Erythema nodosum -Expanding diagnostic workout in COVID-19 pandemic

Case report Erythema nodosum (EN) is considered a delayed type IV hypersensitivity reaction, triggered by exposure to an antigen, which diagnostic workout is usually challenging. Several conditions have been described as possible causes for EN, including infections, sarcoidosis, pregnancy, neoplasic and inflammatory diseases. Rarely, vaccines such as tetanus, diphtheria, BCG, hepatitis B, human papillomavirus, malaria, rabies, smallpox, typhoid, and cholera have been associated with subsequent EN. We present a 31-year- old leucodermic female with suppurative adenitis, who developed painful erythematous nodules on the pretibial area of the lower limbs. Ten days prior to presentation she had received the first dose of the COVID-19 mRNA-1273 vaccine. Fever, lymphadenopathy, fatigue, weight loss, arthritis, cough, diarrhoea, other organ-specifc symptoms and close contact with tuberculosis were excluded. She was under oral contraception for several years, that was not discontinued. Pregnancy was excluded. No positive signs were detected on physical examination besides the referred nodules. Laboratory tests revealed a normal complete blood count, erythrocyte sedimentation rate, C-reactive protein, antistreptolysin O titer, renal and hepatic tests. Interferon-gamma release assay was negative. Circulating rheumatoid factor was normal, anti-nuclear, anti-double stranded DNA and anti-neutrophil cytoplasmatic antibodies were negative. Angiotensin converting enzyme and protein electrophoresis were normal. Hepatitis B and C, HIV 1/2 and syphilis serologic profiles were negative. Urinalysis and fecal calprotectin were unremarkable. The patient was treated with naproxen and topic betamethasone dipropionate. Violaceous involution was reported, with complete resolution of the EN lesions over the following month. In the literature, there are rare reports of EN following SARS-COV2 infection and also after COVID-19 vaccination. To our knowledge this is the second report of EN after the COVID-19 mRNA-1273 vaccine. This case highlights the importance of clinical awareness for the possible association of COVID-19 vaccination and EN, adding to the already extensive list of causes included in the etiological investigation of these patients.

Tixagevimab Plus Cilgavimab Does Not Affect the Interpretation of Electrophoretic and Free Light Chain Assays.

OBJECTIVES: There is concern that the anti-severe acute respiratory syndrome coronavirus 2 therapeutic monoclonal antibodies, used as preexposure prophylaxis in patients with multiple myeloma, may appear as a detectable monoclonal protein by electrophoretic methods, resulting in misinterpretation or inability to measure therapeutic responses in some patients. In this pilot study, we characterize the effect of tixagevimab plus cilgavimab (Evusheld; T + C) on interpretation of serum protein electrophoresis (SPE), immunofixation electrophoresis (IFE), and serum free light chain (sFLC) assays. METHODS: We performed spiking experiments with T + C at serum maximum concentration following a 300-mg dose (1× Cmax) and at 10 times the concentration of Cmax (10× Cmax) with pooled serum samples. SPE and IFE technical procedures were performed on the SPIFE 3000, and sFLC and immunoglobulin G1 (IgG1) subtype quantitation was performed on the Optilite. RESULTS: T + C-associated interference was not visible as an M-spike in normogammaglobulinemic pooled samples. Hypogammaglobulemic pooled samples at 10× Cmax demonstrated an M-spike in SPE and immunoglobulin Gκ pattern in IFE. No increases were noted in the results of sFLC or IgG1 levels. CONCLUSIONS: This study indicates that T + C at pharmacologic Cmax is unlikely to interfere with SPE, IFE, sFLC, or IgG1 analyses when spiked into patient serum samples, but further evaluation of recently injected patients may be warranted.

Characterization of Casirivimab Plus Imdevimab, Sotrovimab, and Bamlanivimab Plus Etesevimab-Derived Interference in Serum Protein Electrophoresis and Immunofixation Electrophoresis.

BACKGROUND: Therapeutic monoclonal antibodies can be a source of assay interference in clinical serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE), producing monoclonal bands that can be misinterpreted as a monoclonal gammopathy related to a B-cell or plasma cell neoplasm. The extent to which new anti-COVID-19 monoclonal antibodies produce this interference is unknown. METHODS: Casirivimab plus imdevimab, sotrovimab, and bamlanivimab plus etesevimab were spiked into patient serum samples to evaluate for SPEP/IFE interference, to characterize the position of therapy-derived bands relative to a reference band (either combined beta band or beta 1 band, depending on instrument platform), and to confirm heavy and light chain utilization of each medication. Serum samples from patients who had recently received casirivimab plus imdevimab or sotrovimab were also evaluated for comparison. RESULTS: When spiked into serum samples, all tested anti-COVID-19 monoclonal antibodies generated interference in SPEP/IFE. Importantly, the patterns of interference differed between spiked serum samples and serum from patients who had recently received casirivimab plus imdevimab or sotrovimab. CONCLUSIONS: Imdevimab can be added to the growing list of therapeutic monoclonal antibodies that produce sustained interference in SPEP/IFE. Although casirivimab and sotrovimab also produce assay interference in vitro, these antibodies are not reliably detected in serum from recently infused patients. The value of relative band position in recognizing bands that may represent therapeutic monoclonal antibodies is also emphasized. Clinicians and laboratorians should consider therapeutic monoclonal antibody interference in diagnostic SPEP/IFE and review a patient's medication list when new or transient monoclonal bands are identified.

COVID VACCINE-INDUCED RHABDOMYOLYSIS. A CASE OF RECURRENT RHABDOMYOLYSIS

CASE: A 46-year-old African-American female was evaluated for generalized body aches five days after receiving second dose of COVID mRNA-1273 (Moderna) vaccine. Six months prior, she received her first dose of Ad26 (Johnson & Johnson) vaccine without sequelae, Family history includes maternal systemic lupus erythematous. Patient has a history of cystic acne and, most notably, frequent episodes of muscle aches and weakness. In 2006 and 2016, patient was hospitalized for episodes of rhabdomyolysis after receiving influenza vaccine. Autoimmune myositis was ruled out. She has never received statin medication. In late 2017, she was admitted for rhabdomyolysis after upper respiratory tract infection. She reported dark urine but no rash or arthralgia. Patient had elevated CK 107,737 U/L, AST 379 U/L, and ALT 115 U/L. Her renal function, sed rate, TSH, HIV, influenza, direct Coombs, protein electrophoresis, and antinuclear antibodies were negative or within normal limits. She was treated with IV fluids, pain medication, and discharged. In her current admission for rhabdomyolysis, she presented with dark urine, CK 130,702 U/L, AST 692 U/L, ALT 208 U/L, and D-dimer 1,544 ng/mL. No acute renal injury was noted. Patient was treated with intravenous crystalloids and pain medication. CK and transaminases steadily trended down. Patient was discharged as she was asymptomatic and CK had dropped significantly. IMPACT/DISCUSSION: Rhabdomyolysis can be an adverse event to vaccine administration, most commonly influenza vaccination. Detection of SARS-CoV-2 inside skeletal muscle has not been documented. Reports on COVID- 19 vaccine-induced rhabdomyolysis focus on the type of vaccine the patient received, the number of doses that triggered the event, CK level, and presence of risk factors for developing rhabdomyolysis. Although no pathophysiologic mechanism has been established, several hypotheses exist to explain muscle damage including genetic factors, autoimmune reactions to the virus nucleic material, or external adjuvant. This has been described as autoimmune/inflammatory syndrome induced by adjuvants. Our patient had a history of recurrent episodes of rhabdomyolysis after receiving influenza and COVID immunizations, as well as viral infection. CONCLUSION: The mechanism of our patients' reaction is unknown. Reported cases support autoimmunity as the major risk factor for vaccinerelated rhabdomyolysis. This patient had elevated CK level on subsequent episodes of rhabdomyolysis fitting the pattern where a more exaggerated response of the immune system is observed every time patient is re-exposed to known insult. Genetic predisposition may also play a role. AfricanAmericans have higher prevalence of slow acetylation and carnitine palmitoyltransferase II deficiency, a disorder of fatty acid. The myopathic form presents with high CK values. Therefore, patients should be counseled to seek medical attention when symptoms occur and physicians should consider vaccination as a possible cause.

Evaluation of a potential prognostic parameter for the inflammatory status in COVID-19 patients: The inflammatory protein ratio.

C-reactive protein (CRP), fibrinogen, and d-dimer are determined in the human plasma of 2745 hospitalized patients with and without coronavirus disease 2019 (COVID-19) by automated-latex enhanced immunoassay and immuno-turbidimetric assay. SARS-COV-2 RNA qualitative test, real time polymerase chain reaction (RT-PCR) based, is performed in nasopharyngeal swabs to confirm those with SARS-COV-2 positivity. Furthermore, serum proteins are separated and quantified in all the patients by serum protein electrophoresis (SPE). A new SPE parameter, inflammatory protein ratio (IPR), is elaborated for the first time by a mathematical equation that considers the albumin, α1-globulin, and α2-globulin. IPR normal reference range (10.7%-28.3%) is calculated considering the normal reference range of albumin, α1-globulin, and α2-globulin obtained for controls. Analysis of variance (ANOVA), Pearson's, Kruskal-Wallis, and Spearman's tests application show that IPR significantly correlates with direct proportionality with d-dimer, CRP, and fibrinogen. Significant (p < 0.001) increase of these parameters, IPR included, is detected in COVID-19 patients only. Our results show that IPR is more specific for monitoring inflammatory status thanks to its correlation with the only three serum proteins involved in inflammation: albumin, α1-globulin, and α2-globulin. Furthermore, IPR can simplify the interpretation of SPE results about inflammatory status, being of unique value compared to the six-serum protein classes separately presented in the typical SPE clinical reports.