Prevalence and Characteristics of Rheumatoid-Associated Autoantibodies in Patients with COVID-19

Figures & data

Table 1 Prevalence and Characteristics of Rheumatoid Factor Antibodies in Patients with COVID-19

Rheumatoid Factor Antibodies	COVID (n=129)
Overall prevalence in any RFs, n (%)	26 (20.16)
RF-IgA	13 (10.32)
RF-IgG	8 (6.35)
RF-IgM	12 (9.52)
RF-IgA +RF-IgG	1 (0.78)
RF-IgA +RF-IgM	2 (1.55)
RF-IgG+RF-IgM	2 (1.55)
RF-IgA +RF-IgG+RF-IgM	1 (0.78)

Note: The cutoff values for positivity in all rheumatoid factor antibodies were set >18 kU/L based on the recommendations of the manufacturer.

Table 2 Demographic and Clinical Characteristics and Laboratory Findings

Characteristic	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5
Demographic characteristics
Age — yr	41	37	62	79	61
Sex	Female	Female	Male	Female	Male
Initial findings
Medical history	Healthy without rheumatoid arthritis	Healthy without rheumatoid arthritis	Healthy without rheumatoid arthritis	Hypertension, no history of rheumatoid arthritis	Cholecystectomy, chronic gastritis, no history of rheumatoid arthritis
Disease severity	Moderate	Mild	Moderate	Severe	Severe
Symptoms at disease onset	Fever, cough, fatigue, muscle soreness, headache	Normal	Paroxysmal dry cough	Nausea, poor appetite, occasional vomiting	Fatigue, diarrhea and dyspnea.
Imaging features	Abnormal density of the upper lobe, Patchy shadow of left upper lobe of lung	Normal	Patchy changes in both lungs	Multiple infection foci in both lungs	Fibrous proliferative foci in both upper lobes of lung
Laboratory findings (Reference range)
Total lymphocytes (per mm^3) (1100–3200)	1070	1270	1000	510	400
Globulin (g/liter)(20–30)	26.5	24.6	27.9	30.6	28.3
Alanine aminotransferase (U/liter) (7–45)	30	20	23	15	110
Aspartate aminotransferase (U/liter) (13–35)	27	16	27	34	52
C-reactive protein (mg/liter)(0–10)	12	2	20.7	39.3	8.2
Serum amyloid A (mg/liter) (0–10)	45.95	25.39	167.56	237.58	139.83
D-dimer (mg/liter) (0–0.5)	0.161	0.089	0.419	6.576	11.902
Prothrombin time (sec) (9.4–12.5)	12.8	12	12.6	10.8	17
Anti-cardiolipin antibody (0–12)	IgA 0.73 (APL/mL) IgG 1.13 (GPL/mL) IgM 1.82 (MPL/mL)	IgA 9.88 (APL/mL) IgG 0.52 (GPL/mL) IgM 1.39 (MPL/mL)	IgA 8.37 (APL/mL) IgG 1.87 (GPL/mL) IgM 0.56 (MPL/mL)	IgA 1.83 (APL/mL) IgG 36.93 (GPL/mL) IgM 4.36 (MPL/mL)	IgA 13.62 (APL/mL) IgG 17.78 (GPL/mL) IgM 30.05 (MPL/mL)
ANA	Negative	Negative	Negative	Negative	Negative
Interleukin-6 (pg/mL)(0–7)	20.93	5.26	6.75	92.58	63.19
Anti-jo-1 (Relative Level)	Feb. 10 7 Mar. 27 88 May 09 76 Jun. 18 65 Jul. 15 63 Jul. 30 55	Negative	Negative	Negative	Negative

Note: The data is the first test result after the patient’s RT-PCR diagnosis except for anti-jo-1.

Figure 1 Dynamic changes in the levels of rheumatoid factor antibodies during COVID-19 among five patients.