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Introduction: The World Health Organization (WHO) advocates the use of reliance practices to enable national regulatory authorities (NRAs) to improve patients' access to medicines. This study considered whether reliance review translates into swifter medicine authorization., Methods: Abridged review outcomes were examined for New Chemical Entity (NCE) and generic applications to the South African Health Products Regulatory Authority (SAHPRA) in Chemistry, Manufacturing and Controls (CMC) and clinical/bioequivalence (BE), as well as overall NCE authorization times., Results: SAHPRA NCE CMC review time was 91 days (abridged) vs. 179 days (full), applicant response time was 34 vs. 105 days, respectively, and there was a >2-fold time reduction for abridged vs. full CMC review (125 vs. 284 days). There was a 99-day decrease in clinical approval time through an abridged review (230 vs. 329 days) and a decrease in marketing authorization time for NCE abridged assessment (446 vs. 619 days). SAHPRA review time for generic applications was 97 days (abridged) vs. 191 days (full); applicant response time was 26 days (abridged) vs. 81 days (full) and there was a >2-fold time reduction for CMC and BE abridged vs. full review (122 vs. 272 days)., Conclusion: These results clearly support World Health Organization recommendations for the use of reliance-based regulatory review to expedite the worldwide availability of safe, effective and needed medications., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Danks, Semete-Makokotlela, Otwombe, Parag, Walker and Salek.)

Introduction: Regulatory reliance, harmonization and work sharing have grown over the last few years, resulting in greater sharing of work and information among regulators, enabling efficient use of limited resources and preventing duplication of work. Various initiatives on the African continent include ZaZiBoNa, the Southern African Development Community (SADC) collaborative medicines registration initiative. ZaZiBoNa has resulted in great savings in time and resources; however, identified challenges include lack of clear information regarding the participating countries registration processes and requirements as well as lengthy registration times. The aim of this study, therefore, was to compare the data requirements and review models employed in the assessment of applications for registration, the target timelines for key milestones and the metrics of applications received and approved in 2019 and 2020 by Mozambique, Namibia, South Africa, Tanzania, Zambia, and Zimbabwe. Methods: A senior member of the division responsible for issuing marketing authorisations completed an established and validated questionnaire, which standardizes the review process, allowing key milestones, activities and practices of the six regulatory authorities to be identified and compared. The completed questionnaires were validated by the heads of the respective agencies. Results: The majority of applications received and approved by all six agencies in 2019 and 2020 were for generics. The mean approval times for generics varied across the countries, with ranges of 218-890 calendar days in 2019 and 158-696 calendar days in 2020. All three types of scientific assessment review models were used by the six agencies and data requirements and extent of scientific assessment were similar for five countries, while one conducted full reviews for new active substances. A large variation was observed in the targets set by the six agencies for the different milestones as well as overall approval times. Conclusions: The study identified the strengths of the countries as well as opportunities for improvement and alignment. Implementation of the recommendations made as in this study will enhance the countries' individual systems, enabling them to efficiently support the ZaZiBoNa initiative., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Sithole, Mahlangu, Capote, Sitoie, Shifotoka, Gaeseb, Danks, Nkambule, Juma, Fimbo, Munkombwe, Mwale, Salek and Walker.)

Background: The aims of this study were to compare the overall regulatory review timelines achieved by the South African Health Products Regulatory Authority (SAHPRA) in 2020 to the timelines historically achieved by the Medicines Control Council (MCC). This study also aimed to evaluate the regulatory review processes and the good review practices that have been implemented by SAHPRA to support the assessment of new chemical entities and generic product applications for market authorization in the business-as-usual and backlog process streams. Methods: A questionnaire was completed and verified by SAHPRA to describe the structure of the organization, the resources available, the process for regulatory review of new chemical entities and generic products and the level of implementation of good review practices and regulatory decision-making practices for market authorization. Data were collected and analyzed on the overall approval timelines for new chemical entities and generic products registered by SAHPRA in 2020 in the business-as-usual and backlog process streams. Results: A full, independent scientific review was conducted for all new chemical entities and generic product applications in the business-as-usual stream. Facilitated regulatory pathways were introduced for the review of new chemical entities and generic products in the backlog stream. As a result, the timelines for approval of applications in the backlog stream were 68% quicker for both new chemical entities and generics, using facilitated regulatory pathways, such as abridged and verification review models. Conclusion: The comparisons made through this study provided insight into the improvements that have been made through the establishment of SAHPRA and the transition in 2018 from the MCC. The re-engineered processes that have been developed and implemented by SAHPRA to address the backlog in the review of the applications for market authorization have demonstrated a decrease in the overall median approval times. The expansion of these processes into the routine review of medical products will contribute to the enhanced regulatory performance of SAHPRA and patients' access to new medicines., Competing Interests: LD, PN and BS-M were employed by the South African Health Products Regulatory Authority (SAHPRA). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Keyter, Salek, Danks, Nkambule, Semete-Makokotlela and Walker.)

Tumour necrosis factor (TNF) is produced by primary human macrophages in response to stimulation by exogenous pathogen-associated molecular patterns (PAMPs) and endogenous damage-associated molecular patterns (DAMPs) via Toll-like receptor (TLR) signalling. However, uncontrolled TNF production can be deleterious and hence it is tightly controlled at multiple stages. We have previously shown that Bruton's tyrosine kinase (Btk) regulates TLR4-induced TNF production via p38 MAP Kinase by stabilising TNF messenger RNA. Using both gene over-expression and siRNA-mediated knockdown we have examined the role of Btk in TLR7/8 mediated TNF production. Our data shows that Btk acts in the TLR7/8 pathway and mediates Ser-536 phosphorylation of p65 RelA and subsequent nuclear entry in primary human macrophages. These data show an important role for Btk in TLR7/8 mediated TNF production and reveal distinct differences for Btk in TLR4 versus TLR7/8 signalling., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: RANKL is mainly expressed by synovial fibroblasts and T cells within the joints of rheumatoid arthritis patients. The relative importance of RANKL expression by these cell types for the formation of bone erosions is unclear. We therefore aimed to quantify the contribution of RANKL by each cell type to osteoclast differentiation and bone destruction during inflammatory arthritis., Methods: RANKL was specifically deleted in T cells (Tnfsf11(flox/Δ) Lck-Cre), in collagen VI expressing cells including synovial fibroblasts (Tnfsf11(flox/Δ) Col6a1-Cre) and in collagen II expressing cells including articular chondrocytes (Tnfsf11(flox/Δ) Col2a1-Cre). Erosive disease was induced using the collagen antibody-induced arthritis (CAIA) and collagen-induced arthritis (CIA) models. Osteoclasts and cartilage degradation were assessed by histology and bone erosions were assessed by micro-CT., Results: The inflammatory joint score during CAIA was equivalent in all mice regardless of cell-targeted deletion of RANKL. Significant increases in osteoclast numbers and bone erosions were observed in both the Tnfsf11(flox/Δ) and the Tnfsf11(flox/Δ) Lck-Cre groups during CAIA; however, the Tnfsf11(flox/Δ) Col6a1-Cre mice showed significant protection against osteoclast formation and bone erosions. Similar results on osteoclast formation and bone erosions were obtained in CIA mice. The deletion of RANKL on any cell type did not prevent articular cartilage loss in either model of arthritis used., Conclusions: The expression of RANKL on synovial fibroblasts rather than T cells is predominantly responsible for the formation of osteoclasts and erosions during inflammatory arthritis. Synovial fibroblasts would be the best direct target in RANKL inhibition therapies., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

The central nervous system (CNS) is an immunologically privileged site protected from uncontrolled access of T cells by the blood-brain barrier (BBB), which is breached upon autoimmune inflammation. Here we have shown that receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) on T cells regulates C-C type chemokine ligand 20 (CCL20) production by astrocytes and T cell localization in the CNS. Importantly, mice specifically lacking RANKL in T cells were resistant to experimental autoimmune encephalomyelitis (EAE) due to altered T cell trafficking. Pharmacological inhibition of RANKL prevented the development of EAE without affecting the peripheral immune response, indicating that RANKL is a potential therapeutic target for treating autoimmune diseases in the CNS., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Self-tolerance to immune reactions is established via promiscuous expression of tissue-restricted antigens (TRAs) in medullary thymic epithelial cells (mTECs), leading to the elimination of T cells that respond to self-antigens. The transcriptional regulator Aire has been thought to be sufficient for the induction of TRAs, despite some indications that other factors may promote TRA expression in the thymus. Here, we show that the transcription factor Fezf2 directly regulates various TRA genes in mTECs independently of Aire. Mice lacking Fezf2 in mTECs displayed severe autoimmune symptoms, including the production of autoantibodies and inflammatory cell infiltration targeted to peripheral organs. These responses differed from those detected in Aire-deficient mice. Furthermore, Fezf2 expression and Aire expression are regulated by distinct signaling pathways and promote the expression of different classes of proteins. Thus, two independent factors, Fezf2 and Aire, permit the expression of TRAs in the thymus to ensure immune tolerance., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Glycosphingolipids (GSLs) are essential constituents of cell membranes and lipid rafts and can modulate signal transduction events. The contribution of GSLs in osteoclast (OC) activation and osteolytic bone diseases in malignancies such as the plasma cell dyscrasia multiple myeloma (MM) is not known. Here, we tested the hypothesis that pathological activation of OCs in MM requires de novo GSL synthesis and is further enhanced by myeloma cell-derived GSLs. Glucosylceramide synthase (GCS) inhibitors, including the clinically approved agent N-butyl-deoxynojirimycin (NB-DNJ), prevented OC development and activation by disrupting RANKL-induced localization of TRAF6 and c-SRC into lipid rafts and preventing nuclear accumulation of transcriptional activator NFATc1. GM3 was the prevailing GSL produced by patient-derived myeloma cells and MM cell lines, and exogenous addition of GM3 synergistically enhanced the ability of the pro-osteoclastogenic factors RANKL and insulin-like growth factor 1 (IGF-1) to induce osteoclastogenesis in precursors. In WT mice, administration of GM3 increased OC numbers and activity, an effect that was reversed by treatment with NB-DNJ. In a murine MM model, treatment with NB-DNJ markedly improved osteolytic bone disease symptoms. Together, these data demonstrate that both tumor-derived and de novo synthesized GSLs influence osteoclastogenesis and suggest that NB-DNJ may reduce pathological OC activation and bone destruction associated with MM.

An immune response is essential for protection against infection, but, in many individuals, aberrant responses against self tissues cause autoimmune diseases such as rheumatoid arthritis (RA). How to diminish the autoimmune response while not augmenting infectious risk is a challenge. Modern targeted therapies such as anti-TNF or anti-CD20 antibodies ameliorate disease, but at the cost of some increase in infectious risk. Approaches that might specifically reduce autoimmunity and tissue damage without infectious risk would be important. Here we describe that TNF superfamily member OX40 ligand (OX40L; CD252), which is expressed predominantly on antigen-presenting cells, and its receptor OX40 (on activated T cells), are restricted to the inflamed joint in arthritis in mice with collagen-induced arthritis and humans with RA. Blockade of this pathway in arthritic mice reduced inflammation and restored tissue integrity predominantly by inhibiting inflammatory cytokine production by OX40L-expressing macrophages. Furthermore, we identify a previously unknown role for OX40L in steady-state bone homeostasis. This work shows that more targeted approaches may augment the "therapeutic window" and increase the benefit/risk in RA, and possibly other autoimmune diseases, and are thus worth testing in humans.

It is now well acknowledged that the immune and skeletal systems interact and affect one another during developmental physiology and pathology. With the aid of modern conditional gene targeting and transgenic technologies, this field of interdisciplinary research, known as osteoimmunology, is rapidly advancing. Numerous bone phenotypes have been described in immune-compromised gene-deficient mice and, albeit to a lesser extent, immune deficiencies exist in osteo-compromised gene-deficient mice, suggesting that bone cells themselves actually regulate the development of immune cells directly. In this review, I discuss the essential role of key cytokines, signalling transduction pathways and transcription factors during immune and bone development, and how pathology driven dysregulation of these shared mechanisms can lead to clinical manifestations. Diseases that are within the remit of osteoimmunology continue to cause significant morbidity, for example, rheumatoid arthritis, osteoporosis, multiple myeloma and breast/prostate cancer. The complexity and overlapping cellular and molecular interactions between the immune and bone tissues, mean that despite fervent research of these diseases, it remains a major challenge to discover therapeutics that can specifically target one system without detrimentally affecting the other.

Over the last decade, the Tec family of nonreceptor tyrosine kinases (Btk, Tec, Bmx, Itk, and Rlk) have been shown to play a key role in inflammation and bone destruction. Bruton's tyrosine kinase (Btk) has been the most widely studied due to the critical role of this kinase in B-cell development and recent evidence showing that blocking Btk signaling is effective in ameliorating lymphoma progression and experimental arthritis. This review will examine the role of TFK in myeloid cell function and the potential of targeting these kinases as a therapeutic intervention in autoimmune disorders such as rheumatoid arthritis.

Invariant NKT (iNKT) cells modulate innate and adaptive immune responses through activation of myeloid dendritic cells and macrophages and via enhanced clonogenicity, differentiation, and egress of their shared myeloid progenitors. Because these same progenitors give rise to osteoclasts (OCs), which also mediate the egress of hematopoietic progenitors and orchestrate bone remodeling, we hypothesized that iNKT cells would extend their myeloid cell regulatory role to the development and function of OCs. In this study, we report that selective activation of iNKT cells by α-galactosylceramide causes myeloid cell egress, enhances OC progenitor and precursor development, modifies the intramedullary kinetics of mature OCs, and enhances their resorptive activity. OC progenitor activity is positively regulated by TNF-α and negatively regulated by IFN-γ, but is IL-4 and IL-17 independent. These data demonstrate a novel role of iNKT cells that couples osteoclastogenesis with myeloid cell egress in conditions of immune activation.

Mutations in Bruton's tyrosine kinase (Btk) cause the B-cell disorder X-linked agammaglobulinaemia (XLA) in humans, but the effect of Btk deficiency in human bone health has not been investigated previously. In this study, we show that human Btk-deficient osteoclasts are defective at resorption activity in vitro owing to a dysregulation of the actin cytoskeletal function. Contrary to expectation, XLA patients did not exhibit increased bone density or alterations in serum markers of bone turnover, indicating that a potential compensation mechanism normalizes bone homeostasis. In contrast to the bone turnover markers, the levels of inflammatory cytokines interleukin 6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α) were significantly elevated in XLA patients' serum compared with control individuals. Supplementation of osteoclast cultures from normal and XLA subjects with serum from XLA patients or recombinant inflammatory cytokines IL-6, IL-1β, and TNF-α resulted in a stimulation of osteoclast activity in vitro, whereas the addition of cytokine-neutralizing antibodies inhibited this stimulatory effect, confirming that elevated inflammatory cytokines in XLA serum heightened osteoclast activity in vitro. This study provides novel evidence that Btk signaling is crucial for optimal actin cytoskeletal organization and lacunar resorption in isolated osteoclasts. In XLA patients, however, these inherent osteoclast defects are corrected by increased inflammatory cytokine levels, restoring osteoclast activity and leading to the normalization of bone density., (© 2011 American Society for Bone and Mineral Research.)

The cellular and humoral mechanisms accounting for tumour osteolysis in metastatic breast cancer are uncertain. Osteoclasts, the specialised multinucleated cells responsible for tumour osteolysis, are derived from monocyte/macrophage precursors. Breast cancer-derived tumour-associated macrophages (TAMs) are capable of osteoclast differentiation but the cellular and humoral mechanisms controlling this activity are uncertain. In this study, TAMs were isolated from primary breast cancers and cultured in the presence and absence of cytokines/growth factors influencing osteoclastogenesis. Extensive TAM-osteoclast differentiation occurred only in the presence of RANKL and M-CSF; this process was inhibited by OPG and RANK:Fc, decoy receptors for RANKL. Breast cancer-derived fibroblasts and human bone stromal cells expressed mRNA for RANKL, OPG and TRAIL, and co-culture of these fibroblasts with human monocytes stimulated osteoclast formation by a RANKL-dependent mechanism. Osteoclast formation and lacunar resorption also occurred by a RANKL-independent mechanism when the conditioned medium from breast cancer cells, MDA-MB-231 and MCF-7, was added (with M-CSF) to monocyte cultures. Our findings indicate that TAMs in breast cancer are capable of osteoclast differentiation and that breast cancer-derived fibroblasts and breast cancer cells contribute to this process by producing soluble factors that influence osteoclast formation by RANKL-dependent and RANKL-independent mechanisms respectively.

Peri-articular bone resorption is a feature of arthritis due to crystal deposition and rheumatoid disease. Under these conditions, the synovial fluid contains numerous inflammatory cells that produce cytokines and growth factors which promote osteoclast formation. The aim of this study was to determine whether inflammatory synovial fluid stimulates the formation of osteoclasts. Synovial fluid from rheumatoid arthritis (RA), pyrophosphate arthropathy (PPA) and osteoarthritis (OA) patients was added to cultures (n=8) of human peripheral blood mononuclear cells (PBMCs) in the presence and absence of macrophage colony-stimulating factor (M-CSF) and the receptor activator of NF-kappaB ligand (RANKL). Osteoclast formation was assessed by the formation of cells positive for tartrate-resistant acid phosphatase (TRAP) and vitronectin receptor (VNR) and the extent of lacunar resorption. The addition of 10% OA, RA and PPA synovial fluid to PBMC cultures resulted in the formation of numerous multinucleated or mononuclear TRAP(+) and VNR(+) cells which were capable of lacunar resorption. In contrast to PBMC cultures incubated with OA synovial fluid, there was marked stimulation of osteoclast formation and resorption in cultures containing inflammatory RA and PPA synovial fluid which contained high levels of tumour necrosis factor alpha, a factor which is known to stimulate RANKL-induced osteoclast formation.

Transforming growth factor beta (TGFbeta) is a multifunctional growth factor that is produced by many cells in bone and is abundant in the bone matrix. TGFbeta is known to regulate RANKL-induced osteoclast formation and bone resorbing activity. In this study we sought to determine whether TGFbeta could directly induce osteoclast formation by a RANKL-independent mechanism. We found that the addition of TGFbeta to cultures of human monocytes and RAW 264.7 cells (in the presence of M-CSF and the absence of RANKL, TNFalpha or IL-6/IL-11) was sufficient to induce the formation of TRAP+ and VNR+ cells, which formed actin rings and were capable of extensive lacunar resorption. The addition of osteoprotegerin or antibodies to TNFalpha and its receptors, as well as antibodies to gp130, did not inhibit lacunar resorption, indicating that TGFbeta did not act by stimulating RANKL, TNF or IL-6 production by monocytes. TGFbeta-induced osteoclast formation was qualitatively different from that induced by RANKL with numerous TRAP+/VNR+ mononuclear and small multinucleated cells being formed; these cells produced many small resorption lacunae. Our results indicate that TGFbeta, which is abundant in the bone matrix, can, in the presence of M-CSF, directly induce mononuclear phagocyte osteoclast precursors to differentiate into osteoclastic cells capable of lacunar resorption.

Objective: Rheumatoid arthritis (RA) is often complicated by generalized osteopenia due to increased bone resorption by osteoclasts. We analysed a number of cellular and humoral factors that influence osteoclast formation from circulating precursors in RA patients., Methods: Monocytes isolated from RA patients and normal controls were cultured with macrophage colony-stimulating factor (M-CSF) and nuclear factor-kappaB ligand (RANKL), or with RANKL-expressing UMR106 cells and 1,25 dihydroxyvitamin D(3) [1,25(OH)(2)D(3)]. Osteoclast differentiation was assessed by expression of tartrate-resistant acid phosphatase (TRAP) and vitronectin receptors (VNR) and lacunar resorption., Results: Osteoclasts formed from RA patients exhibited increased resorptive activity but there was no difference in the relative proportion of circulating osteoclast precursors between RA patients and normal controls. Osteoclast precursors in RA patients were not more sensitive to the osteoclastogenic effects of 1,25(OH)(2)D(3), M-CSF or RANKL. Dexamethasone, but not interleukin (IL) 1beta, tumour necrosis factor alpha and IL-6, increased osteoclast formation and lacunar resorption., Conclusion: There is an increase in the extent of lacunar resorption carried out by osteoclasts formed from circulating precursors in RA patients. This is not due to an increase in the number of circulating precursors or increased sensitivity to the osteoclastogenic effects of 1,25(OH)(2)D(3), M-CSF, RANKL or inflammatory cytokines. Our findings suggest that increased osteoclast functional activity rather than osteoclast formation is more likely to play a role in the generalized bone loss that occurs in RA, and that corticosteroids stimulate osteoclast formation and resorption.

Background: Pathological bone resorption (marginal erosions and juxta-articular osteoporosis) by osteoclasts commonly occurs in rheumatoid arthritis (RA)., Objectives: To define the nature of the mononuclear precursor cells from which osteoclasts are formed in inflamed synovial tissues and to determine the cellular and humoral factors which influence osteoclast differentiation., Method: Macrophage (CD14+), non-macrophage (CD14-), and unsorted (CD14+/CD14-) synovial cell populations from RA and inflammatory/non-inflammatory osteoarthritis (OA) synovium were cultured in the presence of receptor activator for nuclear factor kappaB ligand (RANKL) and monocyte-colony stimulating factor (M-CSF; in the presence/absence of prostaglandin E(2) (PGE(2)), interleukin 1beta (IL1beta), tumour necrosis factor alpha (TNFalpha), and IL6). Osteoclast differentiation was assessed by expression of tartrate resistant acid phosphatase (TRAP), vitronectin receptor (VNR), and lacunar resorption., Results: TRAP+ and VNR+ multinucleated cells capable of lacunar resorption were only formed in cultures of CD14+-containing synovial cell populations (that is, CD14+ and CD14+/CD14- cells). No difference in the extent of osteoclast formation was noted in cultures of CD14+ cells isolated from RA, inflammatory OA, and non-inflammatory OA synovium. However, more TRAP+/VNR+ cells and more lacunar resorption was noted in CD14+/CD14- cells from RA and inflammatory OA synovial tissues. The addition of PGE(2), IL1beta, TNFalpha, and IL6 did not increase RANKL/M-CSF-induced osteoclast formation and lacunar resorption of both CD14+/CD14- and CD14+ synovial cell populations., Conclusions: Osteoclast precursors in synovial tissues are CD14+ monocyte/macrophages. The increase in osteoclast formation in cultures of CD14+/CD14- compared with CD14+ synovial cells in RA and inflammatory OA points to a role for CD14- cells in promoting osteoclast differentiation and bone resorption in inflamed synovial tissues by a mechanism which does not involve a direct effect of proinflammatory cytokines/prostaglandins on RANKL-induced macrophage-osteoclast differentiation.

A retrospective study was conducted to assess glycaemic control in relation to pregnancy outcomes in pre-existing and gestational diabetics. Computerised blood glucose records from 47 pre-existing diabetic patients and 33 gestational diabetics were collected prospectively and then analysed retrospectively in relation to pregnancy outcomes. There were two spontaneous miscarriages from the pre-existing diabetic cohort. A total of 44,279 individual blood glucose estimations were made. The mean fasting glucose for pre-existing diabetic patients fell significantly throughout pregnancy, being 7.7+/-2.1, 7.2+/-3.1 and 6.5+/-2.4 mmol/l, respectively, for trimesters 1,2 and 3 (P<0.01). The mean post-prandial glucose for each trimester were 8.9+/-2.0, 8.6+/-1.6 and 8.2+/-1.2 mmol/l (P<0.01). The HbAlc for pre-existing diabetic patients for each trimester was 7.5+/-1.4%, 6.1+/-1.0% and 5.9+/-0.7%, respectively. Gestational diabetic patients had a mean fasting glucose of 5.6+/-1.5 mmol/l and a mean post-prandial glucose of 8.0+/-2.1 mmol/l during trimester 3. Home glucose monitoring correlated reasonably well with first trimester HbA1c (r2=0.43, P<0.001), but this relationship became less valid as pregnancy progressed. The mean gestation at delivery was 37 weeks, although 30% of women were delivered between 34 and 37 weeks and 8% delivered before 34 weeks. Labour was induced in 49% of patients and the overall caesarean section rate was 58%. The mean birth weight for pre-existing diabetic patients was 3479 g (1410-5000 g) and for women with gestational diabetes was 3605 g (1890-5920 g). For pre-existing diabetic patients HbA1c did not correlate with birth weight; however, home blood glucose data from trimester 2 did correlate (r2=0.15, P <0.005) and there appeared to be stronger relationship with trimester 3 data (r2=0.24, P <0.005). There was no association between trimester 3 glucose data and birth weight in the gestational cohort. The babies born to pre-existing diabetic mothers had a high incidence of admission to a neonatal unit and over 50% of the babies had proven hypoglycaemia. Our present computerised system for home blood glucose monitoring has shown that for pre-existing diabetes patients but not gestational diabetic patients, glycaemic control in the second and third trimester influences birth weight. The current degree of glycaemic control in the mothers did not prevent a high rate of neonatal hypoglycaemia.