The patient's electrolytes, kidney and liver functions and coagulation profile were all normal. Her antinuclear antibodies, rheumatoid factor, c-ANCA, p-ANCA, anticardiolipin antibodies, lupus anticoagulant, antiparietal cell antibodies, anti-smooth muscle antibodies, anti-histone antibodies and anti-mitochondrial antibodies all showed negative results. Serological tests for CMV, EBV, HSV, HAV, HBV, HCV, HIV, adenovirus, parainfluenza, Coxsackie, influenza, Toxoplasma and Brucella were all negative. Serology for parvovirus was positive for IgG antibodies as well as for Coxiella burnetii antibodies (Qfever). A total body computed tomography (CT) scan was performed but did not show any pathology except for a 16-cm enlarged spleen. Bone marrow (BM) biopsy showed no evidence of lymphoma or any other type of malignancy.