One of the best understood mechanisms by which cytokines activate signals, thus eliciting specific responses in target cells, involves enzymes such as Janus kinases (JAKs) and transcriptional factors such as signal transducers and activators of transcription (STATs). For immune mediated diseases, both activating and inactivating mutations of JAKs and STATs may cause abnormalities in immune homeostasis. Polymorphisms of JAK/STAT genes have been linked to susceptibility for rheumatoid arthritis (RA) , systemic lupus erythematosus (SLE), psoriatic arthritis (PA) and inflammatory bowel disease (IBD) .

Janus_kinase 3 expression will be evaluated in the serum and renal tissue of lupus patients during active stage of the disease through this study

Investigators will assess the relationship between the expression of Janus_kinase 3 and the clinical and laboratory parameters of disease activity . Disease activity will be assessed through the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Also, investigators will evaluate the relationship between Janus_ kinase 3 expression and histopathological classes of lupus nephritis according to the 2003 International Society of Nephrology/ Renal Pathology Society (ISN/RPS) classification of lupus nephritis. This will be done through Janus_kinase 3 assessment in the blood and renal tissue of lupus patients.

Inclusion Criteria:

• Age younger than 16 years.

  • Active disease stage
  • Patients with biopsy proven lupus nephritis according to ISN/RPS classification criteria of lupus nephritis

Exclusion Criteria:

• Lupus patients in remission.

  • Lupus patients with end stage renal disease.
  • Lupus patients with secondary thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS).
  • patients with moderate or severe infection

This will include children and adolescents who fulfill the 2012 Systemic Lupus International Collaborating Clinics (SLICC) classification criteria of systemic lupus erythromatosus during a period of 2 years.