Background Rheumatoid factor (RF) in SLE is found in around 25% of patients. Authors associate it with cutaneous involvement, Sicca, anti Ro (+) and a protective role in glomerulonephritis (GMN), suggested by the finding of less frequent and less severe nephritis in lupus patients with RF(+) as in patients with RA.
The proposed protective mechanisms of RF include preventing the complement from joining immune-complexes (IC) and avoiding the IC deposit in the glomerulus.
We aimed to determine the clinical and immunological profile of SLE patients with and without RF and to determine the association between RF and GMN.
Methods Descriptive, retrospective study of SLE (SLICC 2012) patients selected from Rheumatology department of Güemes Hospital, from January 2015-August 2018.
We collected data on demographics, cutaneous-articular, renal, hematological and CNS involvement. Immunoserology: RF IgM by immunoturbidimetric (+)>30 UI/ml, anti Ro, anti La, anti Sm, anti RNP (ELISA), ANA (Hep 2), Anti DNA (Crithidia lucilliae), C3, C4, aPL at least one of the following: LI, anti 2GP1 IgG/IgM, Anti aCL IgG/IgM.
Statistical Analysis: Epiinfo version 22.214.171.124.
Results We reviewed 147 clinical histories, 107 with RF ordered. Female 93/107 (86.9%), mean age 41.6 years (SD ±13.8). Disease duration 98 months (SD ±80.6). Tobacco exposure 10/107 (9.35%). RF (+) 22/107 (20.5%), RF median titer 228.8 IU/ml (31–2825 IU/ml).
RF level in patients with GMN was 142 IU/ml (39–191), without GMN 258 IU/ml (31–2825) p=0.46.
RF level in patients with anti Ro (+) was 248 IU/ml (31–2825), Ro (-) 52.5 IU/ml (31–74) p=0.37.
RF (-) subgroup showed statistically significant association with female sex, discoid lesions and aPL presence. RF(+) was associated with Ab Ro, La and patients with RA. (Table 1).
Not found significant association with: rash, photosensivity, oral ulcer, joint pain, arthritis, serositis, neurologic and hematological involvement.
In those with GMN, we found a significant association with Ab Ro(+) in the absence of RF (table 1).
Conclusions Similar RF frequency was found as the published literature. There was no association with nephritis but the mean RF titer was higher in patients without GMN.
The detection of Ab clusters associated with RF may be useful to suggest absence of renal involvement.
Funding Source(s): None
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