Hassa 2009.

Study characteristics
Patient sampling	Primary objective: to investigate the changes in Th1 and Th2 immune responses, characterised by a change in the levels of IL‐2, IL‐4, IL‐10 and IFN‐γ, and determinations of T helper, T suppressor, NK, and B cells in peripheral blood and peritoneal fluid of different stages of endometriosis Participants: patients who underwent laparoscopy for pain or infertility (cases) and for tubal ligation (controls) Selection criteria: exclusion criteria: any medical treatment employed prior to laparoscopy that may interfere with the results Study design: cross‐sectional two‐gate, prospective collection of samples
Patient characteristics and setting	Clinical presentation: controls had no history of infertility and no pelvic pathology during surgical inspection Age: mean 30.9 ± 5.6; 29.9 ± 6.7 years (endometriosis stage I‐II; III‐IV), 30.1 ± 6.7 years (controls) Number of participants enrolled: 97 women Number of participants available for analysis: 97 women (all in follicular phase of menstrual cycle) Setting: O&G Department, Eskisehir Osmangazi University School of Medicine Place of study: Eskisehir, Turkey Period of study: 2003–2005 Language: English
Index tests	Index test: IL‐2, IL‐4, IL‐10, IFN‐γ, and lymphocytes: Th, Ts, AL and NK Details of the index test procedure as stated: cytokines were measured by using ELISA assay (Cellular Communication Investigations, Beckman Coulter, USA); lymphocytes were assessed by using cluster determinant‐3 (CD‐3), CD4, CD8, CD25, CD28, CD45, CD16, CD23, Abs against early T cell activation antigens such as CD45RA/CD45RO, CD‐69 and late activation antigens such as HLA‐DR; sensitivity limits of the kits were 5 pg/ml, 5 pg/ml, 5 pg/ml, and 0.08 pg/ml for IL‐2, IL‐4, IL‐10, IFN‐γ; sample handling and technique described Threshold for positive result: not provided Examiners: experienced technicians blind to the status of cases at laboratory conducted the detection of both cytokine and immune cell levels Interobserver variability: Intra‐ and interassay CVs were < 10% for all assays
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: n = 60/97 (62%): stage I‐II 42, stage III‐IV 18; controls n = 37 Reference standard: laparoscopy N = 97 (100%) + histology Description of positive case definition by reference standard test as reported: visual inspection confirmed histopathologically; staging according to the rAFS classification Examiners: no information provided
Flow and timing	Time interval between index test and reference standard: not clearly stated, but from the context, blood was collected at surgery Withdrawals: none
Comparative
Key conclusions by the authors	The result of this study did not show any significant difference in peripheral blood and peritoneal fluid cytokine and lymphocyte subgroups between normal women and those with early and late stage endometriosis
Conflict of interest	All the authors had a conflict of interest (financial or otherwise)
Notes	For IL‐2, IL‐4, IL‐10, IFN‐γ, Th, Ts, AL, NK there was not statistically significant difference between the groups ‐ no data available for meta‐analysis
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
Did the study avoid inappropriate exclusions?	Yes
Was a 'two‐gate' design avoided?	No
		High	Low
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	No
Was a cycle phase considered in interpretation of the result of index test?	Yes
		High	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
		Low	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Unclear
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Yes
		Unclear