Partial red cell aplasia

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

Classification

Congenital:

• constitutional;
• anemia of Diamond-Blackfen.

Fetal:

• fetal edema due to intrauterine infection with parvovirus B19.

Purchased:

• transient;
• transient erythroblastopenia of children (TED);
• Parvovirus infection in the background of intense erythropoiesis.

Tumor-associated:

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

Immune:

• idiopathic;
• systemic connective tissue diseases.

Medicinal.

The most frequent forms of such diseases in children are Diemond-Blackfen anemia, transient erythroblastopenia of children, and aplastic crises in congenital hemolytic anemia. Tumor-associated, drug and immune forms of PKA in children are very rare.

Transient erythroblastopenia of children

Transient erythroblastopenia appears, in all probability, the most frequent form of PKA in children, but due to the transient nature, not all cases of transient erythroblastopenia are fixed.

A typical sign is the presence of a "viral" prodrome, a few weeks after which anemic syndrome develops. Anemia in accordance with the name of the syndrome is normochromic and hyporegenerative, that is, it is combined with reticulocytopenia and complete absence of erythroblasts in 90% of patients. Violations of other hematopoietic sprouts are not detected. Congenital developmental anomalies, characteristic for Diamond-Blackfang anemia, do not occur with 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 anemia. At the exit, the convalescent transient erythroblastopenia show signs of "stress" hematopoiesis - the expression of the I antigen on erythrocytes and the increase in fetal hemoglobin. Treatment of transient erythroblastopenia is not required, with the exception of transfusions with poor tolerability of anemia.

Partial red cell aplasia due to parvovirus infection

Parvovirus B19 is a widespread virus in nature. The brightest acute syndrome caused by parvovirus B19 in children is a sudden exanthema. The receptor of the virus is the P-antigen surface of erythrocytes and erythroblasts, so the damage to erythropoiesis is typical for any infection with parvovirus B19. The rapid clearance of the virus and the high "mobilization reserve" of erythropoiesis are the main reasons for the absence of serious hematological consequences of parvovirus B19 infection in the hematologically intact immunocompetent host. If a blood test is taken immediately after an acute infection, it reveals reticulocytopenia. In patients with intense hyperproliferative erythropoiesis, characteristic of chronic hemolytic anemia, thalassemia, dyserothropoietic anemia, erythrocarytic damage to parvovirus B19 causes a severe but transient red cell aplasia, resolved within a few weeks. Less often the aplastic crisis develops with other anemias, in particular, with iron deficiency anemia. For this type of PKA is typical the presence of a few, but practically pathognomonic giant Pronormoblasts. 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 at the time of presentation of PKAA usually have viremia, therefore it is possible to detect the diagnosis of PKA as a result of parvovirus infection by detecting the virus in the bone marrow or blood by dot Mrt-hybridization. Amplification of the viral genome by PCR is less reliable, since parvovirus can persist for a long time in the bone marrow after an acute infection is completely asymptomatic.

In patients with congenital or acquired immunodeficiency, lacking an adequate antiviral response, parvovirus B19 can cause a chronic severe PKA. Such children effectively administer high doses (2-4 g / kg) of commercial intravenous immunoglobulins, which contain sufficient antibodies to parvovirus.

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