Additional laboratory tests (serum angiotensin converting enzyme, β2-microglobulin, rheumatoid factor, complement fractions, immunoglobulin G4, vitamin D, serum calcium) and infectious disease screenings (blood and urine cultures, Treponema Pallidum tests, tuberculosis assay, serology for cytomegalovirus, Epstein–Barr virus, and hepatitis viruses) were unremarkable or negative. Here, ACE is linked to infectious disease.