Chapter 22 Flashcards
Where do afferent lymphatics drain once entering the lymph node?
subcapsular sinus
How does lymph from the subcapsular sinus reach the hilum of the lymph node?
medullary cords
What is found within the cortex of the lymph node?
nodules of B-cells either as primary follicles or germinal centres
what is found wtihin the paracortex or deep cortex?
T cell dependent region
What is found within the medulla of the lymph node?
medullary cords and sinuses which drain into the hilum
What happens to antigen bound to antibody entering thel ymph node?
trapped on the surface of dendritic reciulum cells by their Fc receptors
Where are dendritic reticulum cells found in the lymph node?
primary follicles and germinal centrea
What is the structure of dendritic reticulum cells?
binucelate cells with long cytoplasmic processes linked by desmosomes forming a network throught the germinal centre
What happens to antigen trapped by DRCs?
presented to B cells with the help of T cells
What is the initial step in B cell transformation after antigenic challenge?
formation of the centroblast
what is a centroblast?
rapidly developing cell responeible for exapnsion of the natigen-reactive B-cell clone
What is the function of the germinal centres?
generation of immunoglobulin-secreting plasma cells in response to antigenic challenge
where are plasma cells mainly found within the lymph node?
medullary cords
What is the rim of small,round lymphocytes surrounding the germinal centre called?
mantle zone
What are mantle zone B cells?
a population of post-germinal centre B cells which accumulate adjacent to the mantle zone during florid B cell reactions
What cluster of differentiation antigen is expressed by help T cells?
CD4
What are the specialised antigen-presenting cells found within the paracortex?
interdigitating reticulum cells
Where are medullary cords foudn within the medulla?
between the sinuses
Where are macrophages mainly foudn in the lymph nodes?
lining the sinuses to phagocytose debris
What is sinus histocytosis?
hyperplasia of the lining macrophages of the sinuses
Why are B cells which become Reed-Sternberg cells thought to come from the germinal centre ?
there is evidence of somatic hypermutation of the immunoglobulin genes
What is stage 1 Hodgkins disease?
involvement of a single lymph node region
what is stage 2 Hodgkins disease?
involvement of two or more lymph node regions on the same side of the diaphragm
What is stage 3 Hodgkins disease?
involvement of lymph node regions on both sides of hte diaphragm
What is stage 4 hodgkins disease?
disseminated invovlement of one or more extra-lymphatic organs eg liver, lung and bone marrow with or without lymph node involvement
What does the suffix B on the staging of Hodgkins disease indicate?
presence of B symptoms
What does the prefix X on the staging of Hodgkins indicate?
presence of bulky disease
what does the prefix E on the staging of Hodgkins indicate?
involvement of a single extranodal site contiguous with or poriximal to a known nodal site
What blood abnormalties are seen with Hodgkins?
anaemia; lymphocytopenia; raised ESR and low albumin
What is the difference between affected lymph nodes in Hodgkins and NHL?
in Hodgkins there is rarely breaching of the lymph node capsule
What is the commonest subtype of Hodgkins?
nodular sclerosing
Wat is seen on lymph node architecture with nodular sclerosing Hodgkins?
replaced by cellular nodules which are separated by bands of collagen
What specific cell is seen with nodular sclerosing Hodgkins?
lacunar cell
What is the sex ratio generally seen with Hodgkins?
male predominance
What are solid tumours of the mononuclear phagocytic system called?
histiocytic lymphoma
Waht nuclear antigen do precursor lymphoid neoplasms express?
terminal deoxynucleotidyl transgerase- TdT
How is lymphoblastic lymphoma and leukaemia differentiated?
between number of lymphoblasts present in the bone marrow
What chromosomal translocation is seen with Burkitt’s lymphoam?
c-myc gene at 8p24 into immunoglobulin heavy chain gene locus t(8;14)
What infections are associated with burkitt’s lymphoma?
EBV and malaria
What is classic appearnce of Burkitts lymphoma on histology?
starry sky
Which areas of the world are T-cell lymphomas more common?
Japan and Caribbean
What virus is implicated in T-cell lymphoma?
human T-cell leukaemia/lymphoma virus (HTLV-1)
What are the cutaneous T cell lymphomas?
mycosis fungiodes and sezary syndrome
Where are Peyer’s patches found?
ileum
What pharyngeal pouch does the thymus derive from?
3rd
What germinal layer is the spleen derived from?
mesoderm
What are the aggregates of lymphoid cells aroudn the central arteries and arterioles called?
white pulp
What is foudn wtihin the per-arteriolar lymphoid sheath?
t cells
What is produced in the white pulp?
antibodies
What is found at the junction of red and white pulp, and surrounding the PALS and b-cell follicle?
marginal zone lymphocytes
What is the function of the red pulp?
destruction of senescent red cells and phagocytosis of particulate material
What is the dual circulation seen in the red pulp?
open-splenic cords and closed-sinusoids
What is the removal of Howell-Jolly bodies known as?
pitting
What are the usual post-hepatic causes of splenomegaly?
right-sided heart failure and pulmonary or tricuspid alve disease
What are Gamna-Gandy nodules?
firm brown nodules of areas of healed infarction
What is the difference between mycosis fungoides and sezary syndrome?
mycosis fungiodes initially confined to focal skin lesions whereas in sezary syndrome there is more general involvemtn incl. atylical cells in the blood
What is typicall overexpressed in mantle cell lymphomas?
cyclin D1
Waht are stipple cells assocaited with?
esp. thalassaemia; lead poisoning; megaloblastic anemia; myelodysplastic syndromes
Who are siderotic granules seen in?
iron overload patients and hyposplenic
What is a leukoerythroblastic film?
nucleated red cell precursors amd immature neutrohils presence in peripheral blood
What staining is used to detect reticulocytes?
supravital staining
What are Heinz bodies?
denatured Hb
What are pencil cells seen in?
IDA
When are target cells seen?
IDA; megaloblastic anaemia; haemoglobinopathy; liver disease; hyposplenism
When are microspherocytes seen?
hereditary spherocytosis; immune haemolytic anaemia; burns
When are tear-drop cells seen?
myelofibrosis; marrow infiltration
When are schistocytes seen?
microangiopathic haemolytic anaemia
Waht are causes of microangiopathic haemolytic anaemia?
haemolytic uraemic syndrome; DIC; TTP: physical traum to RBCs as forced through narrow or damaged ares in microvasculature
When are howell-jolly bodies seen?
hyposplenism; megaloblastic anaemia
When are Heinz bodies seen?
G6PD deficiency; hyposplenism; haemologobinopathies
