Why you may want to loose IgM. Oliclonal bands may be a predictor poor outcomes

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Antibody in ciculation is made up of secreted IgG , IgA , and IgM

Oligoclonal bands are often made up of IgG, but there are also IgM present, If they are a are present it seems to be a worse predictor of future outcome

Cabrera CM. Oligoclonal bands: An immunological and clinical approach. Adv Clin Chem. 2022;109:129-163.

Oligoclonal bands (OCBs) in cerebrospinal fluid (CSF) represent an indicator of IgG and IgM immunoglobulins intrathecal synthesis in the central nervous system (CNS). The techniques and detection methods for their determination have evolved from the beginning to isoelectric focusing on an agarose gel as the gold standard technique and immunodetection as the reference method. The evolution, both in techniques and methods for detection of IgG and IgM OCBs is evaluated in this review. In addition to the significance of the presence of a single band of IgG immunoglobulin in CSF, IgG OCBs within the diagnostic criteria of multiple sclerosis (MS), the prevalence of IgG OCBs and the effect of latitude in MS, as well as the clinical and immunological involvement of OCBs (IgG and IgM) in MS and other neurological diseases.

Rosenstein I, Rasch S, Axelsson M, Novakova L, Blennow K, Zetterberg H, Lycke J. Increased intrathecal neurofilament light and immunoglobulin M predict severe disability in relapsing-remitting multiple sclerosis. Front Immunol. 2022 Aug 10;13:967953.

Background: Emerging evidence supports that determination of intrathecal immunoglobulin M (IgM) synthesis (ITMS) and neurofilament light (NfL) concentration in cerebrospinal fluid (CSF) may be clinically useful as disease severity biomarkers in relapsing-remitting multiple sclerosis (RRMS).

Methods: Monocentric observational longitudinal cohort study in which prospectively collected data were retrospectively retrieved. Included were patients with RRMS (n=457) who had a diagnostic investigation including analysis of ITMS and CSF neurofilament light (cNfL). ITMS was calculated with the linear index formula, the intrathecal fraction of IgM according to Reiber (IgMIF), and by qualitative determination of oligoclonal IgM bands (OCMB). Univariable and multivariable models were performed to predict Evidence of Disease Activity-3 (EDA-3) status within 24 months from onset, and the risk of Expanded Disability Status Score (EDSS) ≥3 and ≥6.

Results: All investigated methods to calculate ITMS significantly predicted evidence of disease activity (EDA-3) within 24 months. IgMIF>0% showed the strongest association with EDA-3 status (adjusted hazard ratio [aHR] 3.7, 95%CI 2.7-5, p<0.001). Combining IgM-index>0.1 or OCMB with increased cNfL were strong predictors of EDSS≥3 (for cNfL + /IgM-index + : aHR 4.6, 95%CI 2.6-8.2, p<0.001) and EDSS≥6 (aHR 8.2, 95%CI 2.3-30, p<0.001).

Conclusions: In a real-world setting, ITMS was a useful biomarker in early RRMS to predict disabling MS and its prognostic value was even stronger in combination with cNfL. Our data suggest that determination of ITMS and cNfL should be included in the diagnostic work-up of RRMS for prognostic purposes and in decisions of disease-modifying therapy.

Casanova B, Castillo J, Quintanilla-Bordás C, Sanz MT, Fernández-Velasco JI, Alcalá C, Carratalá S, Gasque R, Rubio A, Cubas L, Villar LM, Pérez-Miralles F. Oligoclonal M bands unveil occult inflammation in multiple sclerosis. Mult Scler Relat Disord. 2022 Aug 15;68:104118.

Introduction: Recent works demonstrate that patients with multiple sclerosis (pwMS) and oligoclonal M bands (OCMB) in cerebrospinal fluid (CSF) are at higher risk of conversion to secondary progressive course, suggesting a distinct pathophysiology pathway in these patients.

Objectives: To analyze the relationship of serum neurofilament light chain (s-NFL) in absence of inflammatory activity in people with multiple sclerosis (pwMS) according to the presence of OCMB versus healthy controls (HC), and the effect of aging.

Methods: Two cohorts of HC were compared to a cohort of pwMS without clinical or radiological signs of acute inflammation. Lack of inflammation was defined as the absence of relapses or gadolinium-enhancing lesions (GEL) brain in an MRI performed within three months before and after s-NFL determination. S-NFL was measured with SIMOa technology. OCMB in the cerebrospinal fluid (CSF) were analyzed with isoelectric focusing and immunoblotting.

Results: 254 people were studied: 124 healthy voluntary controls and 130 pwMS. Despite the absence of inflammatory activity, pwMS and OCMB showed higher levels of s-NFL compared to those without OCMB and HC (11.4 pg/mL, 8.9 pg/mL and 9.0 pg/mL, respectively). A positive and exponential correlation between age and s-NFL was observed, with highest increases among pwMS and OCMB in the CSF.

Discussion: In absence of overt inflammatory activity, pwMS and OCMB exhibit higher s-NFL levels, and a greater age-related increase. Thus, OCMB may portray an underlying inflammatory process not detected by conventional MRI studies and may explain the poorer prognosis of these patients.

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