P035 An unusual ally: coexistence of large vessel vasculitis and pure red cell aplasia

Pure red cell aplasia (PRCA) is a rare autoimmune disorder marked by reduced or absent red cell precursors. It can be inherited or acquired. Inherited cases are often associated with Diamond-Blackfan anaemia, and acquired can be due to autoimmune disorders, thymoma, drugs, infections, especially parvovirus infection. No literature currently exists on the coexistence of PRCA and large vessel vasculitis (LVV). The pathogenesis of this combination is not entirely understood, and no standard treatment approach exists.

66-year-old male presented with progressive shortness of breath and symptomatic anaemia in January 2023. He worked as part-time gardener and was not on regular medications. He is a non-smoker and occasionally drinks alcohol. Systemic examination was unremarkable. His haemoglobin was 62 g/l (13-170), MCV of 84.2 (83-101); other full blood indices, kidney and liver function tests were within normal ranges. His CRP was 22, reticulocyte count was 9.2 (50-100), serum iron was raised to 55(13-32), and ferritin was 702 (24-336). Viral serology for hepatitis, HIV, parvovirus B19, and EBV were negative. Myeloma screen, LDH, vasculitis, CTD screen, parvovirus B19, CMV, EBV, and adenovirus serology were negative. Bone marrow aspirate and trephine performed by haematologists showed low erythroid activity with no dysplastic changes, normal cytogenetics, and myeloid gene panel. CT scan of his chest, abdomen, and pelvis showed no malignancy. A low attenuation splenic lesion was noted. He required weekly blood transfusions. PET CT scan in April 2023 revealed no uptake in the spleen or lymph nodes; however, it showed uptake in the thoracoabdominal aorta and its branches, carotid and subclavian arteries (SUV max 4.3), consistent with LVV. Rheumatology review revealed no polymyalgia, giant cell arteritis or constitutional symptoms. He was commenced on 60mg of prednisolone on a weaning course and started on ciclosporin in April 2023. He achieved transfusion independence in August 2023.

Repeat PET scan in August 2023 showed excellent response to prednisolone. He is on a reducing course of 6mg prednisolone with cyclosporin. He had a Hb of 133 and CRP of 2.2 in September 2024.

This case aims to raise awareness of the coexistence of pure red cell aplasia and large vessel vasculitis. The pathogenesis of this combination is not entirely understood, and no standard treatment approach exists. Published literature exists on PRCA with various rheumatology diseases, including rheumatoid arthritis, SLE and ankylosing spondylitis. We could not determine if our patient’s LVV caused the PRCA or vice versa. However, involvement of his subclavian arteries on the PET scan favours inflammation over arteriosclerosis. Treatment of his PRCA and LVV with high-dose corticosteroids and cyclosporin, and serial monitoring of haematologic and inflammatory parameters, guided treatment adjustments. Considering the rarity of this disease combination, our case provides valuable insights should similar cases arise.

S. Zeb: None. C. Davies: None. A. Oke: None.