Chen N, Nusbaum P, Halbwachs-Mecarelli L, Lesavre P
Department of Nephrology, Hôpital Necker, Paris, France.
Nephrol Dial Transplant. 1991;6(11):846-50. doi: 10.1093/ndt/6.11.846.
A predominant expression of IgA1 in mesangial deposits, serum, and bone marrow culture supernatants has been shown in IgA nephropathy (IgAN). Furthermore an excess of lambda light chains in both mesangial deposits and serum IgA has been observed. However, the origin of mesangial IgA remains controversial. In the present study, we have examined the IgA1 light chain type in IgAN. Total IgA1, IgA1 kappa and IgA1 lambda were measured by ELISA in serum and culture supernatants from spontaneous and pokeweed-mitogen (PWM)-stimulated peripheral blood mononuclear cells (PBMC). We observed an increase in IgA and IgA1 serum concentrations in IgA nephropathy patients, with a ratio of serum IgA1 to total serum IgA identical between patients and controls. The concentration of serum IgA kappa did not differ between patients and controls but patients had a significantly higher concentration of serum IgA lambda. The IgA1 kappa to IgA1 lambda ratio was 1.06 +/- 0.42 in IgAN patients versus 1.55 +/- 0.36 in controls (P less than 0.01). By contrast, the concentrations of IgA1 kappa and IgA1 lambda in PBMC culture supernatants, both spontaneous and PWM-stimulated, were identical in patients and controls. Therefore, there is a specific increase in IgA1 lambda in patients' sera. This contrasts with the normal IgA1 production by PBMC, which are derived from mucosal-associated lymphoid tissues. This suggests that IgA isotypic deregulation is confined to the bone marrow compartment and is not a generalised defect of the IgA system.
IgA肾病（IgAN）中已显示系膜沉积物、血清和骨髓培养上清液中IgA1呈主要表达。此外，在系膜沉积物和血清IgA中均观察到λ轻链过量。然而，系膜IgA的来源仍存在争议。在本研究中，我们检测了IgAN中的IgA1轻链类型。通过ELISA法测定了自发和商陆丝裂原（PWM）刺激的外周血单个核细胞（PBMC）的血清和培养上清液中的总IgA1、IgA1κ和IgA1λ。我们观察到IgA肾病患者血清中IgA和IgA1浓度升高，患者与对照组之间血清IgA1与总血清IgA的比值相同。患者与对照组之间血清IgAκ浓度无差异，但患者血清IgAλ浓度显著更高。IgAN患者的IgA1κ与IgA1λ比值为1.06±0.42，而对照组为1.55±0.36（P<0.01）。相比之下，患者和对照组自发及PWM刺激的PBMC培养上清液中IgA1κ和IgA1λ的浓度相同。因此，患者血清中IgA1λ有特异性升高。这与源自黏膜相关淋巴组织的PBMC正常产生IgA1形成对比。这表明IgA同种型失调局限于骨髓区室，并非IgA系统的普遍缺陷。
