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Unformatted text preview: The haematological features
of HIV infection
British Journal of Haematology,
1997, 99, 1-8
B. J. Bain
• With the continuing rise
in the prevalence of HIV
of the haematological
features of HIV infection
and AIDS is becoming
increasingly The haematological features
of HIV infection
• Infection by the HIV and the consequent
fully developed AIDS can have profound
haematological effects in
– the primary infection period
– the phase of clinical latency, and
– patients with advanced disease Causes of the haematological
• The haematological abnormalities may
be attributable to the:
• Direct and indirect effect of HIV infection
• opportunistic infections
• Toxicity of the drugs Diagnostic confusion
• It is important for the haematologist to be
aware of the features of HIV infection and
AIDS since diagnostic confusion can
• HIV infection can simulate the:
T-cell Primary infection
• Brief febrile illness
• Pharyngitis and cervical lymphadenopathy are
common, simulate infectious mononucleosis.
• Initial lymphopenia
• Followed by lymphocytosis with atypical lymphocytes.
• False positive Paul Bunnell test.
• Neutropenia, thrombocytopenia and transient
pancytopenia can also occur.
pancytopenia Established infection
• Primary infection is followed by a period of
clinical latency or asymptomatic infection.
• Isolated thrombocytopenia as a result of
immune destruction of platelets can occur.
• There is increased platelet associated Ig.
Ig General haematological features of AIDS
• Peripheral blood
– During the asymptomatic period, there is
• Gradual fall in the number of CD4 + lymphocytes
• Initial increase in CD8 lymphocytes
Initial increase CD8 – By the time of diagnosis there is
Anaemia which is usually normochromic, normocytic but
sometimes Peripheral blood changes
• Red cell changes
increased background staining.
Occasionally the blood film shows features of
microangiopathic haemolytic anaemia.
microangiopathic Peripheral blood changes
• Neutrophils may show dysplastic features:
– toxic granulation
presence of detached nuclear fragments
hypogranularity and occasional Pelger forms Neutrophil with a detached
nuclear fragment in AIDS
• a detached nuclear
fragment can be seen in
• It can also be caused by
chemotherapy Peripheral blood changes
• Thrombocytopenia , usually normal size
• Except when there is immune
destruction, large size platelets may be
seen. Bone marrow aspirate
• It is initially hypercellular, but is hypocellular in
hypercellular but hypocellular
the later stages.
• Trilineage dysplasia is common.
Trilineage dysplasia Bone marrow aspirate
• Changes in the erythrocytes include:
– Nuclear lobulation and fragmentation
Bi- and multi-nuclearity
Occasional ring sideroblasts. Bone marrow aspirate
• Changes in the myeloid series include:
– Dysplastic changes
– Giant metamyelocytes are common even in
the absence of megaloblastic
erythropoiesis. Giant metamyelocyte
Giant A hypogranular giant
blood of a patient
with Bone marrow aspirate
• Changes in megakaryopoiesis
– Megakaryocytes are increased early in the
disease and decreased in the later stages.
– They show dysplastic features
• Bizzare nuclear shapes
• Hyperchromatic nuclei
• Nuclear hypolobulation Bone marrow aspirate
• Reactive changes include:
– Increased lymphocytes
– Increased plasma cells
– Increased macrophages
– Haemophagocytic syndrome Differences between HIV and
MDS in the BMA
• In HIV
Ring sideroblasts are
not a prominent feature
Myeloblasts are not
Micromegas are not
Auer rods are not seen In MDS
(common in AIDS)
are quite uncommon
in Bone marrow trephine biopsy
• Initially shows hypercellularity with neutrophil and
• Megakaryocytes are clustered and dysplastic
• There is increased number of bare megakaryocyte
nuclei. Bone marrow trephine biopsy in
AIDS showing dysplastic
megakaryocytes (H & E) • The megakaryocytes
clustered. and Bone marrow trephine biopsy
• Reticulin is often increased.
• Late in the course of the disease the trephine biopsy
will show hypocellular BM with gelatinous
• Patches of necrosis
• Patients with specific infections may show BM
• Lymphomatous infiltration A random focal lymphoid
infiltrate (H & E)
• A random focal
[arrow] in a patient
with Specific infections in AIDS
• Opportunistic infections are very common in
AIDS, among these are:
• Mycobacterial and other bacterial infections
– Mycobacterium tuberculosis
Atypical mycobacterial infection
Mycobacterium avium intracellulare • The bone marrow in patients with mycobacterial
infection may show well-formed, or less formed
• Caseation may occur in tuberculous granulomas.
• Sometimes there is marked proliferation of foamy
• Culture for mycobacteria is obligatory whenever a BM
examination is performed to investigate fever of
unknown origin in an HIV + patient.
unknown Trephine biopsy in atypical
mycobacterial infection Trephine biopsy stained
with a Giemsa stain,
staining organisms within
macrophages Trephine biopsy in atypical
mycobacterial infection (H & E)
• Poorly formed granuloma
composed of epithelioid
macrophages, many of which
This infection is only
likely to be detected on bone
marrow examination of
individuals. Other opportunistic infections
• Viral infections
– CMV infection is common in AIDS
• BM features are non specific, with atypical lymphocytes
haemophagocytosis – Parvovirus B19
• This might lead to chronic red cell aplasia
• There is disproportionate anaemia with reticulocyte count
close to zero
• BMA & TB show red cell aplasia and giant
• Confirmed by detection of viral DNA in the serum.
viral Other opportunistic infections
• Fungal infections
• Sometimes detected in BMA either within the
macrophages or free
• But more readily detected in the trephine
• A cryptococcal antigen test on the PB is a
very good screening test for cryptococcosis,
and PB cultures are often positive in HIV + pt
with fungal infections; these tests may make
marrow exam unnecessary.
unnecessary Bone marrow aspirate in AIDS
neoformans • Bone marrow aspirate
in AIDS showing a
budding form of
neoformans. Bone marrow aspirate in AIDS
- Bone marrow aspirate
in a patient with AIDS
within a macrophage.
- Histoplasma are small
yeast Other opportunistic infections
• Parasitic infections
– Leishmaniasis is usually readily detected in
BMA & TB
– American trypanosomiasis
– Rarely Pneumocystis carinii has been
detected in the BM of pt with AIDS.
detected Leishmania donovani in a
• Blood film in a patient
donovani in a monocyte.
• Leishmania in
circulating monocytes or
neutrophils is rarely
seen except in patients
with AIDS. Lymphoproliferative disorders
• The incidence of NHL is increased 60200 fold in pt with AIDS.
• The incidence of HD may be increased
to NHL in AIDS patients
• The great majority are of B-lineage.
• The strongest association is with
– Burkitt lymphoma
– Burkitt like lymphoma
– Large cell lymphoma of B-lineage • Persistant generalized lymphadenopathy often
precedes the development of lymphoma and
is indicative of increased risk of development
of HD in AIDS patients
• It usually presents in patients in advanced
• Often with B symptoms.
• Bone marrow infiltration
• The TB may be the initial or the only
• Histopathology often shows poor prognostic
types ( MC, or LD).
• HIV infection is associated with a great variety of
• HIV pt may have abnormalities due to drug therapy or
• Diagnostic confusions specially with MDS can occur.
• BMA & TB have a role in the diagnosis of
opportunistic infections and of lymphoma.
• Certain features are common although not
pathognomonic of HIV infection, but sufficient
to suggest this diagnosis;
– numerous bare megakaryocyte nuclei
polymorphic lymphoid aggregates
detached nuclear fragments in granulocytes
giant metamyelocytes in the absence of
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This note was uploaded on 12/24/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.
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