Congenital pure red cell aplastic anemia

Introduction to congenital pure red blood cell aplastic anemia Congenital pure red blood cell aplastic anemia, also known as Diamond-Blckfan syndrome (Diamond-Blackfananemia, DBA) is a rare congenital pure red blood cell regeneration disorder, with anemia as the main clinical manifestations, and involving multiple systemic tissue as the main disease Clinical features. basic knowledge The proportion of illness: 0.001% Susceptible people: infants and young children Mode of infection: non-infectious Complications: hemochromatosis acute myeloid leukemia acute lymphocytic leukemia Hodgkin's disease

Congenital pure red blood cell aplastic anemia

Causes:

This disease is occasionally seen in siblings, suggesting that the disease is a hereditary disease, only less than 10% of patients have a family history, most of the patients are sporadic, one third of patients are autosomal dominant, and the rest are recessive, through Linkage analysis revealed that there are at least 3 genetic loci in DBA, two of which have been identified, 19q13.2 and 8p23.3-p22, respectively. The relevant pathogenic gene has been cloned in the 19q13.2 region, which is ribose. The ribosomal protein S19 (RPS19) gene, sequence analysis found that about 25% of DBA patients had RPS19 mutations.

Pathogenesis:

The pathogenesis is still not fully understood. Conventional colony culture shows that bone marrow erythroid progenitor cells (BFU-E and CFU-E) in DBA patients are significantly reduced or absent. The results of previous experimental studies indicate that there is no erythroid hematopoietic defect in DBA patients. Related cellular and humoral immune dysfunction, and its bone marrow matrix supports hematopoietic function. At present, there is a consensus that DBA patients have intrinsic qualitative abnormalities in erythroid progenitor cells, which leads to differentiation of various regulatory erythroid progenitor cells. Reactivity with proliferating hematopoietic growth factors (HGFs) is reduced.

Because DBA has hematological abnormalities similar to W/Wv and sl/sld mice, it is speculated that the pathogenesis of DBA may be related to the c-kit receptor/ligand (KL) system. Another study found that CD34+ cells in DBA patients. Under the stimulation of single or combined EPO, IL-3, IL-6 and GM-CSF, the yield of BFU-E is still low or absent. Adding KL to the above culture system can significantly increase the yield and volume of BFU-E colonies. It suggests that the expression of c-kit receptor in CD34 cells is not abnormal. The occurrence of anemia may be caused by insufficient or lack of KL production in the body. It is considered that most DBA primary defects are not in the c-kit/KL system, and only some patients exist. Some abnormalities in the -kit/KL system reflect the heterogeneity of the disease. These abnormalities explain the difference in the development of the disease and the outcome of the patient. The Fit-3 ligand (FL) does not cooperate with KL to stimulate the bone marrow of DBA patients. BFU-E grows and has the same low level of FL as normal people, suggesting that some DBA erythroid growth is not associated with FL.

The current study confirmed that DBA patients do not have SCL gene and GATA gene expression and protein structure abnormalities, but their E protein expression is significantly lower, and KL can correct this defect in vitro, so it is revealed at the molecular level that KL may promote SCL/ E protein heterodimer formation plays a role in stimulating DBA erythroid hematopoiesis, and the relationship between E protein abnormalities and DBA erythroid hematopoietic defects needs further study. It is now clear that EPO and EPO-R gene expression and protein structure in DBA patients There were no abnormalities and no anti-EPO-R antibody, but it was not completely excluded from the abnormal signal transmission of EPO combined with EPO-R in DBA, compared with other benign anemia (such as iron deficiency anemia) with the same degree of anemia. The elevated serum EPO level in DBA patients is more significant, and this change may have important physiological significance for protecting the remaining erythroid progenitor cells in the body from excessive excessive apoptosis.

Congenital pure red blood cell aplastic anemia prevention

At the same time as the diet, you need to pay attention to physical changes. The cause of congenital pure red aplastic anemia is unknown, and there is a clear family genetic predisposition. Therefore, we should pay attention to genetic counseling. Prevention of secondary acquired pure red aplastic anemia, should actively prevent severe malnutrition, viral infections, malignant tumors and other diseases, while avoiding chemical poisoning and caution with chloramphenicol, phenytoin and so on.

Congenital erythrocytic aplastic anemia complications Complications hemochromatosis acute myeloid leukemia acute lymphocytic leukemia Hodgkin's disease

1. Congenital pure red blood cell aplastic anemia patients are more likely to be complicated by multiple malignant tumors. More than 480 patients with congenital pure red cell aplastic anemia reported in the literature, 12 of which were diagnosed with malignant tumors 2 to 43 years after diagnosis. There were 6 cases of cell leukemia (AML), 1 case of acute lymphoblastic leukemia (ALL), 2 cases of Hodgkin's disease (HD), 2 cases of myelodysplastic syndrome (MDS) and 1 case of hepatocellular carcinoma.

2. Long-term application of hormone therapy can be combined with developmental disorders and secondary infections.

3. Progression of the disease can lead to heart failure, and advanced blood transfusion can be secondary to hemorrhagic disease, or cardiogenic cirrhosis.

Congenital pure red blood cell aplastic anemia symptoms common symptoms fatigue palpitations dizziness chest tightness

Anemia is the main clinical manifestation of DBA. About 35% of the children are born with anemia. Congenital pure red blood cell aplastic anemia is another clinical manifestation similar to Fanconi anemia (FA), with a lighter congenital physique. Developmental malformations, about 1/4 of children with mild congenital anomalies, such as squinting, nipple retraction, sacral neck, finger or rib abnormalities.

Examination of congenital pure red blood cell aplastic anemia

1. Peripheral blood: positive cell positive pigmentation anemia, hemoglobin 10 ~ 90g / L, the absolute value of reticulocytes decreased, infants and young children are generally not associated with peripheral blood leukocytes and thrombocytopenia, secondary hypersplenism can lead to complete blood cell reduction And there are huge variations.

2. Bone marrow: Proliferation is good, but the red line is significantly reduced, and other bone marrow cells are normal.

3. Red blood cell survival time is normal.

4. Serum iron and serum iron saturation increase, fetal hemoglobin increases, i antigen persists.

5. Blood bilirubin and fecal gallbladder excretion are normal.

According to the condition, clinical manifestations, symptoms, signs, choose to do ECG, B-ultrasound, X-ray and other tests.

Diagnosis and diagnosis of congenital pure red blood cell aplastic anemia

Diagnostic criteria

According to comprehensive literature reports, some scholars have proposed the following diagnostic criteria:

1 Large cell (or positive cell) positive pigmented anemia occurs within 1 year of birth.

2 The number of reticulocytes is reduced.

3 bone marrow hyperplasia is active, with selective red lineage precursor cells significantly reduced.

4 The number of white blood cells is normal or slightly decreased; 5 the number of platelets is normal or slightly increased, and typical cases are not difficult to diagnose.

Differential diagnosis

Should be noted with Fanconi anemia, children with transient erythrocytosis (TEC), chronic hemolytic anemia with B19 parvovirus infection, Pearson syndrome and cartilage dysplasia syndrome, including congenital pure red cell aplastic anemia Differential diagnosis with FA is especially important.

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