GSTM1 and autoimmune hemolytic anemia: AITL: angioimmunoblastic T-cell lymphoma; LL: lower limb; PUO: pyrexia of unknown origin; Hb: haemoglobin; WCC: white blood cell count; CSF: cerebrospinal fluid; NCS: nerve conduction study; GBS: Guillain-Barré syndrome; CTCAP: computed tomography scan of the chest, abdomen, and pelvis; AIHA: autoimmune haemolytic anaemia; LDH: lactate dehydrogenase; DAT: direct antiglobulin test; IgG: immunoglobulin G; FISH: fluorescence in situ hybridisation test; EBV: Epstein-Barr virus