Table 1.

Clinical features of patients with atypical anti-GBM at index biopsy

	Patient
	1	2	3	4	5
Age (years)	67a	23	60b	64	31
Sex	Male	Male	Female	Male	Male
Smoking history	Former, quit 45 years agoa	Smoker	Never smoker	Unknown	Unknown
Serum creatinine (mg/dL)	1.2	1.6	0.73	7.1	‘Normal’
Hematuria	Yes, gross	Yes, 100–200 RBCs	Yes, >50 RBCs, non-dysmorphic	n/a	Yes
Proteinuria	Urine Pr:Cr = 1.2	Urine Pr:Cr = 3.25	0.4 g/day	n/a	n/a
Anti-GBM	IFA positive once, ELISA and other time points negative	Negative	Weak positive at 1.5 (upper limit of normal = 1)	Positive 112 (nl <20)	Positive
ANCA	Negative	Negative	Negative	Negative	n/a
Complements	Normal	Normal	Normal	Mildly low C3 = 82 (nl 83–177) C4 = 7 (nl 12–36)	n/a
Other	ANA negative Hematologic workup negative, including sPEP/uPEP, free light chains and peripheral blood flow cytometry	ANA negative RF negative Hepatitis B, C negative HIV negative sPEP normal	ANA negative ESR and CRP elevated; IgG subclasses normal	IgG-lambda monoclonal spike (>3 g), ESR = 144, Hgb = 7.6 with normal WBC and platelet count	Pulmonary hemorrhage

ANA, anti-nuclear antibody; ANCA, anti-neutrophil cytoplasmic antibody; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; ELISA, enzyme-linked immunosorbent assay; Hgb, hemoglobin; HIV, human immunodeficiency virus; IFA, indirect immunofluorescence assay; n/a, not available; nl, normal range; Pr:Cr, protein to creatinine ratio; RBC, red blood cell; RF, rheumatoid factor; sPEP/uPEP, serum protein electrophoresis/urine protein electrophoresis; WBC, white cell count.

^aProteinuria at age 18 years; also occupational exposure to wood smoke and sulfuric acid fumes.

^bFirst presentation at age 44 years.