Reduced prevalence of allergic disease in patients with multiple sclerosis is associated with enhanced IL-12 production.
BACKGROUND
We previously showed that the prevalence of allergic disease is decreased in patients with multiple sclerosis (MS); however, the mechanisms that explain this finding have not previously been defined.


OBJECTIVE
We have demonstrated that protection of patients with MS from allergic disease may be caused by the production in monocytes from these patients of elevated quantities of IL-12 compared with that observed in monocytes from individuals with allergies.


METHODS
Purified monocytes from peripheral blood of subjects with or without allergies and from individuals with MS were directly stimulated with Staphylococcus aureus Cowan strain I in the absence of T cells. IL-12 was quantitated by a sensitive reverse transcription, competitive PCR.


RESULTS
IL-12 production was 5-fold greater in monocytes from patients with MS (n = 11) than that from individuals with allergies (n = 10) (for subjects with MS, 1.90+/-0.18 vs 1.24+/-0.19 log10 fmol/microL for individuals with allergies) (P = .02). Although the production of IL-12 in monocytes from patients with MS was slightly higher than that from subjects without allergies, this difference was not statistically significant.


CONCLUSIONS
IL-12 production in individuals with MS is much greater than in individuals with allergies. Because IL-12 induces TH1 cytokine synthesis and reduces the production of TH2 cytokines, which amplify and prolong allergic inflammation, these studies suggest that enhanced IL-12 production may protect individuals with MS from the development of allergy but may predispose such individuals toward autoimmune inflammation in the central nervous system.
Department of Pediatrics, Stanford University, Calif 94305-5208, USA.
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L
Tang
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S
Benjaponpitak
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RH
DeKruyff
D T
DT
Umetsu
D000328:Adult; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000276:immunology*; D007370:Interferon Type I / Q000494:pharmacology; D018664:Interleukin-12 / Q000096:biosynthesis* / Q000097:blood; D015847:Interleukin-4 / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D009103:Multiple Sclerosis / Q000097:blood* / Q000276:immunology*; D015995:Prevalence; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000276:immunology
D007370:Interferon Type I; D012333:RNA, Messenger; D011994:Recombinant Proteins; D018664:Interleukin-12; D015847:Interleukin-4