Open Access Short Report

Positive correlation between circulating cathelicidin antimicrobial peptide (hCAP18/LL-37) and 25-hydroxyvitamin D levels in healthy adults

Brian M Dixon1, Tyler Barker2, Toni McKinnon1, John Cuomo1, Balz Frei3, Niels Borregaard4 and Adrian F Gombart3*

Author affiliations

1 USANA Health Sciences, Inc, 3838 West Parkway Boulevard, Salt Lake City, UT 84120, USA

2 Sport Science Department, The Orthopedic Specialty Hospital, Murray, UT 84107, USA

3 Linus Pauling Institute and Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA

4 The Granulocyte Research Laboratory, Department of Hematology, National University Hospital, Copenhagen, Denmark

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Citation and License

BMC Research Notes 2012, 5:575  doi:10.1186/1756-0500-5-575

Published: 24 October 2012



Transcription of the cathelicidin antimicrobial peptide (CAMP) gene is induced by binding of the bioactive form of vitamin D, 1,25-dihydroxyvitamin D, to the vitamin D receptor. Significant levels of the protein hCAP18/LL-37 are found in the blood and may protect against infection and/or sepsis. We hypothesized that serum vitamin D levels may modulate the circulating levels of hCAP18. Only three studies have shown a positive correlation between circulating 25-hydroxyvitamin D and hCAP18 levels. Here we provide additional evidence for such a correlation in healthy, middle-aged adults.


Serum levels of 25-hydroxyvitamin D [25(OH)D] and plasma levels of hCAP18 were determined in 19 healthy middle-aged (mean of 50.1 years) adult men and women. Plasma hCAP18 concentrations correlated with serum 25(OH)D concentrations in subjects with 25(OH)D levels ≤ 32 ng/ml (r = 0.81, p < 0.005) but not in subjects with concentrations > 32 ng/ml (r = 0.19, p = 0.63).


We conclude that plasma hCAP18 levels correlate with serum 25(OH)D levels in subjects with concentrations of 25(OH)D ≤ 32 ng/ml as opposed to those with concentrations > 32 ng/ml and that vitamin D status may regulate systemic levels of hCAP18/LL-37.

Vitamin D; 25-hydroxyvitamin D; Cathelicidin; hCAP18; LL-37; Immunity; Serum; Plasma; CAMP; Infection