B-cell prolymphocytic leukemia, referred to as B-PLL, is a rare blood cancer. It is a more aggressive, but still treatable, form of leukemia. Specifically, B-PLL is a prolymphocytic leukemia (PLL) that affects prolymphocytes – immature forms of B-lymphocytes and T-lymphocytes – in the peripheral blood, bone marrow, and spleen. It is an aggressive cancer that presents poor response to treatment.Mature lymphocytes are infection-fighting immune system cells. B-lymphocytes have two responsibilities:
Production of antibodies – In response to antigens, B-lymphocytes produce and release antibodies specific to foreign substances in order to aid in their identification and elimination phagocytes
Generation of memory cells – Interactions between antibodies and antigens allow B-lymphocytes to establish cellular memories, otherwise known as immunities that allow the body to respond more rapidly and efficiently to previously encountered species

Classification
It is categorized as a lymphoproliferative disorder due to the excessive production of lymphocytes, in B-PLL there is excess production of B-prolymphocytes by the bone marrow. These immature lymphocytes are not normally found in the blood; part of their maturation process is being programmed to produce antibodies against foreign material prior to their departure from the bone marrow. In B-PLL, malignant B-prolymphocytes disrupt the adaptive capabilities of the immune system due to the lack of mature B-lymphocytes.It has been suggested that some cases may represent a variant of mantle cell lymphoma. Signs and symptoms
This type of leukemia is characterized by:
More than 55% of circulating cells in peripheral blood (red blood cells, white blood cells and platelets collectively) are prolymphocytes.
Due to the similarities among lymphoproliferative disorders, it is often difficult to diagnose patients. Immunophenotyping helps distinguish B-PLL from similar diseases, one of its key identifiers is the absence in expression of the surface antigens CD10, CD11c, CD25, CD103 and cyclin D1 – an important regulator of cell-cycle progression.A case has been described as CD20+, CD22+, and CD5-.It can also be CD5+.Another case was described as CD45+, CD19+, CD20+, CD5+, HLA-DR+, CD10-, CD23+/-, CD38+ and FMC7-. Cytogenetics
B-PLL is rare, consequently few genetic studies have focused on this disease. As a result, the associated genetic lesions underlying B-PLL are largely unknown. Chromosomal Mutations
The most commonly reported abnormalities have occurred at chromosome 14, specifically in a region of the chromosome called band q23 (14q23). Translocations to this location lead to overexpression of the cyclin D1 gene which has been linked to both the development and progression of a number of cancers. Other chromosomal abnormalities have been reported on 6q21, 11q23, 12p12, 13q14 and 17p.It can involve deletions from chromosome 11 and chromosome 13. TP53 Gene
Among the documented studies, mutations to the TP53 gene have occurred in 75% of all cases of B-PLL. This is the highest incidence among all sub-types of B-cell malignancies. Mutations to this gene have also been documented in other hematologic malignancies.TP53 is an important transcriptional activator of genes involved in the regulation of the G1 checkpoint of the cell cycle as well as certain genes responsible for programmed-cell death (apoptosis).