Laboratory studies include chest roentgenogram, complete and differential blood cell counts, serum electrolytes, serum protein electrophoresis, erythrocyte sedimentation rate, tuberculin skin test (50), antinuclear antibody, C-reactive protein, venereal disease research laboratory test, serum antibody tests for herpes simplex virus I and II, herpes zoster virus, cytomegalovirus, rubella and measles and serological tests associated with syphilis, toxoplasmosis, systemic lupus erythematosus or rheumatoid arthritis. This evidence concerns the gene CRP and rheumatoid arthritis.