What is lupus?
Lupus is a chronic autoimmune disease. This means that the immune system mistakenly attacks healthy tissues and cells, causing chronic (persistent) inflammation resulting in damage to various parts of the body. Multiple organs and systems can be damaged by lupus, including joints, skin, kidneys, heart, the circulatory system and the brain.
There are multiple types of lupus, including systemic lulus erythematosus (SLE), which is the most common type. Other types are discoid lupus, which causes persistent red rashes, and drug-induces lupus, which is triggered by medications and usually resolves once the patient stops taking the causative drug [1].
Signs and Symptoms of Lupus
The signs and symptoms of lupus can vary from person to person, and they may present at different times, or come and go. Common symptoms include unexplained fever (where doctors rule out all common causes of fever such as an infection), swelling or pain in the joints, fatigue or kidney problems. The most significant symptom is the presence of a "butterfly rash" on the face - a rash under the eyes resembling the wings of a butterfly. Other symtoms are more non-specific, including muscle pain, hair loss, swelling of glands, chest pains when taking a deep breath, sensitivity to sunlight and pale or purple fingers or toes [2, 3, 4, 5].
Consequently, diagnosis of lupus is challenging due to the wide variety of symptoms and affected organ systems. There is no single test for lupus, instead, a combination of physical examination, blood testing, urine testing and biopsies of affected tissues is used. The American College of Rheumatology has established a set of 11 criteria for the diagnosis of lupus, and a person is typically diagnosed with lupus if they meet at least four of these criteria over time.
Treatment of Lupus
While there is currently no cure for lupus, treatments are available to help manage symptoms and prevent complications. The first line of treatment includes administering non-steroidal antiinflammatory drugs (NSAIDs) to treat joint pain and stiffness.
For example, aspirin is used in almost 80% of lupus patients. Additionally, antimalarial drugs can be used to manage fatigue, skin rashes and joint pain - hydroxychloroquine is commonly used.
For more complex cases, corticosteroids and immunosuppressive treatments are used to reduce the systemic inflammation and suppress the immune system. This treatment is usually tailored to the individual patient's symptoms, and may need to be adjusted following the progression of the disease [6, 7].
Additionally, following recent research, new targeted therapies are available. These include biological agents that target molecules important for the disease - usually immune system effectors or molecules involved in signalling of the immune system (cell signalling is a biological process where cells communicate via chemical signals). Some of these molecules include interleukin 6 (IL-6) or interferons (IFNs). Gene therapy is another promising area of research, with preclinical studies showing its potential efficacy in treating lupus [8].
What is leukaemia?
Leukaemia is a collective term encompassing blood cancers that affect the white blood cells and the bone marrow. The bone marrow is an important tissue for the circulatory system, as it is where blood cells originate from.
Leukaemia is a heterogeneous group of diseases, with treatment response and outcome dependent on the specific type of malignancy. Broadly, leukaemia can be classified into acute and chronic types, with different progression of the disease and clinical profile. Of these, chronic lymphocytic leukaemia (CLL) is the most common blood cancer in the Western countries, comprising 30-40% of all the leukaemias [9, 2].
Signs and Symptoms of Leukaemia
While most symptoms of leukaemia are non-specific, certain symptoms can be used to diagnose leukaemia and distinguish between the acute and chronic types.
For chronic leukaemia, the three strongest symptoms are swollen lymph nodes (lymphadenopathy), weight loss, and easy bruising. Acute leukaemia, on the other hand, is often associated with nosebleeds and/or bleeding gums, fever, and fatigue.
It is, however, important to note that the positive predictive value of these symptoms is low, and these symptoms alone cannot be used for definitive diagnosis [3].
Diagnosis of Leukaemia
Consequently, blood and bone marrow tests are needed for a definitive diagnosis. These include a complete blood count, where the presence of different cells in a blood sample is quantified and a bone marrow biopsy, where the bone marrow cells are aspirated with a needle and looked at under the microscope to determine the presence of cancerous cells.
These processes can be automated with computer-aided diagnosis, which can be more accurate compared to manual diagnosis methods [4]. Additionally, genetic testing is an important component of blood cancer testing, where genetic aberrations (defects) are detected such as translocations (where portions of chromosomes, which are units of DNA organisation, swap places), fusions (where products of two genes are stuck to each other) and mutations. These are essential to inform therapeutical decisions.
Treatment of Leukaemia
The treatment for leukaemia relies on killing of the cancerous blood cells to allow new healthy blood cells to form and take over. Treatments often include cytotoxic chemotherapy, typically a combined regimen of multiple drugs. Additionally, stem cell or bone marrow transplantation may be used.
Leukaemias are a very approachable group of cancers form the precision medicine standpoint, as the genetic aberrations are well understood and cancerous material can be easily obtained by a simple blood draw. This allows for opportunities to tailor treatment to the individual patient, as well as monitor treatment in short intervals.
Consequently, a large number of targeted therapies and immunotherapies are available, and have revolutionised the prognoiss of leukaemia [5, 6]. Some of these treatments include bispecific antibodies, cell therapies (CAR-T-cell treatment), and checkpoint blockade [9].
What are the differences?
To summarise, lupus and leukaemia are two distinct medical conditions, each with its unique characteristics and symptoms. While lupus is an autoimmune disease, which involves the body's immune system attacking itself, leukaemia is a group of blood cancers, where white blood cells are damaged and turn cancerous.
Lupus and leukaemia share some common, nonspecific symptoms including fatigue, fever and pain in some places including around the joints. However, the causes and other symptoms of the two conditions differ, as does the clinical progression and treatment strategies.
Lupus is a chronic condition that can be managed but not cured. On the other hand, leukaemia can be potentially cured with treatments like systemic chemotherapy, targeted therapy or stem cell and bone marrow transplant.
Interestingly, while lupus and leukaemia are two separate conditions, there is some evidence to suggest that individuals with lupus may have an increased risk of developing certain types of cancer, including leukaemia, attributed to dysfunction of the immune system [6, 7].