Evaluation – Questions & answers
[expand title=”What is the diagnosis?” tag=”strong”]A 3 month old male with Neonatal lupus Erythematosus (NLE) presenting with thrombocytopenia, anaemia. neutropenia and antiphospholipid antibodies. Complicated by haematochezia, haematuria and intracranial haemorrhage[/expand] [expand title=”Which autoantibodies are associated with NLE?” tag=”strong”]Anti-Ro and anti-La autoantibodies[/expand] [expand title=”What is the mechanism of disease?” tag=”strong”]Passive transfer of IgG anti-nuclear antibodies specifically to Ro and La proteins through the placenta. Once in the foetal circulation these antibodies promote the development of NLE by binding to antigen. Anti-Ro and anti-La autoantibodies bind to nuclear antigens translocated to the cell membranes of apoptotic cells. Macrophages expressing Fc receptors recognise bound IgG and become activated.[/expand] [expand title=”Which organ systems are affected?” tag=”strong”]Cardiac, dermatologic, hepatobilliary and haematologic.[/expand] [expand title=”What are the long term consequences of NLE on the affected infant?” tag=”strong”]For the most part NLE is transient, however if third degree heart block (due to inflammation and fibrosis) develops this is irreversible requiring the implantation of a pacemaker and if coupled with cardiomyopathy may be fatal.There also appears to be an increased risk for development of autoimmune diseases later in childhood or adulthood.[/expand] [expand title=”What causes anaemia, thrombocytopaenia and occasionally pancytopaenia in NLE?” tag=”strong”]Anti-platelet antibodies and anti- red cell antibodies are a common cause of thrombocytopaenia and anaemia. Anaemia can also result from haemorrhage, while pancytopaenia is most likely due to hypersplenism[/expand] [expand title=”What investigations can be carried out to assess pancytopaenia?” tag=”strong”]Investigations that can be carried out include:
- FBC
- Bone marrow trephine biopsy
- LDH where a high reading indicates general cell destruction
- Haptoglobin which decreases when consumed by high release of haemoglobin
- Coombs test which identifies anti-red cell antibodies in plasma – i.e. proof of circulating anti-red cell antibodies
