
Introduction: The present study was conducted with the aim to diagnose and categorize aplastic anemia (AA) according to the severity as non severe (NsAA), severe (sAA) and very severe (VsAA) and to study microvessel density using immunohistochemical stain using CD 34 and morphometric analysis of microvessel density by computer assisted quantitative analyser and to compare it in the three subcategories of aplastic anemia with control group. Material and Methods: The present prospective study was conducted in the Department of Pathology at Pt. B.D. Sharma PGIMS, Rohtak. Thirty cases of AA patients and 10 cases of control were taken. AA patients were diagnosed on the basis of complete blood count, peripheral blood smear, bone marrow aspiration examination and bone marrow trephine biopsy (using Jamshidi’s needle). AA patients were categorized as sAA, NsAA and VsAA using camitta et al criteria. IHC using CD 34 was performed to look for angiogenesis and to calculate microvessel density (MVD). Results: Majority of patients (56%) of AA were between 1st and 3rd decade of life. Females were more commonly affected with a male to female ratio (11/19) of 0.58:1. In Aplastic anemia patients (Group I), using Camitta et al criteria 30 cases were categorized into NsAA (10 cases), sAA (12 cases) and VsAA (8 cases). MVD was calculated using CD 34 which is a good marker of angiogenesis. MVD showed a decreasing trend with increase in severity of the disease. Conclusion: The study shows that Aplastic anemia is associated with reduced bone marrow angiogenesis and mean MVD score shows a decreasing trend from non severe to very severe Aplastic anemia.