Intraepidermal nerve fiber densities in chronic inflammatory autoimmune diseases.
BACKGROUND
Some patients with systemic lupus erythematosus have selective loss of small-diameter nerve fibers, while larger nerve fibers are unaffected.


OBJECTIVE
To determine intraepidermal nerve fiber densities in patients with different chronic inflammatory autoimmune diseases.


METHODS
Cross-sectional study.


METHODS
Stavanger University Hospital, Stavanger, and Haukeland University Hospital, Haukeland, Norway.


METHODS
Sixty patients with systemic lupus erythematosus (SLE) (mean +/- SD age, 43.2 +/- 13.5 years), 61 patients with primary Sjögren syndrome (age, 57.1 +/- 14.7 years), and 52 patients with rheumatoid arthritis (age, 57.4 +/- 12.3 years) were compared with 106 healthy subjects (age, 49.0 +/- 19.6 years).


METHODS
Skin biopsy specimens.


METHODS
To evaluate small-diameter nerve fiber loss, intraepidermal nerve fiber densities were measured in skin punch biopsy specimens obtained from the distal part of the leg.


RESULTS
The mean +/- SD densities were 7.5 +/- 3.8 fibers/mm in patients with SLE, 9.2 +/- 3.8 fibers/mm in primary Sjögren syndrome, and 10.9 +/- 5.4 fibers/mm in rheumatoid arthritis vs 12.4 +/- 4.6 fibers/mm in healthy subjects. Densities were significantly less in patients with SLE vs patients with rheumatoid arthritis and vs healthy subjects (P<.001 for both), as well as in patients with primary Sjögren syndrome vs healthy subjects (P<.001). Eight patients (13%) with SLE, 2 patients (3%) with primary Sjögren syndrome, and 2 patients (4%) with rheumatoid arthritis had densities below the lower reference limit of 3.4 fibers/mm, consistent with small-diameter nerve fiber neuropathy.


CONCLUSIONS
The degree of loss of small-diameter nerve fibers differs among patients with these chronic inflammatory autoimmune diseases, likely reflecting differences in pathogenesis and organ affinity of the individual disease entities.
Gøransson
Lasse G
LG
Clinical Immunology Unit, Department of Internal Medicine, Stavanger University Hospital, Stavanger, Norway. gola@sus.no
Brun
Johan G
JG
Harboe
Erna
E
Mellgren
Svein I
SI
Omdal
Roald
R
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis / Q000473:pathology; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000473:pathology*; D001369:Axons / Q000473:pathology; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D018450:Disease Progression; D004817:Epidermis / Q000294:innervation / Q000473:pathology*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000473:pathology; D011984:Sensory Receptor Cells / Q000473:pathology*; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000473:pathology