BACKGROUND: Beta (β)-lactam antibiotics (BLAs) are the first-line therapy for non-nosocomial and nosocomial bacterial infections and are
most commonly reported to cause allergic reactions. Approximately 50% of all allergic patients in Europe and the USA suffer from drug
allergies and BLA allergies. The AIM of the study was to assess cross-reactivity reactions between 2nd and 3rd generation cephalosporins in patients with a medical history of BLA reactions and the risk of adverse reactions to BLAs based on the results of the basophil activation test.
MATERIALS AND METHODS: we examined 48 females and 8 males (in all 56 patients) aged 26 to 61 with primary reactions to BLAs and
24 healthy volunteers (control group). 19 (34%) patients were treated with amoxicillin, 18 (32,1%) patients were receiving amoxicillin+clavulanic acid, 6 (10,7%) patients were treated with cefuroxime, and 13 (23,2%) patients with ceftriaxone. Quantitative determination of the CD63 marker of basophil degranulation upon antigen stimulation in whole blood was performed with the use of Flow CAST (FK-CCR) (Bühlmann Laboratories AG, Switzerland). Based on the obtained ВАТresults, the patients were divided into two subgroups: the first group included 33 patients with positive stimulation index but lower CD63 expression (<10%), and the second group included 15 patients with a significantly higher level of CD63 expression (>10 %).
THE RESULT: We showed that patients from the second subgroup had the highest level of CD63 expression and stimulation index when
amoxicillin, whereas the level of CD63 expression and stimulation index were lower whith ceftriaxone; at the same time, the level of CD63 expression and stimulation index were the lowest with cefuroxime. The patients who treated with and reacted to amoxicillin, as shown by high
BAT, also had high CD63 expresiion after ceftriaxone and cefuroxime stimulation. In the first subgroup, urticarial and bronchospasm disappeared within 3 hours of the onset of symptoms in 51.5% of patients, the symptoms persisted for 2-3 days in 42.4% of patients with urticaria and angioedema, whereas maculopapular exanthema persisted for more than a week in 6.1% of the patients. Patients from the first subgroup (with low CD63 expression) had a weak reaction to the culprit antibiotic. Patients from the second subgroup had the strongest reaction to culprit antibiotics: anaphylaxis – 60.0%; Stevens-Johnson syndrome – 6.7%. We established that in patients with hypersensitivity to antibiotics the higher the baseline test scores after in vitro stimulation, the more severe clinical symptoms.
CONCLUSION: for patients with clinical manifestations of BLA in case of conflicting anamnesis data, it is recommended to establish true sensitization to antibiotics and to predict the occurrence of cross-reactions

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) are systemic autoimmune diseases that may lead to multiorgan failure due to the destruction of small- and medium-sized blood vessels. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may exacerbate autoimmune diseases and induced vasculitis.
METHODS: 9 patients median age 42 years (IQR, 31 to 50) with AAV after SARS-CoV-2 were assessed for signs of autoimmune disease and
serologic inflammation.
RESULTS: There were no significant differences in median age between male and female groups. Symptoms and comorbidities were comparable in
men and women. All patients were hospitalized with fever, cough, and vasculitis symptoms. Fever (88.9 %), cough (66.7 %), skin and oral lesions
(88.9%), polyarthralgia (55.6%) and myalgia (44.4%) were the most common symptoms. Five patients (55.6%) experienced asthenia. Morbilliform eruptions (44.4%), papules and peripheral erythema (55.6%), and pernio-like acral lesions (33.3%) were distributed symmetrically on all extremities and lower trunk. Microvascular thrombosis was seen in skin biopsies of two patients with vaso-occlusive cutaneous lesions.
Serology showed positive antinuclear antibodies (ANA) and antineutrophil cytoplasmic antibodies-myeloperoxidase (ANCA-MPO). The anti-myeloperoxidase antibody levels were 42.6 67.6 kU/l (N <0.3 ). Eight patients had C-reactive protein levels above the normal range (8.8 mg/L to 156.9 mg/L), elevated liver enzymes, and D-dimer. The appearance was consistent with SARS-CoV-2-associated vasculitis, erythema multiforme, and viral exanthem. Organ function improved after methylprednisolone and IVIG treatment.
CONCLUSIONS: SARS-CoV-2-associated AAV is a rare presentation requiring specific diagnostic assessment and therapy to suppress the severe underlying inflammation associated with ANCA-associated vasculitis.