Regarding rheumatoid ahritis, all of the following statements are true except-
The cricoarytenoid joint may be involved
HLA-D4 and HLA-DR4 are positive in patients with seropositive rheumatoid ahritis
Subcutaneous nodules are more frequent in seronegative patients
Diffuse intestinal fibrosis and pneumonitis may occur
Rheumatoid nodules occur almost exclusively in RF or ACPA positive patients, usually in extensor tendons . Theyare frequently asymptomatic but some may be complicated by ulceration and secondary infection . Ref Davidsons 23e p1023,1024
Immune system