Target antigen(s) in endometrial autoimmunity of endometriosis

Association between endometriosis and risk of systemic lupus erythematosus

To examine the association between endometriosis and the risk of systemic lupus erythematosus (SLE), this nationwide, population-based, retrospective cohort study was conducted based on National Health Insurance Research Database in Taiwan. Endometriosis (N = 16,758) and non-endometriosis (N = 16,758) groups were identified by matching baseline characteristics and comorbidities. Student's t-tests and the Kaplan-Meier estimator were utilized to estimate the hazard ratio (HR) and cumulative probability of SLE in the two groups. The endometriosis group showed a significantly higher incidence density rate (0.3 vs. 0.1 per 1000 person-years) and hazard ratio in SLE group (adjusted HR [aHR], 2.37; 95% confidence interval [CI] 1.35-4.14) compared to the non-endometriosis group. Subgroup analysis revealed that patients with endometriosis between 30 and 45 years of age, or were non-steroidal anti-inflammatory drug users, or were hormonal medications-free participants, had higher risks of SLE. For patients with endometriosis, surgical intervention did not significantly impact on the risk of SLE. Our results demonstrated an increased risk of SLE in patients with endometriosis. Clinicians should be aware of this association when managing patients with endometriosis or SLE.

Serum anti-endometrial antibodies in infertile women - potential risk factor for implantation failure

PROBLEM

Female infertility patients with diverse etiologies show increased production of autoantibodies.

METHOD OF STUDY

Immunoblot analysis of sera from patients with endometriosis and tubal factor infertility (TFI) and mass spectrometry identification of candidate antigens.

RESULTS

The immunoblot results demonstrated the presence of IgA and IgG anti-endometrial antibodies (AEA) to various antigens at molecular weights ranging from 10 to 200 kDa. Differences were detected in certain AEA reactions between the patients' groups and particular AEA were associated with in vitro fertilization (IVF) implantation failure. IgA AEA to a 47-kDa protein were more prevalent in TFI patients and were associated with unsuccessful IVF treatment. This antigen was subsequently identified as alpha-enolase.

CONCLUSION

Determination of the presence and spectra of AEA in patients with endometriosis and TFI undergoing IVF may be a useful marker to predict their pregnancy outcome.

Endometriosis and Systemic Lupus Erythematosus: A Comparative Evaluation of Clinical Manifestations and Serological Autoimmune Phenomena

PROBLEM

In view of evidences suggesting association between endometriosis (EM) and systemic lupus erythematosus (SLE), we have performed a comparative evaluation of clinical and humoral immunologic abnormalities in both diseases.

METHOD OF STUDY

Forty-five women (18-40 years) with histologically confirmed pelvic EM, 21 healthy-women and 15 female SLE-patients (18-40 years) without surgically confirmed EM were prospectively evaluated. Immunologic investigations were performed by blinded researchers.

RESULTS

None of the EM-patients fulfilled criteria for SLE. However, EM-patients presented higher frequencies of arthralgia (62%) and generalized myalgia (18%) superior than normal-controls (24%, P = 0.004/0%, P = 0.048) but comparable with SLE-patients (33%, P = 0.052/27%, P = 0.5). Similarly to SLE (7%), 9% of EM-patients presented fibromyalgia. Antinuclear antibodies (ANA) were detected in 18% of EM-sera, as compared with healthy-women (0%, P = 0.014) and SLE-patients (93%, P = 0.0005). In contrast with SLE, antibodies to dsDNA, Sm and U1RNP were negative in EM-sera. Anti-Ro and anticardiolipin antibodies were more often in SLE (40%, 33%) than in EM-patients (2%, P < 0.001/9%, P = 0.04). Elevated immune-complexes and low total complement were more frequent in SLE (40%, 13%) compared with EM-sera (7%, P = 0.005/0%, P = 0.01).

CONCLUSIONS

Our data indicate differences of ANA antigenic specificity and complement consumption between EM and SLE. The high prevalence of generalized musculoskeletal complaints in EM justifies a multidisciplinary approach.

Blood leukocyte subsets are modulated in patients with endometriosis

OBJECTIVE

To determine whether blood leukocyte populations could be modulated in endometriosis.

DESIGN

Case-control study.

SETTING

Eight clinical institutions of the Montreal area.

PATIENT(S)

Women with regular menstrual cycles who underwent laparoscopy or laparotomy between 1997 and 2001 and who were not under hormonal treatment for at least 3 months were selected. This study includes 175 cases and 131 controls.

MAIN OUTCOME MEASURE(S)

The proportion of blood leukocytes expressing markers for T, B lymphocytes, monocytes, or natural killer (NK) cells were compared by flow cytometric analysis between cases and controls.

RESULT(S)

Age and parity were identified as important confounders. Given that smoking, history of acute infection, and previous use of oral contraceptives strongly correlate with the level of some blood leukocyte populations, these parameters were taken into account in addition with age and parity when the level of blood leukocyte subsets were evaluated in cases and controls. Blood monocytes expressing CD14 and CD44 molecules were increased in patients with endometriosis. Alternatively, B lymphocytes were shown to be significantly decreased in cases compared with controls.

CONCLUSION(S)

Although these results suggest that endometriosis is associated with some systemic manifestations, the exact role of these modulations remains unclear.

Antibodies to endometrial transferrin and alpha 2-Heremans Schmidt (HS) glycoprotein in patients with endometriosis

PROBLEM

Identifying the endometrial antigens inciting autoimmunity is important in setting up an antibody assay for a non-invasive diagnosis and clinical monitoring of endometriosis.

METHODS

Two-dimensional gel electrophoresis of endometrial extracts, Western blot analysis, passive hemagglutination and enzyme-linked immunosorbent assay (ELISA), amino acid sequencing and molecular studies were done on chosen antigens. Forty-six women with endometriosis, 4 women with uterine leiomyomata, 4 with pelvic adhesions, 3 with repeat Cesarean sections (conditions that coexist with or predispose to endometriosis) and 46 controls participated.

RESULTS

Antigens with molecular weights (MW) of 64 kDa [isoelectric point (pI) of 3.5-4.0] and 72 kDa (pI of 4.5) bound to IgG in all patients with endometriosis, but not the controls. Amino acid sequencing of the proteins revealed that they had homology to alpha 2-Heremans Schmidt (HS) glycoprotein (MW: 64 kDa) and transferrin (MW: 72 kDa). Endometriosis patients had significant antibody levels to these two proteins (predictive value of 80-90%). The analysis of patients' endometrial RNA detected the message for alpha 2-HS glycoprotein and transferrin. Albumin (pI 5.5) and collagen (pI 3.5) failed to elicit antibody responses.

CONCLUSIONS

Patients with endometriosis have significant antibodies to endometrial transferrin and alpha 2-HS-glycoprotein. We can effectively use an antibody assay using these antigens for diagnosing endometriosis.