3. Helper T cell (TH2) response: The inhibition of TH1 CD4+ lymphocytes by TNF-α inversely leads to an increased production of TH2 CD4+ lymphocytes. This increase in the levels of circulating TH2 CD4+ lymphocytes brought on by the action of anti–TNF-α agents is thought to promote the development of SCLE.9,10
4. Apoptosis theory: Molecules of TNF-α inhibitors are capable of binding to TNF-α receptors on the cell surface. In doing so, cellular apoptosis is triggered, resulting in the release of nucleosomal autoantigens from the apoptotic cells. In susceptible individuals, autoantibodies then begin to form against the nucleosomal autoantigens, leading to an autoimmune reaction that is characterized by SCLE.11,12
Major histone compatibility (MHC) antigen testing performed by Sontheimer et al12 established the presence of the HLA class I, HLA-B8, and/or HLA-DR3 haplotypes in patients with SCLE.13,14 Furthermore, there is a well-known association between the antinuclear profile of known SCLE patients and the presence of anti-SSA (Ro) antibodies.13 Therefore, we propose that in susceptible individuals, such as those with the HLA class I, HLA-B8, or HLA-DR3 haplotypes, the initiation of a TNF-α inhibitor causes cellular apoptosis with the subsequent release of nucleosomal and cytoplasmic components (namely that of the Ro autoantigens), inducing a state of autoimmunity. An ensuing immunogenic response is then initiated in predisposed individuals for which anti-SSA (Ro) autoantibodies are produced against these previously mentioned autoantigens.
Drug-induced SCLE is most common in females (71%), with a median age of 58 years. The most common site of cutaneous manifestations is the legs.15 Although our patient was in the eighth decade of life with predominant cutaneous involvement of the upper extremity, the erythematous plaques with a symmetric, annular, polycyclic appearance in photosensitive regions raised a heightened suspicion for lupus erythematosus. Histology classically involves an interface dermatitis with vacuolar or hydropic change and lymphocytic infiltrates,16 consistent with the analysis of tissue sections from our patient. Moreover, the speckled ANA profile with positive anti-dsDNA and anti-SSA (Ro) antibodies in the absence of a negative rheumatoid factor and anticyclic citrullinated peptide antibodies strongly favored the diagnosis of SCLE over alternative diagnoses.2
The supraclavicular rash in our patient raises clinical suspicion for the shawl sign of dermatomyositis, which also is associated with musculoskeletal pain and photosensitivity. In addition, skin biopsy revealed vacuolar alteration of the basement membrane zoneand dermal mucin in both lupus erythematosus and dermatomyositis; therefore, skin biopsy is of little use in distinguishing the 2 conditions, and antibody testing must be performed. Although anti-SSA (Ro) antibodies commonly are associated with SCLE, there are reports involving positivity for the extractable nuclear antigen in cases of dermatomyositis.17 Based on our patient’s current drug regimen, including that of a known offending agent for SCLE, a presumptive diagnosis of TAILS was made. Following withdrawal of certolizumab pegol injections and subsequent resolution of the skin lesions, our patient was given a definitive diagnosis of TAILS based on clinical and pathological assessments.
The clinical diagnosis of TAILS should be made according to the triad of at least 1 serologic and 1 nonserologic American College of Rheumatology criteria, such as anti-SSA (Ro) antibodies and a photosensitive rash, respectively, as well as a relationship between the onset of symptoms and TNF-α inhibitor therapy.18 Both the definitive diagnosis and the treatment of TAILS can be made via withdrawal of the TNF-α inhibitor, which was true in our case whereby chronologically the onset of use with a TNF-α inhibitor was associated with disease onset. Furthermore, withdrawal led to complete improvement of all signs and symptoms, collectively supporting a diagnosis of TAILS. Notably, switching to a different TNF-α inhibitor has been shown to be safe and effective.19