IgG4 reagent for clinical analyzers
N-assay LA IgG4 Nittobo

IgG4-relaeted disease

In recent years, attention has been drawn to the concept of IgG4-related diseases that was first proposed in Japan.
IgG4-related diseases are diseases of unknown etiology where, in addition to the presence of immune abnormalities and high IgG4 values in blood, the marked infiltration of lymphocytes and IgG4-positive plasma cells into organs and the resulting fibrosis are seen to cause synchronous or metachronous swelling and nodular or hypertrophic lesions.
A wide range of organs can be affected by IgG4-related diseases (refer to the Figure: Lesions in various organs from IgG4-related diseases), and present with differing organ-specific symptoms.
In addition, the lesions can often spread into multiple organs and present characteristics of a systemic disease, and sometimes there can be serious complications such as organ failure.
The measurement of serum IgG4 has been suggested to be an essential part of the comprehensive diagnostic criteria for IgG4-related diseases, and there are calls for it to be implemented on a wider scale.

*The Research Program for Intractable Disease Ministry of Health, Labour, and Welfare Japan Okazaki Group/Umehara Group.
Comprehensive Diagnostic Criteria for IgG4-related Diseases, 2011.
The Journal of the Japanese Society of Internal Medicine. 101(3): 797, 2012.

Figure: Organ Involvment of IgG4-related diseases

Organ Involvment of IgG4-related diseases

Comprehensive diagnostic criteria for IgG4-related disease(IgG4-RD),2011
The Research Program for intractable Disease, Ministry of Health, Labour, and Welfare Japan, Okazaki Group/Umehara Group.

*From Comprehensive Diagnostic Criteria for IgG4-related Disease, 2011.
The Journal of the Japanese Society of internal Medicine. 101(3):801, 2012.

The Comprehensive Diagnostic Criteria for IgG4-related Disease, 2011, consist of three clinical criteria related to clinical findings, blood test result, and histopathological findings and were created with five basic concepts in mind.

Basic concepts of the Criteria

  1. 1. Can also be used by clinicians not specialized in diseases of specific organs.
  2. 2. Can be used alongside organ-specific diagnostic criteria.
  3. 3. Are as concise as possible.
  4. 4. Emphasize histopathological findings to rule out malignancies, which is important in differential diagnosis.
  5. 5. Do not recommend therapeutic diagnosis with steroids.

Fig.2: Diagnostic algorithm perfomance for comprehensive diagnostic criteria for lgG4-related disease (lgG4-RD)

*From Umehara H, Okazaki K, et al. Mod Rheumatol. 22:21-30. 2012
Comprehensive Diagnostic Criteria for lgG4-「elated Disease (lgG4-RD), 2011. The Journal of the」apanese Society of Internal Medicine. 101 (3): 802, 2012.

Diagnostic algorithm perfomance for comprehensive diagnostic criteria for lgG4-related disease

When clinical symptoms or organ enlargement clinically suggestive of IgG4-RD is observed, blood IgG4 should be measured and pathological examination performed whenever possible.
Even when IgG4-RD is only judged to be possible according to the comprehensive diagnostic criteria for IgG4-RD, it may be possible to reach a definitive diagnosis by also using organ-specific criteria.

As these criteria emphasize histopathology and do not recommend therapeutic diagnosis with steroids, they may not always have high diagnostic sensitivity for lesions in organs that are difficult to biopsy.
Therefore, it is recommended to also use organ-specific criteria for groups diagnosed with possible or probable lgG4-RD, and the diagnosis for different organs of the same patient can vary from definite to probable or possible.

N-assay LA IgG4 Nittobo

product description

  • This reagent can be used in standard clinical analyzers.
  • This reagent employs a monoclonal antibody for specifically measuring IgG4.
  • A mass spectrometer was used to quantify reference material of the reagent on a scientific basis.
  • This reagent employs a method that does not display false low values even at high IgG4 concentrations and can measure samples up to 500 mg/dl.

Superioradaptability and high IgG4 specificity

Enabling IgG4 measurement in laboratories withstandard clinical analyzers

The N-assay LA IgG4 Nittobo is a reagent to measure serum IgG4 by standard clinical analyzers.
By using this reagent, any laboratory equipped with clinical analyzers can measure serum IgG4, facilitating quicker and easier implementation of the test.

Correlation

Excellent correlation with existing reagents up to 200 mg/dL

Correlation

(Measured by JEOL BM6070-model clinical analyzer)

No hook effect

This reagent was designed to employ the method that does not display false low values even in regions of high IgG4 concentration

No hook effect

(Measured by Hitachi 7180-model clinical analyzer)

Specify

Uses monoclonal antibodies with high specificity for IgG4

 IgG1
Myeloma
IgG2
Myeloma
Ig G3
Myeloma
Theoretical value (mg/dL) 3000 3000 3000
value from N-assay LA IgG4 NIttobo (mg/dL) 10 12 4
Percentage of measurement value against theoretical value 0.33% 0.40% 0.13%

Reference range for N-assay LA IgG4 Nittobo:11-121 mg/dL

(n = 471, in-house data)

Copyright © 2018 NITTOBO MEDICAL CO.,LTD. All rights reserved.