Article
A rare case of HLA-B27 negative sacroiliitis in a patient with genetically impaired immunomodulatory function of regulatory T cells
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Published: | August 31, 2022 |
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History: An 18-year-old male with a history of genetically and functionally proven CTLA-4 insufficiency complained about inflammatory back pain. His past medical history was significant for autoimmune hemolytic anemia, which lead to splenectomy at age 6, followed by pneumococcal meningitis and overwhelming postsplenectomy infection (OPSI) at age 15 and prophylactic penicillin treatment since then. Severe thrombocytopenia was treated with Rituximab resulting in hypogammaglobulinemia which required IvIG 20 gr every 4–6 weeks. In addition, he suffered from growth hormone deficiency and approximately 6 months before transition into adult rheumatology, a CD4+ and CD8+ T cell dominated interstitial nephritis was diagnosed. His lower back pain occurred mostly at night and was not accompanied by significant morning stiffness.
Cardinal symptom by manifestation of disease: On clinical examination he had a bilateral positive Menell‘s sign without reduced range of motion. Laboratory tests revealed serologic inflammation (CRP 28,5 mg/l, leukocytosis 26,8 gpt/l), a markedly elevated soluble IL-2 receptor of 7417 U/ml, reduction of peripheral CD25+CD127- regulatory T cells and an increase in effector memory CD4+ and CD8+ T cells.
Diagnostics: An MRI of the sacroiliac joints showed small erosions and a bilateral bone marrow edema together with contrast medium uptake indicative of sacroiliitis. Testing for HLA–B27 was negative and no other symptoms typically present in axial spondyloarthritis (SpA) were reported (uveitis, dactylitis, psoriasis, or inflammatory bowel disease).
Therapy: Oral prednisolone 20 mg daily without non-steroidal antiphlogistics (due to concomitant interstitial nephritis) was initiated. Despite treatment, his symptoms did not improve after 2 months.
Further course: Therefore, he was treated with 1 mg sirolimus per day, which lead to a complete resolution of lower back pain within 5 weeks. Although occurrence of peripheral arthritis is reported in CTLA-4 insufficiency, sacroiliac manifestations have not been described to date. This case adds to our knowledge of the wide spectrum of autoimmune manifestations in CTLA-4 insufficiency and may shed some light on the role of regulatory T cells in sacroiliitis development.
Disclosures: None. Authors Lukas Bossaller and Almut Meyer-Bahlburg contributed equally to the abstract.