Clinicopathological significance of monoclonal IgA deposition in patients with IgA nephropathy.

BACKGROUND: Clinicopathological significance of monoclonal IgA deposition and its relation to bone marrow abnormalities in IgA nephropathy (IgAN) remains unclear. METHODS: We retrospectively investigated the prevalence and clinicopathological significance of monoclonal IgA deposition in 65 patients with IgAN. Serum-free light chain ratio, and urinary Bence Jones protein were also measured. RESULTS: Thirty-nine percent of patients were men, median age was 40 and median observation period was 31 months. Five patients (Group M) showed monoclonal IgA lambda deposition and one showed monoclonal IgA kappa deposition. Fifty-nine patients (Group P) showed polyclonal IgA deposition. There were no significant differences in the degree of proteinuria, hematuria and renal function between Group M and Group P. Total protein and albumin were significantly lower in Group M than in Group P. According to the Oxford classification, the percentage of patients with M1 was significantly higher in Group M than in Group P. One patient in Group P showed serum monoclonal IgG lambda. No patient showed abnormal serum-free light chain ratio. Seventy-five percent in Group M and 42 % in Group P were treated with steroid. Three patients in Group P progressed to end-stage renal disease (ESRD). The frequency of disappearance of proteinuria or hematuria and progression to ESRD was not different between the groups. CONCLUSIONS: The prevalence of monoclonal IgA deposition was 9.2 %. Although some parameters differed between the groups, renal outcome were similar. Thus, IgAN with monoclonal IgA deposition seems not to be different entity from those with polyclonal IgA deposition.

Extrapulmonary tuberculosis presented as fever of unknown origin in two patients with endstage kidney disease not on dialysis: usefulness of 18-FDG-PET/CT in the diagnostic localization of fever of unknown origin.

Tuberculosis is one of the common causes of fever of unknown origin in patients with chronic kidney disease (CKD). Extrapulmonary tuberculosis is more common in CKD patients, and is, unfortunately, often underdiagnosed despite extensive assessments. Recently, fluorine-18-deoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has been available in the diagnosis of malignancy, inflammatory and infectious diseases, and has become a useful diagnostic tool. Here, we present two cases of endstage kidney disease who presented with fever of unknown origin at the time of dialysis initiation. In both cases, although interferon-gamma-releasing assay was positive, combined conventional diagnostic modalities such as computed tomography and gallium-citrate scintigraphy failed to detect the sites infected with tuberculosis. By contrast, extrapulmonary lesions were detected by FDG-PET/CT and successfully treated with combined anti-tuberculous drugs. Diagnosis of extrapulmonary tuberculosis was confirmed by biopsy of the affected lymph node and lumbar spine, followed by PCR of the biopsied specimen. These cases highlight the importance of considering tuberculosis as one of the differential diagnoses in pre-dialysis CKD patients with persistent fever, and the usefulness of FDG-PET/CT in the detection of infectious sites of extrapulmonary tuberculosis.

Osteomalacia secondary to renal tubular acidosis due to Sjögren's syndrome: a case report and review of the literature.

A 43-year-old woman was admitted to our hospital because of generalized bone pain. Arterial blood gas showed pH 7.266, HCO3- 13.5 mEq/l, and anion gap (AG) 12. Since her urine pH was 7.0 despite metabolic acidosis with normal AG, we diagnosed distal renal tubular acidosis (RTA). Serum phosphate was 2.5 mg/dl, the level of ß2 microglobulin was 41100 µg/l, and aminoaciduria was present. These results indicated proximal tubular dysfunction. The radiograph showed pseudofracture in the pubic bone, indicating osteomalacia. Bone scintigram showed abnormal accumulations of 99mTc-HMDP in multiple joints. Then, her generalized bone pain was considered to be a symptom of osteomalacia. Despite the absence of overt Sicca syndrome, the evaluation of Sjögren's syndrome (SjS) as a cause of distal RTA was performed. Antibodies to the SS-A level was 127U/ml. Tear break-up time was 3 s bilaterally and salivary gland scintigraphy showed low uptake of 99mTc in the submandibular glands and the parotids. Thus, we diagnosed SjS finally. Gallium scintigraphy showed mild abnormal uptake in bilateral kidneys, suggesting acute tubulointerstitial nephritis. After treatment with prednisolone, alfacalcidol, and sodium bicarbonate, bone pain was remarkably relieved. Additionally, aminoaciduria disappeared and the level of ß2 microglobulin decreased. We speculated that the coincidence of proximal tubular dysfunction and distal RTA cause a severe manifestation of osteomalacia.

Hypothermia-induced acute kidney injury in a diabetic patient with nephropathy and neuropathy.

Hypothermia is a life-threatening medical condition defined as an unintentional fall in body temperature below 35 degrees C. Exposure to cold environment stimulates the thermoregulatory system to maintain the body temperature within the physiological range. Patients with malnutrition and/or diabetes mellitus are at high risk for accidental hypothermia, and acute kidney injury, which is mainly caused by pre-renal factors, occurs in relation to hypothermia. However, acute exacerbation of pre-existing chronic kidney disease has been rarely reported. Here, we present a patient with diabetes mellitus and malnutrition who developed two separate episodes of hypothermia followed by acute exacerbation of chronic kidney disease.

Changes in choriocapillaris fenestration of rat eyes after intravitreal bevacizumab injection.

BACKGROUND: To examine the effects of anti-VEGF antibody (bevacizumab) on the number of fenestrations in rat choriocapillaris. METHODS: Twenty-four eyes from 24 male Wister rats were injected intravitreally with 0.125 mg of bevacizumab. The rats were perfusion fixated at 1, 3, 7, 14 or 28 days after injection. The surfaces of the choriocapillaris on the RPE side were observed using scanning electron microscopy. Four eyes treated with human IgG were used as controls. The area sieve plate and the number of fenestrations after the bevacizumab injection were measured and compared with controls. RESULTS: In the controls, the sieve plate area was 80.7% of the total choriocapillaris area. The number of fenestrations was 69.2 +/- 0.2 /microm(2) of the fenestrated area. While there were no changes in the fenestrated area for any of the time points after the bevacizumab treatment, the number of fenestrations was significantly reduced to 52.9 +/- 4.4 at day 1, 55.6 +/- 3.6 at day 3 and 53.6 +/- 8.6 /microm(2) of the luminal surface at day 7 (ANOVA, p < 0.05). CONCLUSIONS: In this study, intravitreal bevacizumab injection reduced fenestration of the normal choriocapillaris. These results indicate there is a latent risk inherent with bevacizumab treatment of normal choriocapillaris.