LYMPHOCYTES

Infectious mononucleosis lab findings:
• Early symptoms include lethargy, headache, fever, chills, sore throat, nausea, and anoxia.
• The classic triad presentation of symptoms are fever, pharyngitis, and lymphadenopathy
• The cervical, axillary, and inguinal lymph nodes are commonly enlarged.
• Splenomegaly occurs in 50–75% of these patients, and hepatomegaly occurs in about 25% cases.
• Occasionally, jaundice, autoimmune hemolytic anemia, thrombocytopenia, agranulocytosis, and aplastic anemia rarely developed.
• The disease is usually self-limiting, resolving within a few weeks.

• Peripheral blood film reveals leukocytosis(12- 25×10^9/μl) due to absolute lymphocytosis.
• Lymphocytes usually constitute >50% of the leukocytes >20% reactive lymphocytes.
• The platelet count is often mildly decreased; concentrations of <100 x 10^9/μl are rare.
• Immunoblasts are usually present early in the disease. Plasmacytoid lymphocytes and an occasional plasma cell also can be found.
• Bone marrow aspiration shows hyper cellular marrow of all cells except neutrophils.
• Solid phase immunoassay tests is positive for heterophil antibodies.
• VCA-IgM &IgG,EBV nuclear antigens (EBNA) immunoassay also performed for diagnosis
• Confirmatory diagnosis is done EBV by PCR method.

2. Toxoplasmosis:
• Toxoplasmosis is the result of infection with the intracellular protozoan Toxoplasma gondii.
• This obligate intracellular parasite can multiply in all body cells except erythrocytes.
• Infections are often asymptomatic but carriage a significant risk to the fetus of a pregnant woman.
• Transplacental infection can cause abortion, jaundice, hepatosplenomegaly, chorioretinitis, hydrocephalus, microcephaly, cerebral calcification, and mental retardation.
• Peripheral blood film shows leukocytosis with a relative lymphocytosis or (more rarely) an absolute lymphocytosis with reactive lymphocytes morphologically similar to lymphoblasts or lymphoma cells.
• The heterophile antibody test is negative.
• Biopsy of lymph nodes shows a reactive follicular hyperplasia and can play an important role in diagnosis.
• Diagnosis of an active infection is confirmed by seroconversion and arising titer of antibodies to T. gondii.

3. Cytomegalovirus (CMV):
• It can cause congenital or acquired infections in neonates when CMV infected pregnant woman crosses the placenta and infects the fetus.
• The newborn present with jaundice, microcephaly, and hepatosplenomegaly.
• Only about 10% of infected infants exhibit clinical evidence of the disease.
• The most common hematologic findings in neonates are thrombocytopenia and hemolytic anemia.

• It can cause congenital or acquired infections in neonates when CMV infected pregnant woman crosses the placenta and infects the fetus.
• The newborn present with jaundice, microcephaly, and hepatosplenomegaly.
• Only about 10% of infected infants exhibit clinical evidence of the disease.
• The most common hematologic findings in neonates are thrombocytopenia and hemolytic anemia.

• Acquired infection is spread by close contact, blood transfusions, and sexual contact.
• It is common in immunosuppressed individuals, patient with malignancy due to massive blood transfusions
• It is the most common viral infection complicating tissue transplants.
• Infected adults present with symptoms similar to those of infectious mononucleosis except that pharyngitis is absent.

• Laboratory findings include a leukocytosis with an absolute lymphocytosis with reactive lymphocytes and heterophile antibody test is negative.
• Hepatic enzymes are usually abnormal.
• Diagnosis is confirmed by demonstrating the virus in the urine or blood using a viral DNA (molecular) assay or by a rise in the cytomegalovirus antibody titer

4. Bordetella pertussis:
• Bordetella pertussis causing whooping cough.
• Blood picture is very similar to that of reactive viral lymphocytosis.
• Total leukocyte count increased up to 15- 50×10^9/μl with absolute lymphocytosis of T, B, and natural killer (NK).
• lymphocytes along with increases in neutrophils, monocytes and granulocytes shows toxic changes.
• Virus culture, serology and PCR diagnostic tests

5. Persistent Polyclonal B-Cell Lymphocytosis:
• It is a rare disorder found primarily in the female adult smoker and consist of polyclonal expression of lymphocytes.
• Mostly it is HLA-DR7 haplotype, partial insertion of chromosome 3, i(3q), and multiple IgH/Bcl-2 rearrangements that suggest PPBL could lead to a malignant process.
• Clinically it is asymptomatic and some time it present with symptoms such as fever, fatigue, weight loss, recurrent chest infections or generalized lymphadenopathy.
• Laboratory findings shows lymphocytosis and the presence of binucleated lymphocytes.
• There is a polyclonal increase in serum IgM but low IgG and IgA levels.
• Bone marrow examination reveals lymphocytic infiltrates.