Rheumatology 2004; 43: 254-255
British Society for Rheumatology 2004; all rights reserved
Letter to the Editor |
Reply
Department of Paediatric Rheumatology, 1Department of Paediatric Haematology and 2Department of Paediatric Histopathology, Royal Manchester Children's Hospital, Manchester, UK
Correspondence to: A. V. Ramanan. E-mail: avramanan{at}hotmail.com
SIR, We thank Dr Jawad for his comments and his interest in our paper [1]. To address the issues raised by the author, there was no family history of haemophagocytic lymphohistiocytosis (HLH) or of consanguinity. We did do serology for Epstein–Barr virus (EBV) and parvovirus, both of which were negative (we mentioned in our paper that the viral serology was negative, although we did not specify the viruses checked).
As for his comments on the diagnostic criteria, these are beset with problems. The criteria were designed primarily for the diagnosis of primary HLH, but many clinicians in practice use the criteria for secondary HLH and for HLH associated with rheumatic disease. Henter et al. [2], in their criteria, acknowledge the fact that not all patients will fulfil the criteria and that clinical decisions regarding therapy need to be made even when patients do not satisfy the diagnostic criteria.
There are certain problems with the existing criteria. Low haemoglobin concentration, raised white cell count and raised platelet count are characteristic of active systemic disease in systemic onset juvenile idiopathic arthritis (SoJIA). Hence, relative cytopenia may enable earlier diagnosis of HLH compared with the absolute cytopenia in the present criteria.
One of the major problems with the existing criteria for HLH is the need for tissue demonstration of haemophagocytosis. It is well recognized that bone marrow aspirate or biopsy may not always show haemophagocytosis; furthermore, haemophagocytosis is not always demonstrable at onset [3, 4]. In one series of 27 children with primary HLH, autopsy studies revealed haemophagocytosis in the bone marrow in only 39% (9/23). On the contrary, 71 and 74% showed haemophagocytosis in the spleen and lymph nodes respectively [4]. Whilst this demonstrates that biopsies of the spleen and lymph nodes have higher yields, they constitute a much greater risk in the face of active coagulopathy. There is a need for criteria that take these difficulties into account, yet provide a robust framework for early diagnosis and treatment.
References
- Ramanan AV, Wynn RF, Kelsey A, Baildam EM. Systemic juvenile idiopathic arthritis, Kikuchi's disease and haemophagocytic lymphohistiocytosis—is there a link? Case report and literature review. Rheumatology 2003;42:596–8.
[Free Full Text] - Henter JI, Elinder G, Ost A. Diagnostic guidelines for hemophagocytic lymphohistiocytosis. The FHL Study Group of the Histiocyte Society. Semin Oncol 1991;18:29–33.[Web of Science][Medline]
- Janka GE. Familial hemophagocytic lymphohistiocytosis. Eur J Pediatr 1983;140:221–30.[CrossRef][Web of Science][Medline]
- Ost A, Nilsson-Ardnor S, Henter JI. Autopsy findings in 27 children with haemophagocytic lymphohistiocytosis. Histopathology 1998;32:310–6.[CrossRef][Web of Science][Medline]
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