Haemophagocytic lymphohistiocytosis in pregnancy

Editor - The annual confidential enquiries into maternal mortality in the UK, published by MBBRACE, state that we should ‘Treat pregnant and postpartum women the same as non-pregnant women unless there is a clear reason not to’.¹ Consecutive MBRRACE reports include numerous maternal deaths occurring after standard of care treatment was withheld or delayed due to concerns about its safety in pregnancy. In the paper by Jha et al, the authors state that ‘the safety and efficacy of ... cyclosporin, rituximab and immunoglobulin during pregnancy and lactation are yet to be established.² Evidence-based statements supporting the use in pregnancy of cyclosporin, intravenous immunoglobulins and, for life-threatening maternal disease, rituximab have been produced by the American College of Rheumatology, European League Against Rheumatism and British Society for Rheumatology.^3–5 Therefore, these treatments should not be withheld from pregnant women due to concerns about fetal harm. This is particularly important for women with severe maternal disease such as haemophagocytic lymphohistiocytosis (HLH), as untreated disease could be harmful to both mother and baby.

The HLH label should be viewed as we see sepsis, as a starting point to initiate management while striving to identify an underlying source/trigger. The immunological changes of pregnancy can trigger HLH, with delivery being curative, but HLH in pregnancy can also occur secondary to infection, autoimmunity/autoinflammation and haematological malignancy.⁶ Jha et al state that ‘Biopsy of liver, spleen or lymph nodes could not have revealed any extra information to change the diagnosis’, but we would advise caution with this assumption.² Steroids are often employed early in HLH to control hyperinflammation but can mask or delay the identification of triggers such as lymphoma.⁷ Our practice is to undertake repeated histological examination of abnormal organs, lymph nodes and bone marrow alongside the use of steroid sparing agents, where possible. Managing a pregnant woman with HLH is best done within a multidisciplinary team (MDT) setting, including rheumatology, haematology, infectious diseases, obstetrics and obstetric medicine and with advice from an HLH MDT, in order to best judge the timing of investigations and delivery.

Conflicts of interest

Taryn Youngstein is on industry-sponsored advisory boards for Sobi, Novartis and Roche. Ian Giles is a speaker, has advisory board fees and an unrestricted research grant from UCB Pharma.