Immunohistochemical detection of intravascular platelet microthrombi in patients with lupus nephritis and anti-phospholipid antibodies.
OBJECTIVE
To evaluate whether the use of platelet immunohistochemistry (IHC) markers improves the sensitivity of histological methods to detect microthrombosis in SLE nephritis and aPLs and to analyse the clinicopathological correlations of microthrombosis in this setting.


METHODS
Kidney biopsy specimens from 65 patients with SLE, including 36 with positive aPLs, were studied by IHC using antibodies against platelet glycoproteins CD41 and CD61. Clinical data at the time of kidney biopsy and during a mean follow-up of 7.5 years after biopsy were recorded and analysed with regard to histological or IHC data.


RESULTS
Histological lesions previously defined as APS nephropathy were found in 33% of the SLE kidney biopsies and were not associated with positive aPLs. Microthrombi detected as intravascular CD61(+) platelet deposits were present in 43% of the tissues and were significantly associated with positive aPLs, but not with histological APS nephropathy, nephritis manifestations nor with renal outcome. Histological APS lesions but not CD61(+) microthrombi correlated with an older age at nephritis presentation, previous cardiovascular risk factors and worse renal outcome.


CONCLUSIONS
Immunodetection of intravascular CD61(+) platelet aggregates is more sensitive than histological evaluation to detect acute microthrombosis and provides a better correlation with aPLs in SLE patients. In contrast, histological lesions consistent with APS nephropathy were not associated with aPLs but with cardiovascular risk factors and worse renal outcome.
Galindo
María
M
Servicio de Reumatología, Hospital 12 de Octubre, Madrid, Spain. mgalindo@h12o.es
Gonzalo
Elena
E
Martinez-Vidal
María P
MP
Montes
Santiago
S
Redondo
Natalia
N
Santiago
Begoña
B
Loza
Estibaliz
E
Pablos
José L
JL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017152:Antibodies, Antiphospholipid; D015415:Biomarkers / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D039661:Integrin beta3 / Q000032:analysis; D007668:Kidney / Q000276:immunology / Q000473:pathology; D008181:Lupus Nephritis / Q000150:complications* / Q000276:immunology / Q000473:pathology; D008297:Male; D055806:Microvessels; D008875:Middle Aged; D016017:Odds Ratio; D010974:Platelet Aggregation; D040201:Platelet Membrane Glycoprotein IIb / Q000032:analysis; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000150:complications* / Q000276:immunology / Q000473:pathology; D055815:Young Adult
D017152:Antibodies, Antiphospholipid; D015415:Biomarkers; D039661:Integrin beta3; D040201:Platelet Membrane Glycoprotein IIb