Lai K N, Lai F M, Lo S T, Lam C W
Department of Medicine, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin.
Am J Kidney Dis. 1988 May;11(5):425-9. doi: 10.1016/s0272-6386(88)80056-8.
The immunochemical nature of the light chains of the mesangial IgA deposits were studied in 13 IgA nephritic patients with only IgA isotype in their renal biopsies. Direct immunofluorescence (IF) using rabbit and goat antihuman monospecific antibodies demonstrated lambda light chain IF in all 13 biopsies (100%). Kappa light chain IF was detected in ten renal biopsies by the rabbit antihuman antisera and in eight renal biopsies by the goat antihuman antisera. Monoclonal antibodies studies showed lambda IF in all 13 biopsies and kappa IF in eight biopsies. Twelve biopsies showed a predominance of lambda light chain IF staining in the mesangial deposits. Identical IF patterns were observed when double IF technique with rhodamine-conjugated antihuman alpha heavy chain antiserum and fluorescein-conjugated antihuman light chain antisera were employed, and these findings confirmed that the light chains IF arose directly from the IgA deposits. These IgA nephritic patients had a significantly higher serum concentration of lambda light chain-IgA and a distinct alteration of kappa/lambda ratio of IgA compared with healthy controls. Our results support our preliminary observation that mesangial IgA deposits in IgA nephropathy consist mostly of IgA with lambda light chain.
对13例肾活检仅见IgA同型的IgA肾病患者系膜IgA沉积物轻链的免疫化学性质进行了研究。使用兔和山羊抗人单特异性抗体的直接免疫荧光（IF）显示，所有13例活检标本（100%）均有λ轻链IF。兔抗人抗血清在10例肾活检标本中检测到κ轻链IF，山羊抗人抗血清在8例肾活检标本中检测到κ轻链IF。单克隆抗体研究显示，所有13例活检标本均有λ IF，8例活检标本有κ IF。12例活检标本显示系膜沉积物中λ轻链IF染色占优势。当采用罗丹明偶联的抗人α重链抗血清和荧光素偶联的抗人轻链抗血清的双重IF技术时，观察到相同的IF模式，这些结果证实轻链IF直接来自IgA沉积物。与健康对照相比，这些IgA肾病患者血清λ轻链-IgA浓度显著升高，IgA的κ/λ比值明显改变。我们的结果支持我们的初步观察，即IgA肾病中的系膜IgA沉积物主要由带有λ轻链的IgA组成。
