Sesso R, Almeida M A, Figueiredo M S, Bordin J O
Divisõe de Nefrologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brasil.
Braz J Med Biol Res. 1998 Oct;31(10):1257-62. doi: 10.1590/s0100-879x1998001000004.
Patients with sickle cell anemia (Hb SS) or sickle cell trait (Hb AS) may present several types of renal dysfunction; however, comparison of the prevalence of these abnormalities between these two groups and correlation with the duration of disease in a large number of patients have not been thoroughly investigated. In a cross-sectional study using immunoenzymometric assays to measure tubular proteinuria, microalbuminuria, measurement of creatinine clearance, urinary osmolality and analysis of urine sediment, we evaluated glomerular and tubular renal function in 106 adults and children with Hb SS (N = 66) or Hb AS (N = 40) with no renal failure (glomerular filtration rate (GFR) > 85 ml/min). The percentage of individuals with microalbuminuria was higher among Hb SS than among Hb AS patients (30 vs 8%, P < 0.0001). The prevalence of microhematuria was similar in both groups (26 vs 30%, respectively). Increased urinary levels of retinol-binding protein or beta 2-microglobulin were detected in only 3 Hb SS and 2 Hb AS patients. Urinary osmolality was reduced in patients with Hb SS or with Hb AS; however, it was particularly evident in Hb SS patients older than 15 years (median = 393 mOsm/kg, range = 366-469) compared with Hb AS patients (median = 541 mOsm/kg, range = 406-722). Thus, in addition to the frequently reported early reduction of urinary osmolality and increased GFR, nondysmorphic hematuria was found in 26 and 30% of patients with Hb SS or Hb AS, respectively. Microalbuminuria is an important marker of glomerular injury in patients with Hb SS and may also be demonstrated in some Hb AS individuals. Significant proximal tubular dysfunction is not a common feature in Hb SS and Hb AS population at this stage of the disease (i.e., GFR > 85 ml/min).
镰状细胞贫血（Hb SS）或镰状细胞性状（Hb AS）患者可能会出现几种类型的肾功能障碍；然而，尚未对这两组患者中这些异常情况的患病率进行比较，也未对大量患者中这些异常与疾病持续时间的相关性进行深入研究。在一项横断面研究中，我们使用免疫酶测定法测量肾小管蛋白尿、微量白蛋白尿、肌酐清除率、尿渗透压并分析尿沉渣，评估了106例无肾衰竭（肾小球滤过率（GFR）> 85 ml/min）的成人和儿童Hb SS（N = 66）或Hb AS（N = 40）患者的肾小球和肾小管肾功能。Hb SS患者中微量白蛋白尿个体的百分比高于Hb AS患者（30% 对8%，P < 0.0001）。两组中镜下血尿的患病率相似（分别为26% 和30%）。仅在3例Hb SS患者和2例Hb AS患者中检测到视黄醇结合蛋白或β2 -微球蛋白的尿水平升高。Hb SS或Hb AS患者的尿渗透压均降低；然而，与Hb AS患者（中位数 = 541 mOsm/kg，范围 = 406 - 722）相比，在15岁以上的Hb SS患者中尤为明显（中位数 = 393 mOsm/kg，范围 = 366 - 469）。因此，除了经常报道的早期尿渗透压降低和GFR升高外，分别在26% 的Hb SS患者和30% 的Hb AS患者中发现了非畸形血尿。微量白蛋白尿是Hb SS患者肾小球损伤的重要标志物，在一些Hb AS个体中也可能出现。在疾病的这个阶段（即GFR > 85 ml/min），明显的近端肾小管功能障碍在Hb SS和Hb AS人群中并非常见特征。
