LETTER TO THE EDITOR Bone marrow evaluation in leprosy: clinical implications

We read with great interest the first case report of hemophagocytic lymphohistiocytosis (HLH) in association with leprosy by Høyvoll et al. They described a young female with multibacillary leprosy (MBL) and erythema nodosum leprosum (ENL). After 3 weeks of instituting multidrug therapy (MDT) with rifampin, dapsone, clofazimine, and prednisolone, she developed high-grade fever and other systemic symptoms which led to the diagnosis of HLH. The patient satisfied six of eight HLH-2004 criteria such as fever, splenomegaly, pancytopenia, marked hyperferritinemia, hypertriglyceridemia, and histiocytic hemophagocytosis in bone marrow (BM). In addition, Mycobacterium leprae (M. leprae) was also demonstrated in the BM. However, in spite of immunosuppresive therapy, antibacterial and antifungal treatment, and renal and respiratory support, the patient succumbed to fulminant bacterial and fungal sepsis. The authors attributed HLH in association with leprosy; however, the patient was diagnosed with systemic lupus erythematosus (SLE) 1 year prior to her current presentation. Therefore, a repeat of antibody titers (antinuclear antibodies, anti dsDNA, and/or anti Smith) would have been very informative in the patient because HLH is known to be associated with autoimmune diseases, such as SLE. HLH has a well known association with disseminated tuberculous Mycobacterial infections; and even reported to occur following initiation of first line antituberculous drugs such as rifampin and isoniazid. Although leprosy and tuberculosis have been the scourge of mankind for centuries, surprisingly, the association of HLH with leprosy was described only recently in a middle aged Tunisian man with MBL following the initiation of MDT with dapsone and rifampin; but responded well to corticosteroid. Another report from China described a case of suspected HLH with low natural killer cell activity and high CD25 levels which preceded the histological diagnosis of MBL. Dapsone, an integral component of MDT