Re: Are serological chlamydia specific markers useful to detect asymptomatic cases of LGV proctitis?
Recently we concluded that an elevated IgA antibody response and the age of the infected individual (a total sum score of seven times IgA titre plus individual's age greater than or equal to 50.0) appeared to be of diagnostic value for (early) detection of LGV proctitis.1 Statistical analyses showed that the use of this total sum score had high diagnostic accuracy. As published previously, over 85% of the Rotterdam population of patients with L2 proctitis reported symptoms (rectal discharge and bleeding) and more than 70% had clinical manifestations (discharge and perianal erythema).2
We agree with Henry J. de Vries and co-workers and acknowledge the need for 'simple and affordable diagnostic procedures to screen the (asymptomatic) population at risk'.3 Our data show that Chlamydia-specific IgA antibody titers can be adequately used for the early discrimination between LGV and non-LGV proctitis, a clear reflection of the more invasive character of the LGV serovars.1 Therefore, one might postulate that our sum score can not serologically discriminate between LGV and non-LGV serovars in persons without mucosal abnormalities. After all, there must be at least some degree of tissue invasion (together with visible mucosal abnormalities, such as erythema or ulceration), before a significant antibody response can be mounted.
De Vries et al. did not use the same test as we did in our study. Although both tests use synthetic peptides and a similar format, the test we used, the Savyon test, incorporates more LGV-specific epitopes. In theory, the Sayvon test should be more specific for LGV diagnosis. The conclusion of De Vries et al. that serology in general is of no diagnostic value is premature. The correct conclusion is that the Medac test might not be suitable for LGV diagnostic purposes.
We reanalyzed the data of the 24 Rotterdam patients with LGV proctitis. Only one patient reported no symptoms and had no clinical manifestations of proctitis on examination (patient A). Three patients had symptoms although no clinical manifestations were seen in proctoscopic examination (patient B, C and D). One patient had no symptoms while a mucosal ulcer was seen at proctoscopy (patient E). The total sum score in all rectal LGV patients ranged from 47.7 to 96.2 with a median score of 61.7. Two of the LGV patients did not fulfill the criterion of a score greater than or equal to 50.0 as was reported in our paper.1 Patient A had a sum score of 63.5, just above the median score. Patient B, C and D had a sum score of 55.8, 71.6 and 87.7 respectively. Patient E had a sum score of 68.2. The age of patient A to E did not differ from the other rectal LGV patients (p = 0.19). Though numbers are small, there seems to be no relation between self-reported symptoms, clinical manifestations on proctoscopy and our sum score in the Rotterdam LGV patients. Other researchers also recommend the use of serology.4,5,6,7
The conclusion of our paper was that an increased IgA antibody response and the age of the infected individual are of possible diagnostic value for (early) detection of LGV proctitis.1 Simply put: if you find a high titer you have a high chance for LGV. We do not, however, recommend testing for IgA in order 'to exclude LGV' as suggested by De Vries et al.
In conclusion: a total sum score of seven times IgA titer plus individual's age greater than or equal to 50.0 appeared to be a simple,accurate and affordable diagnostic procedure to discriminate between chlamydial proctitis with serovar L2 and non-LGV serovars in a high-risk population of MSM and is of possible diagnostic value for (early) detection of LGV proctitis, even in the absence of symptoms.
1. Van der Snoek EM, Ossewaarde JM, Van der Meijden WI, Mulder PGH, Thio HB. The use of serologic titers of IgA and IgG in (early) discrimination between rectal infection with non-LGV and LGV serovars of Chlamydia trachomatis. Sex Transm Infect 2007;83:330-4.
2. Waalboer R, Van der Snoek EM, Van der Meijden WI, Mulder PGH, Ossewaarde JM. Analysis of rectal Chlamydia trachomatis serovar distribution including L2 (lymphogranuloma venereum) at the Erasmus MC STI clinic, Rotterdam. Sex Transm Infect 2006;82:207-11.
3. De Vries HJ, Smelov V, Morré SA. Electronic letter, Sex Transm Infect 28 augustus 2007.
4. Forrester B, Pawade J, Horner P. The potential role of serology in diagnosing chronic lymphogranuloma venereum (LGV): a case of LGV mimicking Crohn's disease. Sex Transm Infect 2006;82:139-40.
5. Halioua B, Bohbot JM, Monfort L, Nassar N, de Barbeyrac B, Monsonego J, Sednaoui P. Ano-rectal lymphogranuloma venereum: 22 cases reported in a sexually transmitted infections center in Paris. Eur J Dermatol 2006;16:177-80.
6. Spornraft-Ragaller P, Luck C, Straube E, Meurer M. Lymphogranuloma venereum. Two cases from Dresden. Hautarzt 2006;57:1095-100.
7. Den Hollander JG, Ossewaarde JM, de Marie S. Anorectal ulcer in HIV patients, don't forget lymphogranuloma venereum! AIDS 2004;18:1484-5.
E.M. van der Snoek,
W.I. van der Meijden,
P.G.H. Mulder and H.B. Thio
Eric M. van der Snoek,
Department of Dermatology and Venereology,
Erasmus MC, Rotterdam, the Netherlands.