Induction of the autoantigen proliferating cell nuclear antigen in T lymphocytes by a mycobacterial antigen.

Mycobacteria have been implicated in the pathogenesis of autoimmunity. To determine the potential effect of mycobacterial antigens on peripheral blood mononuclear cells (PBMC), we analyzed PBMC incubated with the acetone-precipitable fraction of Mycobacterium tuberculosis (APMT) for changes in cellular protein expression. Two-dimensional gel analysis showed induction of a 36-kD polypeptide identified as proliferating cell nuclear antigen (PCNA), a known autoantigen, after incubation with AP-MT. PCNA plays a role in cell proliferation and is expressed as a late growth regulated factor. However, its synthesis in response to AP-MT was induced as an early event. The early induction of PCNA was regulated at a posttranscriptional level and was restricted to T cells. Treatment of PBMC with known T cell mitogens, namely PHA, anti-CD3 antibodies, and staphylococcal superantigens failed to induce an early PCNA increase. The distinct characteristics of the AP-MT effect on PCNA expression suggest a separate mechanism of induction in response to AP-MT, compared with the late increase observed in response to mitogens. The induction of PCNA in response to mycobacterial antigens may represent a pathogenically relevant mechanism in autoimmunity.

Is it Crohn's disease? A severe systemic granulomatous reaction to sulfasalazine in patient with rheumatoid arthritis.

BACKGROUND: Sulfasalazine is a widely used anti-inflammatory agent in the treatment of inflammatory bowel disease and several rheumatological disorders. Although as many as 20% of treated patients may experience reversible, dose-dependent side effects, less frequent but potentially severe, systemic reactions have also been reported. CASE PRESENTATION: A severe systemic reaction to sulfasalazine developed in a 21-year old female with rheumatoid arthritis characterized by eosinophilia, granulomatous enteritis and myelotoxicity, cholestatic hepatitis, and seizures. The clinical course and management of this patient are presented as well as a review of the incidence and outcome of severe systemic reactions to sulfasalazine. CONCLUSIONS: Granulomatous myelotoxicity and enteritis developed in a 21 year old female within 3 weeks of initiating sulfasalazine for rheumatoid arthritis. Following a short course of corticosteroids, the patient had resolution of her cholestatic hepatitis, rash, eosinophilia, and gastrointestinal symptoms with no residual manifestations at 7 months follow-up. Although severe reactions to sulfasalazine are rare and unpredictable, practicing physicians should be aware of unusual clinical presentations of toxicity when prescribing sulfasalazine.

Shoulder, knee, and hip pain as initial symptoms of juvenile ankylosing spondylitis: a case report.

Ankylosing spondylitis is a systemic disease typically manifested by persistent back pain or stiffness unrelieved by rest. Although not often recognized, ankylosing spondylitis can also cause peripheral joint pain, particularly in the hips, knees, ankles, and shoulders. In the pediatric form of the disease, juvenile ankylosing spondylitis, peripheral joint involvement is more frequent and can precede, by many years, the onset of back symptomatology. The following case is an example of a teenager who presented to physical therapy with a variety of common peripheral joint complaints over a 3-year period. Eventually, he was diagnosed with juvenile ankylosing spondylitis. Lack of awareness of the manifestations of ankylosing spondylitis and juvenile ankylosing spondylitis may lead to significant delay in diagnosis and initiation of appropriate therapy. A physical therapist may be the first health professional to assess a patient's lack of response to treatment for a seemingly typical diagnosis and should be aware of potential alternate diagnoses.

Expansion of mycobacterium-reactive gamma delta T cells by a subset of memory helper T cells.

Human gamma delta T cells expressing the V gamma 9/V delta 2 T-cell receptor have been previously found to proliferate in response to certain microorganisms and to expand throughout life, presumably because of extrathymic activation by foreign antigens. In vitro expansion of V gamma 9/V delta 2 cells by mycobacteria has been previously shown to be dependent on accessory cells. In order to gain an insight into the mechanisms involved in the expansion of these cells, we have undertaken to identify the peripheral blood subset of cells on which proliferation of V gamma 9/V delta 2 cells in response to mycobacteria is dependent. Contrary to their role in antigen presentation to alpha beta T cells, professional antigen-presenting cells, such as monocytes, B cells, and dendritic cells, were unable to provide the cellular support for the expansion of V gamma 9/V delta 2 cells. Selective depletion of T-cell subsets, as well as the use of highly purified T-cell populations, indicated that the only subset of peripheral blood cells that could expand V gamma 9/V delta 2 cells were CD4+ CD45RO+ CD7- alpha beta T cells. These cells underwent distinct intracellular signaling events after stimulation with the mycobacterial antigen. Expansion of V gamma 9/V delta 2 cells by alpha beta T cells was dependent on cell-cell contact. This is the first evidence that a small subset of the memory helper T-cell population is exclusively responsible for the peripheral expansion of V gamma 9/V delta 2 cells. These data illustrate a unique aspect of antigen recognition by gamma delta T cells and provide new means to study their immune defense role.