Disease Characteristics | IgA-mediated Neutrophil-directed Skin Diseases | Severe COVID-19 Infection with Lung Tissue Injuries |
Circulating IgA | Skin-specific IgA are detected in linear IgA dermatosis and IgA pemphigus. | Early immunoglobulin surge is IgA, rather than IgM. IgA: IgM ratios markedly increase compared to milder cases. IgA levels parallel disease severity. COVID-19-specific IgA levels significantly correlate with disease severity. |
Tissue-bound IgA | Skin tissue IgA deposits are detected in linear IgA dermatosis, IgA pemphigus, and dermatitis herpetiformis. | IgA-vasculitis (with IgA deposited in blood vessels) occurred in some COVID-19 patients. IgA-nephropathy (with IgA deposited in kidney) occurred in some COVID-19 patients. Both dimeric IgA and monomeric IgA against SARS-CoV-2 in respiratory mucosa alveola were detected in severe COVID patients. |
Neutrophil Tissue Infiltration | Neutrophil infiltration in skin is detected in linear IgA dermatosis, IgA pemphigus, and dermatitis herpetiformis. | Neutrophil infiltration in lung tissues is primarily detected in severe cases. Neutrophils adhered to alveola epithelial cells were found in autopsy of COVID patients. |
Response to dapsone treatment | Responses are good to excellent. Rapid resolution of skin diseases can be achieved as early as one to three days. | A small study of 44 ICU-admitted severe COVID-19 patients documented 100% survival (22/22) of patients treated with dapsone, compared to 36% mortality (8/22) of patients who were not treated. Leprosy patients infected by COVID-19 while on dapsone treatment did not become severely ill and recovered. |