What is basophilia
Basophilia refers to when there are too many basophilic granulocytes in a person’s blood. It’s not a condition on its own, but it can be an important indicator of other underlying medical problems. Basophils are a type of white blood cell produced in the bone marrow. In healthy individuals, they represent a minimal amount of the body’s cell population. They are quite rare cells. In addition to producing serotonin and histamine, they are also factors in the production of heparin, which has an anticoagulant function. The lungs are the organs that contain a greater amount of basophils, as are the skin and the digestive system. However, people with basophilia have an abnormally high amount of basophilic leukocytes. Basophilia rarely exists independently and more often indicates the presence of another condition.
Causes and risk factors
The most common causes of basophilia include: allergic disorders, infections, bone marrow disorders and diseases characterized by chronic inflammation.
Infections often trigger an inflammatory response in the body, which can make a person more likely to develop basophilia. However, the development of basophilia following an acute infection or disease is rare. Certain diseases, including chickenpox and tuberculosis, can make a person more likely to develop basophilia. Basophilia also appears in case of parasitosis, or infestation with worms (intestines and other tissues); it can often be the only index to blood tests that must lead to suspicion of a possible presence of worms in the body.
Allergies and contaminants
Allergies and allergic reactions to foods and drugs can cause basophilia. The severity of the allergy or response may be related to the severity of the basophilia. It hase been reported from some time now that chronic (mostly unaware) mercury poisoning, due to professional exposure, may include basophilia as laboratory outcome.
A person with a condition characterized by inflammation may be more likely to develop basophilia. Diseases directly related to chronic inflammation include autoimmune conditions such as rheumatoid arthritis, inflammatory bowel disease (IBD), psoriasis, and Hashimoto’s thyroiditis.
Bone marrow disorders
Myeloproliferative disorders cause the bone marrow to overproduce various types of blood cells, including basophils. Myeloproliferative disorders that may cause basophilia include polycythemia vera, essential thrombocythemia, chronic myeloid leukemia, primary myelofibrosis, systemic mastocytosis, and hyperosinophilic syndrome.
Symptoms: prevalence with the real cause
An abnormally high amount of basophils can cause a variety of nonspecific symptoms such as itching, fatigue, fever, abdominal pain and cramps, and unexplained weight loss. The symptoms of the underlying causes of basophilia are different for everyone. People with unexplained symptoms that don’t resolve over time should visit their doctor. However, the symptoms of a person with basophilia experiences vary depending on their underlying medical condition. People who have basophilia due to an infection will have symptoms of the infection, which can include fever, fatigue, and malaise.
Those with basophilia due to allergies will have typical allergy symptoms, including: itchy eyes, runny nose and sneezing, rash or swelling. A person who has basophilia due to IBD can experience: abdominal cramps, diarrhea in the stool, rectal pain. Basophilia caused by a condition that causes chronic inflammation can cause symptoms such as: muscle aches and pains, swelling, light fever, fatigue, numbness of the hands and feet and / or tingling. People with basophilia as a result of myeloproliferative disease may have different symptoms depending on the disorder they have. Symptoms may include: weakness, headache, easy bleeding and bruising, vision changes, numbness, and bone pain.
The clinical presentation of basophilia is diverse and related to the underlying cause. If splenomegaly is present, myeloproliferative syndrome may be suspected. Constitutional symptoms such as fever, malaise, itching and fatigue may be present. Right upper quadrant pain may be present. In polycythemia vera, erythromelalgia or burning of the palms and soles of the feet is often common. Itching after a hot shower can also be a symptom. However, these patients usually present with much more severe symptoms such as thrombosis. If you have any underlying allergic or hypersensitivity reactions, skin rashes may be present.
For the examination of splenomegaly, a patient must be supine with the abdomen relaxed. The examiner should try to insert 3 fingers into the Traube space (under the left side of the rib cage) during inspiration. Spleen enlargement may be felt under the fingers. Another technique that is also sensitive is an ultrasound examination which can lead to the same results. If concomitant eosinophilia greater than 1500 cells / ul is present, hyper-eosinophilic syndrome may be considered. Symptoms and other systemic manifestations will be related to skin or lung involvement.
The next step is the peripheral blood smear and evaluation. When unexplained left-shift neutrophilia with basophilicity is present, cytogenetic testing is indicated to rule out CML, the molecular biology technique called fluorescent in situ hybridization (FISH) for BCR-ABL1 fusion can be performed on peripheral blood and, if positive, supports the diagnosis of CML. The other major myeloproliferative neoplasms (polycythemia, myeloid fibrosis, thrombocythemia) often harbor mutations and other mutations. Janus kinase 2m (JAK2 V617F) which is an acquired genetic mutation is found in the vast majority of patients with polycythemia vera, over 50% of patients with primary myelofibrosis and essential thrombocythemia.
A minority of patients will have mutations in the calreticulin protein or the c-Mpl receptor. The finding of one of these mutations is not specific for a myeloproliferative neoplasm and must be related to morphology and clinical findings. When a bone marrow biopsy is performed for a suspected myeloid neoplasm, cytogenetic analysis is required. This is where the karyotype or genetic screen of the chromosomes of each white blood cell is tested. Significant anomalies of a conventional karyotype support the diagnosis of a neoplastic process. To speed up the identification of BCR-ABL fusion in case of suspected CML, the FISH test can be performed simultaneously.
Basophilia alone does not cause complications, but the underlying causes of basophilia can. Complications vary based on the cause of basophilia and can be serious, including: frequent infections, heavy bleeding, and an increase in the spleen. Basophilia should not be treated directly. Instead, treatment will focus on the person’s underlying medical condition. Bacterial infections that cause basophilia require antibiotics; your doctor will recommend rest and plenty of fluids. Allergy treatments include antihistamines, hydrocortisone cream, oral steroids, and adrenaline spray. Treatment for inflammatory diseases, such as rheumatoid arthritis and IBD, can include mesalazine, corticosteroids, and other anti-inflammatory drugs. Treatment for a myeloproliferative disorder is likely complex and will vary depending on an individual’s situation. It may include chemotherapy, remission inducers (retinoic acid, 5-azacytidine), surgery to remove the spleen (splenectomy), and stem cell transplantation.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
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