biotherapy alone

7 ml of blood will be taken from each patient before treatment i.e. at the inclusion visit and at the end of treatment.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The diversity index according to the number of species and the number of functional groups will be recorded.

The JADAS CRP clinical score will be used to rate the degree of activity of the disease. The Juvenile Arthritis Disease Activity Score (JADAS) is a recently developed composite tool for scoring disease activity in juvenile idiopathic arthritis. It is a composite disease activity score including four measures:

• the physician's global assessment of disease activity;
• the parent/guardian's or patient's global assessment of overall wellbeing;
• number of joints with active arthritis; and
• C-reactive protein (CRP) which has been determined as an alternative inflammatory marker to the Erythrocyte Sedimentation Rate ESR. JADAS-CRP was calculated similarly to the original JADAS as the simple sum of its four components, yielding a global score of 0-40, 0-57 and 0-101 depending on the joint count used for the JADAS10-CRP, JADAS27-CRP and JADAS71-CRP, respectively.

The number of flare-ups in patients treated with non-steroidal anti-inflammatory drugs alone (Profile A) will be noted.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The diversity index according to the number of species and the number of functional groups will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species in the microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

The JADAS CRP clinical score will be used to rate the degree of activity of the disease. The Juvenile Arthritis Disease Activity Score (JADAS) is a recently developed composite tool for scoring disease activity in juvenile idiopathic arthritis. It is a composite disease activity score including four measures:

• the physician's global assessment of disease activity;
• the parent/guardian's or patient's global assessment of overall wellbeing;
• number of joints with active arthritis; and
• C-reactive protein (CRP) which has been determined as an alternative inflammatory marker to the Erythrocyte Sedimentation Rate ESR. JADAS-CRP was calculated similarly to the original JADAS as the simple sum of its four components, yielding a global score of 0-40, 0-57 and 0-101 depending on the joint count used for the JADAS10-CRP, JADAS27-CRP and JADAS71-CRP, respectively.

The number of flare-ups in patients treated with non-steroidal anti-inflammatory drugs for 1 month followed by methotrexate for 5 months (Profile AM) will be noted.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species in the microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

The JADAS CRP clinical score will be used to rate the degree of activity of the disease. The Juvenile Arthritis Disease Activity Score (JADAS) is a recently developed composite tool for scoring disease activity in juvenile idiopathic arthritis. It is a composite disease activity score including four measures:

• the physician's global assessment of disease activity;
• the parent/guardian's or patient's global assessment of overall wellbeing;
• number of joints with active arthritis; and
• C-reactive protein (CRP) which has been determined as an alternative inflammatory marker to the Erythrocyte Sedimentation Rate ESR. JADAS-CRP was calculated similarly to the original JADAS as the simple sum of its four components, yielding a global score of 0-40, 0-57 and 0-101 depending on the joint count used for the JADAS10-CRP, JADAS27-CRP and JADAS71-CRP, respectively.

The number of flare-ups in patients treated with non-steroidal anti-inflammatory drugs followed by biotherapy (Profile AB) will be noted.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department.The diversity index according to the number of species and the number of functional groups will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The number of species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The distribution of the various bacterial species detected in the intestinal microbiota will be recorded.

Patients will provide 2 stool samples (one for analysis and one for the biobank) taken at the patient's home, preserved at -20°C and transported in a coolerbag to the hospital. One sample will be frozen to -80°C for the biobank and one sample will be kept at -20°C at the pediatric department. The diversity index according to the number of species and the number of functional groups will be recorded.

The JADAS CRP clinical score will be used to rate the degree of activity of the disease. The Juvenile Arthritis Disease Activity Score (JADAS) is a recently developed composite tool for scoring disease activity in juvenile idiopathic arthritis. It is a composite disease activity score including four measures:

• the physician's global assessment of disease activity;
• the parent/guardian's or patient's global assessment of overall wellbeing;
• number of joints with active arthritis; and
• C-reactive protein (CRP) which has been determined as an alternative inflammatory marker to the Erythrocyte Sedimentation Rate ESR. JADAS-CRP was calculated similarly to the original JADAS as the simple sum of its four components, yielding a global score of 0-40, 0-57 and 0-101 depending on the joint count used for the JADAS10-CRP, JADAS27-CRP and JADAS71-CRP, respectively.

The number of flare-ups in patients treated with non-steroidal anti-inflammatory drugs followed by methotrexate then biotherapy (Profile AMB) will be noted.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

The description of the intestinal microbiota profile according to INSERM laboratory Unit 1047 will be correlated with the clinical stage of the disease (on remission or acute flare) before and after treatment.

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

Pre- and post-therapeutic translocation and response to treatment (presence/absence: detection of DNA 16S in the blood, quantification by quantitative PCR and sequencing for identification).

All blood and stool samples used for the study will be deposited in the biobank for reference.

All blood and stool samples used for the study will be deposited in the biobank for reference.

All blood and stool samples used for the study will be deposited in the biobank for reference.

All blood and stool samples used for the study will be deposited in the biobank for reference.

Recorded in years

Recorded in kilos

Recorded in cm.

Male/Female

The investigators will record details of all treatment followed prior to diagnosis of juvenile spondylarthritis:

• NSAIDs : dosage and dates
• Corticoids : dosage and dates
• Antibiotics : dosage and dates
• DMARDs : dosage and dates

The investigators will record details of patients' dietary habits and, more particularly, note all foods which are excluded.

The investigators will record details of patients' food allergies.

The investigators will record details of the patient's lifestyle:

• Brothers and sisters (number and date of birth of each one)
• Communities (date of entry)
• Contact with animals

Recorded in years

Recorded in kilos

Recorded in cm.

Male/Female

The investigators will record details of all treatment followed prior to diagnosis of juvenile spondylarthritis:

• NSAIDs : dosage and dates
• Corticoids : dosage and dates
• Antibiotics : dosage and dates
• DMARDs : dosage and dates

The investigators will record details of all patients' dietary habits and, more particularly, note all foods which are excluded.

The investigators will record details of all patients' food allergies.

The investigators will record details of the patient's lifestyle:

• Brothers and sisters (number and date of birth of each one)
• Communities (date of entry)
• Contact with animals

Recorded in years

Recorded in kilos

Recorded in cm.

Male/Female

The investigators will record details of all treatment followed prior to diagnosis of juvenile spondylarthritis:

• NSAIDs : dosage and dates
• Corticoids : dosage and dates
• Antibiotics : dosage and dates
• DMARDs : dosage and dates

The investigators will record details of all patients' dietary habits and, more particularly, note all foods which are excluded.

The investigators will record details of all patients' food allergies.

The investigators will record details of the patient's lifestyle:

• Brothers and sisters (number and date of birth of each one)
• Communities (date of entry)
• Contact with animals

Recorded in years

Recorded in kilos

Recorded in cm.

Male/Female

The investigators will record details of all treatment followed prior to diagnosis of juvenile spondylarthritis:

• NSAIDs : dosage and dates
• Corticoids : dosage and dates
• Antibiotics : dosage and dates
• DMARDs : dosage and dates

The investigators will record details of all patients' dietary habits and, more particularly, note all foods which are excluded.

The investigators will record details of all patients' food allergies.

The investigators will record details of the patient's lifestyle:

• Brothers and sisters (number and date of birth of each one)
• Communities (date of entry)
• Contact with animals