Effects of low-level laser irradiation on human blood lymphocytes in vitro
Mustafa S Al Musawi1,2, M S Jaafar3, B Al-Gailani4
1School of Physics, Universiti Sains Malaysia, 11800, Pulau Pinang, Malaysia. laser_mu@yahoo.com.
Insights
Low-level laser irradiation (LLLI) significantly increased lymphocyte counts in human whole blood, particularly natural killer (NK) cells. This study highlights LLLI
Area of Science:
- Immunology
- Biophotonics
- Hematology
Background:
- Low-level laser irradiation (LLLI) effects on lymphocytes are established in vitro but poorly understood in whole blood.
- Investigating LLLI's impact on lymphocyte counts in human whole blood is crucial for understanding its potential therapeutic applications.
Purpose of the Study:
- To determine if LLLI influences lymphocyte counts in human whole blood samples.
- To identify specific lymphocyte subsets affected by LLLI and varying laser parameters.
Main Methods:
- 130 human whole blood samples were divided into irradiated and non-irradiated control groups.
- Irradiated samples were exposed to laser wavelengths (405, 589, 780 nm) at fluences (36-90 J/cm²) and fixed irradiance (30 mW/cm²).
- Lymphocyte counts were analyzed using a hematology analyzer and flow cytometry, with statistical comparison via paired t-tests.
Main Results:
- A statistically significant maximum increase of 1.6% in total lymphocyte count was observed at 72 J/cm² (P < 0.02).
- Flow cytometry confirmed increased CD45 lymphocytes and natural killer (NK) cells (CD16, CD56) at 589 nm and 72 J/cm².
- No significant changes were found in CD3 T lymphocytes, T-suppressor (CD3, CD8) cells, T-helper (CD3, CD4) cells, or CD19 B lymphocytes.
Conclusions:
- LLLI significantly alters lymphocyte counts in human whole blood, primarily by increasing NK cell numbers.
- The findings demonstrate that NK cell count is a key factor affected by LLLI, impacting overall lymphocyte levels.
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/cm2 when 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.
