: Advanced Medical and Dental Institute, Universiti Sains Malaysia, Bertam, 13200, Kepala Batas P. Pinang, Malaysia.
authors.forename: Fatanah M
authors.initials: FM
authors.lastname: Suhaimi
authors.affiliation: School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia.
authors.forename: Nursakinah
authors.initials: N
authors.lastname: Suardi
mesh_terms: D000328:Adult; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D028022:Low-Level Light Therapy; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000528:radiation effects; D008214:Lymphocytes / Q000528:radiation effects*; D008297:Male
keywords: Flow cytometry; Hematology analyzer; Low-level laser irradiation; Lymphocytes