Severe Neutropenia After Leukocytosis During an Acute Attack of Mycoplasma Infection-associated Paroxysmal Cold Hemoglobinuria

Epstein-Barr Virus-induced Paroxysmal Cold Hemoglobinuria in a 17-Year-old Male

“…The DL antibody fixes early complement components on the cells, then dissociates once the cells circulate towards the core and warm to body temperature (37°C). In this warming process, the complement remains bound to the red blood cells, which leads to the activation of the classic complement pathway and subsequent intravascular hemolysis of the cells 1 . PCH is a clinical and laboratory diagnosis by (1) positive direct antiglobulin test with complement (usually C3d) coating the red blood cells and the absence of the complement-fixing IgG antibody, given that it dissociates from the cell surface at 37°C; (2) by presence of the DL antibody on specialized testing.…”

“…In this warming process, the complement remains bound to the red blood cells, which leads to the activation of the classic complement pathway and subsequent intravascular hemolysis of the cells. 1 PCH is a clinical and laboratory diagnosis by (1) positive direct antiglobulin test with complement (usually C3d) coating the red blood cells and the absence of the complement-fixing IgG antibody, given that it dissociates from the cell surface at 37°C; (2) by presence of the DL antibody on specialized testing. The DL antibody test consists of combining the patient's serum, test RBCs, and pooled human serum (to supplement complement components) for incubation at 4 °C.…”

“…Paroxysmal cold hemoglobinuria (PCH) is a rare type of autoimmune hemolytic anemia (AIHA) that comprises approximately 1% of AIHA cases 1 and has an incidence rate of 0.4 in ages 0 to 4 years, 0.04 in ages 5 to 9 years, and <0.01 in ages 10 to 39 years per 100,000 people 2 . When PCH was described in the early 1900s, it was often reported in adults with tertiary syphilis or in children with congenital syphilis around 2 to 4 years old.…”