Leukopoiesis, WBC Differentials, and Lymphocyte Function

• the production of white blood cells

• purpose:

  • defend against foreign invaders, such as bacteria, viruses, fungi, or parasites

  • some have granules that contain enzymes used for digestion and destruction

What is leukopoiesis and what is the purpose of leukocytes?

• myeloblast

• promyelocyte

• myelocyte

• metamyelocyte

• band

• segmented neutrophil, eosinophil, or basophil

List the maturation sequence for granulocytes from least mature to mature (neutrophils, eosinophils, and basophils)

• cell size

• N:C ratio

• chromatin pattern (nucleus pattern)

• cytoplasm quality and color

• presence or absence of granules

What are the 5 ways to distinguish cell stages and cell types?

• size: 14-20 um

• N:C ratio is 6:1, nucleus is round/oval, and may be indented

• light red-purple in color, cytoplasm may be a little blue, NO granules

• CD45, CD38, CD34, CD33, CD13

Describe the size, N:C ratio, and appearance of myeloblasts

• size: 15-22 um

• N:C ratio is 3:1, nucleus is oval/round, eccentric, and dark purple

• cytoplasm is blue with fine to large blue-red granules

• CD45, CD33, CD13, & CD15

Describe the size, N:C ratio, and appearance of promyelocytes

• size: 10-18 um

• N:C ratio is 2:1, nucleus is red-purple, oval, indented, and dense

• cytoplasm: fine, red-blue granules

• CD45, CD33, CD13, CD15, CD11

Describe the size, N:C ratio, and appearance of myelocytes

• size: 10-15 um

• N:C ratio is 1:1, nucleus is kidney bean-shaped, chromatin is patchy

• cytoplasm is pale-blue to tan with granules

• CD45, CD33, CD13, CD15, CD11

Describe the size, N:C ratio, and appearance of metamyelocytes

• size: 9-15 um

• nucleus is C or S shaped

• cytoplasm is brown-pink with fine granules

• CD45, CD13, CD15, CD11

Describe the size and appearance of bands

• size: 9-15 um

• N:C ratio is 1:2, nucleus consists of 2-5 lobes connected by filaments

• cytoplasm is pale lilac with many fine granules

• USED FOR defense

Describe the size, N:C ratio, and appearance of segmented neutrophils

• size: 10-16 um

• N:C ratio is 1:2, nucleus is eccentric and usually bilobed

• cytoplasm has large red-orange granules and orange-pink cytoplasm

• responds to parasitic, allergic, and hypersensitive reactions, contains histamine

Describe the size, N:C ratio, and appearance of eosinophils

• size: 10-14 um

• nucleus is coarse, clumped, and bilobed with dark granules

• cytoplasm has purple-black granules

• contains histamine and heparin used to respond to hypersensitive reactions

Describe the size and appearance of basophils

• monoblast

• promonoblast

• monocyte

What are the 3 stages of monocyte maturation?

same as myeloblasts

Describe the size and appearance of monoblast

• size: 12-20 um

• irregular and indented nucleus, gray-blue cytoplasm

Describe the size and appearance of promonoblast

• size: 12-20 um

• N:C ratio is 1:1

• nucleus is loosely woven and thin, and the cytoplasm is light purple/blue or pinkish

• CD33, CD13, CD14 (14 is specific to monocytes)

Describe the size, N:C ratio, and appearance of monocytes

• lymphoblast

• prolymphocyte

• small lymphocyte

• large lymphocyte

List the 4 stages of lymphocyte maturation, from least mature to most

• lymphoblasts

  • size: 10-20 um

  • smudgy nucleus, deep blue

• prolymphocytes

  • size: 9-18 um

  • coarse nucleus, gray-blue cytoplasm

Describe the size and appearance of lymphoblasts AND prolymphocytes

• size: 7-12 um

• coarse, lumpy nucleus, also oval and eccentric, some red granules

Describe the size and appearance of small lymphocytes

• size: 15-18 um

• a lot of cytoplasm, light-blue in color

• dark purple nucleus

Describe the size and appearance of large lymphocytes

to produce:

• graunulocytes (neutrophils, basophils, and eosinophils) (stem cell: CFU GEMM)

• erythrocytes (stem cell: CFU GEMM)

• monocytes (stem cell: CFU GEMM)

• macrophages(stem cell: CFU GEMM)

• and megakaryocytes (stem cell: CFU MEG)

specific interleukins and growth factors stimulate the myeloid stem cell to produce these cells

What is the job of myeloid stem cells?

• blood filtration

• fluid balance

• antibody generation

• lymphopoiesis

What is the lymphatic system responsible for?

• derived from bone marrow stem cells

• eventually matures to plasma cells, cells that secrete antibodies in humoral immunity

• 10-20% of all lymphocytes

Where do B lymphocytes come from and what are they responsible for?

• arise from lymphatic stem cells in the bone marrow, but matures in the THYMUS (T = thymus)

• used in cell mediated immunity

  • T helper cell and cytotoxic T cell

• 60-80% of all lymphs

Where do T lymphocytes come from and what are they responsible for?

to kill bacteria, fungi, and viruses

What is the responsibility of NK cells?

• the manual counting and differentiating between leukocytes

• count is performed at 50x or 100x under the microscope

• 100 cells are counted and differentiated, results are reported as percentages

What are differential WBC counts?

• 9-30 ×10^-9/L

• 6-16 × 10^-9/L

• 4.8-10.8 × 10^-9/L

(move decimal up 3 places)

What are the WBC reference ranges for:

• newborns

• 2-12 years old

• and adults?

• relative is the percentage of each WBC identified in a 100 cell count

  • not a complete representation

• absolute multiplies each WBC percentage by the patient’s total WBC count

What is the difference between relative and absolute WBC counts?

• primary

  • bone marrow and thymus

• secondary

  • spleen, lymph nodes, tonsils, and peyers patches

List the primary and secondary lymphoid organs

• segmented neutrophils: 50-70%

• bands: 2-6%

• lymphocytes: 20-44%

• monocytes: 2-9%

• eosinophils: 0-4%

• basophils: 0-2%

What are the adult reference ranges for the following WBCs:

• segmented neutrophils

• bands

• lymphocytes

• monocytes

• eosinophils

• basophils

• My Pet Mouse Makes Big Messes

  • Myeloblast

  • Promyelocyte

  • Myelocyte

  • Metamyelocyte

  • Band

  • Mature granulocyte (neutrophils, eosinophils, and basophils)

mnemonic to remember the stages of granulocyte maturation