Chronic lymphocytic leukemia (CLL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell). Early on there are typically no symptoms. Later non-painful lymph node swelling, feeling tired, fever, night sweats, or weight loss for no clear reason may occur. Enlargement of the spleen and low red blood cells (anemia) may also occur. It typically worsens gradually over years.Risk factors include having a family history of the disease, with 10% of those who develop CLL having a family history of the disease. Exposure to Agent Orange, certain insecticides, sun exposure, exposure to hepatitis C virus, and common infections are also considered risk factors. CLL results in the buildup of B cell lymphocytes in the bone marrow, lymph nodes, and blood. These cells do not function well and crowd out healthy blood cells. CLL is divided into two main types: those with a mutated IGHV gene and those without. Diagnosis is typically based on blood tests finding high numbers of mature lymphocytes and smudge cells.Early-stage CLL in asymptomatic cases responds better to careful observation, as there is no evidence that early intervention treatment can alter the course of the disease. Immune defects occur early in the course of CLL and these increase the risk of developing serious infection, which should be treated appropriately with antibiotics. In those with significant symptoms, chemotherapy, immunotherapy, or chemoimmunotherapy may be used.
Types
The WHO International Working Group on Morphology of MDS (IWGM-MDS) defined three types of sideroblasts:
Type 1 sideroblasts: fewer than 5 siderotic granules in the cytoplasm
Type 2 sideroblasts: 5 or more siderotic granules, but not in a perinuclear distribution
Type 3 or ring sideroblasts: 5 or more granules in a perinuclear position, surrounding the nucleus or encompassing at least one third of the nuclear circumference.Type 1 and type 2 are found in non-sideroblastic anemias. Type 3 is found only in sideroblastic anemia. Symptoms and signs
Symptoms of sideroblastic anemia include skin paleness, fatigue, dizziness, and enlarged spleen and liver. Heart disease, liver damage, and kidney failure can result from iron buildup in these organs. Causes
Causes of sideroblastic anemia can be categorized into three groups: congenital sideroblastic anemia, acquired clonal sideroblastic anemia, and acquired reversible sideroblastic anemia. All cases involve dysfunctional heme synthesis or processing. This leads to granular deposition of iron in the mitochondria that form a ring around the nucleus of the developing red blood cell. Congenital forms often present with normocytic or microcytic anemia while acquired forms of sideroblastic anemia are often normocytic or macrocytic. Congenital sideroblastic anemia
X-linked sideroblastic anemia: This is the most common congenital cause of sideroblastic anemia and involves a defect in ALAS2, which is involved in the first step of heme synthesis. Although X-linked, approximately one third of patients are women due to skewed X-inactivation (lyonizations). Autosomal recessive sideroblastic anemia involves mutations in the SLC25A38 gene.