Letter Regarding “Fibrillary Glomerulonephritis Is Associated With HLA-DR7 and HLA-B35 Antigens”

To the Editor:

We read with interest the research letter entitled “Fibrillary Glomerulonephritis Is Associated With HLA-DR7 and HLA-B35 Antigens,” by Andeen et al.,¹ published on May 20, 2020. The letter reports the association between fibrillary glomerulonephritis (FGN) and specific human leukocyte antigens (HLAs), namely DR7 and B35, in a cohort of 26 patients from 3 institutions. The cases were composed of transplant recipients with FGN, de novo FGN in an allograft, and a donor with FGN.

We have recently reported on the long-term outcomes of our cohort of kidney transplant recipients with FGN² (n = 14) and have further identified 2 cases of donor-related FGN, totaling 16 cases of FGN with available HLA typing, including DQ data, which is detailed in Table 1. The most common class I and class II antigens in our cohort also included A2 (10/16, 62.5%), DR7 (8/16, 50%), and DQ2 (10/16, 62.5%). In addition, B7 (6/16, 37.5%) was frequently identified. The proportion of B35 was much lower in our cohort, 6.25% (1/16), and DR4 was moderately prevalent at 18.75% (3/16). Compared with the US white population,³ the proportion of each of the A2 (P = 0.41), B7 (P = 0.32), DR7 (P = 0.03), and DQ2 (P = 0.08) alleles was higher in FGN; however, using the χ² test, a significant difference was only identified for DR7. In contrast, the proportion of B35 (P = 0.26) and DR4 (P = 0.36) was lower in FGN, although not statistically significant.

Table 1.

HLA typing of kidney transplant recipient with FGN and donor-related FGN

Patient	HLA-A		HLA-B		HLA-DR		HLA-DQ
1	1	2	51	65	17	11	2	7
2	2	2	56	57	7	15	6	9
3	2	3	35	35	103	7	2	5
4	1	1	8	8	17	17	2	2
5	2	11	7	51	4	11	7	8
6	2	2	57	61	7	8	2	4
7	2	3	51	60	11	13	6	7
8	11	11	18	60	4	7	2	8
9	29	31	27	44	1	7	2	5
10	2	3	7	44	15	15	6	6
11	2	29	8	44	17	7	2	2
12	1	24	7	44	1	7	2	5
13	1	11	8	38	17	13	2	6
14	2	3	7	7	4	15	6	8
15a	1	3	7	13	7	15	2	6
16a	2	2	7	49	103	13	5	6

FGN, fibrillary glomerulonephritis; HLA, human leukocyte antigen

^aDonor-related FGN.

Similar to the previously studied cohort, 87% of subjects in our cohort with the DR7 antigen had DQ2 antigens (7/8) and of the DQ2 subjects, 70% (7/10) had DR7 antigens. Our data provide additional support for the association of DR7 but not B35 with FGN and support the hypothesis for possible underlying genetic cause, which will require further collaborative research studies.