Contributions
Abstract: PB1496
Type: Publication Only
Session title: Chronic lymphocytic leukemia and related disorders - Clinical
Background
The course of chronic lymphocytic leukemia (CLL) is often complicated by autoimmune disorders, including autoimmune hemolytic anemia (AIHA). The direct antiglobulin test (DAT) is playing an important role in the diagnostic of autoimmune hemolysis. The modern capabilities of the DAT make it possible to detect the presence of autoantibodies and complement on the surface of red blood cells (RBC), as well as to determine the class and subclass of antibodies involved in the pathological process.
Aims
The aim of this study was to explore the frequency and features of positive DAT in patients with CLL and its possibilities to prognose AIHA.
Methods
DAT was carried out using equipment (automatic immunohematological analyzer IH-1000) and reagents from Bio-Rad (USA). DiaMed-ID-LISS/Coombs Anti-IgG + C3d cards were used for screening. Upon receiving a positive DAT, immunoglobulin classes, complement components, IgG subclasses were detected using DC-Screening I and DAT IgG1/IgG3 cards (Bio-Rad (USA)). The presence of hemolytic anemia was determined according the usual clinical and laboratory criteria. The levels of hemoglobin, RBC, reticulocytes, total and indirect bilirubin were investigated by conventional methods. DAT results were analyzed in 104 patients with CLL. The median age of the cohort was 65 years (range 53 to 85 years).
Results
Positive DAT was detected in 15.4% patients with CLL (16 out of 104 examined). The intensity of the reaction was: (+) - in 3 patients (18.8%), (++) - in 6 (37.5%), (+++) - in 5 (31.3%), (++++) - in 2 (12.5%).
Positive DAT was due to fixation on RBC IgG 2/4 - in 37.5% of the examined, IgG1 — in 18.8%, IgG1 in combination with the complement component C3d — in 18.8%, IgG1 + IgG3 + IgA + C3d — in 12.5%, only C3d — in 12.5%.
Hemolysis was observed in 9 people (56.3%) among 16 patients with a positive DAT. Patients with positive DAT due to IgG2,4, showed no signs of hemolysis. The detection of C3d both independently and in combination with IgG1, IgG3, IgA, in all cases was associated with signs of hemolysis. IgG1 fixation on RBC was found in 3 patients with CLL, hemolytic anemia developed in 2 of them (66.7%).
Conclusion
Positive DAT was detected in 15.4% of patients with CLL, hemolytic anemia was found in more than half of them (56.3%). The detection of the complement component C3d on the surface of RBC, as well as the combination of C3d with IgG1, IgG1+IgG3+IgA, in 100% of cases was associated with the AIHA. Fixation of IgG1 alone led to AIHA in 66.7% of cases. The role of IgG 2,4 in the development of hemolysis has not been proven.
Keyword(s): Complement, Hemolytic anemia, Immunoglobulin
Abstract: PB1496
Type: Publication Only
Session title: Chronic lymphocytic leukemia and related disorders - Clinical
Background
The course of chronic lymphocytic leukemia (CLL) is often complicated by autoimmune disorders, including autoimmune hemolytic anemia (AIHA). The direct antiglobulin test (DAT) is playing an important role in the diagnostic of autoimmune hemolysis. The modern capabilities of the DAT make it possible to detect the presence of autoantibodies and complement on the surface of red blood cells (RBC), as well as to determine the class and subclass of antibodies involved in the pathological process.
Aims
The aim of this study was to explore the frequency and features of positive DAT in patients with CLL and its possibilities to prognose AIHA.
Methods
DAT was carried out using equipment (automatic immunohematological analyzer IH-1000) and reagents from Bio-Rad (USA). DiaMed-ID-LISS/Coombs Anti-IgG + C3d cards were used for screening. Upon receiving a positive DAT, immunoglobulin classes, complement components, IgG subclasses were detected using DC-Screening I and DAT IgG1/IgG3 cards (Bio-Rad (USA)). The presence of hemolytic anemia was determined according the usual clinical and laboratory criteria. The levels of hemoglobin, RBC, reticulocytes, total and indirect bilirubin were investigated by conventional methods. DAT results were analyzed in 104 patients with CLL. The median age of the cohort was 65 years (range 53 to 85 years).
Results
Positive DAT was detected in 15.4% patients with CLL (16 out of 104 examined). The intensity of the reaction was: (+) - in 3 patients (18.8%), (++) - in 6 (37.5%), (+++) - in 5 (31.3%), (++++) - in 2 (12.5%).
Positive DAT was due to fixation on RBC IgG 2/4 - in 37.5% of the examined, IgG1 — in 18.8%, IgG1 in combination with the complement component C3d — in 18.8%, IgG1 + IgG3 + IgA + C3d — in 12.5%, only C3d — in 12.5%.
Hemolysis was observed in 9 people (56.3%) among 16 patients with a positive DAT. Patients with positive DAT due to IgG2,4, showed no signs of hemolysis. The detection of C3d both independently and in combination with IgG1, IgG3, IgA, in all cases was associated with signs of hemolysis. IgG1 fixation on RBC was found in 3 patients with CLL, hemolytic anemia developed in 2 of them (66.7%).
Conclusion
Positive DAT was detected in 15.4% of patients with CLL, hemolytic anemia was found in more than half of them (56.3%). The detection of the complement component C3d on the surface of RBC, as well as the combination of C3d with IgG1, IgG1+IgG3+IgA, in 100% of cases was associated with the AIHA. Fixation of IgG1 alone led to AIHA in 66.7% of cases. The role of IgG 2,4 in the development of hemolysis has not been proven.
Keyword(s): Complement, Hemolytic anemia, Immunoglobulin