Pulmonary hypertension secondary to seronegative rheumatoid arthritis overlapping antisynthetase syndrome: A case report

Table 1 Primary laboratory test results

Lab	Apr-18	Apr-19	Sep-20	Apr-21	Reference values
ESR	74.0	88.0	56.3	82.1	0-20 mm/h
CRP	17.7	55.8	28.7	36.8	< 10 mg/L
Rheumatoid factor	< 20	20.3	< 20	< 20	< 20 U/mL
Anti-cyclic citrullinated peptide antibody	0.9	0.9	< 0.5	< 0.5	< 5.0 U/mL
Antinuclear antibody titer	1/100	1/100	1/100	1/1000	Negative
C3	0.82	0.9	1.01	1.08	0.79-1.52 g/L
C4	0.13	0.18	0.20	0.19	0.16-0.38 g/L
R0-52 antibody	Positive	Positive	Strong positive	Strong positive	Negative
JO-1 antibody	Positive	Positive	Strong positive	Strong positive	Negative
p-ANCA	Negative	Negative	Negative	Negative	Negative
c-ANCA	Negative	Negative	Negative	Negative	Negative
Creatine kinase	700.8	159.5	-	358.0	26-140 U/L
PaCO2	70.6	68.4	-	62.8	83-108 mmHg
PaO2	29.4	29.4	-	29.0	35-45 mmHg
Pulmonary artery systolic pressure	47	55	-	72	15-30 mmHg

ESR: Erythrocyte sedimentation rate; CRP: C-reactive protein; ANCA: Anti-neutrophil cytoplasmic antibodies; PaO₂: Partial oxygen pressure; PaCO₂: Partial carbon dioxide pressure.