Systemic lupus erythematosus and rheumatoid arthritis

 
Table 2.
The American College of Rheumatology 1987 criteria for the classification of RA. 
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Patients fulfilling 
≥
4 of the criteria are diagnosed with RA. Criterion 1-4 must have been present 
for at least 6 weeks 
Criterion Definition 
1. Morning stiffness 
Morning stiffness in and around the joints, 
lasting at least 1 hour until maximal 
improvement 
2. Arthritis of 3 or more joint 
areas 
Fluid or soft tissue swelling of at least 3 
defined joint areas simultaneously 
3. Arthritis of hand joints 
At least 1 area swollen in a wrist, MCP or 
PIP joint 
4. Symmetric arthritis 
Simultaneous involvement of defined joint 
areas of both sides of the body 
5. Rheumatoid nodules 
Subcutaneous nodules 
6. Serum rheumatoid factor 
Abnormal amounts of serum rheumatoid 
factor detected by any method in which 
95% of control subjects are negative
7. Radiographic changes 
Erosions or periarticular decalcification on 
hand or wrist radiographs 
MCP=Metacarpophalangeal joints, PIP=Proximal interphalangeal joints 
The disease can present with systemic manifestations, including subcutaneous 
nodules, pleuritis, pericarditis and vasculitis, which contribute to the morbidity 
and mortality.
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The disease has, in most untreated cases, a severe outcome with 
joint destruction. An increased co-morbidity, particularly cardiovascular, with 
an increased mortality has been shown in a large number of studies.
62; 63
Overall disease activity is assessed by the disease activity score in 28 joints 
(DAS28), which is calculated based on the number of swollen joints, the 
number of tender joints, the erythrocyte sedimentation rate, and the patients 
global assessment of the disease.
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The response to treatment is assessed 
according to the ACR criteria, which is based on five criteria; patient 
assessment, physician assessment, pain scale, disability/functional 
questionnaire, and erythrocyte sedimentation rate.
65; 66
ACR20/50/70 is defined 
as at least a 20/50/70% improvement of the number of swollen and tender joints 
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or at least a 20/50/70% improvement of three of the five ACR criteria 
mentioned above. 
In the joints, there is an inflammation in the lining of the joint, 
i.e.
, the synovial 
membrane. The synovium becomes hyperplastic and there is an infiltration of 
CD4+ T-cells. B-cells and DCs aggregate with the T-cells resulting in a local 
immunoglobulin (Ig) production of auto-antibodies and the formation of 
immune complexes. The auto-antibodies are believed to recognize articular 
antigens, 
e.g.
, type II collagen and proteoglycans, or normal immunoglobulins 
(Ig).
67
The synovium grows in a malignancy-manner extending to the cartilage 
and destroying the underlying tissue.
The auto-antibodies with the highest specificity and sensitivity for RA are the 
rheumatoid factors (RFs) and the anti-citrullinated protein/peptide antibodies 
(ACPAs). RFs recognize the Fc portion of IgG isotype immunoglobulins and 
their presence is included in the ACR criteria for the diagnosis of RA (Figure 
6). RF is generally of IgM isotype but may also exist as either IgA and IgG 
isotype.
68