Characterization of direct antiglobulin test‐negative autoimmune hemolytic anemia: A study of 154 cases
Direct antiglobulin test (DAT)‐negative (DAT‐)autoimmune hemolytic anemia (AIHA) is empirically thought to show the same clinical conditions as DAT‐positive (DAT+)AIHA, with the exception of an adequate amount of red blood cell (RBC)‐bound immunoglobulin (Ig)G. We investigated the clinical characteristics of DAT−AIHA in comparison with DAT+AIHA. Of the 582 patients referred to our laboratory with undiagnosed hemolytic anemia, AIHA was clinically diagnosed in 216 patients (DAT−AIHA, n = 154; DAT+AIHA, n = 62). The percentage of reticulocytes, mean corpuscular volume, RBC‐IgG levels, white blood cell count, and total protein (TP) levels were significantly higher in patients with DAT+AIHA than patients with DAT−AIHA. The hemoglobin level was significantly lower in patients with DAT+AIHA. No significant differences between patients with DAT−AIHA and DAT+AIHA existed with respect to age, gender, idiopathic/secondary nature, complications such as Evans syndrome, effectiveness of steroid treatment, or survival rate at 1 year following diagnosis. Patients with DAT−AIHA required significantly lower doses of steroids for maintenance therapy. Based on multivariate analysis of idiopathic DAT−AIHA (n = 110), TP and Evans syndrome were associated with the effectiveness of steroids (adjusted odds ratio [aOR], 1.36/[0.1 g/dl]; 95% confidence interval [CI], 1.01–1.84) and survival at the 1‐year follow‐up (aOR, 0.1; 95% CI, 0.01–0.88). Our results indicate that patients with DAT−AIHA generally suffer milder anemia and hemolysis than patients with DAT+AIHA, respond equally well to steroids, and have comparable survival at 1‐year. Am. J. Hematol. 88:93–96, 2013. © 2012 Wiley Periodicals, Inc.
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Document Type: Research Article
Publication date: February 1, 2013