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Background: Hemophagocytic lymphohistiocytosis (HLH) has been described in patients with human immunodeficiency virus (HIV) infection. However, limited data is available in the era of highly active antiretroviral therapy (HAART).
Study design and methods: We conducted this prospective study over a two year period on 30 HIV infected patients. Our aim was to assess the frequency of hemophagocytosis in HIV-infected patients. We also tried to identify the underlying etiology and assess specificity of different parameters for HLH.
Results: Hemophagocytosis was identified in 14(46%) patients. 10/14(71%) had pancytopenia while 4/14(29%) had bicytopenia. 6(43%) had elevated ferritin (>500 μg/l). Fever (5/14), splenomegaly (4/14) and raised triglyceride (2/14) were identified less frequently. Underlying etiology could be identified in 6/14(43%) cases - disseminated tuberculosis in 4/14(29%) and one case each of Japanese encephalitis and disseminated candidiasis. Median CD 4 count was 123/cu.mm. 12(40%) patients were on HAART. 4/30 (13%) patients fulfilled criteria for HLH. Bicytopenia was least specific (25%) for diagnosis of HLH. Morphological evidence of hemophagocytosis had low specificity for HLH (29%); however, moderate / severe hemophagocytosis had higher specificity (66%). Raised ferritin levels (>500
μg/l) had a specificity of 66% while ferritin levels (>800 μg/l) had 100% specificity. Increased triglyceride levels (>265 mg/dl) had 50% sensitivity and 100% specificity.
Conclusion: Opportunistic infections represent the most common identifiable cause of HLH in HIV patients. Bicytopenia has got low specificity while moderate/severe hemophagocytosis, increased ferritin levels (>800 μg/l) and raised triglyceride levels have got high specificity for HLH in this setting. Larger prospective studies would be helpful in identifying modified diagnostic criteria in this setting.