I agree with the authors that the following two points might additionally contribute to the association of IgA nephropathy (IgAN) with systemic lupus erythematosus (SLE).
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Several novel susceptibility genes for SLE and IgAN have been identified in recent genome-wide association studies. Since both LN and IgAN are autoimmune renal diseases, they might share common disease mechanisms that overlap with genetic tendency. This is recently supported by the demonstration of shared genetics between IgAN and SLE.[1,2]
In our case, pathologiclly, this nonlupus form of glomerulonephritis should be considered as IgAN in patients with SLE rather than LN because the prominent IgA deposits in the mesangium dominated the histological picture, and significant proliferation was absent[3] and our case may support that both LN and IgAN are autoimmune renal diseases, they might share common disease mechanisms that overlap with genetic tendency. However, Vuong, et al.[4] did not support an overlap in genetic susceptibility between patients with IgAN or SLE and reveal no specific importance of SLE associated SNPs for the presence of lupus nephritis (LN). In addition, geographic differences in genetic susceptibility to SLE and IgAN[5] must be taken into consideration. Hence, we need further and more studies to support these genetic associations between IgAN and LN in different geographical regions.
In addition, according to the recommendations of Churg et al.,[6] class IV LN is defined by diffuse distribution of subendothelial deposits regardless of the pattern of proliferation and the presence of large subendothelial depositions of immunoglobulins without activation of the complement system and proliferation is exceptional and although C1q, C3, C4, and IgG depositions are more common in typical LN, IgA deposition can also be seen.[7] Thus, our case with predominant mesangial IgA deposits may be proposed to be a special subtype of LN.
Human immunodeficiency virus (HIV) infection associated with a variety of glomerulonephritides, including IgAN, membranoproliferative glomerulonephritis (GN), membranous nephropathy, lupus-like GN, immunotactoid glomerulopathy, and fibrillary GN.[8] However, despite low prevalence of HIV in Kuwait (0.1%),[9] HIV infection was considered by us[3] and HIV infection was negative in our patient.
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Conflicts of Interest
There are no conflicts of interest.
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