Total skin electron beam therapy for cutaneous T-cell lymphomas in the Netherlands: A retrospective analysis of treatment outcomes and selection for high or low dose schedule.

PURPOSE: Total skin electron beam therapy (TSEBT) is used mostly in the treatment of cutaneous T cell lymphoma. In this study we describe the results of TSEBT applied in the Netherlands using two different schedules, a conventional dose schedule of 35 Gy and a low-dose schedule of 12 Gy. We aimed to evaluate the treatment results in and compare treatment outcomes between the two treatment groups and to further define indications for both doses. METHODS: In the LUMC, Leiden, we performed a retrospective analysis of 51 patients treated with TSEBT between January 2008 and December 2018, with follow-up untill December 2019. Thirty one patients were treated with 35 Gy and twenty with 12 Gy. The dose was chosen based on the severity of skin involvement. Outcome measures were time to meaningful progression, survival, response rate and toxicity. RESULTS: Time to meaningful progression was 5.1 months with no significant differences between dose groups (P = 0.77). Overall survival was 27.4 months. Both time to progression and survival were significantly better for T2 vs T3 stage. Overall response rate was 80.4 %. Both dose groups showed improvement of symptoms. Treatment was generally well tolerated. CONCLUSIONS: Both high-dose and low-dose TSEBT offer similar results for TMP and OS. It remains unclear which patients benefit most from a high-dose schedule. We propose to use the low-dose schedule as a standard for TSEBT and use supplementary boosts or escalation to high-dose treatment for patients unresponsive to the low-dose schedule.

HPV type-specific distribution among family members and linen in households of cutaneous wart patients.

BACKGROUND: Common and plantar warts are caused by human papillomaviruses (HPV). Mode of transmission of wart HPVs within families is largely unknown. OBJECTIVE: To demonstrate similarity of HPV type(s) among wart cases, family members and household linen. METHODS: In a cross-sectional study, swabs taken from 123 warts and foreheads of 62 index patients and 157 family members and from 58 kitchen towels and 59 bathroom mats were tested for DNA of 23 cutaneous wart-associated HPV types. Generalized estimating equations (GEE) were used to estimate the chance of detecting the same HPV type as was found in the index patients on the family contacts and on the kitchen towels and bathroom mats. RESULTS: HPV1, HPV2, HPV27 and HPV57 were the most prevalent types in the warts of the index patients. Altogether, 60 (42.3%) of the 142 family members without warts had HPV DNA on their foreheads. When HPV1 and HPV2 were found in the warts, these types were also frequently (>50%) found on the foreheads of index patients and their family members, as well as on the kitchen towels and the bathroom mats. HPV27 and HPV57 were less frequently found (<25%) on foreheads and linen. No associations were found for age, sex and site of HPV DNA presence. CONCLUSION: Dissemination of skin wart-causing HPV types, from wart cases to household contacts and linen, such as kitchen towels and bathroom mats, is more likely for HPV1 and HPV2 than for HPV27 and HPV57. The role of towels and bathroom mats in HPV transmission deserves further investigation.

Quality of life in patients with Mycosis Fungoides and Sézary Syndrome: a systematic review of the literature.

Cutaneous T-cell Lymphoma's (CTCL) are a rare, heterogeneous group of T-cell lymphomas that primarily manifest in the skin. Mycosis fungoides (MF) and Sézary syndrome (SS) are considered the classic types of CTCL. The diverse manifestation of CTCL results in a wide range of symptoms with a possible mild to severe impact on Quality of Life (QoL) depending on the disease stage. Previous studies on QoL in CTCL patients report diverse patient populations and use many different QoL instruments. In the current literature, a clear overview on the influence of the different stages of disease (early MF, late-stage MF/SS or total group) on the QoL is lacking. Therefore, a systematic search of the literature was conducted using the PubMed, Embase, PsycINFO and Web of Science databases. Studies were included if they described QoL in patients with MF and SS retrieved by standardized instruments or qualitative interviews. In total, 24 studies were included using 18 different questionnaires to report on dermatology-specific, cancer-specific and generic QoL. The effect on QoL was found to be greater in patients with late-stage disease as compared to early stage disease, with significant impairments on functional, emotional and physical domains. Nonetheless, even in patients with limited disease, QoL was mildly to moderately affected. Overall, pruritus was the most frequent reported and most bothersome symptom. Significant influence of the disease on daily life activities were found, not only in patients but also on caregivers and family. This broad, structured overview on QoL in MF and SS patients underlines the influence of disease stage on QoL, and therefore, recommends future studies to distinguish between disease stages when reporting results. Furthermore, this overview can inform clinicians in clinical practice by creating awareness of QoL deficits according to disease stage.

Serum and cutaneous transcriptional expression levels of IL31 are minimal in cutaneous T cell lymphoma variants.

AIM: Recent studies suggested a role for IL31 in the pathogenesis of pruritus and disease severity in patients with cutaneous T cell lymphomas (CTCL). However, discrepant results were reported for IL31 serum levels, transcriptional expression levels or immunohistochemistry studies and its relation to pruritus intensity and/or disease severity in CTCL. Most studies did not distinguish between different CTCL variants. We investigated IL31 serum levels in different subtypes of CTCL, including Mycosis Fungoides (MF) (typically not pruritic), Folliculotropic Mycosis Fungoides (FMF) and Sézary syndrome (SS) (both often pruritic). METHODS: From 54 CTCL patients (17 SS, 21 FMF and 16 classic MF) serum samples were analyzed with a high sensitivity V-PLEX immunoassay for IL31. The study group included 35/54 (65%) patients with complaints of pruritus. Thirty-five patients had advanced stage disease (≥stage IIB). A visual analog scale score (VAS score) for pruritus was available in 29 CTCL patients (7 SS, 9 FMF and 13 classic MF) and in other cases complaints of pruritus were retrieved from medical records. qPCR analyses for IL31 expression were performed in lesional skin biopsies from 8 CTCL patients. Serum samples from 4 healthy individuals without pruritus and from 5 atopic dermatitis (AD) patients with severe pruritus were included as controls. RESULTS: In 11/54 (20%) of CTCL patients low serum levels of IL31 were detected (mean 0.48 pg/mL, range 0.20-1.39 pg/mL) including 6/17 (35%) SS patients (mean 0.57 pg/mL) and 5/21 (24%) FMF patients (mean 0.33 pg/mL). All 11 patients with detectable levels of IL31 reported complaints of moderate to severe pruritus and 9/11 patients presented with advanced stage disease (≥IIB). qPCR analyses resulted in lowly expressed IL31 expression levels in 4 of 8 patients; these patients all suffered from pruritus and advanced stage disease. CONCLUSIONS: Translational and transcriptional expression levels of IL31 were very low or undetectable in CTCL patients. Detectable low IL31 serum levels were exclusively observed in SS and FMF patients and not in patients with classic MF. However, these marginal IL31 levels in a small proportion of CTCL patients do not support an essential role for IL31 in CTCL patients.

Frequency and prognosis of associated malignancies in 504 patients with lymphomatoid papulosis.

BACKGROUND: Lymphomatoid papulosis (LyP) can be associated with other haematological malignancies (HM), but reported percentages vary from 20% to over 50%. OBJECTIVE: To evaluate the frequency and prognostic significance of associated HM and non-HM in LyP patients. METHODS: In this multicentre cohort study, the complete Dutch LyP population was included from the Dutch Cutaneous Lymphoma Registry between 1985 and 2018. Clinical and histopathological information was retrieved from every individual patient. RESULTS: After a median follow-up of 120 months (range, 6-585), an associated HM was observed in 78/504 (15.5%) patients. Most common associated HM were mycosis fungoides (MF; n = 31) and anaplastic large-cell lymphoma (ALCL; n = 29), while 19 patients had another HM of B-cell (n = 14) or myeloid origin (n = 5). Even after a 25-year follow-up period, percentages of associated HM did not exceed 20%. Thirty-nine of 465 patients (8.4%) without a prior or concurrent associated HM developed an associated HM during follow-up, after a median of 68 months (range of 3-286 months). Nine of 78 patients died of associated HM, including 6/22 patients developing extracutaneous ALCL, while all patients with associated MF or skin-limited ALCL had an excellent prognosis. Compared with the general population, LyP patients showed an increased risk (relative risk, 2.8; 95% confidence intervals, 2.4-3.3) for non-HM, in particular cutaneous squamous cell carcinoma, melanoma and intestinal/lung/bladder cancer. CONCLUSIONS: An associated HM was reported in 15.5% of the LyP patients, particularly MF and ALCL. Although the frequency of associated HM is lower than suggested and the prognosis of most patients with associated HM is excellent, a small subgroup will develop aggressive disease, in particular extracutaneous ALCL. Furthermore, LyP patients have a higher risk of developing other malignancies. Clinicians should be aware of these risks, and LyP patients require close monitoring.

Evaluation of treatment results in multifocal primary cutaneous anaplastic large cell lymphoma: report of the Dutch Cutaneous Lymphoma Group.

BACKGROUND: There is no consensus on the treatment of multifocal primary cutaneous anaplastic large cell lymphoma (C-ALCL). Radiotherapy (RT) and methotrexate (MTX) are the current treatment options, but their efficacy is unknown. Recently, targeted therapies showed promising results in C-ALCL, and may therefore be an attractive first choice of treatment. OBJECTIVES: To assess the efficacy of conventional treatment strategies for patients with multifocal C-ALCL, and to define which patients may require novel targeted therapies. METHODS: In this multicentre study, treatment was evaluated in patients initially presenting (n = 24) or relapsing with multifocal C-ALCL (n = 17; 23 relapses). Distinction was made between patients with five or less lesions (n = 36) and more than five lesions (n = 11). RESULTS: Treatments most commonly used were RT (n = 21), systemic chemotherapy (n = 9) and low-dose MTX (n = 7) with complete response rates of 100%, 78% and 43%, respectively, and an overall response rate of 100%, 100% and 57%, respectively. Four patients showed complete spontaneous regression. In total, 16 of 24 patients (67%) first presenting with multifocal C-ALCL relapsed, including all five patients initially treated with CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone). Compared with patients presenting with two to five skin lesions, patients presenting with more than five lesions had a higher chance of developing extracutaneous relapse (56% vs. 20%) and more often died of lymphoma (44% vs. 7%). CONCLUSIONS: Patients with five or less lesions should be treated with low-dose RT (2 × 4 Gy). Maintenance low-dose MTX (20 mg weekly) is a suitable option in patients with more than five lesions. Targeted therapies may be considered in rare patients who are refractory to MTX or patients developing extracutaneous disease.

Developing and validating the Cutaneous WARTS (CWARTS) diagnostic tool: a novel clinical assessment and classification system for cutaneous warts.

BACKGROUND: The clinical appearance of cutaneous warts is highly variable and not standardized. OBJECTIVES: To develop and validate a reproducible clinical tool for the standardized assessment of cutaneous warts to distinguish these lesions accurately. METHODS: Nine morphological characteristics were defined and validated regarding intra- and interobserver agreement. Based on literature and semistructured interviews, a systematic dichotomous assessment tool, the Cutaneous WARTS (CWARTS) diagnostic tool was developed. The validation consisted of two independent parts performed with photographs from the recent WARTS-2 trial. In part A, the CWARTS diagnostic tool was tested by 28 experienced physicians who assessed photographs of 10 different warts to investigate interobserver concordance. In part B, morphological characteristics were validated by masked and independent scoring of 299 photographs by six different observers. Part B also entailed reassessment of the photographs after at least 1 week. The primary outcome measurement was the intraclass correlation coefficient (ICC). RESULTS: Presence of black dots (capillary thrombosis) had the greatest ICC (0·85) for interobserver agreement in part A, followed by arrangement (0·65), presence of border erythema (0·64) and sharpness of the border (0·60). In part B, results were similar for interobserver agreement with presence of black dots having the highest ICC (0·68), followed by border erythema (0·64), arrangement (0·58) and colour (0·55). For intraobserver agreement, presence of black dots had the highest agreement (0·70), followed by presence of border erythema (0·694) and colour (0·59). CONCLUSIONS: Wart phenotype can be reliably assessed using the CWARTS diagnostic tool.

Morphological characteristics and human papillomavirus genotype predict the treatment response in cutaneous warts.

BACKGROUND: Cutaneous warts have a cure rate after therapy of no more than approximately 50%. Recently, we developed and validated a standard assessment tool for warts (Cutaneous WARTS diagnostic tool, CWARTS) based on phenotypical characteristics. OBJECTIVES: To assess whether patient and morphological wart characteristics predict the human papillomavirus (HPV) type in a specific wart and whether these characteristics as well as the HPV type predict a favourable treatment response. METHODS: Photographs were used to score nine morphological wart characteristics using the newly developed CWARTS tool. Genotyping of 23 wart-associated HPV types was performed using the hyperkeratotic skin lesion-polymerase chain reaction/multiplex genotyping assay. The results were correlated with a favourable response to treatment with monochloroacetic acid, cryotherapy or a combination of cryotherapy and salicylic acid. Odds ratios were calculated using logistic regression in a generalized estimating equations model. RESULTS: Black dots (capillary thrombosis) strongly predicted the presence of any HPV type in a wart. From all characteristics tested, the HPV type most strongly predicted the treatment response when the warts were treated with monochloroacetic acid or a combination of cryotherapy and salicylic acid with a significantly decreased treatment response if the warts contained HPVs of the alpha genus (HPV2, HPV27 or HPV57). When cryotherapy alone was used for common warts, HPV type did not play a role, but cryotherapy was less effective in the presence of callus and when the wart was located deeper in the skin. CONCLUSIONS: Morphological characteristics of the warts and the HPV genotype influence treatment outcome and thus potentially influence future treatment decisions for common and plantar warts.

Low- and high-risk human papillomavirus genotype infections in intra-anal warts in HIV-positive men who have sex with men.

BACKGROUND: Anogenital warts are often presumed to represent nondysplastic or low-grade anal intraepithelial neoplasia (LGAIN). We previously demonstrated that up to 20% of intra-anal warts in HIV-positive men who have sex with men (MSM) contain regions of high-grade AIN (HGAIN). OBJECTIVES: To determine the causative human papillomavirus (HPV) types of low- and high- grade dysplastic areas in warts from HIV-positive MSM. METHODS: A total of 42 intra-anal warts from 41 HIV-positive MSM were graded as nondysplastic, LGAIN or HGAIN. Whole-tissue sections (WTS) were analysed with the SPF10 polymerase chain reaction/LiPA25 HPV genotyping system. If the WTS contained multiple HPV types, dysplastic regions were isolated by laser capture microdissection (LCM) for HPV genotyping. RESULTS: Overall, 38 of 42 (91%) WTS tested positive for HPV DNA. Of these, 23 (61%) contained a single HPV type and 15 (39%) contained multiple HPV types. All LCM-selected regions contained no more than one HPV type. Ten of 42 (24%) WTS contained HGAIN disease, of which six (60%) were associated with a high-risk HPV (hrHPV) genotype. Twenty-three of 42 WTS contained LGAIN disease, of which two (9%) were associated with hrHPV. AIN lesions containing hrHPV types were identified using p16 staining. CONCLUSIONS: LGAIN lesions can be caused by high-risk HPV genotypes and vice versa. We therefore recommend routine follow-up and treatment of all dysplastic intra-anal warts for HIV-positive MSM.

High prevalence of cutaneous warts in elementary school children and the ubiquitous presence of wart-associated human papillomavirus on clinically normal skin.

BACKGROUND: One-third of Dutch primary school children have cutaneous warts; each year around 20% of them seek medical treatment. However, little is known about the epidemiology of the types of human papillomavirus (HPV) causing these warts. OBJECTIVES: To investigate the distribution of cutaneous wart-associated HPV types in three primary school classes by analysing skin swabs taken from warts, and the forehead, hand dorsum and sole of the foot of included children. METHODS: Using the hyperkeratotic skin lesion polymerase chain reaction/multiplex genotyping assay, each swab sample was used to genotype for 23 cutaneous wart-associated HPV types. RESULTS: Thirty-one (44%) of the 71 children had a total of 69 warts, with a maximum of six warts per child. In the wart swabs, HPV2, HPV27 and HPV57, members of Alphapapillomavirus species 4, were most frequently detected (27%, 32% and 14%, respectively), whereas HPV1 was only found in two plantar warts. The prevalence of HPV carriage, detected in swabs of clinically normal skin of the forehead, left hand and left sole was 80%, with the most prevalent types being HPV1 (59%), HPV2 (42%), HPV63 (25%) and HPV27 (21%). CONCLUSIONS: Cutaneous wart-associated HPV types were highly prevalent in primary school children, but did not correlate with the HPV types in warts. In contrast to the existing literature, HPV1 was frequently detected on clinically normal skin but was much less frequent in warts.

Characterization of skin lesions induced by skin-tropic α- and ß-papillomaviruses in a patient with epidermodysplasia verruciformis.

Epidermodysplasia verruciformis (EV) is a rare, lifelong, autosomal recessive skin disease associated with an unusual susceptibility to infections with ubiquitous ß-human papillomaviruses (ß-HPVs), and in some cases also skin-tropic α genotypes. In this case report, HPV infection patterns were correlated with pathology and clinical manifestations of skin lesions from a patient with EV, without loss-of-function mutations in the EVER genes. HPV infection was investigated by both polymerase chain reaction (PCR) and laser capture microdissection (LCM) PCR, alongside immunofluorescence for the viral proteins E4 and L1. Analysis of eyebrow hair bulbs revealed multiple ß-genus HPV infections, including HPV20 and HPV24, which were consistently found in all 11 skin lesions on the patient. Six lesions were also positive for the skin tropic α-genotype, HPV27. Clear-cut differences between two wart-like lesions, one caused by a skin-tropic α-genotype and the other by ß-genotypes (as detected by LCM PCR) are shown, including the high cellular proliferation rate in ß-HPV-induced lesions. Widespread expression of the early protein E4 was also evident in skin lesions positive for HPV20 by LCM PCR in both tumours and nearby intraepidermal proliferative areas. L1 expression was restricted to areas of intraepidermal proliferation showing productive infection. The patient's inability to control HPV infections is conclusive to the uncontrolled replication of few genotypes from both α and ß genera, which cause proliferative lesions with clear-cut clinical and histological features.

Serogroup distribution of urogenital Chlamydia trachomatis in urban ethnic groups in The Netherlands.

The prevalence of Chlamydia trachomatis varies between ethnic groups in The Netherlands. It is, however, unknown whether this is associated with specific serogroups. The objective of this study was to determine whether serogroup distribution is associated with ethnic origin in the region of The Hague, The Netherlands. Serogroups of 370 microbiologically confirmed C. trachomatis-positive samples were analysed. The samples were obtained from 247 women and 123 men between January and October 2008, of self-reported Dutch Caucasian, Dutch Antillean, Surinamese, N. African/Turkish or other descent. We observed a difference in serogroup distribution comparing Dutch Caucasian women to Dutch Antillean women (χ2 for distribution P = 0·035). Serogroup C was more common in Dutch Antillean women, whereas serogroup B was less common (P = 0·03). This difference was not observed for Dutch Antillean men. The observed difference in distribution of C. trachomatis serogroups between ethnic groups is relevant for further transmission studies.

A misleading urethral smear with polymorphonuclear leucocytes and intracellular diplococci; case report of urethritis caused by Neisseria meningitidis.

The primary pathogens found in men with urethritis are Chlamydia trachomatis and Neisseria gonorrhoeae. Rapid diagnosis of N. gonorrhoeae infection can be made based on a Gram- or methylene blue-stained urethral smear. We describe a case of a man with purulent penile discharge, in which microscopic examination led to the presumptive diagnosis of gonorrhoea. A nucleic acid amplification test was negative for N. gonorrhoeae but positive for C. trachomatis. Culture showed Gram-negative diplococci which were identified as Neisseria meningitidis. N. meningitidis can be sporadically pathogenic in the genito-urinary tract and mimicks gonococcal urethritis, and appears identical by microscopy. When a gonococcal urethritis is suspected based on clinical signs and microscopic examination, but investigatory tests cannot confirm the diagnosis, a N. meningitidis infection should be considered.

Analyses of multiple-site and concurrent Chlamydia trachomatis serovar infections, and serovar tissue tropism for urogenital versus rectal specimens in male and female patients.

OBJECTIVES: The aims of this study were: to determine the incidence of concurrent infections on a serovar level; to determine the incidence of multiple anatomical infected sites on a detection and genotyping level and analyse site-specific serovar distribution; to identify tissue tropism in urogenital versus rectal specimens. METHODS: Chlamydia trachomatis-infected patients in two populations were analysed: 75 visiting the outpatient department of obstetrics and gynaecology of the MC Haaglanden, and 358 visiting the outpatient sexually transmitted disease clinic, The Hague, The Netherlands. The PACE 2 assay (Gen-Probe) was used to detect C trachomatis from urethral, cervical, vaginal, oropharyngeal and anorectal swabs. C trachomatis genotyping was performed on all C trachomatis positive samples, using the CT-DT genotyping assay. RESULTS: Samples from 433 patients (256 female and 177 male) with confirmed C trachomatis infection were analysed. In 11 patients (2.6%), concurrent serovars in one anatomical sample site were present. In 62 (34.1%) female and four (9.3%) male patients, multiple sample site infections were found. A substantial percentage of women tested at the cervical/vaginal and rectal site were found to be positive at both sites (36.1%, 22/61). In men, D/Da and G/Ga serovars were more prevalent in rectal than urogenital specimens (p=0.0081 and p=0.0033, respectively), while serovar E was more prevalent in urogenital specimens (p=0.0012). CONCLUSIONS: The prevalence of multiple serovar infections is relatively low. Significant differences in serovar distribution are found in rectal specimens from men, with serovar G/Ga being the most prominent, suggesting tissue tropism.

Comparison of three genotyping methods to identify Chlamydia trachomatis genotypes in positive men and women.

Chlamydia trachomatis (Ct) comprises 3 serogroups and 19 serovars. Different genotyping methods are available to differentiate between the serovars. The aim of this study was to evaluate the sensitivity and discriminatory power of three genotyping methods, respectively Omp1 sequencing, the Ct Detection and genoTyping (DT) assay and the pmpH real-time PCR discriminating an LGV infection from a non-LGV infection. In total, 50 Aptima Combo 2 (AC2) Ct positive samples were selected and tested with the 3 genotyping methods. The Ct-DT assay detected 3 double Ct infections that caused a non interpretable result by Omp1 sequencing, while Omp1 sequencing has a higher discriminatory power that gave additional information about Ct genovariants. All three methods detected the 6 LGV samples. Although the pmpH real-time PCR detected all LGV infections, a substantial amount (24%) of non-LGV infections were missed. The sensitivity compared to AC2 Ct detection was 80% (95% CI 67-89%) for the Ct-DT assay, 72% (95% CI 58-83%) for Omp1 sequencing and 64% (95% CI 50-76%) for the pmpH real-time PCR. In conclusion, the Ct-DT assay is appropriate for serovar distribution studies, epidemiological studies and differentiation between an LGV and non-LGV Ct infection, while Omp1 sequencing is more appropriate for phylogenetic studies. The pmpH real-time PCR is suitable as second assay to differentiate between an LGV and non-LGV infection, but not as primary detection assay, due to its low sensitivity for non-LGV strains.

Chlamydia trachomatis serovar distributions in Russian men and women: a comparison with Dutch serovar distributions.

The data on serovar distributions of Chlamydia trachomatis - the most diagnosed sexually transmitted infection (STI) worldwide - are important for epidemiologic purposes and transmission studies but are completely lacking in Russia. The aim of the current study is to determine the serogroup and serovar distributions in Russian men and women and compare these data with Dutch serogroup and serovar distributions. In Russian men and women, serogroup B was the most prevalent (46%), followed by the intermediate serogroup (I group; 33%) and serogroup C (21%). The distribution was comparable between men and women. The serogroup distribution was similar to the previously published distribution in Dutch cohorts. However, on a serovar level statistically very significant differences were observed, reaching up to P < 0.0001. The serovars B and G/Ga had higher prevalences compared with the reported Dutch prevalences, while serovars F, H, I/Ia, J and K had lower prevalences compared with the Dutch studies. In conclusion, this is the first report of Russian C. trachomatis serovar/serogroup distributions. Serogroup B is the most prevalent, followed by serogroup I and serogroup C with no statistical differences on the serogroup level. However, significant differences between Russia and the Netherlands were observed in the distribution of C. trachomatis serovars.

Significantly higher serologic responses of Chlamydia trachomatis B group serovars versus C and I serogroups.

Chlamydia trachomatis serovars are divided into three serogroups, namely serogroup B, serogroup I (Intermediate) and serogroup C, and subsequently into 19 different serovars. Worldwide, serogroup B is the most prevalent followed by serogroup I. Clear differences have been observed in the duration of infection and growth kinetics between serovars from different serogroups in murine and cell culture models. Reasons for these observed differences are bacterial and host related, and are not well understood. The aim of this study was to determine the differences in immunoglobulin (Ig) G responses between the three serogroups in a group of patients infected with different serovars. Serovars were assessed from 235 C. trachomatispositive patients and quantitative IgG responses were determined. Analyses of variance were used to compare the IgG responses between the three serogroups. Of the serovars, 46% were B group (with serovar E the most prevalent: 35.3%), 39.6% were I group and 14.3% were C group. A highly significant difference in serologic response was shown when comparing the mean IgG concentrations (AU/mL) of patients having serovars in the most prevalent serogroup compared to the other serogroups: B = 135, C = 46 and I = 60 (B vs. C and B vs. I, P < 0.001). In conclusion, the most prevalent serovars generate the highest serologic responses.