Partial red-cell aplasia.

The term "partial red cell aplasia" (PRCA) describes a group of nosological entities characterized by anemia combined with reticulocytopenia and the disappearance or significant reduction in the number of morphologically determined, as well as early committed precursors of erythropoiesis in the bone marrow. The classification divides PRCA into congenital and acquired forms.

Classification

Congenital:

• constitutional;
• Diamond-Blackfan anemia.

Fetal:

• hydrops fetalis due to intrauterine infection with parvovirus B19.

Acquired:

• transient;
• transient erythroblastopenia of children (TED);
• parvovirus infection against the background of intense erythropoiesis.

Tumor-associated:

• thymoma, lymphomas, chronic lymphocytic leukemia, MDS, chronic myeloid leukemia (CML), carcinomas.

Immune:

• idiopathic;
• systemic connective tissue diseases.

Medicinal.

The most common forms of such diseases in children are Diamond-Blackfan anemia, transient erythroblastopenia of children and aplastic crises in congenital hemolytic anemias. Tumor-associated, drug-induced and immune forms of PRCA in children are very rare.

Transient erythroblastopenia in children

Transient erythroblastopenia is probably the most common form of PKCA in children, however, due to its transient nature, not all cases of transient erythroblastopenia have been recorded.

A typical symptom is the presence of a "viral" prodrome, after which anemic syndrome develops several weeks later. Anemia, in accordance with the name of the syndrome, is normochromic and hyporegenerative, that is, it is combined with reticulocytopenia and a complete absence of erythroblasts in 90% of patients. No disorders of other hematopoietic sprouts are detected. Congenital developmental anomalies characteristic of Diamond-Blackfan anemia do not occur in transient erythroblastopenia. The cause of erythroblastopenia in transient erythroblastopenia is the presence of humoral or cellular inhibitors of erythropoiesis. The diagnosis of transient erythroblastopenia is made retrospectively, after the resolution of the anemia. At the "exit", convalescents of transient erythroblastopenia demonstrate signs of "stress" hematopoiesis - expression of I antigen on erythrocytes and an increase in fetal hemoglobin. Treatment of transient erythroblastopenia is not required, except for transfusions if the anemia is poorly tolerated.

Partial red cell aplasia due to parvovirus infection

Parvovirus B19 is a widespread virus in nature. The most striking acute syndrome caused by parvovirus B19 in children is sudden exanthema. The receptor for the virus is the P-antigen of the surface of erythrocytes and erythroblasts, so damage to erythropoiesis is typical for any infection with parvovirus B19. Rapid clearance of the virus and a high "mobilization reserve" of erythropoiesis are the main reasons for the absence of serious hematological consequences of parvovirus B19 infection in a hematologically intact immunocompetent host. If a blood test is taken immediately after an acute infection, reticulocytopenia is detected in it. In patients with intense hyperproliferative erythropoiesis, characteristic of chronic hemolytic anemias, thalassemias, dyserythropoietic anemias, the defeat of erythrocytes by parvovirus B19 causes severe but transient red cell aplasia, resolving within a few weeks. Less often, aplastic crisis develops in other anemias, in particular, in iron deficiency anemia. For this type of PRCA, the presence of a few, but almost pathognomonic giant pronormoblasts is typical. The diagnosis of transient aplastic crisis is easy to establish in patients with documented chronic hemolysis, but in patients with subclinical hemolytic anemia, aplastic crisis may be the first manifestation of the disease. Patients with aplastic crisis usually have viremia at the time of presentation of PCC, so the diagnosis of PCC due to parvovirus infection can be established by detecting the virus in bone marrow or blood using dot MRT hybridization. Amplification of the viral genome using PCR is less reliable, since parvovirus can persist in the bone marrow for a long time after acute infection completely asymptomatically.

In patients with congenital or acquired immunodeficiency, deprived of an adequate antiviral response, parvovirus B19 can cause chronic severe PRCA. In such children, the administration of high doses (2-4 g/kg) of commercial intravenous immunoglobulins, which contain a sufficient amount of antibodies to parvovirus, is effective.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ], [ 10 ], [ 11 ]