| 1,25-dihydroxycholecalciferol | 1,25(OH)2D3 |
| 25-hydroxyvitamin D | 25(OH)D |
| α1-macroglobulin | α1M |
| α2-microglobulin | α2m |
| α2-plasmin inhibitor | α2PI |
| anticentromere antibodies | ACA |
| anticardiolipin antibodies | aCL |
| American College of Rheumatology | ACR |
| Arthritis Foundation | AF |
| aggregated human IgG | AHG |
| Arthritis Impact Measurement Scales | AIMS |
| antimitochondrial antibodies | AMA |
| antinuclear antibodies | ANA |
| antineutrophil cytoplasmic antibodies | ANCA |
| anti-glomerular basement membrane | anti-GBM |
| alkaline phosphatase | AP |
| antiphospholipid antibodies | aPL |
| antiphospholipid syndrome | APS |
| American Rheumatism Association | ARA |
Arthritis, Rheumatism and Aging Medical Information System | ARAMIS |
| adult respiratory distress syndrome | ARDS |
| acute rheumatic fever | ARF |
| ankylosing spondylitis | AS |
| acetylsalicylic acid | ASA |
| anti-smooth muscle antibodies | ASMA |
| azathioprine | AZA |
| British Isles Lupus Assessment Group | BILAG |
| bone mineral content | BMC |
| bone mineral density | BMD |
| body mass index | BMI |
| bovine serum albumin | BSA |
| cortical area | CA |
| cytoplasmic ANCA or classic ANCA | cANCA |
| complementary DNA | cDNA |
| collagen-induced arthritis | CIA |
| circulating immune complex | CIC |
| counterimmunoelectrophoresis | CIE |
| carpometacarpal joint | CMC joint |
| cytomegalovirus | CMV |
| central nervous system lupus | CNS lupus |
| calcium pyrophosphate deposition disease | CPDD |
| calcium pyrophosphate dihydrate | CPPD |
calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasias | CREST |
| chromosomal RNA | cRNA |
| C-reactive protein | CRP |
| chondroitin sulfate | CS |
| cyclosporin A | CSA |
Cooperative Systematic Studies of the Rheumatic Diseases (group) | CSSRD |
| computed tomography | CT |
| connective tissue disease | CTD |
| cathepsin G | CTG |
| carpal tunnel syndrome | CTS |
| coxsackievirus B | CVB |
| D-penicillamine | D-Pen |
| diffuse cutaneous systemic sclerosis | dcSSc |
| denatured DNA | dDNA |
| dehydroepiandrosterone sulfate | DHEAS |
| direct immunofluorescence | DIF |
| distal interphalangeal joint | DIP joint |
| diffuse idiopathic skeletal hyperostosis | DISH |
| discoid lupus erythematosus | DLE |
| dermatomyositis | DM |
| disease-modifying antirheumatic drug(s) | DMARD(s) |
| Dulbecco's modified Eagle's medium | DMEM |
| deoxyribonucleic acid | DNA |
| dual-photon absorptiometry | DPA |
| double-stranded DNA | dsDNA |
| dual x-ray absorptiometry | DXA |
| Epstein-Barr nuclear antigen | EBNA |
| Epstein-Barr virus | EBV |
| European Consensus Lupus Activity Measure | ECLAM |
| eosinophilic fasciitis | EF |
| enzyme immunoassay | EIA |
| enzyme-linked immunosorbent assay | ELISA |
| electron microscopy | EM |
| electromyography | EMG |
| extractable nuclear antigen | ENA |
| ear, nose, throat | ENT |
| erythrocyte sedimentation rate | ESR |
| European SpondylarthropathyStudy Group | ESSG |
| endothelin 1 | ET-1 |
| fluorescence-activated cell sorter | FACS |
| fluorescent antinuclear antibodies | FANA |
| fluorescence in situ hybridization | FISH |
| fibromyalgia | FM |
| familial Mediterranean fever | FMF |
fast protein (or fast performance) liquid chromatography | FPLC |
| Felty's syndrome | FS |
| fluorescent treponemal antibody absorption | FTA-ABS |
| glycosaminoglycan | GAG |
| giant cell arteritis | GCA |
| granulocyte colony-stimulating factor | G-CSF |
| granulocyte-macrophage colony-stimulating factor | GM-CSF |
| glomerulonephritis | GN |
| IgG phospholipid units | GPL |
| hyaluronic acid | HA |
| Health Assessment Questionnaire | HAQ |
| heat-aggregated IgG | HAGG |
| hepatitis A virus | HAV |
| hepatitis B surface antigen | HBsAg |
| hepatitis B virus | HBV |
| hydroxychloroquine | HCQ |
| hepatitis C virus | HCV |
| hepatitis delta virus | HDV |
| hepatoma cell line | Hep |
| human epithelial cell line 2 | HEp-2 |
| hepatitis E virus | HEV |
| human herpesvirus 6 | HHV-6 |
| histidyl-transfer RNA | his-tRNA |
| human immunodeficiency virus | HIV |
| heterogeneous nuclear RNA | hnRNA |
| heterogeneous nuclear RNP | hnRNP |
| hypertrophic osteoarthropathy | HOA |
high performance (or high pressure) liquid chromatography | HPLC |
| human papilloma virus | HPV |
| human parvovirus B19 | HPV B19 |
| hormone replacement therapy | HRT |
| Henoch-Schönlein purpura | HSP |
| hypersensitivity vasculitis | HSV |
| herpes simplex virus type 1 | HSV-1 |
| human T cell lymphotrophic virus | HTLV |
| hemagglutinin virus of Japan | HVJ |
| intraarticular | IA |
| inflammatory bowel disease | IBD |
| inclusion body myositis | IBM |
| immune complex | IC |
| ionized calcium | iCa |
| immunodiffusion | ID |
| isoelectric focusing | IEF |
| immunofluorescence | IF |
| interferon | IFN |