mlab 1315- hematology fall 2007 keri brophy-martinez unit 3: leukocytes
TRANSCRIPT
MLAB 1315- HematologyFall 2007Keri Brophy-Martinez
Unit 3: Leukocytes
NEUTROPHILS
Myelopoiesis - the production and development of myeloid cells in the bone marrow Growth factors (colony-stimulating
factors - CSF’s) and interleukins regulate blood cell development by:
Mediating proliferation Differentiation into cell lines Maturation of hematopoietic progenitor
cells
NEUTROPHILS
Three series of granulocytes (named for colors taken up by granules in Wright’s stain) Neutrophils
Granules stain equally with eosin and methylene blue
Normal in circulation = 42 - 75% Eosinophils
Granules stain mainly red Normal in circulation = 0-4%
Basophils Granules stain mainly with methylene blue Normal in circulation = 0-2%
Maturation of the neutrophilic series
Stem cell - an unspecified cell that gives rise to a specific specialized cell, such as a blood cell Multipotential and cannot be identified
morphologically Can self-renew and differentiate
Maturation of the neutrophilic series
Myeloblast Size: 10-20µm Cytoplasm
Slight amount/blue
No granules ( possible Auer rods to be discussed in another section)
Nucleus Round/Central
or eccentric Reddish purple 1-3 nucleoli Fine meshlike
chromatin with no clumping
N:C ratio = 4:1
Maturation of the neutrophilic series
Promyelocyte (progranulocyte)
Size: 10-20µm Cytoplasm
Increased amount/blue Fine, azurophilic,
nonspecific granules present
Nucleus Round/Central or
eccentric Reddish-purple Fine, meshlike
chromatin beginning to clump
1-2 nucleoli N:C ratio = 3:1
Maturation of the neutrophilic series
Myelocyte (last myeloid cell capable of division)
Size: 10-18µm Cytoplasm
Increased, bluish-pink (“dawning of neutrophilia”)
Fine azurophilic, specific granules
Nucleus Round or
oval/eccentric Reddish-purple Chromatin loosely
clumped No nucleolus
N:C ratio = 2:1 or 1:1
Maturation of the neutrophilic series
Metamyelocyte (also called “meta” or “juvenile”)
Size: 10-18µm Cytoplasm
Moderate amount Specific granules
(neutrophilic, eosinophilic or basophilic)
Nucleus Indented (kidney-bean
shaped) Central or eccentric Purple Clumped chromatin No nucleolus
N:C ratio = 1:1
Maturation of the neutrophilic series
Band Size: 10-16µm Cytoplasm
Moderate amount Specific granules
(see meta) Nucleus
Elongated, narrow band (sausage) shape with uniform thickness
Central or eccentric Clumped, coarsely
granular chromatin
Maturation of the neutrophilic series
Segmented neutrophil, eosinophil or basophil Size: 10-16µm Cytoplasm
Neutrophil - specific fine violet pink Eosinophil - red uniform specific granules Basophil - coarse violet blue non-uniform specific granules
(Mast cell is a tissue basophil) Nucleus
Neutrophil - purplish-red, clumped granular chromatin, 2-5 distinct nuclear lobes connected by a filament of chromatin
Eosinophil - deep blue purple, coarsely granular chromatin, 2 distinct lobes
Basophil - deep blue purple, coarsely granular chromatin, 2 nuclear lobes (sometimes obscured by cytoplasmic granules)
Maturation of the neutrophilic series
Function of the neutrophilic series
Neutrophils - defense against bacterial infections
Eosinophils Regulate inflammation Respond to antigenic stimulation in chronic
allergies Interact with larval stages of some helminthic
parasites Basophils
Histamine in granules plays a role in acute, systemic allergic reactions (sudden release of histamine can cause anaphylactic shock)
Granules also contain heparin
MONOCYTES
Monopoiesis - the production and development of monocytes, macrophages and their precursors. Monocytes are produced in the bone marrow. Their primary function is phagocytosis.
MONOCYTES
Other names for macrophages Histiocytes in the loose connective tissue Kupffer cells in the liver Osteoclasts in the bone Microglial cells in the nervous system Also scattered throughout the body in all organ
tissues (spleen, lung, abdomen, etc.) One monocytes have grown into macrophages, they do not normally reenter the bloodstream except in cases of inflammation
Maturation of the monocytic series
Monoblast Size: 12-20µm Cytoplasm
Blue, moderate amount
No granules Nucleus
Round, oval or slightly folded
Eccentric Reddish-purple Chromatin fine and
thready Vacuoles may be
present 1-2 nucleoli
N:C ratio = 4:1
Maturation of the monocytic series
Promonocyte (difficult to discern) Size: 21-20µm Cytoplasm
Paler gray-blue and abundant “Bleb-like” pseudopods at periphery May contain fine red “dust-like” particles Vacuoles may be present
Nucleus Round with chromatin creases or brain-like folding Central Reddish-purple with light clumping of chromatin 0-2 nucleoli
N:C ratio = 3:1 or 2:1
Promonocyte
Maturation of the monocytic series
Mature monocyte (Normal in circulation: 2-9%) Size: 15-18µm Cytoplasm
Pale gray-blue and abundant Bleb-like pseudopods at periphery, variable shape Numerous fine pale red dustlike granule scattered
throughout Vacuoles common
Nucleus Increased folding or elongated Central Purplish with finer clumped chromatin No nucleoli
N:C ratio = 2:1 or 1:1
Monocyte
LYMPHOCYTES
Normal adult value: 21-51% Produced in the bone marrow
(primary lymphoid tissue)
LYMPHOCYTES
Growth factors cause lymphs to differentiate. They proliferate and mature in the primary lymphoid organs:
LYMPHOCYTES
Thymus - T cells Function
Cellular immune response (they do not produce antibodies) Regulate antibody reactions by helping or suppressing
activation of B lymphs. T cells act as “helper cells” (HIV or AIDS virus causes a destruction of these helper cells), which are instrumental in aiding B cells in antibody production, and “suppressor cells”, which act as a “thermostat” to shut off the system or keep it under control. The helper to suppressor ratio is very important and is normally 2:1.
Protect against viral, bacterial, fungal or protozoan infection Responsible for chronic organ graft rejection. (T cells have
many unique antigens on their cell surfaces, some of which are the HLA - human lymphocyte antigen - markers. Cytotoxic and helper T cells act against these HLA markers if they are foreign to the host organism. HLA markers are instrumental in chronic graft rejection and that is why tissue typing is done to establish a good donor match.)
LYMPHOCYTES
Bone marrow - B cells Function
Humoral (antibody) immune response by transforming into antibody-producing plasma cells
Defense against encapsulated bacteria such as streptococci
Mediate hyperacute organ rejection
LYMPHOCYTES
Null cells - unknown maturation sequence Function
Destroy by lysis target cells (such as tumor cells) by cytotoxins
Play a role in inflammatory response Host defense when stimulated by
interferon against certain viruses (cytomegalovirus - CM, and hepatitis) by killing the virally infected target cell before the virus replicates
LYMPHOCYTES
T and B cell lymphocytes cannot be differentiated morphologically. They are distinguished functionally and by immunologic marker studies (to be discussed later.) Null cells appear as large lymphocytes with azurophilic granulocytes and are called large granular lymphocytes (LGL).
Secondary lymphoid tissue Lymph node, spleen, Peyer’s patches in
intestine and mucosal tissues such as tonsils
Active immune response occurs in above tissues where lymphs communicate and interact with antigen-presenting cells, phagocytes and macrophages
Maturation sequence of lymphocytes
Lymphoblast (which is preceded by a lymphoid stem cell)
Cell size: 10-20µm Cytoplasm
Blue/scanty No granules, Auer
rods are never present
Nucleus Purple, smooth
chromatin Round, central or
eccentric 1-2 nucleoli
N:C ratio = 4:1
Maturation sequence of lymphocytes
Prolymphocyte (difficult to distinguish)
Size: 9-18µm Cytoplasm
Blue, scanty Usually granules are
absent, but a few azurophilic granules may be present
Nucleus Purple, condensed
chromatin Round or indented,
eccentric 0-1 nucleoli
N:C ratio = 4:1
Maturation sequence of lymphocytes
Mature lymphocyte Cell size: 7-10µm (a typical
normal lymph has a nucleus that is the size of a normal RBC)
Cytoplasm Light blue, scanty to
moderate Few azurophilic granules
may be present Nucleus
Purple, dense, clumped chromatin
Round or indented, eccentric
No nucleoli
Large lymphocytes versus monocytes
Size Large lymph: 12-15µm Mono: 15-18µm
Nucleus Large lymph: clumped, condensed Mono: lacy, brainlike folds
Granules Large lymph: large azurophilic, easy to count Mono: red, fine
Cytoplasm Large lymph: clear, nongranular, may be indented by red
cells Mono: “ground glass” appearance, projection of blunt pseudopod blebs
Maturation sequence of lymphocytes
Variant lymphs Other terms used are reactive, atypical, Downey
cell, transformed, virocyte, plasmacytoid Caused by antigenic stimulants such as viruses,
post-transfusion reactions and organ transplants General characteristics
Increased size due to DNA activity in the nucleus and RNA activity in the cytoplasm
Enlarged and/or monocytoid nucleus Variation in nuclear chromatin pattern Nucleus may contain 1-3 nucleoli Abundant, sometimes foamy or vacuolated cytoplasm Variation in cytoplasmic color - gray-blue to intense blue Absence of granules in cytoplasm
Reactive lymphocyte
Plasma cells
Plasma cells Function is the synthesis and excretion of antibodies
(immunoglobulins) Normally not present in the peripheral blood; comprise
2% of bone marrow cells. (May be seen in the peripheral blood in the disease called multiple myeloma, a disease of uncontrolled production of immunoglobulins.)
End stage of the B lymphocyte Appearance
Size: 10-18µm Cytoplasm is dark blue with perinuclear halo and may contain vacuoles
indicating antibody synthesis Nucleus is round, eccentric, dark purple with dense clumped chromatin
Variant plasma cells Grape or Mott cell - cytoplasm completely filled with red, pink or
colorless globules called Russell bodies Flame cell - cytoplasm stains bright red-staining proteinaceous
material
Plasma cells