Cannabis use and the immune system: white blood cell count
A study has shown that the total white blood cell count in cannabis users is higher among heavy users when compared to non-users.
The study, published in the Journal of Cannabis Research, looked at a number of studies covering cannabis use and the immune system, noting that little is known on circulating white blood cell counts and cannabis use.
The researchers looked at the National Health and Nutrition Examination Survey (2005–2016), a survey designed to be nationally representative of United States non-institutionalised population, and found that there was a modest association between heavy cannabis use and higher white blood cell count but that neither former nor occasional cannabis use was associated with total or differential WBC counts.
White blood cells
White blood cells are the cells in our body that function mainly as immune cells – originating in the bone marrow.
Today, it is known that cigarette smoking generates several chemicals that are implicated in oxidative stress pathways and systemic inflammation and elevated white blood cell count in tobacco cigarette smokers have been well documented, whereas tobacco abstinence is associated with sustained decrease in white blood cell count.
The study highlights how cannabis is able to mediate its effects through the cannabinoid-1 (CB1) and cannabinoid-2 (CB2) receptors.
CB2 receptors can be found in numerous parts of the body related to the immune system, including bone marrow, thymus, tonsils and spleen. CB1 receptors are present in the central nervous system, and at lower levels in the immune system.
Cannabis use and the immune system
The effects of cannabinoids on hematopoiesis, and immune cell proliferation using animal and cell based models has been widely demonstrated and a number of studies have examined the association of cannabis use and white blood cell counts in human immunodeficiency virus (HIV).
The studies have shown a higher white blood cell count in HIV positive men who used cannabis.
Last year a study discovered certain cannabinoids that enhance the immunogenicity of tumour cells, rendering them more susceptible to recognition by the immune system. This discovery is important because the leading class of new cancer fighting agents, termed ‘checkpoint inhibitors’, activates the immune system to destroy cancer cells.
Enhancing recognition of cancer cells with cannabinoids may greatly improve the efficacy of this drug class. The Pascal study was the first to identify a mechanism in which cannabinoids may provide a direct benefit in immunotherapy.
When looking at white blood cell counts the study noted that: ‘Several of the important study limitations merit attention. The observational nature of the study constrained causal inferences. Even though NHANES collects blood and urine specimens, drug testing is not conducted, and cannabis use was self-reported which may lead to non-differential misclassification bias. There was no available information on the route of administration of cannabis (smoking, ingestion, etc.) or cannabis preparation/potency.
‘In addition, the study is based on fairly recent NHANES surveys (2005–16) which might be more representative of the increasing cannabis potency compared to NHANES III (1988–1994) surveys.’
A number of laboratory studies have reported suppression of immune responses with cannabinoid administration, and some epidemiological studies found lower levels of inflammatory biomarkers such as fibrinogen, C-reactive protein and interleukin-6 in adult cannabis users.
The study also noted that the reported anti-inflammatory effects of cannabis were greatly attenuated when body weight is controlled for and suggests that the inverse cannabis-body weight association might explain the lower levels of circulating inflammatory biomarkers in adult cannabis users.
Correlation is not causation
The study highlights that these alterations of immune responses by cannabis use might be associated with increased susceptibility to infections and hence the higher white blood cell count, however, it notes that it is possible that the elevated white blood cell count and suboptimal health status contributed to cannabis use rather than cannabis use caused suboptimal health.
The study states: ‘This hypothesis, though, cannot be tested as NHANES does not collect information on cannabis use motives. Another potential mechanism can be through the effect of cannabinoids on stem cells. Pre-clinical studies suggest that cannabinoids stimulate hematopoiesis and hence this stimulation to bone marrow tissues can be associated with increased circulating white blood cell count in cannabis users.
‘Positive associations between heavy cannabis use, and total white blood cell and neutrophil counts were detected. Clinicians should consider heavy cannabis use in patients presenting with elevated white blood cell count.’
Research on cannabis use and the immune system is lacking and the study suggests further research is needed to understand the immune related effects of different modes of cannabis use.
The study noted: ‘Research on heavy cannabis use and cardiovascular health is needed as systemic inflammation, increased cardiovascular risk and increased mortality risk have been all associated with white blood cell elevation within the normal physiologic range.
‘Studies with repeated measures are needed to study immunomodulatory changes in cannabis users, and whether the mode of cannabis use can differentially affect immune responses.
‘Additional research is needed to understand the immune related effects of different modes of cannabis use and to elucidate the role of proinflammatory chemicals generated from smoking cannabis.’
The study, published in the Journal of Cannabis Research, looked at a number of studies covering cannabis use and the immune system.
The Effects of Marijuana on Your Body
Marijuana is made from the shredded and dried parts of the cannabis plant, including the flowers, seeds, leaves, and stems. It’s also known as pot, weed, hash, and dozens of other names. While many people smoke or vape it, you can also consume marijuana as an ingredient in food, brewed tea, or oils.
Different methods of taking the drug may affect your body differently. When you inhale marijuana smoke into your lungs, the drug is quickly released into your bloodstream and makes its way to your brain and other organs. It takes a little longer to feel the effects if you eat or drink marijuana.
There is ongoing controversy around the effects of marijuana on the body. People report various physical and psychological effects, from harm and discomfort to pain relief and relaxation.
Here’s what happens to your body when this drug enters your bloodstream.
Marijuana can be used in some states for medical reasons, and in some areas, recreational use is legal as well. No matter how you use marijuana, the drug can cause immediate and long-term effects, such as changes in perception and increased heart rate. Over time, smoking marijuana may cause chronic cough and other health issues.
The effects of marijuana on the body are often immediate. Longer-term effects may depend on how you take it, how much you use, and how often you use it. The exact effects are hard to determine because marijuana has been illegal in the U.S., making studies difficult and expensive to conduct.
But in recent years, the medicinal properties of marijuana are gaining public acceptance. As of 2017, 29 states plus the District of Columbia have legalized medical marijuana to some extent. THC and another ingredient called cannabidiol (CBD) are the main substances of therapeutic interest. The National Institutes of Health funded research into the possible medicinal uses of THC and CBD, which is still ongoing.
With the potential for increased recreational use, knowing the effects that marijuana can have on your body is as important as ever. Read on to see how it affects each system in your body.
Much like tobacco smoke, marijuana smoke is made up of a variety of toxic chemicals, including ammonia and hydrogen cyanide, which can irritate your bronchial passages and lungs. If you’re a regular smoker, you’re more likely to wheeze, cough, and produce phlegm. You’re also at an increased risk of bronchitis and lung infections. Marijuana may aggravate existing respiratory illnesses, such as asthma and cystic fibrosis.
Marijuana smoke contains carcinogens, so it may increase your risk of lung cancer too. However, studies on the subject have had mixed results. According to the National Institute of Drug Abuse (NIDA), there is no conclusive evidence that marijuana smoke causes lung cancer. More research is needed.
THC moves from your lungs into your bloodstream and throughout your body. Within minutes, your heart rate may increase by 20 to 50 beats per minute. That rapid heartbeat can continue for up to three hours. If you have heart disease, this could raise your risk of heart attack.
One of the telltale signs of recent marijuana use is bloodshot eyes. The eyes look red because marijuana causes blood vessels in the eyes to expand.
THC can also lower pressure in the eyes, which can ease symptoms of glaucoma for a few hours. More research is needed to understand the active ingredients in marijuana and whether it’s a good treatment for glaucoma.
In the long term, marijuana has a possible positive effect on your circulatory system. Research isn’t conclusive yet, but marijuana may help stop the growth of blood vessels that feed cancerous tumors. Opportunities exist in both cancer treatment and prevention, but more research is needed.
The effects of marijuana extend throughout the central nervous system (CNS). Marijuana is thought to ease pain and inflammation and help control spasms and seizures. Still, there are some long-term negative effects on the CNS to consider.
THC triggers your brain to release large amounts of dopamine, a naturally occurring “feel good” chemical. It’s what gives you a pleasant high. It may heighten your sensory perception and your perception of time. In the hippocampus, THC changes the way you process information, so your judgment may be impaired. The hippocampus is responsible for memory, so it may also be difficult to form new memories when you’re high.
Changes also take place in the cerebellum and basal ganglia, brain areas that play roles in movement and balance. Marijuana may alter your balance, coordination, and reflex response. All those changes mean that it’s not safe to drive.
Very large doses of marijuana or high concentrations of THC can cause hallucinations or delusions. According to the NIDA, there may be an association between marijuana use and some mental health disorders like depression and anxiety. More research is needed to understand the connection. You may want to avoid marijuana if you have schizophrenia, as it may make symptoms worse.
When you come down from the high, you may feel tired or a bit depressed. In some people, marijuana can cause anxiety. About 30 percent of marijuana users develop a marijuana use disorder. Addiction is considered rare, but very real. Symptoms of withdrawal may include irritability, insomnia, and loss of appetite.
In people younger than 25 years, whose brains have not yet fully developed, marijuana can have a lasting impact on thinking and memory processes. Using marijuana while pregnant can also affect the brain of your unborn baby. Your child may have trouble with memory, concentration, and problem-solving skills.
What happens when you smoke or ingest marijuana? Learn the effects it has on your body with this interactive graphic.