Severe acute respiratory syndrome coronavirus 2 infection: Role of interleukin-6 and the inflammatory cascade

Since December 2019, a novel coronavirus that represents a serious threat to human lives has emerged. There is still no definite treatment for severe cases of the disease caused by this virus, named coronavirus disease 2019 (COVID-19). One of the most considered treatment strategies targets the exaggerated immune regulator, and interleukin (IL)-6 is a crucial pro-inflammatory mediator. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases show an elevated level of IL-6 related to disease severity. IL-6 activity can be inhibited by the following: IL-6 itself, IL-6 signaling pathways such as Janus kinase and signal transducer and activator of transcription (JAK-STAT), gp130, IL-6R, and downstream activated ILs, such as IL-17 and IL-6 cytokine. Currently, according to these studies and their results, IL-6 blockade with anti-IL-6 or its receptor antibodies such as tocilizumab in COVID-19 is beneficial in severe cases and may reduce the mortality rate. JAK-STAT inhibitors block the cytokine storm by inhibiting several crucial pro-inflammatory mediators such as TNF-α and IL-6 and have shown various results in clinical trials. IL-6 induces IL-17 secretion, and IL-17 is involved in the pathogenesis of inflammatory processes. Clinical trials of anti-IL-17 drugs are currently recruiting, and anti-gp130 antibody is preclinical. However, this agent has shown positive effects in inflammatory bowel disease clinical trials and could be tested for SARS-CoV-2. This study aimed to review the role of IL-6 in the cytokine storm and studies regarding IL-6 and blockade of its inflammatory pathways in COVID-19 to determine if any of these agents are beneficial for COVID-19 patients.

Safe and successful treatment of refractory polyarteritis nodosa with tocilizumab in a patient with past hepatitis B virus infection: a case-based review

Polyarteritis nodosa is a primary systemic necrotizing vasculitis whose evolution follows, in many cases, a chronic remitting-recurrent course with refractoriness to conventional immunosuppressants. We report here the clinical case of a 75-year-old patient with serologies suggestive of past hepatitis B virus infection who presented a flare of polyarteritis nodosa with great secondary functional impairment. She had not responded to several previous immunosuppressants and required high doses of glucocorticoids to control the flare. After the initiation of biological therapy with tocilizumab, the patient experienced a rapid and marked clinical and analytical improvement, going into clinical remission and being able to remarkably lower the corticosteroid dose and stop the rest of the immunosuppressants. There was no evidence of hepatitis B virus reactivation or changes in the titers of any of the parameters related to the aforementioned infection. This clinical case represents the first case reported in the literature about the successful and safe treatment of polyarteritis nodosa with tocilizumab in a patient with serologies suggestive of past hepatitis B virus infection.

Anti-interleukin-6 (tocilizumab) therapy in Takayasu’s arteritis: a real life experience

Background/aim

Tumour necrosis factor inhibitors and anti-interleukin-6 (anti-IL-6) therapies are increasingly being used in Takayasu’s arteritis (TA) patients who are unresponsive to corticosteroids ± conventional immunosuppressive agents. The aim of this study is to assess the efficacy and safety of anti-IL-6 (tocilizumab) therapy in refractory TA patients in real life.

Materials and methods

Fifteen TA patients (86.7% were female) who received at least 3 cycles of tocilizumab therapy were retrospectively assessed by clinical, laboratory, and radiological evaluations before and after tocilizumab therapy.

Results

The median (min–max) age of the patients at evaluation was 35 (20–58) years and the median disease duration from diagnosis was 24 (12–168) months. The median (min.–max.) duration of follow-up after tocilizumab was 15 (3–42) months. There was a significant decrease in erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and patient global visual analogue scale (VAS) scores of patients after tocilizumab therapy. The median (min.–max.) ESR was 26 (5–119) vs. 3 (2–49) mm/h, P = 0.02; CRP was 39.8 (2.4–149.0) vs. 7.9 (0–92.9) mg/L, P = 0.017; and patient global VAS was 50 (0–90) vs. 30 (0–60), P = 0.027, respectively. In 8 patients, ESR and CRP levels were in the normal range in the last control. Imaging modality results after tocilizumab were available for 9 patients; 8 patients were radiologically stable and regression was seen in 1 patient. Comparable imaging modality results before and after tocilizumab were available for 5 patients; 4 patients were radiologically stable and regression was seen in 1 patient. Radiological findings were consistent with laboratory responses. Glucocorticoid dosages decreased from a mean dosage of 16.2 (9.1) mg/day at baseline to 7.1 (3.8) mg/day (P = 0.001) at the last follow-up visit. There was no increase in the steroid dosage in any of the patients. All patients tolerated tocilizumab well.

Conclusion

Based on retrospective real life data, anti-IL-6 (tocilizumab) appears to be an effective and tolerable treatment option in refractory TA patients.