Overview of infectious lymphocytosis
Infectious lymphocytosis is an infectious disease that occurs mainly in children, with a few cases in adults, and was differentiated from infectious mononucleosis by Smith in 1941. The disease is characterized by an increase in the total number of leukocytes in the peripheral blood, with a predominance of lymphocytosis, which lasts for a long period of time, is mild and nonspecific, and may be detected only on routine blood tests without symptoms or signs.
Etiology
The etiology of the disease is unknown and is generally considered to be viral; in 1964, Olson et al. isolated adenovirus type 12 from the upper respiratory tract of four children, and Horowitz isolated an enterovirus, EVU-16, which is similar to coxsackievirus subtype A from the feces of 21% of the patients in an epidemic, and the majority of the patients had a 4-fold increase in serum neutralizing antibodies against this enterovirus, but inoculation of EVU-16 to various animals, including immunodeficiency, resulted in a 4-fold increase in antibodies against this enterovirus, and the majority of the patients had a 4-fold increase in antibodies against this enterovirus. 16 to various animals, including immunocompromised animals, to induce lymphocyte proliferation was unsuccessful. Serial antibody assays to Epstein-Barr virus, cytomegalovirus, and herpes simplex virus have been performed and were negative. Antibodies to CoxA, Echo7, and CoxB have been detected, but it has not been possible to determine which virus is responsible.
Symptoms
Many patients are asymptomatic and have no abnormal signs, and those with clinical manifestations tend to be mild or transient.
1. Fever
About <50% of the patients have low-grade fever, the average is 38.9℃ with malaise.
2. Symptoms of upper respiratory tract infection
Such as nasal congestion, runny nose, cough, sore throat and so on.
3. Digestive system symptoms
Mild diarrhea, nausea, vomiting, abdominal pain and loss of appetite, usually lasts only 1 to 3 days, a few may have abdominal pain due to enlarged mesenteric lymph nodes, which is mistaken for acute abdomen.
4. Meningitis symptoms
Very few cases may have meningitis symptoms with mild increase in cell count in cerebrospinal fluid, and paralysis has been reported.
5. Rash
In the early stages of the disease, a red maculopapular rash, similar to infectious mononucleosis, is sometimes seen.
Examination
1. Hemoglobin and red blood cell count of peripheral blood.
The peripheral blood is characterized by an increase in the total number of white blood cells (WBC) and lymphocytes (LBC) within the normal range. The average leukocyte count has been reported to be between (20-30) × 109/L, with a maximum of 178 × 109/L. The maximum leukocyte count in the first week continues to increase for 3 to 5 weeks. Lymphocytes accounted for 60% to 97% of the absolute value of about (8 to 10) × 109 / L, can continue to increase for 3 months Lymphocyte percentage in the peak eosinophilic low; lymphocytes decline, eosinophils can be increased in the average of about 2.3 × 109 / L, returned to normal in 4 to 6 weeks. Most of the increased lymphocytes are mature small lymphocytes, with different sizes, tightly arranged nuclear chromatin and little cytoplasm, and basophilic Ritter stain; a few large mature lymphocytes or over-mature small lymphocytes smaller than normal small lymphocytes and with deeper staining can also be seen.
2. Bone marrow
Bone marrow cell count is increased, granulocytes and red blood cells are normal, and mature small lymphocytes are increased.
3. Serologic examination
Heterophilic agglutination reaction is negative, even if the titer is mildly increased, it is below the diagnostic requirement of infectious mononucleosis.
4. Other auxiliary tests
Chest X-ray, electrocardiogram, ultrasound and other examinations should be selected according to clinical manifestations, symptoms and signs.
Diagnosis
The white blood cell and lymphocyte counts of children of all ages vary greatly, and this feature must be noted when diagnosing the disease. The mean total leukocyte count is 18.1×109/L at birth and decreases gradually thereafter.11.2×109/L at 1 to 3 years of age, 9.1×109/L at 4 years of age, 8.3×109/L at 8 years of age, and 7.8×109/L at 16 years of age.The mean lymphocyte percentage is 30% at birth and is similar to the percentage of neutrophils at 4-6 days of age, and then the lymphocyte Later, the lymphocyte percentage increases to a maximum of about 60%, and at the age of 4-6 years, the lymphocyte and neutrophil percentages are similar again, each at about 50%, and then gradually decreases, approaching the level of 30% of normal adults at the age of 8 years. If the total number of leukocytes and small lymphocytes are higher than a certain level at that age, the disease should be considered when there are no symptoms or only mild upper respiratory and gastrointestinal symptoms, and when there are no generalized lymph nodes or splenomegaly.
Treatment
No specific treatment is usually required. Quarantine is not required for children in the diaspora. Respiratory and gastrointestinal quarantine is recommended when the disease occurs in childcare facilities to avoid epidemics.
Prognosis
The prognosis of the disease is good, with blood counts returning to normal after a few weeks, and the disease is benign on long-term follow-up.