Partial Red Cell Aplasia

What is Partial Red Cell Aplasia?

Partial red cell aplasia (PRCA) is a syndrome with a sharp suppression of red blood cell production, isolated normochromic anemia, and deep reticulocytopenia.

For the first time, PRCA described Kaznelson in 1922. In the future, a number of cases of this disease were described, while a significant portion of patients revealed a thymus tumor (thymoma).

Subsequently, descriptions of the congenital form of PRCA appeared, which manifested itself in the first 2 years of life. Currently, no more than 300 patients with PRCA are described and it is shown that this is not one, but several different diseases. In some cases, even with prolonged follow-up of the patient, it is not possible to identify the association of PRCA with any other diseases (idiopathic form of PRCA). In other cases, PRCA is associated with a thymus tumor; often this syndrome becomes the first manifestation of any hemoblastosis. Some authors identify a special (adolescent) form of PRCA with a favorable course.

Causes of Particular Red Cell Aplasia

The disease begins gradually. Complaints made by patients: malaise, severe weakness, fatigue, pain in the heart.

With an objective examination of such patients, pallor of the skin, as well as visible mucous membranes, is observed, while their jaundice is absent. As a rule, body temperature is within normal limits. In connection with hemosiderosis, the liver often enlarges. The spleen is rarely enlarged.

Diagnosis of Parcinal Red Cell Aplasia

In most patients with PRCA, pronounced normochromic anemia with a small number of reticulocytes is detected; the number of leukocytes is usually normal or even increased, however, in some patients moderate leukopenia is detected, sometimes a neutrophilic shift to the left. The platelet count is often normal, much less often slightly reduced. ESR is significantly increased.

In the bone marrow, inhibition of the erythroid germ is more often detected with a normal content of megakaryocytes and granulocytes, sometimes phagocytosis of erythrokaryocytes by macrophages. In the bone marrow, the ratio between the hematopoietic part and fat is normal; structural changes are characteristic.

The course is chronic, in some cases it is possible to achieve remission, but in most therapeutic measures do not lead to a complete normalization of hematological parameters. In a number of patients, against the background of PRCA, signs of hemoblastosis begin to gradually manifest. A stab shift or resembling a Pelger anomaly is detected, basophilia, eosinophilia, and sometimes monocytosis appear. A cytogenetic study in the initial stages of the disease does not reveal changes. In rare cases, as the process progresses, a clone of tumor (leukemia) cells may be detected. Sometimes signs of a peculiar myeloproliferative disease without the Ph’chromosome are gradually revealed. In some cases, erythromyelosis develops, acute undifferentiated leukemia, in which an erythroblastic antigen can be found on the surface of the blasts. In some patients with PRCA, an M-gradient is detected, which most often includes IgG.