Toll-like receptor 9 (TLR9) often known as CD289 (cluster of differentiation 289), is a member of the Toll-like receptor family that recognizes pathogen-associated molecular pattern. TLR9 was first cloned and identified as a receptor for unmethylated CpG-DNA as well as for bacterial DNA. It is essential not only for pro-inflammatory cytokine production and other inflammatory responses, but it also plays a role in the induction of T helper 1 (Th1) acquired immune response and in the proliferation of B cells. Like all other members of the TLR family, TLR9 is composed of an extracellular domain containing multiple leucine-rich repeats (LRRs), a transmembrane region, and a cytoplasmic tail containing the conserved TIR domain. The TLR9 sequence encodes a 1032 aa protein containing 27 N-terminal LRRs with a calculated molecular weight of 116 kDa . The gene for TLR9 has been mapped to human chromosome 3p21.3. TLR9 is most closely related to TLR7 and TLR8 with 36% and 35% overall amino acid sequence identity, respectively and thus along with TLR7 and TLR8 constitutes a new sub-family of the TLRs.

7 thoughts on “Lab Tests Systemic Lupus Erythematosus

  1. FutureRN

    For experienced physicians: what diagnostics tests would you order if you suspected a patient had lupus??
    I’m currently completing a case study for Systemic Lupus Erythematosus and it would really help if I knew the correct tests. Please help!

    1. Linda R

      There are no definitive tests for lupus. In order to arrive at a diagnosis of lupus, one must first eliminate other disorders that can cause similar symptoms. After that, a combination of lab tests, medical history, and symptoms matched against the American College of Rheumatology’s 11 criteria for lupus and finding a match for 4, some carrying more weight than others.

      Tests for ANA, anti-double stranded DNA, sed rate, C reactive protein, ro and la, CBC, CMP, and 24 hour urine with protein excretion and creatine clearance can all provide clues.

      Dr. Sam Lim and the CDC are involved in the National Lupus Patient Registry in an attempt to find a specific, definitive biomarker for lupus.

      The link below can take you to common diagnositc tests for lupus.

  2. sekhmet179

    SLE and/or TB?
    I have an ANA titer 1:320 speckled and anti-SSA/RO strong positive and a red slightly raised and sore TB skin Tests (not sure if its positive/border line positive/negative-will be getting a call later though) of about 18mm/1.5cm

    I have all the symptoms and test results but not enough time to call what I have Systemic Lupus Erythematosus although it is suspected but some of the symptoms do overlap with tuberculosis so can What I have just be TB or can it be Lupus with Tuberculosis

    Is it a combination of the two or is it really TB?

    I also Have a rheumatoid factor of 36 (don’t really know what this means-so if you do help!), normal is anything under 20 and a`slightly raised erythrocyte sed rate

    All other test Anti-dsDNA,Sm,La, etc came back negative

    1. Dynamite

      You have a dysfunctional immune system. You may have an autoimmune condition yet to be given diagnostic label. It may change with time and it is causing a false positive PPD and rheumatoid factor positivity
      YOU do not have TB
      Keep a chronologic profile of your history and summary of lab tests for the rest of your life

  3. Anonymous

    Need help for my biology assignment?
    A 45 year old man came to the emergency department complaining about shortness of breath, chest pain which is came to the emergency department complaining about shortness of breath, chest pain which is severe by deep breathing of one week duration. he had generalize easy fatigability, malaise,skin rash that worsens with sun exposure, fever and joint pain for about three weeks prior to his current complaint. Physical examination revealed the following:
    General appearance: Acutely sick looking, in sever cardiorespiratory distress
    Respiratory rate 32 , Heart rate 112, Blood pressure 110/68, Temperature 37.8 C
    He has erythematous malar rash, decreased air entry on both sides of the lung, there is pericardial friction rub on the pericardium.
    The knee and wrist joints are swollen and painful.

    The attending physician ordered the following lab tests with the impression of Systemic lupus erythematosus.
    White blood count elevated, ESR (Sedimentation Rate) very elevated, Xray bilateral pleaural and mild pericardial effusion
    ANA and Anti Ds antibody positive.
    Then the patient was started with high dose prednisolone by the intravenous route and responded well to treatment after a couple of weeks.

    .What are the organ systems affected in this patient
    do you think the prednisolone helped the patient?
    What is the pathophysiology behind this illness?

    1. Anonymous

      Lupus is an autoimmune disease. Autoimmune diseases are when a persons own immune system messes up and doesn’t recognize part of the patients body and then attacks it as if it were an invader. This means, that the pathophysiology is that antibodies are created against the part of the patients own body. Normally, (normal physiology) antibodies are only created to recognize intruders, like viruses and bacteria. In systemic lupus erythematosus, the immune system generates antibodies against connective tissue, which is the stuff that holds your body together, like collagen, and cartilage.

      Prednisone should help the patient because it is a corticosteroid, which are drugs that regulate the immune system to reduce inflammation.

      If you want to read more, check out the Mayo Clinic’s website. It is a great resource for easy to understand info.

  4. Song_bird

    Systemic Lupus Erythematosus or Rheumatoid Arthritis?
    My symptoms are: Extremely painful to walk, rashes, blood in urine, Anemia (had to get iron infusions), headaches, extreme fatigue, ect. I seen a doctor who did some x-rays, blood work & a physical exam. She recently called me & told me from my lab results came back & said i have either Systemic Lupus Erythematosus or Rheumatoid Arthritis. She said my blood work showed alot of abnormalities & even infection. She wanted me to start on a steroid right away. She put me on (10 mg pills of Prednisone) for 10 days until my follow up with a Rheumatologist. Okay my question: What is Lupus & Rheumatoid Arthritis?
    Are these 2 illnesses simular? She will be calling me back within 5 days with the other test results. Has anyone personally experienced this? She said my illness is treatable but not cureable. I’m still pretty young & this is a shock to me & i’m having a hard time dealing with not knowing what i’m dealing with i guess my new doctor will be able to answer alot of questions later.
    Thanks for the advice i will go look there.

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