Análise da participação das subclasses de IgH nos processos hemolíticos secundários à doença hemolítica perinatal e à anemia hemolítica auto-imune

Abstract

The diagnosis of immune haemolytic diseases might be done by clinicai syndrome, biochemical tests and by the demonstration of antibody fixed to red cells, also called direct antiglobulin test (DAT). The red cells are activated by G immunoglobulin (IgG) and/or by the component C3 of the complement. The human IgG is comprised in four subclasses (lgG1, lgG2, lgG3 and lgG4) that differ of each other by unique Chemical and biological characteristics producing specific activities. lgG1 and lgG3 have high affinity to Fcy receptors from macrophages, therefore being essentials to the extravascular haemolytic process. This study aimed to determine the lgG1 and lgG3 subclasses in the perinatal haemolytic disease (PNHD) and autoimmune haemolytic anemia (AIHA), correlating the subclasses with the severity of the haemolysis. Forty- two samples of isoimmunised pregnant women were analysed by the method of flow cytometry and 23 samples from patients with AIHA by the method of gel test. According to the severity of the disease the foetuses or newborns from 42 pregnants were distributed as 13 mild, 16 moderates and 13 severe diseases. Moreover according with the severity of the disease, the 23 patients with AIHA were distributed as 6 mild, 8 moderate and 9 severe cases. High leveis of subclasses were detected in 33 out of 42 (72%) pregnant women samples and in 16 out of 23 (69.6%) AIHA patients. lgG1 was the most frequent, in 14 out of 33 (42.4%) PNHD samples and in 12 out of 16 (75%) AIHA samples. Leveis of only lgG1 were also found in the three categories of each analysed population. In addition, from the fluorescence intensity were significantly higher in the severe cases of PNHD (p<0.01).