MR.
L, 69, HAS A HISTORY of dyslipidemia and coronary artery disease. When
he visits his primary care provider for an annual physical exam, his
only complaints are new-onset fatigue and unexplained weight loss over
the last 4 weeks.
 |
His
vital signs are temperature, 97.5[degrees] F (36.4[degrees] C); pulse,
54, regular; respirations, 16, unlabored; and BP, 144/58 mm Hg. He has
no S3, S4,
or murmurs; lungs are clear to auscultation, and his abdomen is soft,
nontender, and nondistended with normal active bowel sounds and no
hepatosplenomegaly. Bilateral axillary lymphadenopathy is present with
nodes that measure approximately 1 cm on the left and 1.5 cm on the
right.
Abnormal
lab results include hemoglobin 11 g/dL (normal in men, 14 to 17.4
g/dL), platelets 140,000/uL (normal, 150,000 to 400,000/uL), white blood
cell (WBC) count 47,900 cells/mm3 (normal in men, 4500 to 10,500 cells/mm3),
lymphocytes 86% (normal, 25% to 40% of the total leukocyte count).
These results are consistent with anemia, thrombocytopenia,
leukocytosis, and lymphocytosis.
This
article reviews the function of lymphocytes and discusses what lab
results like those for Mr. L tell you about your patient's condition.
Let's start with a quick physiology review.
First line of defense
The two main groups of WBCs (also called leukocytes) are granulocytes and agranulocytes. (See A closer look at leukocytes.)
Lymphocytes, the most common type of agranulocyte, play a major role in
the body's immune response, including antibody production and
cell-mediated immunity. For a summary of WBC types and functions, see Five infection fighters.
The
main cells of the immune system, lymphocytes control the intensity and
specificity of the immune response. The WBC count and differential
(percentages of the different types of leukocytes) provide clues about a
patient's immune status.1(See Sorting out the WBC count and differential.)
Like
all WBCs, lymphocytes originate in the bone marrow. The thymus and the
spleen are accessory lymphoid organs that can also be involved in
lymphocyte production and development if necessary.2
Lymphocytes are classified into three main types: B lymphocytes, T lymphocytes, and natural killer cells.3
* B lymphocytes (B cells) produce five distinct classes of immunoglobulins (Igs) and mediate humoral immunity. Humoral immunity is the part of the immune response that eliminates extracellular microbes and microbial toxins, including bacteria and viruses. (See How immunoglobulins come into play.)
* T lymphocytes (T cells) activate B cells and other T cells (helper T cells and cytotoxic T cells) that target intracellular
viruses and play a role in delayed hypersensitivity reactions, as well
as foreign tissue graft rejection. These functions are referred to as cell-mediated immunity.
* natural killer (NK) cells
move within the blood and lymph and play a frontline role to destroy
foreign cells, including cancer cells and virus-infected cells, until
the body can mount a full humoral and cell-mediated immune response
against them.3,4
Lymphocytopenia and lymphocytosis
Decreased production or increased destruction of lymphocytes is called lymphocytopenia (or lymphopenia),
which may be seen in many disorders including aplastic anemia, Hodgkin
lymphoma, and immunodeficiency states. The patient with lymphocytopenia
is immunocompromised and vulnerable to infection. Transient
lymphocytopenia can be caused by chemotherapy and radiation therapy.
Some medications used to treat autoimmune disorders, including
corticosteroids, temporarily suppress a patient's immune system and
decrease lymphocyte production.1,5
Lymphocytosis,
or the increased production of circulating lymphocytes, can be
associated with various disorders including infectious mononucleosis and
other viral diseases such as cytomegalovirus, measles, mumps, and acute
viral hepatitis; it's also associated with some bacterial infections
such as pertussis. An abnormally high level of lymphocytes is one of the
classic warning signs of acute or chronic lymphocytic leukemia (CLL).1
If
lymphocytosis or lymphocytopenia appear in an initial WBC differential,
more specific tests to evaluate lymphocytes may be indicated, depending
on the patient's symptoms and physical assessment findings.
When further lab testing is needed
A lymphocyte subset analysis
is often ordered to evaluate the immunologic status in a patient with
lymphocytosis or lymphocytopenia to help evaluate the patient's
immunologic status when the underlying cause or disease is unknown.3 This analysis includes:
* a helper/suppressor cell panel,
which is used to evaluate the percent positive and absolute numbers of
total T cells (CD3), helper cells (CD4), suppressor cells (CD8), total B
cells (CD19), a CD4/CD8 ratio, and NK cells (CD16, CD56). A process
called flow cytometry is used to identify the lymphocyte types based on
specific and unique cell surface markers.6 This information helps the healthcare provider determine the patient's underlying disorder and appropriate therapy.
* CD4 cell subset, used mainly for evaluating and monitoring patients diagnosed with HIV.7
It may also be ordered after organ or allogeneic bone marrow transplant
to help evaluate the effect of immunosuppressive medications.4,8
* CD4/CD8 ratio,
commonly used to monitor patients with HIV/AIDS. The number of helper
(CD4) T cells should be higher than the number of suppressor (CD8) T
cells. If suppressor (CD8) cells exceed the total amount of helper (CD4)
cells in the presence of increased viral load, this indicates increased
destruction of helper T cells by the virus and suggests that antiviral
medications aren't working optimally.4
A diagnosis for Mr. L
The
results of Mr. L's lymphocyte subset analysis for immunologic status
was positive for B-cell lymphoid CD markers. He's diagnosed with CLL.9
CLL
is an indolent lymphoproliferative disorder typically characterized by
lymphocytosis, lymphadenopathy, and splenomegaly. CLL is one of the most
common occurring leukemias in middle-aged and older adults, with a
median age at diagnosis of about 72 years. About 14,900 new cases are
diagnosed annually.10
In
the course of CLL, the abnormal WBCs begin to infiltrate the bone
marrow and cause bone marrow failure, shutting down production of normal
cells. CLL has been described as an accumulation of developmentally
delayed and immunologically incompetent lymphocytes.
Hypogammaglobulinemia
is a major complication of CLL. Anemia and thrombocytopenia, found in
approximately one third of patients at diagnosis, may result from bone
marrow replacement by ineffective lymphocytes.11
After
CCL is diagnosed and staged, the primary treatment option is usually
chemotherapy. Because CLL often progresses slowly, however, asymptomatic
patients may not be treated right away.5,10,12 The need for treatment is dictated chiefly by thrombocytopenia, anemia, and symptomatic lymphadenopathy.9 Disease progression is monitored by following the lymphocyte count closely.
The
nurse's assessment and critical thinking skills will play a pivotal
role in the care of any patient who has leukemia. Because CLL cells
don't produce functional Igs, the patient is at increased risk for
infection, particularly community-acquired infections of the upper
respiratory tract.5
 |
Table. Sorting out the WBC count and differential |
* fatigue, weakness, inability to perform usual activities of daily living, and changes in sleep patterns
* depression, withdrawal, anxiety, or fear secondary to deficient knowledge of disease and treatment
* anorexia and weight loss
* splenomegaly, hepatomegaly, or abdominal pain due to tissue invasion of the leukemic cells
* lymphadenopathy, pale mucous membranes, bleeding gums, and oral mucosal ulceration
* arthralgia and myalgia
* ecchymoses and petechiae due to bone marrow suppression
* spontaneous uncontrolled bleeding, including epistaxis
* signs of dehydration, such as tachycardia and hypotension
* current or history of recent or recurrent infections, such as urinary tract or upper respiratory tract infections
* pain, which may indicate developing complications.
Remember,
the results of the initial CBC count are only a partial reflection of a
patient's condition. When the lab test results are put into the context
of the clinical picture, they provide a key to assessing the patient's
immune status and planning appropriate nursing interventions.
Provide
support and education to the patient and family. Emphasize the need for
regular, ongoing monitoring as directed by the healthcare provider,
even if the patient is asymptomatic. The course of disease varies widely
among patients and survival can range from a few months to a normal
life expectancy.14
By
understanding lymphocytes and the extraordinary role they play in
humoral and cell-mediated immunity, you can strengthen critical thinking
skills, plan appropriate care, collaborate with others on the
healthcare team to prevent complications, and educate the patient and
family members.
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Figure. How immunoglobulins come into play |
Five infection fighters
WBCs
are categorized as granulocytes (neutrophils, basophils, and
eosinophils) and agranulocytes (monocytes and lymphocytes). Each of
these five types of WBC is associated with specific functions.
GRANULOCYTES
* Neutrophils,
a fast-acting first line of defense against bacteria, consist of
segments (mature neutrophils that respond during an acute infection) and
bands (immature neutrophils that can multiply quickly, if necessary, to
help fight acute infection).
* Basophilsplay a primary role in hypersensitivity reactions.
* Eosinophilsdetoxify allergens and defend against parasites; to a lesser extent, eosinophils also help restrain hypersensitivity reactions.
* Monocytes are the largest WBCs; they act as a second line of defense against bacterial infections and inflammatory responses.
* Lymphocytes are the main cells of the immune system; they control the intensity and specificity of the immune response.
| Sourced from- Cheryl Kaufman BSN, RN, CLCP, CNLCP |
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