Common causes of lymphocytosis or decrease [Note]

Lymphocytes (lymphocyte) can be divided into large lymphocytes and small lymphocytes according to their size, normal reference value: 20% ~ 40%; The absolute value is (0.
8 ~ 4)× 10⁹/L
.
Lymphocytosis refers to an absolute lymphocyte count greater than 4× 10 9/L, while lymphopenia refers to an absolute lymphocyte count below 1.
0 × 10⁹/L
.
1.
Common causes of lymphocytosis 1.
Physiological increase (lymphocytosis): physiological increase of lymphocytes in childhood, the proportion gradually decreases after the age of 4~6, and the proportion of granulocytes increases, gradually reaching the normal adult level.

2.
Pathological increase (1) infection: mainly viral infection, but also can be seen in pertussis, Mycobacterium tuberculosis, Brucella, treponema pallidum, Toxoplasma gondii and other infections
.
(2) Tumors: such as acute/chronic lymphocytic leukemia, lymphoma
.
(3) Recovery period of acute infectious diseases (4) Transplant rejection: seen in graft-versus-host reaction or graft-versus-host disease
.
(5) Relative increase in lymphocyte ratio: aplastic anemia, granulocytopenia and neutrophilia are reduced in neutrogenesis, and the lymphatic proportion is relatively increased, but the absolute value is not increased
.
3.
Reactive lymphocytes (atypic lymphocytes) increase pathogens (mainly viruses) infect the body, lymphocytes participating in the anti-pathogen response will activate into activated lymphocytes, peripheral blood can be seen compared with the conventional form of atypical lymphocytes, called reactive lymphocytes, also known as atypical lymphocytes
.
More common in: (1) infection: reactive lymphocytosis can occur in viral diseases that cause lymphocytosis, especially leaflets and epidemic hemorrhagic fever caused by EB infection, which can be as high as more than 10%; It can persist in peripheral blood for weeks or months after recovery; It can also be seen in certain bacterial infections, spirochetes, rickettsial disease, or protozoal infections such as malaria
.
(2) Drug allergy (3) After blood transfusion, hemodialysis or cardiopulmonary bypass, it may be related to
CMV infection.
(4) Others: such as immune diseases, granular deficiency, radiotherapy, etc
.
Second, the common cause of lymphopenia It is mainly seen in the application of adrenal corticosteroids, alkylating agents, anti-lymphocyte globulins, etc.
, as well as radiation injury, T-cell immunodeficiency disease, gammaglobulin deficiency (B lymphocyte immunodeficiency), etc
.
Severe acute respiratory syndrome coronavirus (SARS-CoV), COVID-19 infection, H1N1, SARS, Middle East respiratory syndrome (MERS) and other patients with decreased lymphocytes
.