Reactive histiocytosis

Introduction to reactive histiocytosis Reactive histiocytosis (RH), also known as hemophagocytic syndrome, is a benign disease of the mononuclear macrophage system, mostly associated with infection, immunoregulatory disorders, connective tissue disease, subacute bacterial heart Endometritis, immunosuppression, etc. basic knowledge The proportion of illness: 0.003% Susceptible people: no special people Mode of infection: non-infectious Complications: disseminated intravascular coagulation

Causes of reactive histiocytosis

(1) Causes of the disease

Infections of various pathogens can cause disease, accounting for 65% to 78% of infections, and viral infections are the most common, accounting for 36%, such as viral hepatitis, infectious mononucleosis, adenovirus, B19 virus, Dengue virus, especially cytomegalovirus, herpes virus and EB virus are common. In bacterial infection, mainly Gram-negative bacilli in the intestine, also in typhoid fever, tuberculosis, etc., parasitic diseases such as malaria, toxoplasmosis, schistosomiasis And brucellosis and more are more common, in addition, fungi, Leishmania, mycoplasma and rickettsia infection have also been reported, connective tissue disease, X-linked lymphoproliferative syndrome, familial erythroblastic lymphoblastic disease Subacute bacterial endocarditis, rheumatism, leukemia, malignant lymphoma, bone marrow metastasis and acquired immunodeficiency syndrome, and spleen resection, alcoholism, etc. have also been reported, also seen after the use of immunosuppressants, Twenty-seven of the 42 patients reported a history of immunosuppressive therapy.

(two) pathogenesis

Progressive reduction of whole blood cells, mechanism of hematopoietic cell reduction in the bone marrow:

1 increased tissue cells phagocytosis of blood cells;

2 inhibitory monocyte factor and lymphokine production, such as interferon gamma, interleukin-1;

3 virus or immunosuppressive agents cause Th and Ts disorders, induce immunomodulatory disorders, and increase blood cell damage.

Well-differentiated tissue cells increased, cell morphology was mostly normal or only slightly deformed, and a small number of cell malformations were caused by typhoid or miliary tuberculosis, but the difference in morphology, size, nuclei, and maturity between cells Less than malignant histiocytosis, often accompanied by obvious phagocytosis, tissue cells invade the bone marrow, lymph node sinusoids and myelin, spleen red pulp and hepatic sinusoids, due to hepatic sinusoids and involvement around the portal vein, liver The cells have necrotic manifestations, and the lymphoid tissue structure in the lymph node tissue sections is mostly non-destructive. Individual necrosis and extensive fibrosis, lymphocyte reduction, especially in the lymph node germinal center and spleen red pulp area.

It is also possible to see the pathological manifestations and cellular components of underlying diseases. In the case of reactive viral histiocytosis caused by some viruses, extensive atypical lymphoid cell infiltration with lymphocytes, plasma cells and immature primitive immune cells is common. .

Reactive histiocytosis prevention

1. Patients with viral infections are common, and immunosuppressive agents should be used with caution.

2. If the bacterial infection can be cured, the drug sensitivity test can be adjusted in time.

Reactive histiocytosis complications Complications, disseminated intravascular coagulation

The main complications are severe liver and kidney damage and disseminated intravascular coagulation, and central nervous system damage, which aggravates the condition and is life-threatening.

Reactive histiocytosis symptoms Common symptoms Lymph node enlargement Hyperthermia Hepatic dysfunction Hypoproteinemia Night sweats Hyponatremia

It varies with the primary disease, but most patients have fever, mostly with high fever, can be associated with night sweats, weight loss, liver and spleen or lymphadenopathy, rash is very common, such as involving the central nervous system and lungs, can produce corresponding symptoms and Signs, severe liver damage or concurrent disseminated intravascular coagulation (DIC), can cause multiple sites of bleeding, although most cases with the primary disease improved, especially the infection control gradually relieved, but about 30% of patients due to multiple organs Death due to functional impairment or coagulopathy, clinical signs and malignant histiocytosis are often difficult to identify.

Examination of reactive histiocytosis

1. Blood cells have different degrees of blood loss. In the 82 cases, the anemia accounted for 48.4%, the whole blood cell reduction accounted for 14.6%, the blood smear showed mature tissue cells accounted for 17.8%, foreign cases, red blood cells, white blood cells or thrombocytopenia. At more than 80%, hematocytopenia and infection-induced myelosuppression, as well as phagocytosis by proliferating tissue cells.

2. Bone marrow hyperplasia is active, the number of tissue cell proliferation is different, most <30%, its morphology is mature, that is, normal tissue cells, can also be lymphoid or mononuclear, often accompanied by phagocytosis, mainly phagocytic mature Red blood cells can also phagocytose neutrophils, young red blood cells, but phagocytic platelets are rare, sometimes a small number of abnormal tissue cells, and even individual multinucleated giant cells.

3. Blood biochemical serum aminotransferase, bilirubin, creatinine, urea nitrogen can be elevated.

4. Pathological biopsy lymph nodes, liver and other biopsy showed tissue cell proliferation, and some have blood-sucking phenomenon, the normal tissue structure is not destroyed.

5. Other examinations can increase the levels of various inflammatory cytokines in the blood, and the virus-infected antibodies (IgM and IgG) have increased titers.

6. According to clinical manifestations, symptoms, signs, choose to do X-ray, CT, B-ultrasound, ECG.

Diagnosis and differentiation of reactive histiocytosis

Diagnostic criteria

1 fever for more than 1 week (peak 38.5 ° C);

2 hepatosplenomegaly with complete blood cell reduction;

3 abnormal liver function and coagulopathy;

4 hemophagocytic cells accounted for 2% (or 3%) or 2500 cells/ml of bone marrow smear in bone marrow smear, and/or biopsy showed involvement of bone marrow, lymph nodes, liver, and spleen.

The following items strongly suggest a diagnosis:

1 increased mononuclear cells in cerebrospinal fluid;

2 liver biopsy showed chronic persistent hepatitis;

3 natural killer cell activity is reduced.

The following items are useful for the diagnosis of HPS:

1 lymphadenopathy, jaundice, edema and rash, symptoms and signs of meningeal involvement;

2 hyponatremia, increased serum iron, increased protein in cerebrospinal fluid;

3 increased liver transaminase, hypoproteinemia, increased blood low-density lipoprotein cholesterol and decreased high-density lipoprotein cholesterol;

4 The peripheral blood soluble interleukin-2 receptor increased.

Differential diagnosis

Malignant histiocytosis

HPS is sometimes in serious condition, with clinical and cell morphology and histological lack of specific identification tests for malignant histiocytosis (MH). The following items contribute to the identification of both:

(1) In peripheral blood or concentrated blood samples, malignant tissue cells can be found in tissues such as bone marrow or lymph nodes, liver and spleen to support MH.

(2) Malignant tissue cells stained positive for -naphthol esterase acetate, positive for acid phosphatase staining, and immunohistochemistry showed positive chain and chain in cells.

(3) HPS neutrophil alkaline phosphatase activity can be increased, serum ferritin is significantly higher in MH than normal people and HPS.

(4) Angiotensin-converting enzyme was increased in MH serum, and a large amount of -antitrypsin in macrophages was observed by histochemical staining.

(5) Some MH have specific chromosomal abnormalities, such as t(2;5)(p23;q35) breakpoints at 17p12 and 17p, partial trisomy 1 (1qter-lp11) and translocation involving 1p11, and some Clonal rearrangements of Ig and TCR genes can occur in MH patients.

2. Langerhans cell histiocytosis

The incidence of Langerhans cell histiocytosis (LCH) is also more common in infants, less than 2 years old, can also be expressed as fever, rash, hepatosplenomegaly, lymphadenopathy and pulmonary infiltration and central nervous system involvement, However, the rash of LCH is a specific rash, which is distributed in the chest and abdomen of the trunk and the hair and the neck of the hair. It can be differentiated from the transient rash of HPS, and the bone destruction often occurs in LCH patients. Hans cells are the main basis for the diagnosis of LCH. It can be seen by electron microscopy that the Langerhans cells contain Birbeek particles.

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