T lymphocytes and muscle condition act like seeds and soil in a murine polymyositis model

Abstract

Objective. It has been reported that polymyositis (PM) is driven by CD8؉ cytotoxic T lymphocytes. The C protein-induced myositis (CIM) model we have established is similar to PM in pathology except that it undergoes spontaneous remission. We undertook the present study to delineate the roles of innate and acquired immunity in myositis.Methods. C57BL/6 mice were immunized with recombinant C protein fragments together with

Biologic Mechanism of C Protein–Induced Myositis: Comment on the Article by Okiyama et al

“…The former involves priming of naive CD8 T cells, whereas the latter involves activation of effector/memory CD8 T cells. Likewise, it is necessary to distinguish between myositis in hind legs immunized with CFA-emulsified C protein fragments and myositis in forelegs treated with CFA alone (1). The immune response elicited in CFA-treated forelegs is thought to be a secondary immune response similar to reinduction of CIM, since T cells recruited in forelegs have been primed at the regional lymph nodes drained from immunized hind legs.…”

“…Third, the rate of MPO ANCA versus PR3 ANCA differs among geographic areas (6). Fourth, the age at diagnosis or the signs and symptoms are different according to ANCA specificity (1,2). Fifth, besides the differences shown in uncontrolled trials or cohort reports (7), the Rituximab in ANCA-Associated Vasculitis randomized controlled trial comparing rituximab versus cyclophosphamide (8) showed that the percentage of patients who became ANCA negative differed according to the study drug and ANCA specificity.…”

“…In the clinical setting, far removed from clinical trials, physicians need easy and unbiased tools to assess prognosis and counsel patients. The classification of AAV according to the CHCC nomenclature (3) or the American College of Rheumatology criteria (9) produces overlapping and conflicting classifications (1). Differentiation between MPA and GPA is difficult in most patients, especially in patients with renal disease, which is the most common clinical presentation (2), and renal biopsy is the principal tool for confirmation of the diagnosis.…”

“…The use of ANCA specificity, as proposed by Lionaki et al (1), can oversimplify the diagnosis of renal AAV and exclude seronegative patients. But if a simple and unbiased laboratory test could enable physicians to more accurately forecast disease relapse or death, what is the point of not using it with, or even without, the more complex and biased set of clinical definitions?…”

Reply

“…The notion that parasitic worms can protect against the development of allergic and autoimmune inflammatory conditions in humans has recently been accepted by many researchers (1,2). This has triggered a race to find the individual worm components that protect against disease development.…”