Flow Cytometry Pre-rotation Test

Right angle side scatter is a measurement used in flow cytometry to assess the complexity of a cell. It provides information about the internal structure and granularity of the cell. Nuclear/cytoplasmic complexity refers to the differences in complexity between the nucleus and the cytoplasm of a cell. Therefore, it is reasonable to conclude that the right angle side scatter is proportional to nuclear/cytoplasmic complexity, as an increase in complexity would result in a higher scatter signal.

Forward angle light scatter is proportional to cell size because larger cells will scatter more light than smaller cells. This is because larger cells have a larger surface area and more internal structures that can scatter the incident light. Therefore, when measuring forward angle light scatter, the intensity of the scattered light can be used as an indicator of the cell size.

The correct answer is "Weaker than on mature lymphocytes". This suggests that the intensity of CD45 fluorescence on lymphoblasts is lower compared to mature lymphocytes. CD45 is a protein found on the surface of immune cells, including lymphocytes. Lymphoblasts are immature lymphocytes that have not fully developed, so it is expected that they would have lower levels of CD45 compared to mature lymphocytes.

The given flow cytometric profile shows positive expression of CD19, CD20, CD103, CD123, monoclonal surface light chain, and negative expression of CD5, CD10, CD138. This pattern is consistent with the diagnosis of Hairy cell leukemia. Hairy cell leukemia is characterized by the presence of abnormal B lymphocytes that express CD19, CD20, CD103, and CD123, and show monoclonal surface light chain expression. Additionally, hairy cell leukemia typically lacks expression of CD5, CD10, and CD138, which is in line with the given profile.

All of these parameters can be used in the analysis

The immunophenotype of B cell chronic lymphocytic leukemia typically includes CD19, CD5, and CD23. CD10 is not typically expressed in B cell chronic lymphocytic leukemia.

Cytoplasmic CD3 is the most specific marker identifying T lymphocytic differentiation in acute leukemia. This is based on the information provided in the 2008 WHO monograph. The other options, surface CD7 and surface CD3, are not as specific in identifying T lymphocytic differentiation.

Cytoplasmic myeloperoxidase is the most specific marker for identifying myeloid differentiation in acute leukemia according to the 2008 WHO monograph. This marker is used to distinguish between different types of leukemia and specifically indicates the presence of myeloid cells. CD33, CD117, and CD13 are also markers used in the diagnosis of leukemia, but cytoplasmic myeloperoxidase is the most specific marker for myeloid differentiation.

Burkitt lymphoma is a type of non-Hodgkin lymphoma that typically expresses CD19, CD10, and monoclonal surface light chain. However, it does not express CD5. CD5 is commonly found on B-cell chronic lymphocytic leukemia (CLL) cells, but it is not present on Burkitt lymphoma cells. Therefore, CD5 is the correct answer as it is not part of the typical flow immunophenotype of Burkitt lymphoma.

HLA-DR is used as an antigen in flow cytometric analysis to distinguish acute promyelocytic leukemia from other types of acute myeloid leukemia. This is because HLA-DR expression is typically absent or low in acute promyelocytic leukemia, while it is expressed in other types of acute myeloid leukemia. Therefore, the presence or absence of HLA-DR can help differentiate between these two types of leukemia.

Burkitt lymphoma is a high-grade B-cell lymphoma that is characterized by the presence of c-Myc gene rearrangement. It typically presents as a rapidly growing tumor in children and young adults. Unlike the other lymphomas listed, Burkitt lymphoma does not express CD5. CD5 is a marker commonly found on T cells and a subset of B cells, but it is not expressed in Burkitt lymphoma. Therefore, Burkitt lymphoma is the correct answer for this question.

Follicular lymphoma is a type of non-Hodgkin lymphoma that typically expresses CD19, CD10, and monoclonal surface light chain. However, CD5 is not typically expressed in follicular lymphoma. CD5 is a marker that is commonly associated with chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), but it is not a characteristic marker of follicular lymphoma. Therefore, CD5 is the correct answer as it is not typically part of the flow immunophenotype of follicular lymphoma.

Loss of expression of some but not all T cell antigens is the best immunophenotypic profile for identifying T cell lymphoma by flow cytometric analysis. This is because T cell lymphomas often show aberrant or partial loss of expression of T cell antigens, such as CD2, CD3, CD5, and CD7, while maintaining expression of other T cell antigens. This loss of expression pattern can help differentiate T cell lymphoma from reactive T cell populations, which typically show intact expression of these antigens.

Although CD23 is usually absent, a minority of mantle cell lymphomas are CD23 weak positive. Hence correlation with the intensity of light chain expression, expression of FMC7 and other antibodies such as CD79a, as well as cytogenetic/FISH studies may be necessary in definitive DDX.

The explanation for the answer "False" is that flow immunophenotype cannot be used to distinguish between CLL/SLL and monoclonal B cell lymphocytosis. While flow immunophenotyping is a useful tool in the diagnosis and classification of CLL/SLL, it is not specific enough to differentiate between these two conditions. Additional tests, such as cytogenetic analysis or molecular studies, are required to make a definitive diagnosis. Therefore, the statement provided in the question is incorrect.

CD41 and CD61 are two antigens used in the flow lab to distinguish megakaryocytic differentiation. CD41, also known as integrin alpha IIb, is a glycoprotein that is expressed on the surface of platelets and megakaryocytes. CD61, also known as integrin beta 3, forms a complex with CD41 and is involved in platelet aggregation and adhesion. By detecting the presence of CD41 and CD61, researchers can identify and study cells that are undergoing megakaryocytic differentiation.

Glycophorin is used as an antigen in flow cytometry to distinguish erythroid differentiation. Glycophorin is a protein found on the surface of red blood cells, and its expression increases during erythroid differentiation. By detecting the presence of glycophorin using flow cytometry, we can identify and analyze the different stages of erythroid differentiation.

FLAER, CD55, and CD59 are antigens that are used for the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH) by flow cytometric analysis. FLAER is a fluorescent protein that binds to glycosylphosphatidylinositol (GPI) anchors, which are deficient in PNH cells. CD55 and CD59 are cell surface proteins that are also deficient in PNH cells. By analyzing the expression levels of these antigens using flow cytometry, PNH can be diagnosed. CD14 is not directly used for the diagnosis of PNH but may be included in the analysis for additional information or as a control.

The given immunophenotype shows a dominant population of cells that are positive for CD45 dim, CD7, CD2, CD5, CD4, and CD8. These markers are commonly seen in T lymphoblastic lymphoma/leukemia, which is a type of cancer that affects immature T cells. The absence of CD19, CD20, surface light chain, CD3, and HLA-DR further supports this diagnosis, as these markers are typically not expressed in T lymphoblastic lymphoma/leukemia. Therefore, based on the immunophenotype, the diagnosis is T lymphoblastic lymphoma/leukemia.

Acute myeloid leukemia with t(8;21) is a subtype of acute myeloid leukemia that often aberrantly co-expresses CD19 and CD56, with down regulation of CD33 and CD13. This specific chromosomal translocation results in the fusion of the RUNX1 gene on chromosome 21 with the RUNX1T1 gene on chromosome 8. The resulting fusion protein disrupts normal hematopoiesis and leads to the characteristic immunophenotype seen in this subtype of acute myeloid leukemia.

The three antigens that can be used to distinguish B cell acute lymphoblastic leukemia from Burkitt lymphoma are dim versus bright CD45 expression, nuclear tdt expression, and absence of surface light chain expression. In B cell acute lymphoblastic leukemia, the CD45 expression is dim, while in Burkitt lymphoma, it is bright. Nuclear tdt expression is present in B cell acute lymphoblastic leukemia but absent in Burkitt lymphoma. Additionally, B cell acute lymphoblastic leukemia shows an absence of surface light chain expression, whereas Burkitt lymphoma does not. These differences in antigen expression patterns can help differentiate between the two conditions.

The flow cytometric analysis shows that the cell population is negative for CD45, CD19, CD20, CD3, CD13, CD33, and HLA-DR, but positive for CD56 bright. This immunophenotype is consistent with neurendocrine carcinoma. Neurendocrine carcinomas are known to have a characteristic immunophenotype, with loss of expression of common leukocyte antigens (such as CD45) and lineage-specific markers (such as CD19, CD20, CD3, CD13, and CD33), while showing positivity for CD56. Therefore, based on the given immunophenotype, the diagnosis of suspicious for neurendocrine carcinoma is appropriate.