Dear Editor,
Fleiss et al. make several dubious claims in their article[1], but one is of particular interest. Some authors have now begun to rely upon the assertion that the subpreputial wetness contains lysozyme, and suggest that this may help to protect against HIV.[2,3] Although the epidemiological evidence suggests otherwise,[2] our understanding of the mechanisms involved is important, and this claim is worthy of careful examination.
Fleiss et al. rely upon two sources.[4,5] One found lysozyme in apocrine glands, among other enzymes.[5] The other is a case report involving an apocrine gland in the prepuce.[4] However, a more recent pathological study,[6] cited by the authors, found that "unlike true skin of the penile shaft and outer surface of the prepuce, the mucosal surface of the prepuce is completely free of lanugo hair follicles, sweat and sebaceous glands."
If the mucosal surface is completely free of such glands, then it must be the outer surface of the prepuce that benefits from the lysozyme. Indeed, if the prepuce functions as a "one way valve" as the authors assert, the subpreputial moisture would be completely unaffected.
With such weak evidence, the assertion that the subpreputial wetness contains lysozyme must be regarded as an untested hypothesis at best.
References
- Fleiss P, Hodges F, Van Howe RS. Immunological functions of the human prepuce. Sex Trans Infect. 1998;74(5):364-7
- Siegfried N, Muller M, Volmink J, et al. Male circumcision for prevention of heterosexual acquisition of HIV in men (Cochrane Review). The Cochrane Library, issue 3. Oxford: Update Software; 2003.
- Hill G, Denniston GC. HIV and circumcision: new factors to consider. Sex Transm Infect. 2003;79:495-496
- Ahmed A, Jones AW. Apocrine cystodenoma: a report of two cases occurring on the prepuce. Br J Derm. 1969;81:899-901
- Frolich E, Shaumberg-Lever F, Kissen C. Immunelectron microscopic localization of cathepsin B in human apocrine glands. J Cutan Pathol. 1993; 20: 54-60
- Taylor JR, Lockwood AP, Taylor AJ. The prepuce: specialized mucosa of the penis and its loss to circumcision. Br J Urol. 1996;77:591-5
